Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0001664 G protein-coupled receptor binding	IBA GO_REF:0000033	MARK AS OVER ANNOTATED	Summary: POMC-derived peptides (ACTH, alpha-MSH, beta-MSH, gamma-MSH) are well-established ligands for melanocortin receptors, but GO:0001664 is a generic parent that is less informative than the accepted specific melanocortin receptor binding terms. Reason: The underlying biology is correct, but POMC curation should prefer specific melanocortin receptor binding terms over generic GPCR binding. ACTH binds MC2R and alpha-MSH binds MC1R/MC3R/MC4R/MC5R; the specific accepted terms in this review capture those activities more cleanly. Supporting Evidence: PMID:19743876 Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R. file:human/POMC/POMC-deep-research-falcon.md Melanocortin receptor binding vs generic GPCR binding: Prefer melanocortin receptor binding terms, with MC2R specificity for ACTH explicitly supported; do not use generic “GPCR binding” for POMC gene product as a catch-all.
GO:0005179 hormone activity	IEA GO_REF:0000120	ACCEPT	Summary: POMC gives rise to multiple peptide hormones including ACTH, MSH peptides, and beta-endorphin. Hormone activity is a core function. IEA is consistent with extensive experimental evidence. Reason: This is the defining function of POMC - it is a prohormone that produces multiple bioactive peptide hormones. UniProt classifies it under "Hormone" keywords, and PMID:9620771 demonstrates hormonal functions through mutation phenotypes. Supporting Evidence: PMID:9620771 Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin. file:human/POMC/POMC-deep-research-falcon.md Pro-opiomelanocortin (POMC) is best curated in GO as a secreted prohormone precursor that is sorted to regulated secretory granules and proteolytically processed in a tissue-specific manner to yield multiple bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs embedded in the β-LPH/β-endorphin region).
GO:0005179 hormone activity	ISS GO_REF:0000024	ACCEPT	Summary: Duplicate annotation with IEA above, ISS inference from orthologs is appropriate. Reason: Hormone activity is conserved across mammals. ISS annotation is appropriate and consistent with experimental evidence.
GO:0005179 hormone activity	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	ACCEPT	Summary: The Krude et al. 1998 paper describes POMC-null patients with adrenal insufficiency (loss of ACTH hormone function) and obesity (loss of alpha-MSH hormone function). IMP from mutant phenotype is well-justified. Reason: Loss of POMC function results in loss of hormonal activity - ACTH deficiency causes secondary hypocortisolism, alpha-MSH deficiency causes obesity and red hair. This directly demonstrates hormone activity through loss-of-function. Supporting Evidence: PMID:9620771 early-onset obesity, adrenal insufficiency and red hair pigmentation caused by POMC mutations in humans
GO:0005515 protein binding	IPI PMID:32296183 A reference map of the human binary protein interactome.	REMOVE	Summary: High-throughput Y2H interactome study (HuRI) identified POMC interactors. However, 'protein binding' is uninformative for a secreted prohormone. The actual function is GPCR binding, which is separately annotated. Reason: 'Protein binding' is too vague and uninformative for a prohormone. The meaningful interactions are with melanocortin receptors and opioid receptors, which are captured by more specific MF terms. HuRI Y2H interactions for a secreted/processed prohormone are likely not physiologically relevant - POMC is processed in the secretory pathway and its products function extracellularly. Supporting Evidence: PMID:32296183 HuRI is estimated to represent 2–11% of the binary protein interactome file:human/POMC/POMC-deep-research-falcon.md Generic protein binding / identical protein binding: Do not annotate generic binding (including “identical protein binding”) unless there is direct biochemical interaction evidence for the relevant molecular entity (precursor vs peptide).
GO:0005102 signaling receptor binding	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	ACCEPT	Summary: Loss of POMC function causes phenotypes consistent with loss of signaling through melanocortin receptors (MC1R for pigmentation, MC4R for appetite, MC2R for ACTH). This is a valid parent term for the more specific MCR binding terms. Reason: POMC-derived peptides bind melanocortin receptors (signaling receptors). This is correctly inferred from mutant phenotype - loss of receptor activation. More specific terms (MC1R/MC3R/MC4R binding) provide additional detail. Supporting Evidence: PMID:9620771 Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)
GO:0070996 type 1 melanocortin receptor binding	IPI PMID:19743876 Novel binding motif of ACTH analogues at the melanocortin re...	ACCEPT	Summary: Yang et al. 2009 directly tested ACTH and MSH peptide binding to melanocortin receptors. ACTH and alpha-MSH bind MC1R. This is a core molecular function. Reason: Direct binding studies demonstrate alpha-MSH and ACTH bind MC1R. This receptor mediates pigmentation effects of MSH peptides. MC1R binding is a core function of alpha-MSH (POMC 138-150). Supporting Evidence: PMID:19743876 Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R.
GO:0070996 type 1 melanocortin receptor binding	IDA PMID:18292087 Melanocortin-1 receptor signaling markedly induces the expre...	ACCEPT	Summary: Smith et al. 2008 studied MC1R signaling using alpha-MSH agonists. Confirms MC1R binding by melanocortin peptides. Reason: The study uses MC1R agonist (NDP-alpha-MSH) and wild-type alpha-MSH to study MC1R signaling in melanocytes, confirming MC1R binding as a core function. Supporting Evidence: PMID:18292087 the potent MC1R agonist (Nle4,D-Phe7)-alpha-melanocyte-stimulating hormone
GO:0031781 type 3 melanocortin receptor binding	IPI PMID:19743876 Novel binding motif of ACTH analogues at the melanocortin re...	ACCEPT	Summary: Yang et al. 2009 demonstrated ACTH and alpha-MSH binding to MC3R through receptor binding and activation studies. Reason: MC3R is a target of alpha-MSH and ACTH peptides. The paper directly demonstrates receptor binding and activation at hMC3R. Gamma-MSH from POMC preferentially binds MC3R. Supporting Evidence: PMID:19743876 Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R
GO:0031782 type 4 melanocortin receptor binding	IPI PMID:19743876 Novel binding motif of ACTH analogues at the melanocortin re...	ACCEPT	Summary: MC4R binding is critical for appetite regulation by alpha-MSH. This is the key receptor mediating anorexigenic effects of alpha-MSH in hypothalamus. Reason: MC4R binding by alpha-MSH is the molecular basis of POMC's role in appetite suppression. Loss of this interaction explains obesity in POMC-null patients. Core molecular function. Supporting Evidence: PMID:19743876 Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R PMID:9620771 Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)
GO:0001664 G protein-coupled receptor binding	IDA PMID:19452503 Aberrant trafficking of human melanocortin 1 receptor varian...	MARK AS OVER ANNOTATED	Summary: Sanchez-Laorden et al. 2009 studied MC1R trafficking and activation, demonstrating melanocortin ligand biology, but the GO annotation uses a generic GPCR binding parent. Reason: The paper supports MC1R pathway biology, but specific melanocortin receptor binding terms are already present and more informative. GO:0001664 should not be retained as a core generic catch-all for POMC-derived peptide receptor binding. Supporting Evidence: PMID:19452503 The melanocortin 1 receptor (MC1R), a Gs protein-coupled receptor (GPCR) expressed in melanocytes file:human/POMC/POMC-deep-research-falcon.md Melanocortin receptor binding vs generic GPCR binding: Prefer melanocortin receptor binding terms, with MC2R specificity for ACTH explicitly supported; do not use generic “GPCR binding” for POMC gene product as a catch-all.
GO:0005615 extracellular space	IBA GO_REF:0000033	ACCEPT	Summary: POMC-derived peptides are secreted hormones that function in the extracellular space. IBA phylogenetic inference is appropriate. Reason: All POMC-derived bioactive peptides (ACTH, MSH, beta-endorphin) are secreted and function extracellularly to bind receptors on target cells. UniProt notes "Secreted" for subcellular location.
GO:0005576 extracellular region	IEA GO_REF:0000120	ACCEPT	Summary: Extracellular region is the broader parent term. POMC products are secreted and act extracellularly. Reason: Consistent with secreted hormone function. Appropriate IEA inference.
GO:0030141 secretory granule	IBA GO_REF:0000033	ACCEPT	Summary: POMC is stored in and processed within secretory granules in pituitary and hypothalamic neurons before release. IBA is appropriate. Reason: UniProt notes that alpha-MSH and beta-endorphin are stored in separate granules in hypothalamic POMC neurons. Secretory granule localization is well-established. Supporting Evidence: UniProtKB:P01189 Melanocyte-stimulating hormone alpha and beta-endorphin are stored in separate granules in hypothalamic POMC neurons
GO:0005615 extracellular space	IEA GO_REF:0000107	ACCEPT	Summary: Duplicate of IBA annotation above. Extracellular space is correct for secreted peptide hormones. Reason: IEA inference consistent with experimental evidence for secreted localization.
GO:0005737 cytoplasm	IEA GO_REF:0000107	MARK AS OVER ANNOTATED	Summary: POMC transits through cytoplasm during biosynthesis but this is not its functional location. This is over-annotation. Reason: While POMC precursor passes through the cytoplasm during synthesis, this is not meaningful for function. POMC enters the secretory pathway via signal peptide and is processed in ER/Golgi/secretory granules. Cytoplasm annotation is technically true but functionally misleading.
GO:0030141 secretory granule	IEA GO_REF:0000107	ACCEPT	Summary: Duplicate of IBA annotation. Secretory granule localization is correct. Reason: IEA inference consistent with IBA and experimental evidence.
GO:0005576 extracellular region	TAS Reactome:R-HSA-379044	ACCEPT	Summary: Reactome pathway annotation for GPCR signaling. Extracellular region is where ligands interact with receptors. Reason: Appropriate localization for secreted hormone peptides.
GO:0005576 extracellular region	TAS Reactome:R-HSA-388596	ACCEPT	Summary: Reactome annotation for melanocortin receptor binding. Multiple Reactome TAS annotations to same GO term represent different pathway contexts. Reason: Valid annotation - POMC peptides bind melanocortin receptors extracellularly.
GO:0005576 extracellular region	TAS Reactome:R-HSA-744886	ACCEPT	Summary: Reactome annotation for GPCR:Gs complex dissociation pathway. Reason: Valid - ligands act extracellularly to activate GPCRs.
GO:0005576 extracellular region	TAS Reactome:R-HSA-744887	ACCEPT	Summary: Reactome annotation for liganded Gs-activating GPCRs. Reason: Valid - melanocortins bind Gs-coupled MCRs extracellularly.
GO:0005576 extracellular region	TAS Reactome:R-HSA-5603251	ACCEPT	Summary: Reactome annotation for defective ACTH not binding MC2R. Reason: Valid pathway annotation - ACTH acts extracellularly on MC2R.
GO:0005576 extracellular region	TAS Reactome:R-HSA-112042	ACCEPT	Summary: Reactome annotation for opioid binding to MOR (mu opioid receptor). Beta-endorphin is the POMC product that binds opioid receptors. Reason: Beta-endorphin (POMC 237-267) binds mu-opioid receptor extracellularly.
GO:0005576 extracellular region	TAS Reactome:R-HSA-112271	ACCEPT	Summary: Reactome annotation for receptor:G-protein complex dissociation in opioid signaling. Reason: Valid pathway annotation for beta-endorphin function.
GO:0005576 extracellular region	TAS Reactome:R-HSA-167408	ACCEPT	Summary: Reactome annotation for high affinity receptor:G-protein binding. Reason: Valid - POMC peptides act as extracellular ligands for GPCRs.
GO:0005576 extracellular region	TAS Reactome:R-HSA-167419	ACCEPT	Summary: Reactome annotation for GDP release from receptor:G-protein complex. Reason: Valid pathway annotation.
GO:0005576 extracellular region	TAS Reactome:R-HSA-167427	ACCEPT	Summary: Reactome annotation for opioid dissociation from MOR. Reason: Valid - beta-endorphin binds MOR extracellularly.
GO:0005576 extracellular region	TAS Reactome:R-HSA-167429	ACCEPT	Summary: Reactome annotation for GTP binding to receptor:G-protein complex. Reason: Valid pathway annotation.
GO:0005576 extracellular region	TAS Reactome:R-HSA-374298	ACCEPT	Summary: Reactome annotation for opioid receptors binding opioid peptides. Reason: Beta-endorphin and met-enkephalin from POMC bind opioid receptors extracellularly.
GO:0005576 extracellular region	TAS Reactome:R-HSA-380073	ACCEPT	Summary: Reactome annotation for Gi-coupled GPCR activation (opioid signaling). Reason: Valid - opioid receptors are Gi-coupled, beta-endorphin acts extracellularly.
GO:0005576 extracellular region	TAS Reactome:R-HSA-388605	ACCEPT	Summary: Reactome annotation specifically for ACTH (POMC 138-176) binding MC2R. Reason: Core function - ACTH binds MC2R extracellularly to stimulate cortisol release.
GO:0005576 extracellular region	TAS Reactome:R-HSA-6789615	ACCEPT	Summary: Reactome annotation for STAT3-upregulated extracellular proteins. Reason: Valid - POMC products are extracellular.
GO:0005576 extracellular region	TAS Reactome:R-HSA-749454	ACCEPT	Summary: Reactome annotation for Gi complex dissociation. Reason: Valid pathway annotation for opioid signaling.
GO:0005576 extracellular region	TAS Reactome:R-HSA-749456	ACCEPT	Summary: Reactome annotation for Gi-coupled GPCR binding. Reason: Valid - opioid peptides act extracellularly.
GO:0034774 secretory granule lumen	TAS Reactome:R-HSA-265301	ACCEPT	Summary: Reactome annotation for corticotropin cleavage from POMC. Processing occurs in secretory granule lumen. Reason: POMC processing by prohormone convertases (PC1/3, PC2) occurs in the lumen of secretory granules. This is where the mature peptides are generated.
GO:0005782 peroxisomal matrix	IDA PMID:20810565 Peroxisomal localization of the proopiomelanocortin-derived ...	KEEP AS NON CORE	Summary: Hoftberger et al. 2010 report surprising peroxisomal localization of beta-LPH and beta-endorphin in cells expressing ALDP. This is tissue-specific and applies only to the C-terminal POMC products. Reason: The paper demonstrates peroxisomal localization specifically for beta-LPH and beta-endorphin (C-terminal POMC products) in cells expressing ALDP. However, N-terminal peptides (ACTH, alpha-MSH, gamma-MSH) were NOT found in peroxisomes. This is a specialized localization, not a core function. Supporting Evidence: PMID:20810565 In contrast to the peptide hormones β-LPH and β-endorphin, which are derived from the C terminus of POMC, the N-terminal peptides ACTH, α-MSH, and γ-MSH were never detected in peroxisomes.
GO:0005615 extracellular space	IDA PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	ACCEPT	Summary: The Krude paper describes POMC mutation phenotypes but does not directly demonstrate extracellular localization. However, the inferred hormonal function implies extracellular action. Reason: While not directly demonstrated in this paper, POMC products function as circulating hormones, which by definition are extracellular. Supporting Evidence: PMID:9620771 Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin
GO:0005737 cytoplasm	ISS GO_REF:0000024	MARK AS OVER ANNOTATED	Summary: ISS annotation for cytoplasm. Like the IEA annotation, this is technically true but functionally misleading. Reason: Cytoplasm is not a meaningful functional location for POMC. The protein enters the secretory pathway and functions extracellularly.
GO:0030141 secretory granule	ISS GO_REF:0000024	ACCEPT	Summary: ISS annotation consistent with IBA and IEA annotations. Secretory granule is a valid localization. Reason: Secretory granule storage and processing is conserved across POMC orthologs.
GO:2000852 regulation of corticosterone secretion	IBA GO_REF:0000033	ACCEPT	Summary: ACTH (POMC 138-176) stimulates adrenal cortex to release glucocorticoids. In rodents, this is corticosterone; in humans, cortisol. IBA annotation is appropriate for the conserved function. Reason: ACTH regulation of adrenal glucocorticoid secretion is the primary function of the HPA axis. This is conserved across mammals - the specific glucocorticoid varies but the mechanism is the same. Supporting Evidence: PMID:9620771 While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far.
GO:0007218 neuropeptide signaling pathway	IEA GO_REF:0000043	ACCEPT	Summary: POMC produces multiple neuropeptides (alpha-MSH, beta-endorphin) that function in hypothalamic signaling. UniProt keyword mapping is appropriate. Reason: Alpha-MSH and beta-endorphin are classical neuropeptides produced in hypothalamic POMC neurons. Neuropeptide signaling is a core function.
GO:0106071 positive regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway	IEA GO_REF:0000107	ACCEPT	Summary: Melanocortin receptors (MC1R-MC5R) are Gs-coupled GPCRs that activate adenylate cyclase. POMC peptides as ligands positively regulate this pathway. Reason: MC1R, MC2R, MC3R, MC4R, and MC5R are all coupled to Gs and activate adenylate cyclase upon binding melanocortin peptides. This is the signaling mechanism.
GO:0140668 positive regulation of oxytocin production	IEA GO_REF:0000107	MARK AS OVER ANNOTATED	Summary: Some evidence suggests melanocortins affect oxytocin release, but this is not a well-established core function of POMC. Reason: While there may be some regulatory effects of melanocortins on oxytocin, this is not a direct or primary function of POMC. The evidence base is limited and this appears to be an over-extension of IEA transfer.
GO:1990680 response to melanocyte-stimulating hormone	IEA GO_REF:0000107	REMOVE	Summary: This annotation is problematic - POMC PRODUCES melanocyte-stimulating hormone, it does not respond to it. This appears to be an erroneous annotation. Reason: POMC is the precursor that produces MSH peptides. It does not respond to MSH. This annotation appears to confuse POMC with MSH receptors or downstream targets. POMC-expressing cells may respond to feedback, but the gene product itself does not "respond to MSH."
GO:0106071 positive regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway	ISS GO_REF:0000024	ACCEPT	Summary: Duplicate of IEA annotation. ISS is appropriate as melanocortin receptor signaling mechanism is conserved. Reason: Conserved function - melanocortin receptors couple to Gs and activate AC.
GO:0019722 calcium-mediated signaling	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: Some melanocortin receptors can couple to calcium signaling, but this is not the primary signaling mechanism for most MCRs. Reason: While MC1R and other MCRs can activate calcium signaling in some contexts, the primary signaling mechanism is cAMP/PKA via Gs coupling. Calcium signaling is a secondary effect, not a core function.
GO:1990680 response to melanocyte-stimulating hormone	ISS GO_REF:0000024	REMOVE	Summary: Same issue as IEA annotation - POMC produces MSH, it does not respond to it. Reason: POMC is the source of MSH, not a responder. This annotation is erroneous.
GO:0006091 generation of precursor metabolites and energy	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	MARK AS OVER ANNOTATED	Summary: POMC-null patients have metabolic abnormalities, but this is an indirect effect of hormone loss, not a direct molecular function. This term is too general. Reason: While POMC loss affects metabolism (obesity, adrenal insufficiency), this is an indirect consequence of loss of hormonal regulation, not a direct role in energy generation pathways. This annotation is over-interpretation of phenotype data. Supporting Evidence: PMID:9620771 early-onset obesity, adrenal insufficiency and red hair pigmentation
GO:0007165 signal transduction	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	ACCEPT	Summary: POMC-derived peptides are signaling molecules that activate receptor signaling. This is correct but very general. Reason: All POMC peptide hormones function by activating signal transduction cascades through their receptors. This is a valid high-level annotation. Supporting Evidence: PMID:9620771 Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5) and the linkage of human obesity to chromosome 2 in close proximity to the POMC locus, led to the proposal of an association of POMC with human obesity
GO:0007267 cell-cell signaling	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	ACCEPT	Summary: POMC-derived peptides mediate cell-cell signaling between endocrine cells and target tissues. This is a core function. Reason: ACTH signals from pituitary to adrenal cortex, alpha-MSH signals between hypothalamic neurons and melanocytes/hypothalamic circuits. Classical cell-cell signaling function. Supporting Evidence: PMID:9620771 Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin
GO:0008217 regulation of blood pressure	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: ACTH affects blood pressure through cortisol release; alpha-MSH may have direct cardiovascular effects via MC3R/MC4R. However, this is not a primary function of POMC. Reason: Blood pressure regulation is an indirect effect of POMC peptides, primarily through ACTH-stimulated glucocorticoid release. Not a core direct function.
GO:0032098 regulation of appetite	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	MODIFY	Summary: POMC-null patients have severe obesity due to hyperphagia, demonstrating POMC role in appetite regulation. HOWEVER, this annotation conflates antagonistic functions: alpha-MSH suppresses appetite (anorexigenic) while beta-endorphin stimulates appetite (orexigenic). Reason: The term "regulation of appetite" is appropriate at the gene level because POMC produces BOTH appetite-suppressing (alpha-MSH via MC4R) AND appetite- stimulating (beta-endorphin via opioid receptors) peptides. The net effect in POMC-null patients is obesity because alpha-MSH loss predominates. However, ideally this should be annotated at the peptide level with specific terms (GO:0032099 negative regulation of appetite for alpha-MSH; GO:0032100 positive regulation of appetite for beta-endorphin). Proposed replacements: negative regulation of appetite positive regulation of appetite Supporting Evidence: PMID:9620771 alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor UniProtKB:P01189 -!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate. file:human/POMC/POMC-deep-research-falcon.md Appetite and stress are supported mechanistically through defined endocrine/neuropeptide pathways (α-MSH → MC3R/MC4R; ACTH → MC2R). Prefer pathway-grounded BP terms (e.g., regulation of food intake; regulation of glucocorticoid secretion) over very broad behavior/development annotations.
GO:0033059 cellular pigmentation	IMP PMID:9620771 Severe early-onset obesity, adrenal insufficiency and red ha...	ACCEPT	Summary: POMC-null patients have red hair and fair skin, demonstrating alpha-MSH role in pigmentation via MC1R. This is a core function of alpha-MSH. Reason: Alpha-MSH binding to MC1R in melanocytes stimulates melanin production. Loss of alpha-MSH (POMC mutation) causes red hair/fair skin phenotype. Core function. Supporting Evidence: PMID:9620771 red hair pigmentation caused by POMC mutations UniProtKB:P01189 [Melanocyte-stimulating hormone alpha]: Increases the pigmentation of skin by increasing melanin production in melanocytes.
GO:0032720 negative regulation of tumor necrosis factor production	IDA PMID:10233018 alpha-MSH and its receptors in regulation of tumor necrosis ...	KEEP AS NON CORE	Summary: Taherzadeh et al. 1999 demonstrated alpha-MSH inhibits TNF-alpha production in macrophages. This is an anti-inflammatory function of alpha-MSH. Reason: The paper demonstrates alpha-MSH suppresses TNF-alpha in LPS-stimulated macrophages via MC1R. This is a validated function but represents the immunomodulatory role of alpha-MSH, which is secondary to its pigmentation and appetite regulation functions. Supporting Evidence: PMID:10233018 The inflammatory cytokine tumor necrosis factor (TNF)-alpha was inhibited in relation to alpha-MSH concentration.
GO:0045944 positive regulation of transcription by RNA polymerase II	IDA PMID:18292087 Melanocortin-1 receptor signaling markedly induces the expre...	MARK AS OVER ANNOTATED	Summary: Smith et al. 2008 showed MC1R signaling (via alpha-MSH) induces transcription of NR4A nuclear receptors in melanocytes. This is downstream of receptor activation, not a direct function of POMC. Reason: This annotation conflates ligand function with downstream transcriptional effects. Alpha-MSH binding to MC1R activates cAMP/PKA which then activates transcription factors. POMC peptides do not directly regulate transcription; they bind extracellular receptors. This is over-annotation. Supporting Evidence: PMID:18292087 Here we show that MC1R signaling in B16 mouse melanoma cells and primary human melanocytes rapidly, and transiently, induces the transcription of the NR4A subfamily of orphan nuclear receptors
GO:0016486 peptide hormone processing	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: PMID:9620771 Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin. UniProtKB:P01189 Specific enzymatic cleavages at paired basic residues yield the different active peptides. file:human/POMC/POMC-deep-research-falcon.md Canonical regulated-secretory-pathway processing of POMC uses PCSK1/PC1-3 and PCSK2/PC2 endoproteolysis, followed by exopeptidase trimming (e.g., CPE) and additional modifications that can alter activity (e.g., acetylation affecting β-endorphin opioid activity).
GO:0031780 corticotropin hormone receptor binding	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: PMID:9620771 While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far. Reactome:R-HSA-388605 POMC(138-176) binds MC2R file:human/POMC/POMC-deep-research-falcon.md MC2R (ACTH receptor) is uniquely selective: MC2R binds a single endogenous ligand, ACTH—important for GO term choice (melanocortin receptor binding rather than generic GPCR binding).
GO:2000851 positive regulation of glucocorticoid secretion	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: Reactome:R-HSA-388605 POMC(138-176) binds MC2R
GO:0051464 positive regulation of cortisol secretion	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: PMID:9620771 early-onset obesity, adrenal insufficiency and red hair pigmentation Reactome:R-HSA-388605 POMC(138-176) binds MC2R
GO:0097009 energy homeostasis	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: PMID:9620771 Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5) PMID:19743876 Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R.
GO:0042438 melanin biosynthetic process	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: PMID:9620771 red hair pigmentation caused by POMC mutations UniProtKB:P01189 [Melanocyte-stimulating hormone alpha]: Increases the pigmentation of skin by increasing melanin production in melanocytes. PMID:18292087 MC1R signaling in B16 mouse melanoma cells and primary human melanocytes
GO:0001515 opioid peptide activity	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: UniProtKB:P01189 -!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate. Reactome:R-HSA-374298 Opioid receptors bind opioid peptides file:human/POMC/POMC-deep-research-falcon.md β-endorphin is described as a POMC-derived peptide that binds opioid receptors (μ/δ/κ) with agonist activity for major forms.
GO:0051930 regulation of sensory perception of pain	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: UniProtKB:P01189 -!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate. Reactome:R-HSA-374298 Opioid receptors bind opioid peptides

Core Functions

Serves as a polyprotein precursor that is proteolytically processed by prohormone convertases (PC1/PC3, PC2) in a tissue-specific manner to generate multiple bioactive neuropeptide hormones including ACTH, melanocyte-stimulating hormones (alpha-, beta-, gamma-MSH), beta-endorphin, and beta-lipotropin. Processing occurs in secretory granules within neuroendocrine cells of the pituitary and hypothalamus.

Molecular Function:

hormone activity

Directly Involved In:

neuropeptide signaling pathway peptide hormone processing

Cellular Locations:

secretory granule lumen secretory granule extracellular region

Supporting Evidence:

PMID:9620771
Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin.
UniProtKB:P01189
This is a prohormone that is cleaved to give multiple peptide hormones.
file:human/POMC/POMC-deep-research-falcon.md
**Pro-opiomelanocortin (POMC)** is best curated in GO as a **secreted prohormone precursor** that is sorted to regulated secretory granules and **proteolytically processed in a tissue-specific manner** to yield multiple bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs embedded in the β-LPH/β-endorphin region).

Regulates the hypothalamic-pituitary-adrenal (HPA) axis via the cleavage product ACTH (corticotropin, residues 138-176). ACTH binds MC2R (corticotropin receptor) on adrenal cortex cells to stimulate glucocorticoid (cortisol in humans) secretion. Loss of POMC causes isolated ACTH deficiency with secondary adrenal insufficiency.

Molecular Function:

corticotropin hormone receptor binding

Directly Involved In:

positive regulation of glucocorticoid secretion positive regulation of cortisol secretion cell-cell signaling

Cellular Locations:

extracellular region

Supporting Evidence:

PMID:9620771
While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far.
Reactome:R-HSA-388605
POMC(138-176) binds MC2R
file:human/POMC/POMC-deep-research-falcon.md
**MC2R (ACTH receptor) is uniquely selective**: MC2R binds a **single endogenous ligand, ACTH**—important for GO term choice (**melanocortin receptor binding** rather than generic GPCR binding).

Suppresses appetite and promotes negative energy balance via the cleavage product alpha-MSH (melanotropin alpha, residues 138-150). In hypothalamic arcuate nucleus POMC neurons, alpha-MSH is released and binds MC4R to reduce food intake and increase energy expenditure. Loss of POMC causes severe early-onset obesity due to absence of this anorexigenic signal. Note: This is ANTAGONISTIC to beta-endorphin's orexigenic function.

Molecular Function:

type 4 melanocortin receptor binding

Directly Involved In:

negative regulation of appetite energy homeostasis

Cellular Locations:

extracellular region

Supporting Evidence:

PMID:9620771
Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)
PMID:19743876
Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R.
file:human/POMC/POMC-deep-research-falcon.md
A 2023 review summarizes evidence that **α-MSH** (cleaved from POMC) is released from arcuate POMC neurons and acts on **MC3R/MC4R-expressing neurons** to suppress appetite and increase energy expenditure, integrating with AgRP antagonism and other appetite signals.

Stimulates melanin production and skin/hair pigmentation via the cleavage products alpha-MSH (138-150) and beta-MSH (217-234). These melanocortins bind MC1R on melanocytes to activate cAMP signaling and induce eumelanin synthesis. Loss of POMC causes red hair pigmentation and fair skin phenotype due to absence of MC1R agonism.

Molecular Function:

type 1 melanocortin receptor binding

Directly Involved In:

cellular pigmentation melanin biosynthetic process

Cellular Locations:

extracellular region

Supporting Evidence:

PMID:9620771
red hair pigmentation caused by POMC mutations
UniProtKB:P01189
[Melanocyte-stimulating hormone alpha]: Increases the pigmentation of skin by increasing melanin production in melanocytes.
PMID:18292087
MC1R signaling in B16 mouse melanoma cells and primary human melanocytes

Functions as an endogenous opioid via the cleavage product beta-endorphin (residues 237-267). Beta-endorphin binds mu-opioid receptor (OPRM1) to modulate pain perception, stress response, and reward. Critically, beta-endorphin is OREXIGENIC (appetite-stimulating), which is ANTAGONISTIC to alpha-MSH's anorexigenic function. Both peptides are released from the same hypothalamic POMC neurons but stored in separate granules with distinct release mechanisms.

Molecular Function:

opioid peptide activity

Directly Involved In:

positive regulation of appetite regulation of sensory perception of pain

Cellular Locations:

extracellular region

Supporting Evidence:

UniProtKB:P01189
-!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate.
Reactome:R-HSA-374298
Opioid receptors bind opioid peptides
file:human/POMC/POMC-deep-research-falcon.md
β-endorphin is described as a POMC-derived peptide that binds opioid receptors (μ/δ/κ) with agonist activity for major forms.

References

file:human/POMC/POMC-deep-research-falcon.md

Falcon deep research report for human POMC

POMC is best curated as a secreted, tissue-specifically processed prohormone precursor, with most receptor-binding functions belonging to mature cleavage products.

"**Pro-opiomelanocortin (POMC)** is best curated in GO as a **secreted prohormone precursor** that is sorted to regulated secretory granules and **proteolytically processed in a tissue-specific manner** to yield multiple bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs embedded in the β-LPH/β-endorphin region)."
Gene-level POMC curation should avoid conflating distinct cleavage-product functions.

"**Gene-level conflation:** Avoid annotating POMC (precursor) directly with all cleavage-product functions (e.g., both “melanocortin receptor binding” and “opioid receptor binding”) unless the annotation model explicitly supports product-level entities."
Melanocortin receptor specificity should be preferred over generic GPCR-binding assertions.

"**Melanocortin receptor binding vs generic GPCR binding:** Prefer **melanocortin receptor binding** terms, with **MC2R specificity for ACTH** explicitly supported; do not use generic “GPCR binding” for POMC gene product as a catch-all."

GO_REF:0000024

Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity

GO_REF:0000033

Annotation inferences using phylogenetic trees

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

GO_REF:0000107

Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

PMID:10233018

alpha-MSH and its receptors in regulation of tumor necrosis factor-alpha production by human monocyte/macrophages.

PMID:18292087

Melanocortin-1 receptor signaling markedly induces the expression of the NR4A nuclear receptor subgroup in melanocytic cells.

PMID:19452503

Aberrant trafficking of human melanocortin 1 receptor variants associated with red hair and skin cancer: Steady-state retention of mutant forms in the proximal golgi.

PMID:19743876

Novel binding motif of ACTH analogues at the melanocortin receptors.

PMID:20810565

Peroxisomal localization of the proopiomelanocortin-derived peptides beta-lipotropin and beta-endorphin.

PMID:32296183

A reference map of the human binary protein interactome.

PMID:9620771

Severe early-onset obesity, adrenal insufficiency and red hair pigmentation caused by POMC mutations in humans.

Reactome:R-HSA-112042

Opioid binds MOR

Reactome:R-HSA-112271

The receptor:G-protein complex dissociates

Reactome:R-HSA-167408

The high affinity receptor complex binds to G-protein

Reactome:R-HSA-167419

The receptor:G-protein complex releases GDP

Reactome:R-HSA-167427

Opioid dissociates from MOR

Reactome:R-HSA-167429

The receptor:G-protein complex binds GTP

Reactome:R-HSA-265301

Corticotropin cleavage from POMC

Reactome:R-HSA-374298

Opioid receptors bind opioid peptides

Reactome:R-HSA-379044

Liganded Gs-activating GPCR acts as a GEF for Gs

Reactome:R-HSA-380073

Liganded Gi-activating GPCR acts as a GEF for Gi

Reactome:R-HSA-388596

Melanocortin receptors bind melanocortins

Reactome:R-HSA-388605

POMC(138-176) binds MC2R

Reactome:R-HSA-5603251

Defective ACTH does not bind MCR2

Reactome:R-HSA-6789615

Expression of STAT3-upregulated extracellular proteins

Reactome:R-HSA-744886

The Ligand:GPCR:Gs complex dissociates

Reactome:R-HSA-744887

Liganded Gs-activating GPCRs bind inactive heterotrimeric Gs

Reactome:R-HSA-749454

The Ligand:GPCR:Gi complex dissociates

Reactome:R-HSA-749456

Liganded Gi-activating GPCRs bind inactive heterotrimeric G-protein Gi

Deep Research

Falcon

(POMC-deep-research-falcon.md)

Question: You are an expert researcher providing comprehensive, well-cited information. Falcon Edison Scientific Literature 24 citations 2026-05-12T14:35:14.133362

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Concise GO annotation research for human POMC / UniProt P01189. Focus only on evidence relevant to GO curation: POMC as a secreted prohormone cleaved into ACTH, alpha-MSH, beta-MSH, gamma-MSH, beta-endorphin and met-enkephalin; melanocortin receptor binding versus generic GPCR binding; hormone activity; regulation of appetite, pigmentation, glucocorticoid secretion, adrenal cortex function, pain/opioid signaling and stress response; processing by PCSK1/PC1-3 and PCSK2; tissue-specific processing in pituitary and hypothalamic neurons; caveats for gene-level annotations that conflate distinct cleavage-product functions, generic protein binding, identical protein binding, and broad developmental/behavioral terms. Include PMID/DOI citations and keep under 1500 words.

Concise GO-annotation research report: human POMC (UniProt P01189)

Scope and GO-curation framing

Pro-opiomelanocortin (POMC) is best curated in GO as a secreted prohormone precursor that is sorted to regulated secretory granules and proteolytically processed in a tissue-specific manner to yield multiple bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs embedded in the β-LPH/β-endorphin region). Most experimentally demonstrated receptor binding and “hormone activity” properties belong to the cleavage products rather than the intact precursor, which is a central curation caveat. (cawley201660yearsof pages 15-16, harno2018pomcthephysiological pages 1-2)

1) Key concepts/definitions (GO-relevant)

Processing enzymes / pathway concepts
- Canonical regulated-secretory-pathway processing of POMC uses PCSK1/PC1-3 and PCSK2/PC2 endoproteolysis, followed by exopeptidase trimming (e.g., CPE) and additional modifications that can alter activity (e.g., acetylation affecting β-endorphin opioid activity). (cawley201660yearsof pages 10-11, lindberg2021obesitypomcand pages 2-3)
- Tissue specificity: anterior pituitary corticotrophs predominantly generate ACTH (less extensive processing), while tissues with additional convertase activities (e.g., pars intermedia/hypothalamic contexts) generate further products such as α-MSH and β-endorphin. (harno2018pomcthephysiological pages 2-3, cawley201660yearsof pages 15-16)
- Human pituitary evidence for dual processing systems: human pituitary contains components for both the classic PC pathway (PC1/3, PC2, CPE) and an alternative cathepsin L + aminopeptidase B processing pathway; western blots detect ACTH- and β-endorphin-immunoreactive products consistent with POMC processing. (Hook et al., 2009-04-03, https://doi.org/10.1007/s12020-009-9163-5) (hook2009humanpituitarycontains pages 1-2, hook2009humanpituitarycontains pages 4-5)

Melanocortins and receptor specificity (avoid generic GPCR binding)
- Melanocortins are POMC-derived peptides sharing a conserved HFRW pharmacophore and binding melanocortin receptors (MCRs). (fridmanis2017acthreceptor(mc2r) pages 1-2)
- MC2R (ACTH receptor) is uniquely selective: MC2R binds a single endogenous ligand, ACTH—important for GO term choice (melanocortin receptor binding rather than generic GPCR binding). (Fridmanis et al., 2017-02-06, https://doi.org/10.3389/fendo.2017.00013) (fridmanis2017acthreceptor(mc2r) pages 1-2)

Opioid peptides / embedded enkephalins
- Sequence/biochemistry literature documents that Met-enkephalin and Leu-enkephalin motifs are embedded within the β-LPH/β-endorphin region and can be liberated by proteolytic processing/digestion, supporting an evidential link from POMC processing to opioid peptide generation (but not necessarily implying high abundance of free enkephalin in every POMC tissue). (Smyth, 2016-05, https://doi.org/10.1530/jme-16-0033) (smyth201660yearsof pages 2-4)

2) Recent developments (prioritizing 2023–2024)

Appetite regulation update (2023)
- A 2023 review summarizes evidence that α-MSH (cleaved from POMC) is released from arcuate POMC neurons and acts on MC3R/MC4R-expressing neurons to suppress appetite and increase energy expenditure, integrating with AgRP antagonism and other appetite signals. (Wu et al., 2023-04-24, https://doi.org/10.1159/000530804) (wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2)

Tool-compounds/drug-discovery context (2024)
- A 2024 pharmacology review highlights how synthetic α-MSH derivatives (e.g., NDP-α-MSH analog series) are widely used as tool compounds to interrogate melanocortin receptors and as scaffolds for therapeutics, reinforcing that the relevant molecular function is melanocortin receptor binding, not generic GPCR binding. (Weirath & Haskell-Luevano, 2024-08, https://doi.org/10.1021/acsptsci.4c00129) (weirath2024recommendedtoolcompounds pages 19-19)

3) Current applications / real-world implementations (GO-relevant)

Clinical melanocortin pharmacology relies on receptor specificity: MC2R-selective antagonism has been pursued as a strategy to block ACTH-driven steroidogenesis (e.g., ACTH excess conditions), leveraging the “single endogenous ligand” specificity concept. (yuan2022ligandsformelanocortin pages 3-4)
Central melanocortin pathways are a major translational axis for obesity therapeutics (e.g., pharmacologic modulation of MC4R circuits); this supports GO BP annotation around regulation of feeding behavior/appetite/energy homeostasis but should be attributed to α/β-MSH → MC3R/MC4R signaling, not to “POMC binds GPCRs” generically. (wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2, lindberg2021obesitypomcand pages 2-3)

4) Authoritative expert synthesis and curation caveats

Key expert/authoritative sources emphasize that POMC biology depends on which peptide(s) are produced, in which tissue, and in what modified state, and that measurement of precursor vs fragments can confound interpretation—directly relevant to GO curation boundaries. (harno2018pomcthephysiological pages 1-2, cawley201660yearsof pages 10-11)

Specific caveats requested for GO curation
1. Gene-level conflation: Avoid annotating POMC (precursor) directly with all cleavage-product functions (e.g., both “melanocortin receptor binding” and “opioid receptor binding”) unless the annotation model explicitly supports product-level entities. (harno2018pomcthephysiological pages 44-45, cawley201660yearsof pages 15-16)
2. Melanocortin receptor binding vs generic GPCR binding: Prefer melanocortin receptor binding terms, with MC2R specificity for ACTH explicitly supported; do not use generic “GPCR binding” for POMC gene product as a catch-all. (fridmanis2017acthreceptor(mc2r) pages 1-2, yuan2022ligandsformelanocortin pages 3-4)
3. Generic protein binding / identical protein binding: Do not annotate generic binding (including “identical protein binding”) unless there is direct biochemical interaction evidence for the relevant molecular entity (precursor vs peptide). The reviewed literature instead supports processing-dependent receptor binding. (cawley201660yearsof pages 10-11, harno2018pomcthephysiological pages 1-2)
4. Broad behavior/development terms: Appetite and stress are supported mechanistically through defined endocrine/neuropeptide pathways (α-MSH → MC3R/MC4R; ACTH → MC2R). Prefer pathway-grounded BP terms (e.g., regulation of food intake; regulation of glucocorticoid secretion) over very broad behavior/development annotations. (wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2, fridmanis2017acthreceptor(mc2r) pages 1-2)

5) Curation-relevant functions/processes and quantitative evidence

Processing evidence and peptide quantitation (human pituitary)
- Hook et al. report western blots detecting POMC-derived ACTH products (including a band co-migrating with standard ACTH) and β-endorphin products (including a band co-migrating with standard β-endorphin), alongside detection of processing enzymes (PC1/3, PC2, CPE) and cathepsin L pathway components in human pituitary. (hook2009humanpituitarycontains pages 4-5, hook2009humanpituitarycontains pages 1-2)
- Quantitation in this study reports (units as presented): ACTH 4.94 ± 1.73 pmol/µg, α-MSH 0.138 pmol/µg, β-endorphin 0.382 fmol/µg pituitary protein. (hook2009humanpituitarycontains pages 4-5)
- Visual evidence: the dual-pathway processing schematic and mapping of ACTH/α-MSH/β-endorphin within POMC are shown in Hook et al. figures. (hook2009humanpituitarycontains media 305ec3c4, hook2009humanpituitarycontains media e02b8ab2)

Receptor-binding specificity and binding constants
- MC2R specificity: MC2R binds only ACTH endogenously. (fridmanis2017acthreceptor(mc2r) pages 1-2, yuan2022ligandsformelanocortin pages 3-4)
- Quantitative receptor pharmacology compiled for melanocortin peptides includes example Ki values for α-MSH and ACTH across MCRs (illustrating higher affinity at MC1R and differing affinities across receptors) and notes the requirement of the N-terminal ACTH residues for MC2R activation. (yuan2022ligandsformelanocortin pages 3-4)

Appetite/energy homeostasis statistics
- Review synthesis indicates ~2–5% of morbidly obese humans have loss-of-function MC4R mutations, contextualizing the importance of α/β-MSH→MC4R signaling for feeding regulation. (lindberg2021obesitypomcand pages 2-3)

Opioid receptor binding evidence
- β-endorphin is described as a POMC-derived peptide that binds opioid receptors (μ/δ/κ) with agonist activity for major forms. (lindberg2021obesitypomcand pages 2-3)
- Embedded enkephalin motifs within β-LPH/β-endorphin are supported by sequence/digestion evidence, consistent with opioid-signaling potential arising from POMC processing. (smyth201660yearsof pages 2-4, harno2018pomcthephysiological pages 1-2)

Curation-focused mapping table

Entity	Processing / evidence basis	Recommended GO MF	Recommended GO BP	Curation caveats / NOT guidance	Key citations
POMC precursor (human P01189)	Secreted prohormone sorted to dense-core granules; tissue-specific cleavage by PCSK1/PC1-3 and PCSK2/PC2 with trimming by CPE; human pituitary also contains cathepsin L + aminopeptidase B alternative processing components. Anterior pituitary mainly PC1/3→ACTH/β-LPH; hypothalamus/pars intermedia uses additional PC2 for more extensive processing.	hormone activity only if curator policy allows precursor-level annotation for secreted prohormone; otherwise reserve direct receptor-binding MF for mature peptides.	peptide hormone processing, regulated secretory pathway, broad precursor role in endocrine/neuropeptide secretion.	Do NOT assign peptide-specific receptor binding to intact precursor; avoid generic GPCR binding, protein binding, identical protein binding unless direct evidence exists for intact POMC; avoid collapsing all cleavage-product biology into one gene-level annotation.	(cawley201660yearsof pages 15-16, hook2009humanpituitarycontains pages 1-2)
ACTH	Generated from POMC primarily by PC1/3; further processing can occur in tissues with PC2.	hormone activity; melanocortin receptor binding with specific support for MC2R/ACTH receptor binding rather than generic GPCR binding.	positive regulation of glucocorticoid secretion; adrenal cortex development/function/homeostasis; stress response / HPA axis.	Prefer melanocortin receptor binding or ACTH-specific receptor statements over generic GPCR binding. ACTH is the sole endogenous ligand for MC2R; do not generalize this specificity to all POMC products.	(fridmanis2017acthreceptor(mc2r) pages 1-2, yuan2022ligandsformelanocortin pages 3-4)
α-MSH	Produced from ACTH region after additional cleavage in PC2-expressing tissues; acetylation/amidation influence bioactivity.	hormone activity; melanocortin receptor binding (especially MC1R, MC3R, MC4R; not MC2R).	regulation of appetite/food intake, energy homeostasis, pigmentation, also stress-linked melanocortin signaling.	Curate to peptide-level where possible. Do not annotate as generic GPCR binding. For appetite, prefer specific melanocortin-process terms over broad behavior terms.	(wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2, lindberg2021obesitypomcand pages 2-3)
β-MSH	Human POMC product generated by processing of β-LPH region; absent in some rodents, so use human-specific evidence carefully.	hormone activity; melanocortin receptor binding.	regulation of appetite / feeding / body weight; possible pigmentation-related melanocortin signaling.	Strong caveat against inferring from mouse where β-MSH is not produced. Avoid assigning to intact precursor without human peptide evidence.	(lindberg2021obesitypomcand pages 2-3, yuan2022ligandsformelanocortin pages 4-5)
γ-MSH	Derived from N-terminal POMC domain with additional cleavage/amidation steps.	hormone activity; melanocortin receptor binding.	Melanocortin signaling; some appetite/energy-homeostasis relevance depending on subtype/context.	Evidence is weaker/more context-dependent than for ACTH or α-MSH; avoid over-annotation to broad systemic physiology without direct support.	(yuan2022ligandsformelanocortin pages 4-5, harno2018pomcthephysiological pages 44-45)
β-endorphin	Derived from β-LPH region via PC processing; human pituitary western blots detect β-endorphin products; acetylation/proteolysis modulate activity.	hormone activity / neuropeptide hormone activity; opioid receptor binding (μ/δ/κ, strongest emphasis often on μ).	pain / antinociception, opioid signaling, stress response, some energy homeostasis roles.	Use opioid receptor binding, not generic receptor binding or generic protein binding. Distinguish β-endorphin from melanocortin-mediated functions of other POMC peptides.	(lindberg2021obesitypomcand pages 2-3, hook2009humanpituitarycontains pages 4-5)
Met-enkephalin sequence within POMC-derived β-endorphin / β-LPH	Sequence evidence shows Met-enkephalin motif embedded in β-LPH/β-endorphin and can be liberated by proteolytic processing/digestion.	If annotated at all, use peptide-level opioid receptor binding / hormone activity only for the liberated opioid peptide, not for intact POMC.	opioid signaling, antinociception/pain modulation.	Major caveat: evidence often shows embedded sequence / potential liberation, not necessarily abundant standalone peptide production in every human POMC-expressing tissue. Avoid assigning met-enkephalin functions directly to intact precursor or without peptide-level evidence.	(smyth201660yearsof pages 2-4, harno2018pomcthephysiological pages 1-2)
Gene-level summary annotation policy	Aggregate only precursor-supported facts: secreted prohormone, regulated secretion, proteolytic processing by PCSK1/2 (and cathepsin L pathway components in human pituitary).	Conservative gene-level MF: precursor hormone activity may be acceptable; peptide-specific receptor binding should usually remain product-level.	Conservative BP: peptide hormone processing, regulated secretion, and only well-supported shared processes.	Avoid generic GPCR binding, protein binding, identical protein binding, broad behavior, development, or omnibus endocrine annotations that conflate ACTH, melanocortins, and opioid peptides.	(harno2018pomcthephysiological pages 44-45, harno2018pomcthephysiological pages 2-3)

Table: This table maps human POMC precursor and major cleavage products to GO-relevant molecular functions and biological processes, while highlighting the processing evidence and the main annotation pitfalls. It is useful for separating precursor-level annotations from mature peptide-specific functions during GO curation.

Recommended minimal GO annotation set (high-confidence, gene-level)

If constrained to gene-level annotations only (without peptide-level product entities), conservative high-confidence choices supported by direct evidence include:
- Extracellular / secretory granule / regulated secretion context and peptide hormone processing (processing by PCSK1/PCSK2; evidence of pituitary processing components). (cawley201660yearsof pages 15-16, hook2009humanpituitarycontains pages 1-2)
- Precursor role in endocrine/neuropeptide hormone production (avoid assigning specific receptor binding unless using peptide-level entities). (harno2018pomcthephysiological pages 1-2, cawley201660yearsof pages 15-16)

For peptide-level annotations (preferred), assign receptor-binding and downstream process terms to ACTH, α/β/γ-MSH, β-endorphin separately, per the table. (fridmanis2017acthreceptor(mc2r) pages 1-2, wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2)

References

(cawley201660yearsof pages 15-16): Niamh X Cawley, Zhaojin Li, and Y Peng Loh. 60 years of pomc: biosynthesis, trafficking, and secretion of pro-opiomelanocortin-derived peptides. Journal of molecular endocrinology, 56 4:T77-97, May 2016. URL: https://doi.org/10.1530/jme-15-0323, doi:10.1530/jme-15-0323. This article has 210 citations and is from a peer-reviewed journal.
(harno2018pomcthephysiological pages 1-2): Erika Harno, Thanuja Gali Ramamoorthy, Anthony P. Coll, and Anne White. Pomc: the physiological power of hormone processing. Physiological reviews, 98 4:2381-2430, Oct 2018. URL: https://doi.org/10.1152/physrev.00024.2017, doi:10.1152/physrev.00024.2017. This article has 299 citations and is from a highest quality peer-reviewed journal.
(cawley201660yearsof pages 10-11): Niamh X Cawley, Zhaojin Li, and Y Peng Loh. 60 years of pomc: biosynthesis, trafficking, and secretion of pro-opiomelanocortin-derived peptides. Journal of molecular endocrinology, 56 4:T77-97, May 2016. URL: https://doi.org/10.1530/jme-15-0323, doi:10.1530/jme-15-0323. This article has 210 citations and is from a peer-reviewed journal.
(lindberg2021obesitypomcand pages 2-3): Iris Lindberg and Lloyd D Fricker. Obesity, pomc, and pomc-processing enzymes: surprising results from animal models. Endocrinology, Aug 2021. URL: https://doi.org/10.1210/endocr/bqab155, doi:10.1210/endocr/bqab155. This article has 50 citations and is from a domain leading peer-reviewed journal.
(harno2018pomcthephysiological pages 2-3): Erika Harno, Thanuja Gali Ramamoorthy, Anthony P. Coll, and Anne White. Pomc: the physiological power of hormone processing. Physiological reviews, 98 4:2381-2430, Oct 2018. URL: https://doi.org/10.1152/physrev.00024.2017, doi:10.1152/physrev.00024.2017. This article has 299 citations and is from a highest quality peer-reviewed journal.
(hook2009humanpituitarycontains pages 1-2): Vivian Hook, Lydiane Funkelstein, Thomas Toneff, Charles Mosier, and Shin-Rong Hwang. Human pituitary contains dual cathepsin l and prohormone convertase processing pathway components involved in converting pomc into the peptide hormones acth, α-msh, and β-endorphin. Endocrine, 35:429-437, Apr 2009. URL: https://doi.org/10.1007/s12020-009-9163-5, doi:10.1007/s12020-009-9163-5. This article has 39 citations and is from a peer-reviewed journal.
(hook2009humanpituitarycontains pages 4-5): Vivian Hook, Lydiane Funkelstein, Thomas Toneff, Charles Mosier, and Shin-Rong Hwang. Human pituitary contains dual cathepsin l and prohormone convertase processing pathway components involved in converting pomc into the peptide hormones acth, α-msh, and β-endorphin. Endocrine, 35:429-437, Apr 2009. URL: https://doi.org/10.1007/s12020-009-9163-5, doi:10.1007/s12020-009-9163-5. This article has 39 citations and is from a peer-reviewed journal.
(fridmanis2017acthreceptor(mc2r) pages 1-2): Davids Fridmanis, Ance Roga, and Janis Klovins. Acth receptor (mc2r) specificity: what do we know about underlying molecular mechanisms? Frontiers in Endocrinology, Feb 2017. URL: https://doi.org/10.3389/fendo.2017.00013, doi:10.3389/fendo.2017.00013. This article has 97 citations.
(smyth201660yearsof pages 2-4): Derek Smyth. 60 years of pomc: lipotropin and beta-endorphin: a perspective. Journal of molecular endocrinology, 56 4:T13-25, May 2016. URL: https://doi.org/10.1530/jme-16-0033, doi:10.1530/jme-16-0033. This article has 56 citations and is from a peer-reviewed journal.
(wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2): Qiwen Wu, Jingmei Chen, Tingyu Hua, and Jinyan Cai. Alpha-melanocyte-stimulating hormone-mediated appetite regulation in the central nervous system. Neuroendocrinology, 113:885-904, Apr 2023. URL: https://doi.org/10.1159/000530804, doi:10.1159/000530804. This article has 49 citations and is from a peer-reviewed journal.
(weirath2024recommendedtoolcompounds pages 19-19): Nicholas A. Weirath and Carrie Haskell-Luevano. Recommended tool compounds for the melanocortin receptor (mcr) g protein-coupled receptors (gpcrs). ACS pharmacology & translational science, 7 9:2706-2724, Aug 2024. URL: https://doi.org/10.1021/acsptsci.4c00129, doi:10.1021/acsptsci.4c00129. This article has 5 citations and is from a peer-reviewed journal.
(yuan2022ligandsformelanocortin pages 3-4): Xiao-Chen Yuan and Ya-Xiong Tao. Ligands for melanocortin receptors: beyond melanocyte-stimulating hormones and adrenocorticotropin. Biomolecules, 12:1407, Oct 2022. URL: https://doi.org/10.3390/biom12101407, doi:10.3390/biom12101407. This article has 25 citations.
(harno2018pomcthephysiological pages 44-45): Erika Harno, Thanuja Gali Ramamoorthy, Anthony P. Coll, and Anne White. Pomc: the physiological power of hormone processing. Physiological reviews, 98 4:2381-2430, Oct 2018. URL: https://doi.org/10.1152/physrev.00024.2017, doi:10.1152/physrev.00024.2017. This article has 299 citations and is from a highest quality peer-reviewed journal.
(hook2009humanpituitarycontains media 305ec3c4): Vivian Hook, Lydiane Funkelstein, Thomas Toneff, Charles Mosier, and Shin-Rong Hwang. Human pituitary contains dual cathepsin l and prohormone convertase processing pathway components involved in converting pomc into the peptide hormones acth, α-msh, and β-endorphin. Endocrine, 35:429-437, Apr 2009. URL: https://doi.org/10.1007/s12020-009-9163-5, doi:10.1007/s12020-009-9163-5. This article has 39 citations and is from a peer-reviewed journal.
(hook2009humanpituitarycontains media e02b8ab2): Vivian Hook, Lydiane Funkelstein, Thomas Toneff, Charles Mosier, and Shin-Rong Hwang. Human pituitary contains dual cathepsin l and prohormone convertase processing pathway components involved in converting pomc into the peptide hormones acth, α-msh, and β-endorphin. Endocrine, 35:429-437, Apr 2009. URL: https://doi.org/10.1007/s12020-009-9163-5, doi:10.1007/s12020-009-9163-5. This article has 39 citations and is from a peer-reviewed journal.
(yuan2022ligandsformelanocortin pages 4-5): Xiao-Chen Yuan and Ya-Xiong Tao. Ligands for melanocortin receptors: beyond melanocyte-stimulating hormones and adrenocorticotropin. Biomolecules, 12:1407, Oct 2022. URL: https://doi.org/10.3390/biom12101407, doi:10.3390/biom12101407. This article has 25 citations.

Citations

wu2023alphamelanocytestimulatinghormonemediatedappetite pages 1-2
weirath2024recommendedtoolcompounds pages 19-19
yuan2022ligandsformelanocortin pages 3-4
hook2009humanpituitarycontains pages 4-5
lindberg2021obesitypomcand pages 2-3
harno2018pomcthephysiological pages 1-2
harno2018pomcthephysiological pages 2-3
hook2009humanpituitarycontains pages 1-2
harno2018pomcthephysiological pages 44-45
yuan2022ligandsformelanocortin pages 4-5
https://doi.org/10.1007/s12020-009-9163-5
https://doi.org/10.3389/fendo.2017.00013
https://doi.org/10.1530/jme-16-0033
https://doi.org/10.1159/000530804
https://doi.org/10.1021/acsptsci.4c00129
https://doi.org/10.1530/jme-15-0323,
https://doi.org/10.1152/physrev.00024.2017,
https://doi.org/10.1210/endocr/bqab155,
https://doi.org/10.1007/s12020-009-9163-5,
https://doi.org/10.3389/fendo.2017.00013,
https://doi.org/10.1530/jme-16-0033,
https://doi.org/10.1159/000530804,
https://doi.org/10.1021/acsptsci.4c00129,
https://doi.org/10.3390/biom12101407,

📚 Additional Documentation

Notes

(POMC-notes.md)

POMC - Pro-opiomelanocortin Notes

Polyprotein Biology

POMC is a paradigm for post-translational processing - fundamentally different from alternative splicing. A single mRNA produces ONE precursor protein that is then proteolytically cleaved into multiple bioactive peptides with distinct and sometimes antagonistic functions.

Cleavage Products (from UniProt)

Peptide	Residues	PRO ID	Function
Signal peptide	1-26	-	Secretion
NPP	27-102	PRO_0000024966	Unknown
Gamma-MSH	77-87	PRO_0000024967	Pigmentation
Potential peptide	105-134	PRO_0000024968	Unknown
ACTH	138-176	PRO_0000024969	Stimulates cortisol release
Alpha-MSH	138-150	PRO_0000024970	Anorexigenic, pigmentation
CLIP	156-176	PRO_0000024971	Unknown
Beta-LPH	179-267	PRO_0000024972	Lipotropic
Gamma-LPH	179-234	PRO_0000024973	Lipotropic
Beta-MSH	217-234	PRO_0000024974	Pigmentation
Beta-endorphin	237-267	PRO_0000024975	Orexigenic opiate
Met-enkephalin	237-241	PRO_0000024976	Opiate

Tissue-Specific Processing

The key insight is that different tissues produce different peptide combinations:

Anterior pituitary (corticotrophs): ACTH is the primary product
ACTH stimulates adrenal cortex to release cortisol
Processing stops at ACTH level - alpha-MSH is NOT produced here
Intermediate pituitary (minimal in adult humans): MSH peptides
ACTH is further cleaved to produce alpha-MSH and CLIP
This is the main source of MSH in other species
Hypothalamus (arcuate nucleus): Both alpha-MSH and beta-endorphin
Alpha-MSH: reduces appetite (anorexigenic) via MC4R
Beta-endorphin: stimulates appetite (orexigenic), pain modulation

Antagonistic Functions Within Same Precursor

This is critical for GO annotation:
- Alpha-MSH: Anorexigenic (suppresses appetite)
- Beta-endorphin: Orexigenic (stimulates appetite)

Both peptides are produced in the same hypothalamic neurons! The balance between them affects feeding behavior.

GO Annotation Challenges

Gene-level vs peptide-level: GO annotates the gene, but functions are peptide-specific
Antagonistic functions: The gene should NOT be simply annotated to both "positive regulation of appetite" and "negative regulation of appetite" without context
Tissue specificity: ACTH function is relevant for pituitary; MSH function for hypothalamus
PRO ontology: UniProt provides PRO IDs for each peptide - ideal for peptide-specific GO annotation

Key References

PMID:9620771 - POMC mutations cause obesity, adrenal insufficiency, red hair (Krude et al. 1998)
PMID:12165561 - R236G variant affects beta-endorphin processing, causes obesity

Comparison to Alternative Splicing

Feature	Alternative Splicing (e.g., BCL2L1)	Polyprotein Processing (POMC)
Mechanism	Pre-mRNA splicing	Post-translational proteolysis
Regulation point	Nucleus (splicing)	ER/Golgi/secretory pathway
mRNA products	Multiple distinct mRNAs	Single mRNA
Protein products	Different full-length proteins	Multiple peptides from one precursor
Tissue specificity	Splice factor expression	Prohormone convertase expression
Example enzymes	-	PC1/3, PC2, carboxypeptidases

Questions for GO Curation

Should annotations be made at the PRO level for peptide-specific functions?
How to handle antagonistic functions from the same gene?
Is "regulation of appetite" appropriate when the gene produces both appetite-increasing and appetite-decreasing peptides?

Falcon deep research integration - 2026-05-12

Falcon deep research was added as POMC-deep-research-falcon.md. It reinforces
the existing review's main caution: POMC should be treated as a secreted
prohormone precursor whose cleavage products carry distinct receptor-binding and
physiological activities [file:human/POMC/POMC-deep-research-falcon.md
"Pro-opiomelanocortin (POMC) is best curated in GO as a secreted
prohormone precursor that is sorted to regulated secretory granules and
proteolytically processed in a tissue-specific manner to yield multiple
bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs embedded in
the β-LPH/β-endorphin region)."].

The report specifically supports keeping the generic protein-binding annotation
removed and preferring peptide/receptor-specific terms over broad GPCR or
behavior terms [file:human/POMC/POMC-deep-research-falcon.md "Generic protein
binding / identical protein binding: Do not annotate generic binding
(including “identical protein binding”) unless there is direct biochemical
interaction evidence for the relevant molecular entity (precursor vs peptide)."]
and [file:human/POMC/POMC-deep-research-falcon.md "Melanocortin receptor
binding vs generic GPCR binding: Prefer melanocortin receptor binding
terms, with MC2R specificity for ACTH explicitly supported; do not use
generic “GPCR binding” for POMC gene product as a catch-all."].

📄 View Raw YAML

id: P01189
gene_symbol: POMC
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >
  Pro-opiomelanocortin is a paradigm for post-translational polyprotein processing.
  A single
  267 AA precursor is proteolytically cleaved by prohormone convertases (PC1/3, PC2)
  into
  multiple bioactive peptides with distinct and sometimes ANTAGONISTIC functions.
  Key products
  include ACTH (stimulates cortisol release from adrenal cortex), alpha-MSH (anorexigenic,
  increases pigmentation via MC1R), beta-endorphin (orexigenic opiate), and met-enkephalin.
  Critically, tissue-specific processing produces different peptide combinations:
  anterior
  pituitary corticotrophs produce mainly ACTH; hypothalamic neurons produce both alpha-MSH
  (appetite suppression) and beta-endorphin (appetite stimulation). GO annotations
  at the
  gene level conflate functions that are peptide-specific - ideally annotations should
  use
  PRO ontology IDs for peptide-specific functions. POMC mutations cause obesity with
  adrenal
  insufficiency and red hair (PMID:9620771).
functional_isoforms:
- id: POMC_ACTH
  name: ACTH (Corticotropin)
  type: CLEAVAGE_PRODUCT
  maps_to:
  - type: UNIPROT_CHAIN
    ids: [PRO_0000024969]
    residues: "138-176"
  description: >
    Adrenocorticotropic hormone. Primary product in anterior pituitary corticotrophs.
    Stimulates the adrenal cortex to release cortisol (glucocorticoids). ACTH binds
    MC2R (melanocortin receptor 2), which is exclusively expressed in adrenal cortex.
    This is the primary endpoint of the HPA axis. ACTH itself contains alpha-MSH
    sequence (residues 1-13 of ACTH = alpha-MSH) but ACTH is NOT further processed
    in anterior pituitary - only in intermediate pituitary is ACTH cleaved to alpha-MSH.
  isoform_specific_terms:
  - id: GO:0031780
    label: corticotropin hormone receptor binding
  - id: GO:2000851
    label: positive regulation of glucocorticoid secretion

- id: POMC_ALPHA_MSH
  name: Alpha-MSH (Melanotropin alpha)
  type: CLEAVAGE_PRODUCT
  maps_to:
  - type: UNIPROT_CHAIN
    ids: [PRO_0000024970]
    residues: "138-150"
  description: >
    ANOREXIGENIC peptide - suppresses appetite. Produced in hypothalamic arcuate
    nucleus
    (POMC neurons) and intermediate pituitary. Signals through MC4R in hypothalamus
    to
    reduce food intake and increase energy expenditure. Also increases pigmentation
    via
    MC1R in melanocytes (hence red hair in POMC-deficient patients). Alpha-MSH has
    OPPOSITE effects to beta-endorphin on appetite - both are produced in the same
    hypothalamic neurons but stored in separate granules with distinct release mechanisms.
  isoform_specific_terms:
  - id: GO:0032099
    label: negative regulation of appetite
  - id: GO:0033059
    label: cellular pigmentation
  - id: GO:0070996
    label: type 1 melanocortin receptor binding
  - id: GO:0031782
    label: type 4 melanocortin receptor binding

- id: POMC_BETA_ENDORPHIN
  name: Beta-endorphin
  type: CLEAVAGE_PRODUCT
  maps_to:
  - type: UNIPROT_CHAIN
    ids: [PRO_0000024975]
    residues: "237-267"
  description: >
    OREXIGENIC opiate - STIMULATES appetite. This is the OPPOSITE effect to alpha-MSH!
    Endogenous opioid peptide that binds mu-opioid receptors (OPRM1). Produced in
    hypothalamic POMC neurons (same cells as alpha-MSH) and pituitary. Functions
    in
    pain modulation, stress response, and reward. The beta-endorphin/alpha-MSH balance
    in hypothalamus affects feeding behavior - both peptides are from the same precursor
    but have antagonistic effects on appetite.
  isoform_specific_terms:
  - id: GO:0032100
    label: positive regulation of appetite
  - id: GO:0019233
    label: sensory perception of pain

- id: POMC_BETA_MSH
  name: Beta-MSH (Melanotropin beta)
  type: CLEAVAGE_PRODUCT
  maps_to:
  - type: UNIPROT_CHAIN
    ids: [PRO_0000024974]
    residues: "217-234"
  description: >
    Melanocyte-stimulating hormone. Increases pigmentation via MC1R binding.
    Less well characterized than alpha-MSH. Produced primarily in intermediate
    pituitary (minimal in adult humans). May also have effects on appetite
    regulation via MC4R, similar to alpha-MSH.
  isoform_specific_terms:
  - id: GO:0033059
    label: cellular pigmentation

- id: POMC_GAMMA_MSH
  name: Gamma-MSH (Melanotropin gamma)
  type: CLEAVAGE_PRODUCT
  maps_to:
  - type: UNIPROT_CHAIN
    ids: [PRO_0000024967]
    residues: "77-87"
  description: >
    Part of the N-terminal peptide (NPP) region. Less characterized than alpha/beta-MSH.
    May have cardiovascular effects and adrenal functions distinct from other MSH
    peptides.
    Binds MC3R. The gamma-MSH-containing fragment (NPP) may have aldosterone-stimulating
    activity.
  isoform_specific_terms:
  - id: GO:0031781
    label: type 3 melanocortin receptor binding
existing_annotations:
# =====================================================================
# MOLECULAR FUNCTION ANNOTATIONS
# =====================================================================
- term:
    id: GO:0001664
    label: G protein-coupled receptor binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >
      POMC-derived peptides (ACTH, alpha-MSH, beta-MSH, gamma-MSH) are well-established
      ligands for melanocortin receptors, but GO:0001664 is a generic parent
      that is less informative than the accepted specific melanocortin receptor
      binding terms.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      The underlying biology is correct, but POMC curation should prefer specific
      melanocortin receptor binding terms over generic GPCR binding. ACTH binds
      MC2R and alpha-MSH binds MC1R/MC3R/MC4R/MC5R; the specific accepted terms
      in this review capture those activities more cleanly.
    supported_by:
    - reference_id: PMID:19743876
      supporting_text: "Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R."
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        **Melanocortin receptor binding vs generic GPCR binding:** Prefer
        **melanocortin receptor binding** terms, with **MC2R specificity for
        ACTH** explicitly supported; do not use generic “GPCR binding” for POMC
        gene product as a catch-all.

- term:
    id: GO:0005179
    label: hormone activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >
      POMC gives rise to multiple peptide hormones including ACTH, MSH peptides,
      and
      beta-endorphin. Hormone activity is a core function. IEA is consistent with
      extensive experimental evidence.
    action: ACCEPT
    reason: >
      This is the defining function of POMC - it is a prohormone that produces multiple
      bioactive peptide hormones. UniProt classifies it under "Hormone" keywords,
      and
      PMID:9620771 demonstrates hormonal functions through mutation phenotypes.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin."
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        **Pro-opiomelanocortin (POMC)** is best curated in GO as a **secreted
        prohormone precursor** that is sorted to regulated secretory granules
        and **proteolytically processed in a tissue-specific manner** to yield
        multiple bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin
        motifs embedded in the β-LPH/β-endorphin region).

- term:
    id: GO:0005179
    label: hormone activity
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      Duplicate annotation with IEA above, ISS inference from orthologs is appropriate.
    action: ACCEPT
    reason: >
      Hormone activity is conserved across mammals. ISS annotation is appropriate
      and
      consistent with experimental evidence.

- term:
    id: GO:0005179
    label: hormone activity
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      The Krude et al. 1998 paper describes POMC-null patients with adrenal insufficiency
      (loss of ACTH hormone function) and obesity (loss of alpha-MSH hormone function).
      IMP from mutant phenotype is well-justified.
    action: ACCEPT
    reason: >
      Loss of POMC function results in loss of hormonal activity - ACTH deficiency
      causes secondary hypocortisolism, alpha-MSH deficiency causes obesity and
      red hair.
      This directly demonstrates hormone activity through loss-of-function.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "early-onset obesity, adrenal insufficiency and red hair pigmentation caused by POMC mutations in humans"

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32296183
  review:
    summary: >
      High-throughput Y2H interactome study (HuRI) identified POMC interactors.
      However,
      'protein binding' is uninformative for a secreted prohormone. The actual function
      is GPCR binding, which is separately annotated.
    action: REMOVE
    reason: >
      'Protein binding' is too vague and uninformative for a prohormone. The meaningful
      interactions are with melanocortin receptors and opioid receptors, which are
      captured by more specific MF terms. HuRI Y2H interactions for a secreted/processed
      prohormone are likely not physiologically relevant - POMC is processed in
      the
      secretory pathway and its products function extracellularly.
    supported_by:
    - reference_id: PMID:32296183
      supporting_text: "HuRI is estimated to represent 2–11% of the binary protein interactome"
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        **Generic protein binding / identical protein binding:** Do not annotate
        generic binding (including “identical protein binding”) unless there is
        direct biochemical interaction evidence for the relevant molecular entity
        (precursor vs peptide).

- term:
    id: GO:0005102
    label: signaling receptor binding
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      Loss of POMC function causes phenotypes consistent with loss of signaling
      through
      melanocortin receptors (MC1R for pigmentation, MC4R for appetite, MC2R for
      ACTH).
      This is a valid parent term for the more specific MCR binding terms.
    action: ACCEPT
    reason: >
      POMC-derived peptides bind melanocortin receptors (signaling receptors). This
      is correctly inferred from mutant phenotype - loss of receptor activation.
      More specific terms (MC1R/MC3R/MC4R binding) provide additional detail.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)"

- term:
    id: GO:0070996
    label: type 1 melanocortin receptor binding
  evidence_type: IPI
  original_reference_id: PMID:19743876
  review:
    summary: >
      Yang et al. 2009 directly tested ACTH and MSH peptide binding to melanocortin
      receptors. ACTH and alpha-MSH bind MC1R. This is a core molecular function.
    action: ACCEPT
    reason: >
      Direct binding studies demonstrate alpha-MSH and ACTH bind MC1R. This receptor
      mediates pigmentation effects of MSH peptides. MC1R binding is a core function
      of alpha-MSH (POMC 138-150).
    supported_by:
    - reference_id: PMID:19743876
      supporting_text: "Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R."

- term:
    id: GO:0070996
    label: type 1 melanocortin receptor binding
  evidence_type: IDA
  original_reference_id: PMID:18292087
  review:
    summary: >
      Smith et al. 2008 studied MC1R signaling using alpha-MSH agonists. Confirms
      MC1R binding by melanocortin peptides.
    action: ACCEPT
    reason: >
      The study uses MC1R agonist (NDP-alpha-MSH) and wild-type alpha-MSH to study
      MC1R signaling in melanocytes, confirming MC1R binding as a core function.
    supported_by:
    - reference_id: PMID:18292087
      supporting_text: "the potent MC1R agonist (Nle4,D-Phe7)-alpha-melanocyte-stimulating hormone"

- term:
    id: GO:0031781
    label: type 3 melanocortin receptor binding
  evidence_type: IPI
  original_reference_id: PMID:19743876
  review:
    summary: >
      Yang et al. 2009 demonstrated ACTH and alpha-MSH binding to MC3R through
      receptor binding and activation studies.
    action: ACCEPT
    reason: >
      MC3R is a target of alpha-MSH and ACTH peptides. The paper directly demonstrates
      receptor binding and activation at hMC3R. Gamma-MSH from POMC preferentially
      binds MC3R.
    supported_by:
    - reference_id: PMID:19743876
      supporting_text: "Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R"

- term:
    id: GO:0031782
    label: type 4 melanocortin receptor binding
  evidence_type: IPI
  original_reference_id: PMID:19743876
  review:
    summary: >
      MC4R binding is critical for appetite regulation by alpha-MSH. This is the
      key receptor mediating anorexigenic effects of alpha-MSH in hypothalamus.
    action: ACCEPT
    reason: >
      MC4R binding by alpha-MSH is the molecular basis of POMC's role in appetite
      suppression. Loss of this interaction explains obesity in POMC-null patients.
      Core molecular function.
    supported_by:
    - reference_id: PMID:19743876
      supporting_text: "Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R"
    - reference_id: PMID:9620771
      supporting_text: "Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)"

- term:
    id: GO:0001664
    label: G protein-coupled receptor binding
  evidence_type: IDA
  original_reference_id: PMID:19452503
  review:
    summary: >
      Sanchez-Laorden et al. 2009 studied MC1R trafficking and activation, demonstrating
      melanocortin ligand biology, but the GO annotation uses a generic GPCR
      binding parent.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      The paper supports MC1R pathway biology, but specific melanocortin receptor
      binding terms are already present and more informative. GO:0001664 should
      not be retained as a core generic catch-all for POMC-derived peptide
      receptor binding.
    supported_by:
    - reference_id: PMID:19452503
      supporting_text: "The melanocortin 1 receptor (MC1R), a Gs protein-coupled receptor (GPCR) expressed in melanocytes"
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        **Melanocortin receptor binding vs generic GPCR binding:** Prefer
        **melanocortin receptor binding** terms, with **MC2R specificity for
        ACTH** explicitly supported; do not use generic “GPCR binding” for POMC
        gene product as a catch-all.

# =====================================================================
# CELLULAR COMPONENT ANNOTATIONS
# =====================================================================
- term:
    id: GO:0005615
    label: extracellular space
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >
      POMC-derived peptides are secreted hormones that function in the extracellular
      space. IBA phylogenetic inference is appropriate.
    action: ACCEPT
    reason: >
      All POMC-derived bioactive peptides (ACTH, MSH, beta-endorphin) are secreted
      and function extracellularly to bind receptors on target cells. UniProt notes
      "Secreted" for subcellular location.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >
      Extracellular region is the broader parent term. POMC products are secreted
      and act extracellularly.
    action: ACCEPT
    reason: >
      Consistent with secreted hormone function. Appropriate IEA inference.

- term:
    id: GO:0030141
    label: secretory granule
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >
      POMC is stored in and processed within secretory granules in pituitary and
      hypothalamic neurons before release. IBA is appropriate.
    action: ACCEPT
    reason: >
      UniProt notes that alpha-MSH and beta-endorphin are stored in separate granules
      in hypothalamic POMC neurons. Secretory granule localization is well-established.
    supported_by:
    - reference_id: UniProtKB:P01189
      supporting_text: "Melanocyte-stimulating hormone alpha and beta-endorphin are stored in separate granules in hypothalamic POMC neurons"

- term:
    id: GO:0005615
    label: extracellular space
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      Duplicate of IBA annotation above. Extracellular space is correct for secreted
      peptide hormones.
    action: ACCEPT
    reason: >
      IEA inference consistent with experimental evidence for secreted localization.

- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      POMC transits through cytoplasm during biosynthesis but this is not its
      functional location. This is over-annotation.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      While POMC precursor passes through the cytoplasm during synthesis, this is
      not meaningful for function. POMC enters the secretory pathway via signal
      peptide and is processed in ER/Golgi/secretory granules. Cytoplasm annotation
      is technically true but functionally misleading.

- term:
    id: GO:0030141
    label: secretory granule
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      Duplicate of IBA annotation. Secretory granule localization is correct.
    action: ACCEPT
    reason: >
      IEA inference consistent with IBA and experimental evidence.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-379044
  review:
    summary: >
      Reactome pathway annotation for GPCR signaling. Extracellular region is where
      ligands interact with receptors.
    action: ACCEPT
    reason: >
      Appropriate localization for secreted hormone peptides.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-388596
  review:
    summary: >
      Reactome annotation for melanocortin receptor binding. Multiple Reactome
      TAS annotations to same GO term represent different pathway contexts.
    action: ACCEPT
    reason: >
      Valid annotation - POMC peptides bind melanocortin receptors extracellularly.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-744886
  review:
    summary: >
      Reactome annotation for GPCR:Gs complex dissociation pathway.
    action: ACCEPT
    reason: >
      Valid - ligands act extracellularly to activate GPCRs.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-744887
  review:
    summary: >
      Reactome annotation for liganded Gs-activating GPCRs.
    action: ACCEPT
    reason: >
      Valid - melanocortins bind Gs-coupled MCRs extracellularly.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-5603251
  review:
    summary: >
      Reactome annotation for defective ACTH not binding MC2R.
    action: ACCEPT
    reason: >
      Valid pathway annotation - ACTH acts extracellularly on MC2R.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-112042
  review:
    summary: >
      Reactome annotation for opioid binding to MOR (mu opioid receptor).
      Beta-endorphin is the POMC product that binds opioid receptors.
    action: ACCEPT
    reason: >
      Beta-endorphin (POMC 237-267) binds mu-opioid receptor extracellularly.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-112271
  review:
    summary: >
      Reactome annotation for receptor:G-protein complex dissociation in opioid
      signaling.
    action: ACCEPT
    reason: >
      Valid pathway annotation for beta-endorphin function.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-167408
  review:
    summary: >
      Reactome annotation for high affinity receptor:G-protein binding.
    action: ACCEPT
    reason: >
      Valid - POMC peptides act as extracellular ligands for GPCRs.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-167419
  review:
    summary: >
      Reactome annotation for GDP release from receptor:G-protein complex.
    action: ACCEPT
    reason: >
      Valid pathway annotation.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-167427
  review:
    summary: >
      Reactome annotation for opioid dissociation from MOR.
    action: ACCEPT
    reason: >
      Valid - beta-endorphin binds MOR extracellularly.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-167429
  review:
    summary: >
      Reactome annotation for GTP binding to receptor:G-protein complex.
    action: ACCEPT
    reason: >
      Valid pathway annotation.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-374298
  review:
    summary: >
      Reactome annotation for opioid receptors binding opioid peptides.
    action: ACCEPT
    reason: >
      Beta-endorphin and met-enkephalin from POMC bind opioid receptors extracellularly.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-380073
  review:
    summary: >
      Reactome annotation for Gi-coupled GPCR activation (opioid signaling).
    action: ACCEPT
    reason: >
      Valid - opioid receptors are Gi-coupled, beta-endorphin acts extracellularly.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-388605
  review:
    summary: >
      Reactome annotation specifically for ACTH (POMC 138-176) binding MC2R.
    action: ACCEPT
    reason: >
      Core function - ACTH binds MC2R extracellularly to stimulate cortisol release.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-6789615
  review:
    summary: >
      Reactome annotation for STAT3-upregulated extracellular proteins.
    action: ACCEPT
    reason: >
      Valid - POMC products are extracellular.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-749454
  review:
    summary: >
      Reactome annotation for Gi complex dissociation.
    action: ACCEPT
    reason: >
      Valid pathway annotation for opioid signaling.

- term:
    id: GO:0005576
    label: extracellular region
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-749456
  review:
    summary: >
      Reactome annotation for Gi-coupled GPCR binding.
    action: ACCEPT
    reason: >
      Valid - opioid peptides act extracellularly.

- term:
    id: GO:0034774
    label: secretory granule lumen
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-265301
  review:
    summary: >
      Reactome annotation for corticotropin cleavage from POMC. Processing occurs
      in secretory granule lumen.
    action: ACCEPT
    reason: >
      POMC processing by prohormone convertases (PC1/3, PC2) occurs in the lumen
      of secretory granules. This is where the mature peptides are generated.

- term:
    id: GO:0005782
    label: peroxisomal matrix
  evidence_type: IDA
  original_reference_id: PMID:20810565
  review:
    summary: >
      Hoftberger et al. 2010 report surprising peroxisomal localization of beta-LPH
      and beta-endorphin in cells expressing ALDP. This is tissue-specific and applies
      only to the C-terminal POMC products.
    action: KEEP_AS_NON_CORE
    reason: >
      The paper demonstrates peroxisomal localization specifically for beta-LPH
      and
      beta-endorphin (C-terminal POMC products) in cells expressing ALDP. However,
      N-terminal peptides (ACTH, alpha-MSH, gamma-MSH) were NOT found in peroxisomes.
      This is a specialized localization, not a core function.
    supported_by:
    - reference_id: PMID:20810565
      supporting_text: "In contrast to the peptide hormones β-LPH and β-endorphin, which are derived from the C terminus of POMC, the N-terminal peptides ACTH, α-MSH, and γ-MSH were never detected in peroxisomes."

- term:
    id: GO:0005615
    label: extracellular space
  evidence_type: IDA
  original_reference_id: PMID:9620771
  review:
    summary: >
      The Krude paper describes POMC mutation phenotypes but does not directly
      demonstrate extracellular localization. However, the inferred hormonal function
      implies extracellular action.
    action: ACCEPT
    reason: >
      While not directly demonstrated in this paper, POMC products function as
      circulating hormones, which by definition are extracellular.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: 'Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin'

- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      ISS annotation for cytoplasm. Like the IEA annotation, this is technically
      true but functionally misleading.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      Cytoplasm is not a meaningful functional location for POMC. The protein
      enters the secretory pathway and functions extracellularly.

- term:
    id: GO:0030141
    label: secretory granule
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      ISS annotation consistent with IBA and IEA annotations. Secretory granule
      is a valid localization.
    action: ACCEPT
    reason: >
      Secretory granule storage and processing is conserved across POMC orthologs.

# =====================================================================
# BIOLOGICAL PROCESS ANNOTATIONS
# =====================================================================
- term:
    id: GO:2000852
    label: regulation of corticosterone secretion
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >
      ACTH (POMC 138-176) stimulates adrenal cortex to release glucocorticoids.
      In rodents, this is corticosterone; in humans, cortisol. IBA annotation is
      appropriate for the conserved function.
    action: ACCEPT
    reason: >
      ACTH regulation of adrenal glucocorticoid secretion is the primary function
      of the HPA axis. This is conserved across mammals - the specific glucocorticoid
      varies but the mechanism is the same.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far."

- term:
    id: GO:0007218
    label: neuropeptide signaling pathway
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: >
      POMC produces multiple neuropeptides (alpha-MSH, beta-endorphin) that function
      in hypothalamic signaling. UniProt keyword mapping is appropriate.
    action: ACCEPT
    reason: >
      Alpha-MSH and beta-endorphin are classical neuropeptides produced in
      hypothalamic POMC neurons. Neuropeptide signaling is a core function.

- term:
    id: GO:0106071
    label: positive regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      Melanocortin receptors (MC1R-MC5R) are Gs-coupled GPCRs that activate
      adenylate cyclase. POMC peptides as ligands positively regulate this pathway.
    action: ACCEPT
    reason: >
      MC1R, MC2R, MC3R, MC4R, and MC5R are all coupled to Gs and activate adenylate
      cyclase upon binding melanocortin peptides. This is the signaling mechanism.

- term:
    id: GO:0140668
    label: positive regulation of oxytocin production
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      Some evidence suggests melanocortins affect oxytocin release, but this is
      not a well-established core function of POMC.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      While there may be some regulatory effects of melanocortins on oxytocin,
      this is not a direct or primary function of POMC. The evidence base is
      limited and this appears to be an over-extension of IEA transfer.

- term:
    id: GO:1990680
    label: response to melanocyte-stimulating hormone
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      This annotation is problematic - POMC PRODUCES melanocyte-stimulating hormone,
      it does not respond to it. This appears to be an erroneous annotation.
    action: REMOVE
    reason: >
      POMC is the precursor that produces MSH peptides. It does not respond to MSH.
      This annotation appears to confuse POMC with MSH receptors or downstream
      targets. POMC-expressing cells may respond to feedback, but the gene product
      itself does not "respond to MSH."

- term:
    id: GO:0106071
    label: positive regulation of adenylate cyclase-activating G protein-coupled receptor signaling pathway
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      Duplicate of IEA annotation. ISS is appropriate as melanocortin receptor
      signaling mechanism is conserved.
    action: ACCEPT
    reason: >
      Conserved function - melanocortin receptors couple to Gs and activate AC.

- term:
    id: GO:0019722
    label: calcium-mediated signaling
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      Some melanocortin receptors can couple to calcium signaling, but this is
      not the primary signaling mechanism for most MCRs.
    action: KEEP_AS_NON_CORE
    reason: >
      While MC1R and other MCRs can activate calcium signaling in some contexts,
      the primary signaling mechanism is cAMP/PKA via Gs coupling. Calcium signaling
      is a secondary effect, not a core function.

- term:
    id: GO:1990680
    label: response to melanocyte-stimulating hormone
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      Same issue as IEA annotation - POMC produces MSH, it does not respond to it.
    action: REMOVE
    reason: >
      POMC is the source of MSH, not a responder. This annotation is erroneous.

- term:
    id: GO:0006091
    label: generation of precursor metabolites and energy
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      POMC-null patients have metabolic abnormalities, but this is an indirect effect
      of hormone loss, not a direct molecular function. This term is too general.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      While POMC loss affects metabolism (obesity, adrenal insufficiency), this
      is an indirect consequence of loss of hormonal regulation, not a direct
      role in energy generation pathways. This annotation is over-interpretation
      of phenotype data.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "early-onset obesity, adrenal insufficiency and red hair pigmentation"

- term:
    id: GO:0007165
    label: signal transduction
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      POMC-derived peptides are signaling molecules that activate receptor signaling.
      This is correct but very general.
    action: ACCEPT
    reason: >
      All POMC peptide hormones function by activating signal transduction cascades
      through their receptors. This is a valid high-level annotation.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: 'Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5) and the linkage of human obesity to chromosome 2 in close proximity to the POMC locus, led to the proposal of an association of POMC with human obesity'

- term:
    id: GO:0007267
    label: cell-cell signaling
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      POMC-derived peptides mediate cell-cell signaling between endocrine cells
      and target tissues. This is a core function.
    action: ACCEPT
    reason: >
      ACTH signals from pituitary to adrenal cortex, alpha-MSH signals between
      hypothalamic neurons and melanocytes/hypothalamic circuits. Classical
      cell-cell signaling function.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: 'Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin'

- term:
    id: GO:0008217
    label: regulation of blood pressure
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >
      ACTH affects blood pressure through cortisol release; alpha-MSH may have
      direct cardiovascular effects via MC3R/MC4R. However, this is not a primary
      function of POMC.
    action: KEEP_AS_NON_CORE
    reason: >
      Blood pressure regulation is an indirect effect of POMC peptides, primarily
      through ACTH-stimulated glucocorticoid release. Not a core direct function.

- term:
    id: GO:0032098
    label: regulation of appetite
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      POMC-null patients have severe obesity due to hyperphagia, demonstrating
      POMC role in appetite regulation. HOWEVER, this annotation conflates
      antagonistic functions: alpha-MSH suppresses appetite (anorexigenic) while
      beta-endorphin stimulates appetite (orexigenic).
    action: MODIFY
    reason: >
      The term "regulation of appetite" is appropriate at the gene level because
      POMC produces BOTH appetite-suppressing (alpha-MSH via MC4R) AND appetite-
      stimulating (beta-endorphin via opioid receptors) peptides. The net effect
      in POMC-null patients is obesity because alpha-MSH loss predominates. However,
      ideally this should be annotated at the peptide level with specific terms
      (GO:0032099 negative regulation of appetite for alpha-MSH; GO:0032100 positive
      regulation of appetite for beta-endorphin).
    proposed_replacement_terms:
    - id: GO:0032099
      label: negative regulation of appetite
    - id: GO:0032100
      label: positive regulation of appetite
    additional_reference_ids:
    - UniProtKB:P01189
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor"
    - reference_id: UniProtKB:P01189
      supporting_text: "-!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate."
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        Appetite and stress are supported mechanistically through defined
        endocrine/neuropeptide pathways (α-MSH → MC3R/MC4R; ACTH → MC2R).
        Prefer pathway-grounded BP terms (e.g., regulation of food intake;
        regulation of glucocorticoid secretion) over very broad
        behavior/development annotations.

- term:
    id: GO:0033059
    label: cellular pigmentation
  evidence_type: IMP
  original_reference_id: PMID:9620771
  review:
    summary: >
      POMC-null patients have red hair and fair skin, demonstrating alpha-MSH
      role in pigmentation via MC1R. This is a core function of alpha-MSH.
    action: ACCEPT
    reason: >
      Alpha-MSH binding to MC1R in melanocytes stimulates melanin production.
      Loss of alpha-MSH (POMC mutation) causes red hair/fair skin phenotype.
      Core function.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "red hair pigmentation caused by POMC mutations"
    - reference_id: UniProtKB:P01189
      supporting_text: "[Melanocyte-stimulating hormone alpha]: Increases the pigmentation of skin by increasing melanin production in melanocytes."

- term:
    id: GO:0032720
    label: negative regulation of tumor necrosis factor production
  evidence_type: IDA
  original_reference_id: PMID:10233018
  review:
    summary: >
      Taherzadeh et al. 1999 demonstrated alpha-MSH inhibits TNF-alpha production
      in macrophages. This is an anti-inflammatory function of alpha-MSH.
    action: KEEP_AS_NON_CORE
    reason: >
      The paper demonstrates alpha-MSH suppresses TNF-alpha in LPS-stimulated
      macrophages via MC1R. This is a validated function but represents the
      immunomodulatory role of alpha-MSH, which is secondary to its pigmentation
      and appetite regulation functions.
    supported_by:
    - reference_id: PMID:10233018
      supporting_text: "The inflammatory cytokine tumor necrosis factor (TNF)-alpha was inhibited in relation to alpha-MSH concentration."

- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IDA
  original_reference_id: PMID:18292087
  review:
    summary: >
      Smith et al. 2008 showed MC1R signaling (via alpha-MSH) induces transcription
      of NR4A nuclear receptors in melanocytes. This is downstream of receptor
      activation, not a direct function of POMC.
    action: MARK_AS_OVER_ANNOTATED
    reason: >
      This annotation conflates ligand function with downstream transcriptional
      effects. Alpha-MSH binding to MC1R activates cAMP/PKA which then activates
      transcription factors. POMC peptides do not directly regulate transcription;
      they bind extracellular receptors. This is over-annotation.
    supported_by:
    - reference_id: PMID:18292087
      supporting_text: "Here we show that MC1R signaling in B16 mouse melanoma cells and primary human melanocytes rapidly, and transiently, induces the transcription of the NR4A subfamily of orphan nuclear receptors"

# =====================================================================
# CORE FUNCTIONS
# =====================================================================
# IMPORTANT: POMC is a POLYPROTEIN precursor - a single gene product that is
# proteolytically cleaved into multiple bioactive peptides with DISTINCT
# and sometimes ANTAGONISTIC functions. The core functions below describe
# the gene's role through its various cleavage products. Ideally, peptide-
# specific functions would be annotated at the PRO level (e.g., PRO:0000024969
# for ACTH), but GO annotations are typically made at the gene level.

- term:
    id: GO:0016486
    label: peptide hormone processing
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin."
    - reference_id: UniProtKB:P01189
      supporting_text: "Specific enzymatic cleavages at paired basic residues yield the different active peptides."
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        Canonical regulated-secretory-pathway processing of POMC uses
        **PCSK1/PC1-3** and **PCSK2/PC2** endoproteolysis, followed by
        exopeptidase trimming (e.g., **CPE**) and additional modifications that
        can alter activity (e.g., acetylation affecting β-endorphin opioid
        activity).

# ---------------------------------------------------------------------
# Core Function 2: HPA Axis Regulation via ACTH
# ---------------------------------------------------------------------
# ACTH (residues 138-176) is the primary product in anterior pituitary
# corticotrophs. ACTH binds MC2R on adrenal cortex cells to stimulate
# glucocorticoid (cortisol) release. This is the endpoint of the HPA axis.
- term:
    id: GO:0031780
    label: corticotropin hormone receptor binding
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far."
    - reference_id: Reactome:R-HSA-388605
      supporting_text: "POMC(138-176) binds MC2R"
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        **MC2R (ACTH receptor) is uniquely selective**: MC2R binds a **single
        endogenous ligand, ACTH**—important for GO term choice (**melanocortin
        receptor binding** rather than generic GPCR binding).

# ---------------------------------------------------------------------
# Core Function 2: HPA Axis Regulation via ACTH
# ---------------------------------------------------------------------
# Alpha-MSH (residues 138-150, contained within ACTH) is released by
# hypothalamic POMC neurons. It binds MC4R to suppress appetite and
# increase energy expenditure. This is the ANOREXIGENIC function.
- term:
    id: GO:2000851
    label: positive regulation of glucocorticoid secretion
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: Reactome:R-HSA-388605
      supporting_text: "POMC(138-176) binds MC2R"

# ---------------------------------------------------------------------
# Core Function 2: HPA Axis Regulation via ACTH
# ---------------------------------------------------------------------
# Alpha-MSH (residues 138-150, contained within ACTH) is released by
# hypothalamic POMC neurons. It binds MC4R to suppress appetite and
# increase energy expenditure. This is the ANOREXIGENIC function.
- term:
    id: GO:0051464
    label: positive regulation of cortisol secretion
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "early-onset obesity, adrenal insufficiency and red hair pigmentation"
    - reference_id: Reactome:R-HSA-388605
      supporting_text: "POMC(138-176) binds MC2R"

# ---------------------------------------------------------------------
# Core Function 3: Appetite Suppression via Alpha-MSH
# ---------------------------------------------------------------------
# Alpha-MSH (residues 138-150, contained within ACTH) is released by
# hypothalamic POMC neurons. It binds MC4R to suppress appetite and
# increase energy expenditure. This is the ANOREXIGENIC function.
- term:
    id: GO:0097009
    label: energy homeostasis
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)"
    - reference_id: PMID:19743876
      supporting_text: "Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R."

# ---------------------------------------------------------------------
# Core Function 4: Skin Pigmentation via MSH Peptides
# ---------------------------------------------------------------------
# Alpha-MSH and beta-MSH bind MC1R on melanocytes to stimulate melanin
# production. Loss of POMC results in fair skin and red hair due to
# absence of MC1R stimulation.
- term:
    id: GO:0042438
    label: melanin biosynthetic process
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: PMID:9620771
      supporting_text: "red hair pigmentation caused by POMC mutations"
    - reference_id: UniProtKB:P01189
      supporting_text: "[Melanocyte-stimulating hormone alpha]: Increases the pigmentation of skin by increasing melanin production in melanocytes."
    - reference_id: PMID:18292087
      supporting_text: "MC1R signaling in B16 mouse melanoma cells and primary human melanocytes"

# ---------------------------------------------------------------------
# Core Function 5: Opioid Signaling and Appetite Stimulation via Beta-Endorphin
# ---------------------------------------------------------------------
# Beta-endorphin (residues 237-267) is an endogenous opioid peptide that
# binds mu-opioid receptor. It is OREXIGENIC (stimulates appetite), which
# is ANTAGONISTIC to alpha-MSH's anorexigenic effect. Both are produced
# from the same precursor in hypothalamic neurons.
- term:
    id: GO:0001515
    label: opioid peptide activity
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: UniProtKB:P01189
      supporting_text: "-!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate."
    - reference_id: Reactome:R-HSA-374298
      supporting_text: "Opioid receptors bind opioid peptides"
    - reference_id: file:human/POMC/POMC-deep-research-falcon.md
      supporting_text: >-
        β-endorphin is described as a POMC-derived peptide that binds opioid
        receptors (μ/δ/κ) with agonist activity for major forms.

- term:
    id: GO:0051930
    label: regulation of sensory perception of pain
  evidence_type: NAS
  review:
    summary: Added to align core_functions with existing annotations.
    action: NEW
    reason: Core function term not present in existing_annotations.
    supported_by:
    - reference_id: UniProtKB:P01189
      supporting_text: "-!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate."
    - reference_id: Reactome:R-HSA-374298
      supporting_text: "Opioid receptors bind opioid peptides"

core_functions:
# ---------------------------------------------------------------------
# Core Function 1: Neuropeptide Hormone Precursor
# ---------------------------------------------------------------------
# This is the PRIMARY function of POMC - serving as a precursor for multiple
# bioactive peptides. The precursor itself has no activity; the function
# emerges through post-translational processing by PC1/3 and PC2.
- description: >
    Serves as a polyprotein precursor that is proteolytically processed by
    prohormone convertases (PC1/PC3, PC2) in a tissue-specific manner to
    generate multiple bioactive neuropeptide hormones including ACTH,
    melanocyte-stimulating hormones (alpha-, beta-, gamma-MSH), beta-endorphin,
    and beta-lipotropin. Processing occurs in secretory granules within
    neuroendocrine cells of the pituitary and hypothalamus.
  molecular_function:
    id: GO:0005179
    label: hormone activity
  directly_involved_in:
  - id: GO:0007218
    label: neuropeptide signaling pathway
  - id: GO:0016486
    label: peptide hormone processing
  locations:
  - id: GO:0034774
    label: secretory granule lumen
  - id: GO:0030141
    label: secretory granule
  - id: GO:0005576
    label: extracellular region
  anatomical_locations:
  - id: UBERON:0002196
    label: adenohypophysis
  - id: UBERON:0001898
    label: hypothalamus
  supported_by:
  - reference_id: PMID:9620771
    supporting_text: "Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin."
  - reference_id: UniProtKB:P01189
    supporting_text: "This is a prohormone that is cleaved to give multiple peptide hormones."
  - reference_id: file:human/POMC/POMC-deep-research-falcon.md
    supporting_text: >-
      **Pro-opiomelanocortin (POMC)** is best curated in GO as a **secreted
      prohormone precursor** that is sorted to regulated secretory granules and
      **proteolytically processed in a tissue-specific manner** to yield multiple
      bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs
      embedded in the β-LPH/β-endorphin region).

# ---------------------------------------------------------------------
# Core Function 2: HPA Axis Regulation via ACTH
# ---------------------------------------------------------------------
# ACTH (residues 138-176) is the primary product in anterior pituitary
# corticotrophs. ACTH binds MC2R on adrenal cortex cells to stimulate
# glucocorticoid (cortisol) release. This is the endpoint of the HPA axis.
- description: >
    Regulates the hypothalamic-pituitary-adrenal (HPA) axis via the cleavage
    product ACTH (corticotropin, residues 138-176). ACTH binds MC2R
    (corticotropin receptor) on adrenal cortex cells to stimulate
    glucocorticoid (cortisol in humans) secretion. Loss of POMC causes
    isolated ACTH deficiency with secondary adrenal insufficiency.
  molecular_function:
    id: GO:0031780
    label: corticotropin hormone receptor binding
  directly_involved_in:
  - id: GO:2000851
    label: positive regulation of glucocorticoid secretion
  - id: GO:0051464
    label: positive regulation of cortisol secretion
  - id: GO:0007267
    label: cell-cell signaling
  locations:
  - id: GO:0005576
    label: extracellular region
  anatomical_locations:
  - id: UBERON:0002196
    label: adenohypophysis
  - id: UBERON:0001235
    label: adrenal cortex
  supported_by:
  - reference_id: PMID:9620771
    supporting_text: "While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far."
  - reference_id: Reactome:R-HSA-388605
    supporting_text: "POMC(138-176) binds MC2R"
  - reference_id: file:human/POMC/POMC-deep-research-falcon.md
    supporting_text: >-
      **MC2R (ACTH receptor) is uniquely selective**: MC2R binds a **single
      endogenous ligand, ACTH**—important for GO term choice (**melanocortin
      receptor binding** rather than generic GPCR binding).

# ---------------------------------------------------------------------
# Core Function 3: Appetite Suppression via Alpha-MSH
# ---------------------------------------------------------------------
# Alpha-MSH (residues 138-150, contained within ACTH) is released by
# hypothalamic POMC neurons. It binds MC4R to suppress appetite and
# increase energy expenditure. This is the ANOREXIGENIC function.
- description: >
    Suppresses appetite and promotes negative energy balance via the cleavage
    product alpha-MSH (melanotropin alpha, residues 138-150). In hypothalamic
    arcuate nucleus POMC neurons, alpha-MSH is released and binds MC4R to
    reduce food intake and increase energy expenditure. Loss of POMC causes
    severe early-onset obesity due to absence of this anorexigenic signal.
    Note: This is ANTAGONISTIC to beta-endorphin's orexigenic function.
  molecular_function:
    id: GO:0031782
    label: type 4 melanocortin receptor binding
  directly_involved_in:
  - id: GO:0032099
    label: negative regulation of appetite
  - id: GO:0097009
    label: energy homeostasis
  locations:
  - id: GO:0005576
    label: extracellular region
  anatomical_locations:
  - id: UBERON:0001898
    label: hypothalamus
  supported_by:
  - reference_id: PMID:9620771
    supporting_text: "Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5)"
  - reference_id: PMID:19743876
    supporting_text: "Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R."
  - reference_id: file:human/POMC/POMC-deep-research-falcon.md
    supporting_text: >-
      A 2023 review summarizes evidence that **α-MSH** (cleaved from POMC) is
      released from arcuate POMC neurons and acts on **MC3R/MC4R-expressing
      neurons** to suppress appetite and increase energy expenditure, integrating
      with AgRP antagonism and other appetite signals.

# ---------------------------------------------------------------------
# Core Function 4: Skin Pigmentation via MSH Peptides
# ---------------------------------------------------------------------
# Alpha-MSH and beta-MSH bind MC1R on melanocytes to stimulate melanin
# production. Loss of POMC results in fair skin and red hair due to
# absence of MC1R stimulation.
- description: >
    Stimulates melanin production and skin/hair pigmentation via the cleavage
    products alpha-MSH (138-150) and beta-MSH (217-234). These melanocortins
    bind MC1R on melanocytes to activate cAMP signaling and induce
    eumelanin synthesis. Loss of POMC causes red hair pigmentation and
    fair skin phenotype due to absence of MC1R agonism.
  molecular_function:
    id: GO:0070996
    label: type 1 melanocortin receptor binding
  directly_involved_in:
  - id: GO:0033059
    label: cellular pigmentation
  - id: GO:0042438
    label: melanin biosynthetic process
  locations:
  - id: GO:0005576
    label: extracellular region
  anatomical_locations:
  - id: UBERON:0001416
    label: skin of body
  supported_by:
  - reference_id: PMID:9620771
    supporting_text: "red hair pigmentation caused by POMC mutations"
  - reference_id: UniProtKB:P01189
    supporting_text: "[Melanocyte-stimulating hormone alpha]: Increases the pigmentation of skin by increasing melanin production in melanocytes."
  - reference_id: PMID:18292087
    supporting_text: "MC1R signaling in B16 mouse melanoma cells and primary human melanocytes"

# ---------------------------------------------------------------------
# Core Function 5: Opioid Signaling and Appetite Stimulation via Beta-Endorphin
# ---------------------------------------------------------------------
# Beta-endorphin (residues 237-267) is an endogenous opioid peptide that
# binds mu-opioid receptor. It is OREXIGENIC (stimulates appetite), which
# is ANTAGONISTIC to alpha-MSH's anorexigenic effect. Both are produced
# from the same precursor in hypothalamic neurons.
- description: >
    Functions as an endogenous opioid via the cleavage product beta-endorphin
    (residues 237-267). Beta-endorphin binds mu-opioid receptor (OPRM1) to
    modulate pain perception, stress response, and reward. Critically,
    beta-endorphin is OREXIGENIC (appetite-stimulating), which is
    ANTAGONISTIC to alpha-MSH's anorexigenic function. Both peptides are
    released from the same hypothalamic POMC neurons but stored in separate
    granules with distinct release mechanisms.
  molecular_function:
    id: GO:0001515
    label: opioid peptide activity
  directly_involved_in:
  - id: GO:0032100
    label: positive regulation of appetite
  - id: GO:0051930
    label: regulation of sensory perception of pain
  locations:
  - id: GO:0005576
    label: extracellular region
  anatomical_locations:
  - id: UBERON:0001898
    label: hypothalamus
  - id: UBERON:0002196
    label: adenohypophysis
  supported_by:
  - reference_id: UniProtKB:P01189
    supporting_text: "-!- FUNCTION: [Beta-endorphin]: Endogenous orexigenic opiate."
  - reference_id: Reactome:R-HSA-374298
    supporting_text: "Opioid receptors bind opioid peptides"
  - reference_id: file:human/POMC/POMC-deep-research-falcon.md
    supporting_text: >-
      β-endorphin is described as a POMC-derived peptide that binds opioid
      receptors (μ/δ/κ) with agonist activity for major forms.

references:
- id: file:human/POMC/POMC-deep-research-falcon.md
  title: Falcon deep research report for human POMC
  findings:
  - statement: POMC is best curated as a secreted, tissue-specifically processed
      prohormone precursor, with most receptor-binding functions belonging to
      mature cleavage products.
    supporting_text: >-
      **Pro-opiomelanocortin (POMC)** is best curated in GO as a **secreted
      prohormone precursor** that is sorted to regulated secretory granules and
      **proteolytically processed in a tissue-specific manner** to yield multiple
      bioactive peptides (ACTH, α/β/γ-MSH, β-endorphin; enkephalin motifs
      embedded in the β-LPH/β-endorphin region).
  - statement: Gene-level POMC curation should avoid conflating distinct
      cleavage-product functions.
    supporting_text: >-
      **Gene-level conflation:** Avoid annotating POMC (precursor) directly with
      all cleavage-product functions (e.g., both “melanocortin receptor binding”
      and “opioid receptor binding”) unless the annotation model explicitly
      supports product-level entities.
  - statement: Melanocortin receptor specificity should be preferred over generic
      GPCR-binding assertions.
    supporting_text: >-
      **Melanocortin receptor binding vs generic GPCR binding:** Prefer
      **melanocortin receptor binding** terms, with **MC2R specificity for ACTH**
      explicitly supported; do not use generic “GPCR binding” for POMC gene
      product as a catch-all.
- id: GO_REF:0000024
  title: Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:10233018
  title: alpha-MSH and its receptors in regulation of tumor necrosis factor-alpha production by human monocyte/macrophages.
  findings: []
- id: PMID:18292087
  title: Melanocortin-1 receptor signaling markedly induces the expression of the NR4A nuclear receptor subgroup in melanocytic cells.
  findings: []
- id: PMID:19452503
  title: 'Aberrant trafficking of human melanocortin 1 receptor variants associated with red hair and skin cancer: Steady-state retention of mutant forms in the proximal golgi.'
  findings: []
- id: PMID:19743876
  title: Novel binding motif of ACTH analogues at the melanocortin receptors.
  findings: []
- id: PMID:20810565
  title: Peroxisomal localization of the proopiomelanocortin-derived peptides beta-lipotropin and beta-endorphin.
  findings: []
- id: PMID:32296183
  title: A reference map of the human binary protein interactome.
  findings: []
- id: PMID:9620771
  title: Severe early-onset obesity, adrenal insufficiency and red hair pigmentation caused by POMC mutations in humans.
  findings: []
- id: Reactome:R-HSA-112042
  title: Opioid binds MOR
  findings: []
- id: Reactome:R-HSA-112271
  title: The receptor:G-protein complex dissociates
  findings: []
- id: Reactome:R-HSA-167408
  title: The high affinity receptor complex binds to G-protein
  findings: []
- id: Reactome:R-HSA-167419
  title: The receptor:G-protein complex releases GDP
  findings: []
- id: Reactome:R-HSA-167427
  title: Opioid dissociates from MOR
  findings: []
- id: Reactome:R-HSA-167429
  title: The receptor:G-protein complex  binds GTP
  findings: []
- id: Reactome:R-HSA-265301
  title: Corticotropin cleavage from POMC
  findings: []
- id: Reactome:R-HSA-374298
  title: Opioid receptors bind opioid peptides
  findings: []
- id: Reactome:R-HSA-379044
  title: Liganded Gs-activating GPCR acts as a GEF for Gs
  findings: []
- id: Reactome:R-HSA-380073
  title: Liganded Gi-activating GPCR acts as a GEF for Gi
  findings: []
- id: Reactome:R-HSA-388596
  title: Melanocortin receptors bind melanocortins
  findings: []
- id: Reactome:R-HSA-388605
  title: POMC(138-176) binds MC2R
  findings: []
- id: Reactome:R-HSA-5603251
  title: Defective ACTH does not bind MCR2
  findings: []
- id: Reactome:R-HSA-6789615
  title: Expression of STAT3-upregulated extracellular proteins
  findings: []
- id: Reactome:R-HSA-744886
  title: The Ligand:GPCR:Gs complex dissociates
  findings: []
- id: Reactome:R-HSA-744887
  title: Liganded Gs-activating GPCRs bind inactive heterotrimeric Gs
  findings: []
- id: Reactome:R-HSA-749454
  title: The Ligand:GPCR:Gi complex dissociates
  findings: []
- id: Reactome:R-HSA-749456
  title: Liganded Gi-activating GPCRs bind inactive heterotrimeric G-protein Gi
  findings: []

POMC

Gene Description

Functional Isoforms

Existing Annotations Review

Core Functions

References

Deep Research

Falcon

Concise GO-annotation research report: human POMC (UniProt P01189)

Scope and GO-curation framing

1) Key concepts/definitions (GO-relevant)

2) Recent developments (prioritizing 2023–2024)

3) Current applications / real-world implementations (GO-relevant)

4) Authoritative expert synthesis and curation caveats

5) Curation-relevant functions/processes and quantitative evidence

Curation-focused mapping table

Recommended minimal GO annotation set (high-confidence, gene-level)

Citations

📚 Additional Documentation

Notes

POMC - Pro-opiomelanocortin Notes

Polyprotein Biology

Cleavage Products (from UniProt)

Tissue-Specific Processing

Antagonistic Functions Within Same Precursor

GO Annotation Challenges

Key References

Comparison to Alternative Splicing

Questions for GO Curation

Falcon deep research integration - 2026-05-12

📄 View Raw YAML