NESP55 (UniProt O95467) is a maternally expressed, chromogranin-like neuroendocrine secretory protein encoded by the complex GNAS locus. NESP55 is distinct from the canonical Gs-alpha products of the same locus; it is expressed in neuroendocrine/chromaffin lineages, processed into smaller peptides, and functions as a regulated secretory-granule precursor and marker of neuroendocrine differentiation. GNAS-locus imprinting defects involving the NESP55 region can cause endocrine disease, but those locus-level effects are distinct from direct NESP55 protein activity.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005576 extracellular region | IEA GO_REF:0000044 | ACCEPT | Summary: NESP55 is a secretory precursor, so extracellular-region annotation is plausible for processed/secreted material but is not the most specific functional compartment. Reason: NESP55 is a secretory precursor and the extracellular-region term is a valid broad location for processed/secreted material, although secretory granule is the more specific intracellular context. Supporting Evidence: PMID:10729789 NESP55 open reading frame encoded a hydrophilic protein file:human/GNAS/GNAS-uniprot.txt May be proteolytically processed to give rise to a number of active peptides. |
| GO:0030133 transport vesicle | IEA GO_REF:0000044 | MODIFY | Summary: Transport vesicle is too generic; the evidence for NESP55 points more specifically to neuroendocrine secretory granules/secretory pathway compartments. Reason: NESP55 is chromogranin-like and shows finely granular cytoplasmic staining in pituitary adenomas, fitting secretory granule biology better than a generic transport vesicle term. Proposed replacements: secretory granule Supporting Evidence: PMID:21584660 marker of the constitutive secretory pathway PMID:21584660 brown finely granular cytoplasmic staining |
| GO:0071107 response to parathyroid hormone | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: The PTH-response evidence reflects GNAS-locus imprinting and methylation effects rather than a direct NESP55 protein activity. Reason: PMID:22378814 shows that a deletion removing NESP55 affects imprinting and PHP1B, but this is a regulatory-locus effect. It should not be treated as a core biological process of the NESP55 protein product. Supporting Evidence: PMID:22378814 A novel deletion of 18,988 bp that removes NESP55 PMID:22378814 NESP55 is an additional imprinting |
| GO:0005886 plasma membrane | IDA GO_REF:0000052 | REMOVE | Summary: Plasma membrane is not supported as a normal NESP55 protein location by the reviewed literature; NESP55 is a secretory/granin-like product. Reason: The evidence points to secretory granule/cytoplasmic granular staining and secretion rather than a plasma-membrane resident role. Supporting Evidence: PMID:21584660 brown finely granular cytoplasmic staining |
| GO:0120162 positive regulation of cold-induced thermogenesis | ISS PMID:20374964 G(s)alpha deficiency in adipose tissue leads to a lean pheno... | REMOVE | Summary: Cold-induced thermogenesis is a Gs-alpha/adipose signaling phenotype and should not be assigned to the NESP55 protein product represented by O95467. Reason: PMID:20374964 studies Gs-alpha deficiency in adipose tissue. That is not evidence for NESP55 acting in cold-induced thermogenesis. Supporting Evidence: PMID:20374964 Gsalpha plays a critical role in adipogenesis in vivo |
| GO:0005737 cytoplasm | IDA PMID:20862257 Differentiation in neuroblastoma: diffusion-limited hypoxia ... | ACCEPT | Summary: Cytoplasmic localization is supported as broad localization for NESP55-containing secretory granules and cytoplasmic immunostaining. Reason: The term is broad but compatible with the granular cytoplasmic staining seen in pituitary adenomas and neuroendocrine/chromaffin cells. Supporting Evidence: PMID:21584660 brown finely granular cytoplasmic staining |
| GO:0005634 nucleus | IDA PMID:20862257 Differentiation in neuroblastoma: diffusion-limited hypoxia ... | REMOVE | Summary: Nuclear localization is not supported as a normal NESP55 location in the reviewed sources. Reason: The main evidence supports cytoplasmic secretory granule/neuroendocrine localization, not nuclear residence. Supporting Evidence: PMID:20862257 NESP55 is a highly specific marker for chromaffin cell types during development |
| GO:0040015 negative regulation of multicellular organism growth | ISS GO_REF:0000024 | REMOVE | Summary: Negative regulation of organism growth is a broad GNAS-locus/Gs-alpha phenotype and not a direct NESP55 function. Reason: The NESP55 product is a chromogranin-like secretory precursor; growth phenotypes from GNAS models should not be propagated to this product without product-specific evidence. Supporting Evidence: file:human/GNAS/GNAS-deep-research-falcon_artifacts/artifact-00.md NESP55 should not be conflated with canonical Gsalpha signaling protein products. |
| GO:0048471 perinuclear region of cytoplasm | IDA PMID:21584660 Immunohistochemical expression of neuroendocrine secretory p... | KEEP AS NON CORE | Summary: Perinuclear cytoplasmic localization is plausible for secretory-pathway/granular staining but is not the core location term. Reason: NESP55 is associated with neuroendocrine secretory compartments; perinuclear cytoplasm can be retained as broad localization evidence. Supporting Evidence: PMID:21584660 brown finely granular cytoplasmic staining |
| GO:0071107 response to parathyroid hormone | IMP PMID:22378814 A new deletion ablating NESP55 causes loss of maternal impri... | MARK AS OVER ANNOTATED | Summary: The PTH-response evidence reflects GNAS-locus imprinting and methylation effects rather than a direct NESP55 protein activity. Reason: PMID:22378814 shows that a deletion removing NESP55 affects imprinting and PHP1B, but this is a regulatory-locus effect. It should not be treated as a core biological process of the NESP55 protein product. Supporting Evidence: PMID:22378814 A novel deletion of 18,988 bp that removes NESP55 PMID:22378814 NESP55 is an additional imprinting |
| GO:0007565 female pregnancy | NAS PMID:10729789 Neuroendocrine secretory protein 55 (NESP55): alternative sp... | REMOVE | Summary: Female pregnancy is not supported as a direct process for the NESP55 protein product. Reason: The cited NESP55 cloning/processing paper describes a neuroendocrine secretory protein and tissue-specific splicing, not a direct pregnancy function. Supporting Evidence: PMID:10729789 NESP55 open reading frame encoded a hydrophilic protein |
| GO:0009306 protein secretion | NAS PMID:10729789 Neuroendocrine secretory protein 55 (NESP55): alternative sp... | MARK AS OVER ANNOTATED | Summary: NESP55 is a secretory protein/cargo, but the available evidence does not show that it actively mediates protein secretion. Reason: A secreted or processed cargo should not automatically receive a protein secretion process annotation as if it controls secretion machinery. Supporting Evidence: PMID:10729789 posttranslational processing of a maternally expressed protein PMID:21584660 marker of the constitutive secretory pathway |
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Download this section (compressed HTML)Q: Which processed NESP55 peptides have reproducible physiological activity in human neuroendocrine tissues?
Q: Can GNAS annotations be separated more cleanly by product so that NESP55-specific annotations are not mixed with Gs-alpha signaling phenotypes?
Experiment: Use isoform/product-specific antibodies or tagged endogenous NESP55 to define secretory granule localization and secretion dynamics in neuroendocrine cells.
Hypothesis: NESP55 will localize to regulated secretory compartments and be secreted or processed in neuroendocrine cells.
Experiment: Profile processed NESP55 peptides by targeted mass spectrometry in pituitary, adrenal medulla, and neuroendocrine tumor samples.
Hypothesis: Product-specific peptide profiling will identify which NESP55-derived peptides are reproducibly produced in relevant tissues.
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