Archain 1 (ARCN1) encodes the delta subunit of the coat protein I (COPI) coatomer complex, a heptameric protein assembly essential for retrograde vesicle-mediated transport from the Golgi apparatus to the endoplasmic reticulum and for intra-Golgi trafficking. As Ξ΄-COP, ARCN1 functions as a structural component of the F-subcomplex (adaptor-like complex) of coatomer, participating in cargo recognition of proteins bearing dilysine motifs and HDEL-type ER retrieval signals. The protein localizes to the Golgi membrane, ER membrane, COPI-coated vesicles, and cytosol, where it cycles between membrane-bound and cytoplasmic pools depending on ARF1 GTPase activity. ARCN1 is highly evolutionarily conserved across eukaryotes and is essential for cell viability; heterozygous loss-of-function mutations cause a recognizable developmental syndrome with micrognathia, short stature, and developmental delay.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0051645 Golgi localization | IBA GO_REF:0000033 | ACCEPT | Summary: IBA annotation for Golgi localization based on phylogenetic inference. ARCN1 as a COPI coatomer subunit is involved in maintaining Golgi organization through retrograde transport and cisternal maturation mechanisms. Reason: This annotation accurately reflects a core function of ARCN1. The deep research indicates that "ARCN1 participates in retrograde transport within the Golgi stack itself, a process critical for driving cisternal maturation and maintaining proper Golgi organization" and that "disruption of COPI function results in Golgi fragmentation and dispersal into punctate cytoplasmic structures." The IBA evidence is well-supported by the protein's essential role in COPI-mediated recycling that maintains Golgi structural integrity. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The participation of ARCN1 in maintaining Golgi morphology and structural integrity represents another important aspect of its cellular functions. The Golgi apparatus adopts a characteristic stacked cisternae organization in most mammalian cells, maintained through precise balance between anterograde cargo flux and retrograde recycling of membrane components. Disruption of COPI function, whether through depleting ARCN1 or other COPI subunits, results in Golgi fragmentation and dispersal into punctate cytoplasmic structures, indicating that COPI-dependent recycling actively maintains Golgi architectural organization. file:human/ARCN1/ARCN1-deep-research-openai.md See deep research file for comprehensive analysis |
| GO:0006888 endoplasmic reticulum to Golgi vesicle-mediated transport | IBA GO_REF:0000033 | MODIFY | Summary: IBA annotation for ER to Golgi transport. While ARCN1/COPI primarily mediates retrograde (Golgi to ER) transport, it does participate indirectly in maintaining the forward ER-to-Golgi pathway through recycling mechanisms. Reason: This annotation is partially correct but misleading regarding the primary directionality of ARCN1 function. ARCN1 is a component of COPI, which primarily mediates retrograde transport FROM Golgi TO ER, not the anterograde direction implied by this term. While COPI function is essential for maintaining ER-Golgi cycling and indirectly supports anterograde transport by recycling ER-escaped proteins and Golgi enzymes, the primary role is retrograde. The more accurate annotation would be the retrograde process GO:0006890, which is also present in the annotation set. Proposed replacements: retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The most thoroughly characterized function of ARCN1, operating as the Ξ΄-COP subunit of coatomer, is mediation of COPI-dependent retrograde transport of proteins and lipids from post-ER compartments back to the endoplasmic reticulum. |
| GO:0006890 retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum | IBA GO_REF:0000033 | ACCEPT | Summary: IBA annotation for retrograde Golgi-to-ER transport. This represents the primary and most thoroughly characterized function of ARCN1 as Ξ΄-COP within the COPI coatomer complex. Reason: This annotation accurately captures the core biological process function of ARCN1. As stated in the deep research, "The most thoroughly characterized function of ARCN1, operating as the Ξ΄-COP subunit of coatomer, is mediation of COPI-dependent retrograde transport of proteins and lipids from post-ER compartments back to the endoplasmic reticulum." This is the primary function of COPI and represents ARCN1's essential role in maintaining ER protein homeostasis by retrieving ER-resident proteins that escape to the Golgi. The IBA evidence based on phylogenetic conservation is appropriate for this fundamental COPI function. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The most thoroughly characterized function of ARCN1, operating as the Ξ΄-COP subunit of coatomer, is mediation of COPI-dependent retrograde transport of proteins and lipids from post-ER compartments back to the endoplasmic reticulum. This transport process is essential for maintaining the ER pool of resident proteins, including molecular chaperones and quality control components, that continuously escape the ER despite the presence of ER retention signals. |
| GO:0030126 COPI vesicle coat | IBA GO_REF:0000033 | ACCEPT | Summary: IBA annotation for COPI vesicle coat localization. ARCN1 encodes the delta subunit of the heptameric COPI coatomer complex and is an essential structural component of the COPI coat. Reason: This is a core cellular component annotation that precisely describes ARCN1's molecular identity and localization. The UniProt record states "Component of the coatomer, a cytosolic protein complex" and the deep research confirms "ARCN1 encodes archain 1, a critical component of the coat protein I (COPI) complex, also known as the delta subunit of coatomer (Ξ΄-COP)." ARCN1 is specifically part of the F-subcomplex of coatomer and is essential for coat assembly and vesicle formation. This annotation represents the protein's primary cellular component identity. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The ARCN1 gene, located on human chromosome 11q23.3, encodes archain 1, a critical component of the coat protein I (COPI) complex, also known as the delta subunit of coatomer (Ξ΄-COP). The primary function of ARCN1 is to serve as a structural and functional component of the COPI coatomer complex, a heptameric protein assembly. file:human/ARCN1/ARCN1-uniprot.txt Component of the coatomer, a cytosolic protein complex that binds to dilysine motifs and reversibly associates with Golgi non-clathrin-coated vesicles |
| GO:0000139 Golgi membrane | IEA GO_REF:0000044 | ACCEPT | Summary: IEA annotation from UniProtKB subcellular location mapping. ARCN1 localizes to Golgi membrane as part of the COPI coat during vesicle formation and cargo sorting. Reason: This annotation is correct and well-supported. The UniProt subcellular location states "Golgi apparatus membrane; Peripheral membrane protein; Cytoplasmic side" and the deep research confirms "ARCN1 exhibits a characteristic intracellular distribution reflecting its role in early secretory pathway transport. In cultured mammalian cells, ARCN1 demonstrates prominent colocalization with markers of the Golgi apparatus, accumulating particularly at the cis-Golgi compartment." The protein associates with Golgi membranes as a peripheral membrane protein during COPI coat assembly and vesicle budding. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md In cultured mammalian cells, ARCN1 demonstrates prominent colocalization with markers of the Golgi apparatus, accumulating particularly at the cis-Golgi compartment where retrograde transport from the Golgi to the ER predominates. file:human/ARCN1/ARCN1-uniprot.txt Golgi apparatus membrane; Peripheral membrane protein; Cytoplasmic side |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | MODIFY | Summary: IEA annotation from UniProtKB subcellular location. While technically correct, this term is too general for ARCN1's specific localization pattern. Reason: This annotation is overly broad and not informative. ARCN1 does localize to cytoplasm but more specifically to cytosol as part of the soluble coatomer complex pool, and to specific membrane-associated compartments. The term GO:0005829 (cytosol) is more accurate and is already present in multiple annotations. The cytoplasm annotation adds little value when more specific localizations (Golgi membrane, ER membrane, COPI vesicles, cytosol) are available. Proposed replacements: cytosol Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The recruitment of ARCN1 to membrane compartments occurs primarily through its integration into the pre-assembled heptameric coatomer complex in the cytosol. The coatomer complex circulates in the soluble cytoplasmic pool, maintained in an inactive conformation through intramolecular interactions that prevent premature coat assembly on membranes. |
| GO:0006890 retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum | IEA GO_REF:0000002 | ACCEPT | Summary: IEA annotation from InterPro domain mapping. This is a duplicate of the IBA annotation with the same GO term. Both correctly identify ARCN1's core function. Reason: This annotation is correct and represents ARCN1's primary biological process function. Although it duplicates the IBA annotation with GO:0006890, having multiple lines of evidence (IBA and IEA from InterPro) is acceptable and reinforces the annotation. The InterPro domain IPR027059 (Coatomer delta subunit) correctly maps to retrograde transport function. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The most thoroughly characterized function of ARCN1, operating as the Ξ΄-COP subunit of coatomer, is mediation of COPI-dependent retrograde transport of proteins and lipids from post-ER compartments back to the endoplasmic reticulum. |
| GO:0015031 protein transport | IEA GO_REF:0000043 | ACCEPT | Summary: IEA annotation from UniProtKB keyword mapping. This is an accurate but overly general term for ARCN1's function. Reason: This annotation is technically correct as ARCN1 does participate in protein transport, but it is very broad and less informative than the more specific terms like GO:0006890 (retrograde vesicle-mediated transport) or GO:0006886 (intracellular protein transport). However, such general parent terms are acceptable in GO as they provide hierarchical context. The annotation is valid but the more specific child terms better capture ARCN1's actual function. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The primary function of ARCN1 is to serve as a structural and functional component of the COPI coatomer complex, a heptameric protein assembly that mediates retrograde transport of proteins and lipids from the Golgi apparatus back to the endoplasmic reticulum (ER), as well as participating in intra-Golgi trafficking. |
| GO:0016192 vesicle-mediated transport | IEA GO_REF:0000043 | ACCEPT | Summary: IEA annotation from UniProtKB keyword mapping. This is an accurate but very general parent term for ARCN1's vesicular transport functions. Reason: This is a correct high-level annotation that accurately describes ARCN1's role in vesicular transport. While very general, it serves as an appropriate parent term in the GO hierarchy. The more specific child terms (retrograde transport, COPI vesicle-mediated processes) provide the mechanistic detail, while this term captures the broad functional category. This is standard GO annotation practice. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The primary function of ARCN1 is to serve as a structural and functional component of the COPI coatomer complex, a heptameric protein assembly that mediates retrograde transport of proteins and lipids from the Golgi apparatus back to the endoplasmic reticulum (ER), as well as participating in intra-Golgi trafficking. |
| GO:0030126 COPI vesicle coat | IEA GO_REF:0000002 | ACCEPT | Summary: IEA annotation from InterPro domain mapping. This duplicates the IBA annotation for the same term but provides independent supporting evidence from domain architecture. Reason: This annotation is correct and represents ARCN1's core cellular component identity. The InterPro domain IPR027059 (Coatomer delta subunit) correctly maps to COPI vesicle coat. While this duplicates the IBA annotation, having multiple evidence codes strengthens the annotation confidence. ARCN1 is definitively a core structural component of the COPI coat. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 encodes archain 1, a critical component of the coat protein I (COPI) complex, also known as the delta subunit of coatomer (Ξ΄-COP). |
| GO:0030663 COPI-coated vesicle membrane | IEA GO_REF:0000044 | ACCEPT | Summary: IEA annotation from UniProtKB subcellular location. ARCN1 associates with COPI-coated vesicle membranes as a peripheral membrane protein on the cytoplasmic face. Reason: This annotation is accurate and well-supported. The UniProt record specifies "Cytoplasmic vesicle, COPI-coated vesicle membrane; Peripheral membrane protein; Cytoplasmic side." ARCN1 associates with vesicle membranes during the budding and transport phases of COPI vesicle-mediated trafficking. This is a more specific and informative localization than the general COPI vesicle coat (GO:0030126), as it specifies the membrane component. Supporting Evidence: file:human/ARCN1/ARCN1-uniprot.txt Cytoplasmic vesicle, COPI-coated vesicle membrane; Peripheral membrane protein; Cytoplasmic side |
| GO:0031410 cytoplasmic vesicle | IEA GO_REF:0000120 | ACCEPT | Summary: IEA annotation from automated combined methods. This is a correct but overly general term compared to the more specific COPI vesicle annotations. Reason: This annotation is technically correct as ARCN1 does localize to cytoplasmic vesicles (specifically COPI-coated vesicles), but it is less informative than the more specific terms GO:0030126 (COPI vesicle coat) and GO:0030663 (COPI-coated vesicle membrane). However, as a parent term in the GO hierarchy, it provides appropriate broader context and is acceptable to retain alongside the more specific terms. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md Beyond these major localization sites, ARCN1 exhibits a punctate staining pattern throughout the cytoplasm, suggesting presence on multiple vesicular structures |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | REMOVE | Summary: IPI annotation from large-scale protein interactome study. Detects interactions with COPB1 and LBHD1, though only the COPB1 interaction represents a core COPI complex function. Reason: The generic "protein binding" term is explicitly discouraged per curation guidelines as it is uninformative. While ARCN1 does bind to other proteins (particularly Ξ²-COP/COPB1 as part of the coatomer complex), this MF annotation provides no functional insight beyond stating the obvious. ARCN1's molecular function is better captured as a structural constituent of the COPI complex rather than generic protein binding. The structural and cargo recognition functions are already captured by the CC (COPI vesicle coat) and BP (retrograde transport) annotations. This large-scale interactome study (PMID:32296183) detected interactions but does not provide mechanistic functional data warranting a specific MF term beyond the protein's known coatomer assembly role. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The interaction between Ξ΄-COP and Ξ²-COP represents a particularly strong association, mediated through the N-terminal region of Ξ²-COP and multiple contact points on Ξ΄-COP that facilitate stable assembly of this functional unit. PMID:32296183 Apr 8. A reference map of the human binary protein interactome. |
| GO:0005515 protein binding | IPI PMID:32814053 Interactome Mapping Provides a Network of Neurodegenerative ... | REMOVE | Summary: IPI annotation from neurodegenerative disease interactome study detecting interaction with huntingtin (HTT). This is likely a non-core peripheral interaction. Reason: As with the previous protein binding annotation, this generic term is uninformative and discouraged. PMID:32814053 studied protein aggregation in neurodegenerative diseases and identified ARCN1-HTT interaction, but this does not provide functional mechanistic data about ARCN1's molecular function. The interaction may be real but peripheral to ARCN1's core function as a COPI coatomer subunit. Without specific evidence that this interaction is functionally important for ARCN1's role in vesicular transport or that it represents a distinct molecular function beyond coatomer assembly, this annotation should be removed. Supporting Evidence: PMID:32814053 Interactome Mapping Provides a Network of Neurodegenerative Disease Proteins and Uncovers Widespread Protein Aggregation |
| GO:0005783 endoplasmic reticulum | IEA GO_REF:0000107 | MODIFY | Summary: IEA annotation from Ensembl orthology projection (mouse to human). ARCN1 does localize to ER during retrograde transport and cargo retrieval operations. Reason: This annotation is correct but not specific enough. ARCN1 does localize to the ER but more specifically to the ER membrane (GO:0005789), which is already annotated from Reactome. The general ER term is less informative than the more specific ER membrane localization. The protein associates with ER membranes during the targeting and fusion of retrograde COPI vesicles carrying retrieved cargo back to the ER. Proposed replacements: endoplasmic reticulum membrane Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The protein also shows substantial localization to the ER membrane system, indicating its participation in recognition and recruitment of retrograded cargo in post-Golgi compartments for retrieval. |
| GO:0005794 Golgi apparatus | IEA GO_REF:0000120 | MODIFY | Summary: IEA annotation from automated methods. ARCN1 localizes to Golgi apparatus, though the more specific Golgi membrane term is more accurate. Reason: This annotation is correct but less specific than GO:0000139 (Golgi membrane), which is already well-supported by multiple evidence codes. ARCN1 associates with Golgi as a peripheral membrane protein, not as a luminal or matrix component. The Golgi membrane term better captures the actual localization. Proposed replacements: Golgi membrane Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md In cultured mammalian cells, ARCN1 demonstrates prominent colocalization with markers of the Golgi apparatus, accumulating particularly at the cis-Golgi compartment where retrograde transport from the Golgi to the ER predominates. |
| GO:0008344 adult locomotory behavior | IEA GO_REF:0000107 | KEEP AS NON CORE | Summary: IEA annotation from mouse ortholog projection. This represents a pleiotropic developmental phenotype in mouse knockouts, not a core function of ARCN1. Reason: This annotation is based on mouse phenotype projection and represents a pleiotropic effect rather than ARCN1's core molecular or cellular function. ARCN1 mutations cause broad developmental defects including neurological abnormalities, and locomotory defects in mice likely reflect the general requirement for COPI-mediated transport in neuronal development and function rather than a specific role in locomotory behavior per se. This is a non-core annotation that reflects the consequences of disrupting an essential housekeeping protein during development. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The clinical phenotype of ARCN1-related syndrome encompasses a recognizable constellation of developmental abnormalities affecting skeletal, craniofacial, and neurological systems. |
| GO:0021691 cerebellar Purkinje cell layer maturation | IEA GO_REF:0000107 | KEEP AS NON CORE | Summary: IEA annotation from mouse ortholog projection. This reflects a developmental phenotype rather than ARCN1's direct molecular function. Reason: This annotation is based on mouse phenotype data and represents a pleiotropic developmental consequence of ARCN1 deficiency rather than a core function. ARCN1 is required for proper secretory pathway function in all cells, including developing Purkinje cells. Defects in these cells when ARCN1 is disrupted reflect the general cellular requirement for COPI transport during development rather than a specific role in cerebellar maturation. This is a non-core peripheral annotation. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The protein atlas database indicates substantial protein expression in neural tissues including hippocampal formation, cerebral cortex, cerebellum, and spinal cord, correlating with the neurodevelopmental phenotypes observed in ARCN1-related syndrome. |
| GO:0030137 COPI-coated vesicle | IEA GO_REF:0000107 | ACCEPT | Summary: IEA annotation from mouse ortholog projection. ARCN1 is a core component of COPI-coated vesicles. Reason: This annotation is correct and represents a core cellular component localization of ARCN1. The term GO:0030137 (COPI-coated vesicle) is closely related to GO:0030126 (COPI vesicle coat) and GO:0030663 (COPI-coated vesicle membrane) which are already annotated. This term appropriately captures ARCN1's presence on the complete COPI vesicle structure. While there is some redundancy with other COPI component terms, the different aspects (coat vs vesicle vs membrane) provide complementary information about the protein's localization. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The protein exhibits a distinctive localization pattern, distributing across the ER and Golgi compartments while also being present in vesicular structures throughout the cytoplasm, reflecting its role in maintaining the dynamic equilibrium of protein trafficking between these compartments. |
| GO:0043473 pigmentation | IEA GO_REF:0000107 | KEEP AS NON CORE | Summary: IEA annotation from mouse ortholog projection indicating role in pigmentation. This is a pleiotropic developmental phenotype rather than a core ARCN1 function. Reason: This annotation reflects a mouse phenotype where ARCN1 deficiency affects pigmentation, likely due to defects in melanosome transport or melanocyte function. This is an indirect, pleiotropic consequence of disrupting the essential COPI transport system rather than a direct, specific function of ARCN1 in pigmentation. COPI is required for proper secretory pathway function in melanocytes as in all cells. This should be retained as a non-core annotation documenting the phenotypic consequences but not representing ARCN1's primary molecular or cellular role. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md [Mouse ortholog phenotype data suggests pigmentation defects when ARCN1 is disrupted, consistent with general requirement for secretory pathway function] |
| GO:0048193 Golgi vesicle transport | IEA GO_REF:0000107 | ACCEPT | Summary: IEA annotation from mouse ortholog projection. This is an accurate general term for ARCN1's role in COPI-mediated Golgi transport processes. Reason: This annotation correctly captures ARCN1's role in Golgi vesicle transport, encompassing both retrograde transport to the ER and intra-Golgi recycling. This is a valid parent term that appropriately describes ARCN1's biological process function. The more specific child terms (GO:0006890 retrograde transport, GO:0051645 Golgi localization) provide mechanistic detail, while this term captures the broader functional category of Golgi vesicular trafficking. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md In addition to ER-Golgi transport, ARCN1 participates in retrograde transport within the Golgi stack itself, a process critical for driving cisternal maturation and maintaining proper Golgi organization. |
| GO:0000139 Golgi membrane | NAS PMID:33378371 A genetic screen in Drosophila reveals an unexpected role fo... | ACCEPT | Summary: NAS annotation from ComplexPortal database entry describing the COPI complex. This correctly identifies ARCN1's localization to Golgi membrane as part of the coatomer complex. Reason: This annotation is correct and well-supported. The NAS (Non-traceable Author Statement) evidence comes from ComplexPortal's curated description of the COPI complex (PMID:33378371), which documents ARCN1 as a component localizing to Golgi membrane. This is consistent with all other evidence and represents a core localization of ARCN1 during COPI coat assembly and vesicle formation. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md In cultured mammalian cells, ARCN1 demonstrates prominent colocalization with markers of the Golgi apparatus, accumulating particularly at the cis-Golgi compartment where retrograde transport from the Golgi to the ER predominates. PMID:33378371 eCollection 2020 Dec. |
| GO:0006890 retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum | NAS PMID:33378371 A genetic screen in Drosophila reveals an unexpected role fo... | ACCEPT | Summary: NAS annotation from ComplexPortal describing COPI complex function. This correctly identifies the primary biological process function of ARCN1. Reason: This annotation accurately captures ARCN1's core function. The ComplexPortal curation (PMID:33378371) describes the COPI complex's role in retrograde transport, which is ARCN1's most thoroughly characterized function. This represents a third independent line of evidence (along with IBA and IEA) supporting this critical annotation, strengthening confidence in this core functional assignment. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The most thoroughly characterized function of ARCN1, operating as the Ξ΄-COP subunit of coatomer, is mediation of COPI-dependent retrograde transport of proteins and lipids from post-ER compartments back to the endoplasmic reticulum. PMID:33378371 eCollection 2020 Dec. |
| GO:0030126 COPI vesicle coat | NAS PMID:33378371 A genetic screen in Drosophila reveals an unexpected role fo... | ACCEPT | Summary: NAS annotation from ComplexPortal documenting ARCN1 as a structural component of the COPI vesicle coat complex. Reason: This annotation is correct and represents ARCN1's fundamental cellular component identity. The ComplexPortal entry for COPI complex (PMID:33378371) provides expert-curated information about the complex composition and localization. This is a third independent line of evidence (IBA, IEA, NAS) confirming ARCN1's role as a COPI coat component, which is its defining molecular characteristic. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 encodes archain 1, a critical component of the coat protein I (COPI) complex, also known as the delta subunit of coatomer (Ξ΄-COP). PMID:33378371 eCollection 2020 Dec. |
| GO:0005789 endoplasmic reticulum membrane | TAS Reactome:R-HSA-6811423 | ACCEPT | Summary: TAS annotation from Reactome pathway "Retrograde vesicle is tethered at the ER by the NRZ complex and t-SNAREs". ARCN1 associates with ER membrane during retrograde COPI vesicle targeting and fusion. Reason: This annotation is correct. ARCN1 as part of COPI-coated vesicles associates with ER membrane during the targeting and fusion phase of retrograde transport. The Reactome pathway documentation describes ARCN1's role in this process. This is a specific and accurate localization annotation. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The protein also shows substantial localization to the ER membrane system, indicating its participation in recognition and recruitment of retrograded cargo in post-Golgi compartments for retrieval. |
| GO:0005789 endoplasmic reticulum membrane | TAS Reactome:R-HSA-6811427 | ACCEPT | Summary: TAS annotation from Reactome pathway "COPI vesicle uncoating at the ER". ARCN1 is present on COPI vesicles that undergo uncoating at the ER membrane. Reason: This annotation correctly identifies ARCN1's localization to ER membrane during the uncoating phase of COPI vesicles. After retrograde vesicles reach the ER, the coat including ARCN1 dissociates from the membrane. This Reactome pathway documents this process. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The dynamic nature of coatomer assembly and disassembly, driven by cycles of Arf1 GTP hydrolysis, creates a continuous cycle in which ARCN1-containing coatomer complexes are recruited to membranes, assemble into coat lattices, facilitate cargo packaging, and subsequently undergo uncoating upon GTPase activation. |
| GO:0000139 Golgi membrane | TAS Reactome:R-HSA-6809006 | ACCEPT | Summary: TAS annotation from Reactome pathway "Vesicle is tethered through binding GOLGA2 GORASP1, GOLGB1 and the COG complex". Documents ARCN1 on vesicles tethering to Golgi. Reason: This annotation is correct. ARCN1 as part of COPI vesicles participates in vesicle tethering events at Golgi membranes. The Reactome pathway describes intra-Golgi transport where COPI vesicles tether to acceptor membranes. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md In cultured mammalian cells, ARCN1 demonstrates prominent colocalization with markers of the Golgi apparatus, accumulating particularly at the cis-Golgi compartment. |
| GO:0000139 Golgi membrane | TAS Reactome:R-HSA-6809010 | ACCEPT | Summary: TAS annotation from Reactome pathway "COPI vesicle uncoating". Documents ARCN1 during vesicle uncoating at Golgi membranes. Reason: This annotation correctly identifies ARCN1 at Golgi membrane during COPI vesicle uncoating. After intra-Golgi transport vesicles reach their target cisterna, the COPI coat including ARCN1 disassembles. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The dynamic nature of coatomer assembly and disassembly creates a continuous cycle in which ARCN1-containing coatomer complexes undergo uncoating upon GTPase activation. |
| GO:0000139 Golgi membrane | TAS Reactome:R-HSA-6809011 | ACCEPT | Summary: TAS annotation from Reactome pathway "cis-Golgi t-SNAREs bind YKT6 on tethered vesicle". Documents ARCN1 on vesicles engaging with Golgi SNARE machinery. Reason: This annotation is correct. ARCN1 is present on COPI vesicles that engage with target membrane SNAREs during fusion at the Golgi. This Reactome pathway describes the SNARE-mediated fusion events. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 participates in transport of SNARE proteins between ER and Golgi compartments and within the secretory pathway. |
| GO:0030133 transport vesicle | TAS Reactome:R-HSA-6807877 | ACCEPT | Summary: TAS annotation from Reactome pathway "ARFGAPs stimulate ARF GTPase activity". ARCN1 is on transport vesicles during ARF-GAP mediated vesicle scission. Reason: This annotation is correct. ARCN1 localizes to transport vesicles (specifically COPI vesicles) during all phases of vesicle formation and transport. This term is more general than the specific COPI vesicle terms but is accurate. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The protein exhibits a distinctive localization pattern, distributing across the ER and Golgi compartments while also being present in vesicular structures throughout the cytoplasm. |
| GO:0030133 transport vesicle | TAS Reactome:R-HSA-6809003 | ACCEPT | Summary: TAS annotation from Reactome pathway "ERGIC-to-Golgi vesicles bind dynein dynactin". ARCN1 on transport vesicles engaging motor proteins. Reason: This annotation correctly identifies ARCN1 on transport vesicles. COPI vesicles engage with microtubule motor proteins for transport between compartments. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 exhibits a punctate staining pattern throughout the cytoplasm, suggesting presence on multiple vesicular structures. |
| GO:0030133 transport vesicle | TAS Reactome:R-HSA-6809006 | ACCEPT | Summary: TAS annotation from Reactome pathway documenting ARCN1 on transport vesicles during tethering. Reason: Correct annotation. ARCN1 is present on COPI transport vesicles during tethering to target membranes. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 as part of COPI-coated vesicles participates in vesicle tethering events. |
| GO:0030133 transport vesicle | TAS Reactome:R-HSA-6811418 | ACCEPT | Summary: TAS annotation from Reactome pathway "ARFGAPs stimulate ARF GTPase activity at the Golgi membrane". ARCN1 on vesicles during Golgi-based budding. Reason: Correct annotation documenting ARCN1's presence on transport vesicles formed at Golgi membranes. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 participates in retrograde transport within the Golgi stack itself. |
| GO:0030133 transport vesicle | TAS Reactome:R-HSA-6811423 | ACCEPT | Summary: TAS annotation from Reactome pathway documenting ARCN1 on retrograde transport vesicles targeting the ER. Reason: Correct annotation. ARCN1 is present on COPI transport vesicles during retrograde transport to ER. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 mediates COPI-dependent retrograde transport of proteins and lipids from post-ER compartments back to the endoplasmic reticulum. |
| GO:0030133 transport vesicle | TAS Reactome:R-HSA-6811426 | ACCEPT | Summary: TAS annotation from Reactome pathway "Retrograde COPI vesicles bind kinesin and microtubules". ARCN1 on vesicles engaging motor proteins. Reason: Correct annotation. COPI vesicles containing ARCN1 engage with kinesin motors and microtubules for transport. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md COPI vesicles engage with microtubule motor proteins for transport between compartments. |
| GO:0016020 membrane | HDA PMID:19946888 Defining the membrane proteome of NK cells. | MODIFY | Summary: HDA annotation from high-throughput study of NK cell membrane proteome. This is overly general and less informative than specific membrane terms. Reason: This annotation is too general. While technically correct that ARCN1 associates with membranes (as a peripheral membrane protein on Golgi and ER membranes and COPI vesicles), this high-level term provides little information. The more specific annotations (Golgi membrane, ER membrane, COPI-coated vesicle membrane) are already present and more informative. PMID:19946888 was a large-scale membrane proteomics study that detected ARCN1 but does not provide specific localization data beyond "membrane." Proposed replacements: Golgi membrane endoplasmic reticulum membrane Supporting Evidence: PMID:19946888 Isolated membranes were treated with reagents that have been reported to remove peripheral membrane proteins |
| GO:0003723 RNA binding | HDA PMID:22658674 Insights into RNA biology from an atlas of mammalian mRNA-bi... | UNDECIDED | Summary: HDA annotation from mRNA-binding protein atlas study. This identifies a potential RNA binding activity of ARCN1 or the coatomer complex. Reason: This annotation requires more investigation. PMID:22658674 is a large-scale study identifying mRNA-binding proteins, and detected ARCN1 in RNA-binding fractions. The deep research mentions that "Ξ±-COP subunit that interacts closely with Ξ΄-COP within coatomer, binds to RNA binding proteins including nucleolin" and suggests "potential roles for COPI in intracellular RNA trafficking." However, it is unclear whether ARCN1 itself directly binds RNA, whether this is mediated through associated proteins, or whether this represents a non-specific association. Without mechanistic data demonstrating direct RNA binding by ARCN1 or showing that this activity is functionally important for ARCN1's role in vesicular transport, this annotation status is uncertain. More specific functional studies would be needed to confirm this as a bona fide molecular function of ARCN1. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md Recent discoveries have revealed that ARCN1, specifically the Ξ±-COP subunit that interacts closely with Ξ΄-COP within coatomer, binds to RNA binding proteins including nucleolin through C-terminal dilysine motifs. These interactions suggest potential roles for COPI in intracellular RNA trafficking, a function previously less well-characterized than the protein trafficking roles. PMID:22658674 Insights into RNA biology from an atlas of mammalian mRNA-binding proteins |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6807872 | ACCEPT | Summary: TAS annotation from Reactome pathway "Active ARF recruits coatomer". ARCN1 exists in cytosol as part of the soluble coatomer complex pool before membrane recruitment. Reason: This annotation is correct. ARCN1 is present in the cytosol as part of the pre-assembled heptameric coatomer complex. The Reactome pathway describes how cytosolic coatomer is recruited to membranes by active ARF1-GTP. This represents a key aspect of ARCN1's cellular localization and functional cycle. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The recruitment of ARCN1 to membrane compartments occurs primarily through its integration into the pre-assembled heptameric coatomer complex in the cytosol. The coatomer complex circulates in the soluble cytoplasmic pool, maintained in an inactive conformation through intramolecular interactions that prevent premature coat assembly on membranes. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6807875 | ACCEPT | Summary: TAS annotation from Reactome pathway documenting ARCN1 in cytosol during coatomer complex formation and cargo binding. Reason: Correct annotation. ARCN1 is present in cytosol as part of the coatomer complex before and during the cargo binding process. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The coatomer complex circulates in the soluble cytoplasmic pool. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6807877 | ACCEPT | Summary: TAS annotation from Reactome documenting ARCN1 in cytosol during vesicle budding and ARF-GAP activity. Reason: Correct annotation. ARCN1 returns to cytosol after coat disassembly. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1-containing coatomer complexes undergo uncoating and return to the cytosolic pool. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6809010 | ACCEPT | Summary: TAS annotation from Reactome pathway "COPI vesicle uncoating". ARCN1 returns to cytosol after vesicle coat disassembly. Reason: Correct annotation. After COPI vesicles undergo uncoating, ARCN1 as part of the disassembled coatomer returns to the cytosolic pool for another cycle of membrane recruitment. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The dynamic nature of coatomer assembly and disassembly creates a continuous cycle in which ARCN1-containing coatomer complexes undergo uncoating and return to the cytosolic pool. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6811412 | ACCEPT | Summary: TAS annotation from Reactome pathway "Active ARF recruits coatomer to the Golgi". Documents cytosolic coatomer containing ARCN1 before Golgi recruitment. Reason: Correct annotation. ARCN1 exists in cytosol before recruitment to Golgi membranes. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The recruitment of ARCN1 to membrane compartments occurs primarily through its integration into the pre-assembled heptameric coatomer complex in the cytosol. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6811417 | ACCEPT | Summary: TAS annotation from Reactome documenting ARCN1 in cytosol during Golgi-based COPI vesicle formation. Reason: Correct annotation documenting ARCN1's cytosolic localization during the COPI vesicle formation cycle. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The coatomer complex circulates in the soluble cytoplasmic pool. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6811418 | ACCEPT | Summary: TAS annotation from Reactome documenting ARCN1 in cytosol during ARF-GAP mediated vesicle scission at Golgi. Reason: Correct annotation. ARCN1 cycles between membrane-bound and cytosolic pools. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md ARCN1 cycles between membrane-bound and cytoplasmic pools depending on ARF1 GTPase activity. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-6811427 | ACCEPT | Summary: TAS annotation from Reactome pathway "COPI vesicle uncoating at the ER". ARCN1 returns to cytosol after ER-targeted vesicles undergo coat disassembly. Reason: Correct annotation. After retrograde COPI vesicles reach the ER and undergo uncoating, ARCN1 as part of the disassembled coatomer returns to the cytosolic pool. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The dynamic nature of coatomer assembly and disassembly creates a continuous cycle in which ARCN1-containing coatomer complexes undergo uncoating and return to the cytosolic pool. |
| GO:0030126 COPI vesicle coat | ISS GO_REF:0000024 | ACCEPT | Summary: ISS annotation based on sequence similarity to experimentally characterized ortholog (likely yeast Ret2). ARCN1 is a core COPI vesicle coat component. Reason: This annotation is correct. ISS (Inferred from Sequence or Structural Similarity) evidence from orthologs like yeast Ret2 (the S. cerevisiae ortholog of ARCN1) supports this annotation. The COPI complex and its delta subunit are highly conserved across eukaryotes. This represents a fourth independent line of evidence (IBA, IEA, NAS, ISS) for ARCN1's fundamental role as a COPI coat component, which is well-justified given the extreme evolutionary conservation of this function. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The remarkable conservation of ARCN1 sequence and function across such divergent organisms strongly suggests that the COPI system, and particularly Ξ΄-COP's role within it, performs fundamental functions essential for eukaryotic cell viability. The conservation extends beyond simple sequence identity to encompass functional equivalence, as yeast Ret2 can substitute for mammalian ARCN1 in complementation experiments. |
| GO:0006886 intracellular protein transport | TAS PMID:7782067 The human archain gene, ARCN1, has highly conserved homologs... | ACCEPT | Summary: TAS annotation from the original ARCN1 gene characterization paper. This is an accurate general term for ARCN1's biological process function. Reason: This annotation is correct and comes from the seminal paper characterizing the human ARCN1 gene (PMID:7782067). The abstract states ARCN1 has "a possible role in vesicle structure or trafficking" based on its relationship to clathrin-associated proteins. While this is a general parent term, it accurately captures ARCN1's role in intracellular protein transport. The more specific child terms (retrograde transport, ER-Golgi transport) provide mechanistic detail, while this appropriately describes the broad functional category. This is one of the earliest experimental characterizations linking ARCN1 to protein transport. Supporting Evidence: PMID:7782067 A more distant relationship to the group of clathrin-associated proteins suggests a possible role in vesicle structure or trafficking. file:human/ARCN1/ARCN1-deep-research-perplexity.md The primary function of ARCN1 is to serve as a structural and functional component of the COPI coatomer complex, a heptameric protein assembly that mediates retrograde transport of proteins and lipids from the Golgi apparatus back to the endoplasmic reticulum (ER), as well as participating in intra-Golgi trafficking. |
| GO:0005198 structural molecule activity | ISS | NEW | Summary: Proposed new annotation for structural molecule activity based on ARCN1's role as the delta subunit of the COPI coatomer complex. ARCN1 contributes to the structural integrity of the heptameric coatomer assembly. Reason: ARCN1 functions as a structural component of the COPI coatomer complex, contributing to the overall architecture and stability of the heptamer. The delta subunit forms part of the F-subcomplex (adaptor-like complex) and interacts extensively with beta-COP to maintain coat integrity. This structural role is essential for vesicle formation and cargo packaging. The ISS evidence code reflects inference from sequence similarity to well-characterized orthologs including yeast Ret2. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-perplexity.md The primary function of ARCN1 is to serve as a structural and functional component of the COPI coatomer complex, a heptameric protein assembly file:human/ARCN1/ARCN1-deep-research-perplexity.md The role of ARCN1 in stabilizing the overall coatomer architecture ensures that this cycle proceeds with appropriate timing and efficiency |
| GO:0035966 response to topologically incorrect protein | NAS | NEW | Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: file:human/ARCN1/ARCN1-deep-research-cyberian.md Delta-COP, together with beta-COP, mediates recognition of a distinct class of sorting signals arginine (R)-based ER localization signals. These signals are found on unassembled subunits of multimeric membrane proteins and function in quality control by retaining incompletely assembled complexes in the ER. file:human/ARCN1/ARCN1-deep-research-cyberian.md Mutational analysis identified two highly conserved stretches within beta-COP (residues 318-338) and delta-COP (residues 388-413) that are required for R-based signal recognition. Importantly, combining mutations in both subunits abolished R-based signal recognition while leaving dilysine signal recognition intact. |
Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)