SCAMP4 (Secretory carrier-associated membrane protein 4) is a member of the SCAMP family of integral membrane proteins involved in vesicle trafficking. SCAMP4 is a shorter (~25 kDa) SCAMP family member that lacks most of the large N-terminal cytosolic domain found in SCAMP1-3, but retains the conserved four-transmembrane domain core with cytosolic N- and C-termini. Like other SCAMPs, SCAMP4 localizes primarily to the trans-Golgi network (TGN) and recycling endosome membranes, with some presence at the plasma membrane. The SCAMP family functions as membrane-trafficking machinery at cytosolic interfaces, participating in vesicle formation, fusion, and recycling between the plasma membrane and internal compartments. Recent studies have identified SCAMP4 as a senescent cell surface protein potentially involved in promoting SASP (senescence-associated secretory phenotype) secretion, though direct mechanistic evidence for SCAMP4-specific functions remains limited.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0006887 exocytosis | IBA GO_REF:0000033 | ACCEPT | Summary: This IBA annotation is based on phylogenetic inference from the SCAMP family (PANTHER). SCAMP family proteins function as membrane-trafficking machinery involved in vesicle formation and fusion. The family is implicated in exocytic processes. While SCAMP4-specific exocytosis data is limited, the phylogenetic inference is supported by family-level functional evidence. Reason: Exocytosis is a well-established function for the SCAMP family based on family-level studies. The IBA annotation appropriately captures this conserved family function at a reasonable level of specificity. SCAMP4 retention of the conserved membrane core supports functional conservation. Supporting Evidence: file:human/SCAMP4/SCAMP4-deep-research-falcon.md SCAMPs are implicated as trafficking machinery at sites of vesicle formation and fusion |
| GO:0032588 trans-Golgi network membrane | IBA GO_REF:0000033 | ACCEPT | Summary: This IBA annotation for TGN membrane localization is strongly supported by SCAMP family localization studies that demonstrated SCAMPs 1-4 concentrate in the trans-Golgi network and endosomal recycling compartment. Reason: TGN localization is a core characteristic of the SCAMP family. Family-level localization studies explicitly included SCAMP4 and demonstrated concentration at the TGN membrane. This represents a fundamental aspect of SCAMP4 cellular localization. Supporting Evidence: file:human/SCAMP4/SCAMP4-deep-research-falcon.md SCAMP family members concentrate in the trans-Golgi network and endosomal recycling compartment |
| GO:0055038 recycling endosome membrane | IBA GO_REF:0000033 | ACCEPT | Summary: This IBA annotation for recycling endosome membrane localization is well-supported by family-level studies showing SCAMPs 1-4 localize to endosomal recycling compartments alongside TGN. Reason: Recycling endosome localization is a well-documented characteristic of SCAMP family proteins. The phylogenetic inference appropriately extends this localization to SCAMP4 based on conserved family properties. Supporting Evidence: file:human/SCAMP4/SCAMP4-deep-research-falcon.md SCAMP family members concentrate in the trans-Golgi network and endosomal recycling compartment |
| GO:0015031 protein transport | IEA GO_REF:0000120 | ACCEPT | Summary: This IEA annotation is derived from InterPro domain mapping (IPR007273 SCAMP domain) and UniProtKB keywords. While accurate, this is a broad term. The SCAMP family is involved in protein transport, functioning as trafficking machinery for vesicle-mediated transport between compartments. Reason: The term is appropriately broad for an automated annotation. SCAMP family function in membrane protein trafficking supports this annotation. More specific terms (exocytosis) are already captured by the IBA annotations, so this broader IEA annotation provides acceptable coverage without being misleading. Supporting Evidence: file:human/SCAMP4/SCAMP4-deep-research-falcon.md SCAMPs are implicated as trafficking machinery at sites of vesicle formation and fusion |
| GO:0016020 membrane | IEA GO_REF:0000120 | ACCEPT | Summary: This IEA annotation identifies SCAMP4 as a membrane protein. This is accurate but very general. SCAMP4 is a multi-pass integral membrane protein with four transmembrane domains. More specific localization terms (TGN membrane, recycling endosome membrane) are already captured by IBA annotations. Reason: While this is a generic term, it is accurate and not misleading. SCAMP4 is unambiguously a membrane protein with four transmembrane helices. The more specific IBA annotations provide the detailed localization information. Supporting Evidence: file:human/SCAMP4/SCAMP4-deep-research-falcon.md Like other SCAMPs, it contains a conserved membrane core with four TMs |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | MARK AS OVER ANNOTATED | Summary: This annotation comes from the HuRI (Human Reference Interactome) project, a systematic yeast two-hybrid screen that identified approximately 53,000 protein-protein interactions. SCAMP4 was found to interact with multiple membrane proteins. Reason: Per curation guidelines, 'protein binding' (GO:0005515) is an uninformative molecular function term that does not convey specific functional information about SCAMP4's role. The HuRI study is a high-throughput interactome mapping study that detected binary PPIs but does not provide mechanistic insight into SCAMP4's molecular function. Supporting Evidence: PMID:32296183 Here we present a human 'all-by-all' reference interactome map of human binary protein interactions, or 'HuRI' |
| GO:0005515 protein binding | IPI PMID:32814053 Interactome Mapping Provides a Network of Neurodegenerative ... | MARK AS OVER ANNOTATED | Summary: This annotation derives from a neurodegenerative disease-focused interactome mapping study that used systematic Y2H screening. These are high-throughput Y2H results focused on identifying disease-relevant protein networks. Reason: As with the other protein binding annotation, GO:0005515 is an uninformative molecular function term. The neurodegenerative disease interactome study provides network context but not specific functional insight into SCAMP4's molecular mechanism. Supporting Evidence: PMID:32814053 Here, we report on an interactome map that focuses on neurodegenerative disease (ND), connects ∼5,000 human proteins via ∼30,000 candidate interactions and is generated by systematic yeast two-hybrid interaction screening of ∼500 ND-related proteins and integration of literature interactions |
| GO:0003674 molecular_function | NAS | NEW | Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. Supporting Evidence: file:human/SCAMP4/SCAMP4-deep-research-falcon.md SCAMP family members concentrate in the trans-Golgi network and endosomal recycling compartment |
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Download this section (compressed HTML)Q: What are the specific protein interactions and mechanistic roles of SCAMP4 compared to other SCAMP family members (SCAMP1-3, SCAMP5)? SCAMP4 lacks the E-peptide region that mediates SCAMP2-NHE7 interactions, suggesting functional divergence. The specific binding partners and mechanisms of SCAMP4 remain understudied.
Q: What is the role of SCAMP4 in senescence-associated secretory phenotype (SASP) and senescent cell biology? Recent reviews identify SCAMP4 as a senescent cell surface protein potentially promoting SASP secretion, but direct functional evidence is lacking.
Experiment: CRISPR knockout or siRNA knockdown of SCAMP4 in senescent cell models followed by quantitative secretomics to assess effects on SASP factor secretion. This would directly test the proposed role of SCAMP4 in promoting SASP secretion suggested by surfaceome studies.
Experiment: Proximity labeling (BioID/APEX2) of SCAMP4 to identify the specific interactome in different cellular compartments. This would provide context-specific interaction data beyond high-throughput Y2H and identify functional partners in native cellular environments.
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