SNAP23 (synaptosomal-associated protein 23) is the ubiquitously expressed member of the SNAP-25 family of Qbc-SNAREs. It has no transmembrane segment. It carries two SNARE motifs (Qb and Qc t-SNARE coiled-coil domains) joined by a cysteine-rich linker, and S-palmitoylation of that linker anchors it to the cytoplasmic face of the plasma membrane. SNAP23 pairs with a syntaxin (STX4, STX11, STX3 and others) and a vesicular R-SNARE (VAMP3, VAMP7, VAMP8, VAMP4) to form the four-helix SNARE bundle that fuses vesicles or secretory granules with the plasma membrane. It thereby acts in constitutive and regulated exocytosis in non-neuronal cells, including histamine release by mast cells, mediator release by granulocytes, cytokine secretion, lytic granule release by cytotoxic lymphocytes with STX11, and recycling of surface receptors such as TLR4 from endosomes. Its neuronal paralog SNAP25 carries out synaptic vesicle exocytosis. Smaller pools of SNAP23 are found on granule, phagosome and endosome membranes. A splice isoform (SNAP-23b) lacks the palmitoylated linker region.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0001772 immunological synapse | IDA PMID:26771955 Munc18-2 is required for Syntaxin 11 Localization on the Pla... | UNDECIDED | Summary: IDA for immunological synapse from a study of STX11 and Munc18-2 localisation in human CTLs. Reason: The cached full text of PMID:26771955 describes STX11 and Munc18-2 at the CTL immune synapse but does not mention SNAP23 at all, so the evidence for SNAP23 localising there could not be found (it may lie in a figure or supplement). SNAP23 as the plasma membrane Qbc-SNARE for lytic granule fusion would be expected at the synapse, but this has not been verified here. Supporting Evidence: PMID:26771955 During CTL attack, these granules are delivered to the synapse where they fuse with the plasma membrane and release their deadly contents onto the target |
| GO:0002553 histamine secretion by mast cell | IMP PMID:18253931 Vesicle associated membrane protein (VAMP)-7 and VAMP-8, but... | ACCEPT | Summary: Inhibiting SNAP-23 in primary human intestinal mast cells markedly reduced IgE receptor-triggered histamine release; activated VAMP-7/VAMP-8 bind SNAP-23 and STX4 at the plasma membrane. Reason: Direct human evidence that SNAP23 acts as the plasma membrane Qbc-SNARE in mast cell degranulation. SNAP23 does part of the work: it contributes two SNARE motifs to the fusing STX4/VAMP7/VAMP8 complex. This is a cell-type-specific instance of its core exocytic function. Supporting Evidence: PMID:18253931 Inhibition of SNAP-23, STX-4, VAMP-7 or VAMP-8, but not VAMP-2 or VAMP-3, resulted in a markedly reduced high-affinity IgE receptor-mediated histamine release. PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005484 helical-bundle zippering fusogenic activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PAINT node PTN000447753 (SNAP-25 family), with human SNAP23 itself among the donors. Reason: SNAP23 is a Qbc-SNARE: two SNARE motifs (t-SNARE coiled-coil homology domains 14-76 and 146-208) zipper with a syntaxin and a VAMP into the four-helix bundle that drives fusion. This is the core molecular function of SNAP23, the ubiquitous paralog of SNAP25. Human SNAP23 appearing as a donor of the IBD node indicates its own experimental grounding; the function is ancestral to the SNAP23/SNAP25 clade (PTHR19305:SF4 is the SNAP23 subfamily). Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. file:human/SNAP23/SNAP23-uniprot.txt DR PANTHER; PTHR19305:SF4; SYNAPTOSOMAL-ASSOCIATED PROTEIN 23; 1. |
| GO:0005484 helical-bundle zippering fusogenic activity | IDA PMID:28265073 SM protein Munc18-2 facilitates transition of Syntaxin 11-me... | ACCEPT | Summary: Reconstituted 'flipped' cell-cell fusion assay with lipid-anchored STX11 and its cognate SNAREs (SNAP23 and VAMP8). Reason: SNAP23 is a Qbc-SNARE: two SNARE motifs (t-SNARE coiled-coil homology domains 14-76 and 146-208) zipper with a syntaxin and a VAMP into the four-helix bundle that drives fusion. This is the core molecular function of SNAP23, the ubiquitous paralog of SNAP25. In this assay the STX11-containing SNARE set supported lipid mixing, and Munc18-2 promoted complete fusion. Full text not in cache; the abstract supports the claim and the curator read the full text. Supporting Evidence: PMID:28265073 lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion PMID:28265073 Munc18-2 is not just a chaperone of STX11 but also directly contributes to complete membrane merging by promoting SNARE complex assembly |
| GO:0005484 helical-bundle zippering fusogenic activity | IDA PMID:30811271 Syntaxin 11 regulates the stimulus-dependent transport of To... | ACCEPT | Summary: SNAP-23 FRET probe in macrophages reports LPS-induced, STX11-dependent SNARE complex formation at the plasma membrane. Reason: SNAP23 is a Qbc-SNARE: two SNARE motifs (t-SNARE coiled-coil homology domains 14-76 and 146-208) zipper with a syntaxin and a VAMP into the four-helix bundle that drives fusion. This is the core molecular function of SNAP23, the ubiquitous paralog of SNAP25. Note that this paper used the mouse J774 macrophage line, so it is ortholog evidence for human SNAP23; the activity is independently established for human SNAP23 by in vitro binding and structural data. Supporting Evidence: PMID:30811271 indicating that stx11 is responsible for the structural alteration of SNAP-23 caused by LPS-induced SNARE complex formation on the plasma membrane PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. |
| GO:0005484 helical-bundle zippering fusogenic activity | IEA GO_REF:0000120 | ACCEPT | Summary: Electronic annotation (combined methods, including ARBA and Ensembl Compara transfer from mouse Snap23). Reason: SNAP23 is a Qbc-SNARE: two SNARE motifs (t-SNARE coiled-coil homology domains 14-76 and 146-208) zipper with a syntaxin and a VAMP into the four-helix bundle that drives fusion. This is the core molecular function of SNAP23, the ubiquitous paralog of SNAP25. Consistent with the experimental and IBA rows. Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro file:human/SNAP23/SNAP23-uniprot.txt PubMed:9070898). SNAP23 is a t-SNARE (target-SNARE) that resides on |
| GO:0005515 protein binding | IPI PMID:12773094 A role for Sec1/Munc18 proteins in platelet exocytosis. | REMOVE | Summary: Interaction of SNAP23 with STXBP2 (Munc18-2/Munc18b) (PMID:12773094). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. STXBP2 associates with a complex containing SNAP23 and VAMP3 in platelets; the association is indirect, via the syntaxin, and adds nothing beyond the SNARE complex annotation. Supporting Evidence: PMID:12773094 Munc18b associates with a larger complex that contains synaptosome-associated protein of 23 kDa (SNAP-23) and cellubrevin/vesicle-associated membrane protein 3. |
| GO:0005515 protein binding | IPI PMID:16189514 Towards a proteome-scale map of the human protein-protein in... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX11 (PMID:16189514). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX11, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0005515 protein binding | IPI PMID:16189514 Towards a proteome-scale map of the human protein-protein in... | REMOVE | Summary: Interaction of SNAP23 with SCGN (secretagogin) (PMID:16189514). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. Secretagogin is a calcium sensor reported to bind SNAP-25 family proteins; no specific molecular function of SNAP23 follows from this interaction. |
| GO:0005515 protein binding | IPI PMID:16189514 Towards a proteome-scale map of the human protein-protein in... | REMOVE | Summary: Interaction of SNAP23 with NAPA (alpha-SNAP) (PMID:16189514). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. NAPA binds assembled SNARE complexes as the NSF adaptor for disassembly; the interaction places SNAP23 in SNARE complexes, which is already captured by the SNARE complex annotations. |
| GO:0005515 protein binding | IPI PMID:21900206 A directed protein interaction network for investigating int... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX11 (PMID:21900206). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX11, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0005515 protein binding | IPI PMID:24373201 SNAP-23 and VAMP-3 contribute to the release of IL-6 and TNF... | MODIFY | Summary: Interaction of SNAP23 with the R-SNARE VAMP3 (cellubrevin) (PMID:24373201). Reason: VAMP3 is an R-SNARE that zippers with SNAP23 and a syntaxin into the SNARE four-helix bundle. SNARE binding is the informative term. SNAP23-VAMP3 complexes are seen in human cells and in the crystallised heterotetramer. Proposed replacements: SNARE binding Supporting Evidence: PMID:24373201 A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. |
| GO:0005515 protein binding | IPI PMID:24705354 The palmitoyl acyltransferase HIP14 shares a high proportion... | REMOVE | Summary: Interaction of SNAP23 with ZDHHC17 (HIP14) palmitoyltransferase (PMID:24705354). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. SNAP23 is a substrate of the ankyrin-repeat zDHHC17 S-acyltransferase; enzyme-substrate binding of this kind does not describe a SNAP23 activity. |
| GO:0005515 protein binding | IPI PMID:25416956 A proteome-scale map of the human interactome network. | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX11 (PMID:25416956). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX11, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0005515 protein binding | IPI PMID:25416956 A proteome-scale map of the human interactome network. | REMOVE | Summary: Interaction of SNAP23 with NAPB (beta-SNAP) (PMID:25416956). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. beta-SNAP is the NSF adaptor for SNARE complex disassembly; the interaction is consistent with SNAP23 in SNARE complexes, already captured elsewhere. |
| GO:0005515 protein binding | IPI PMID:26359495 The Q-soluble N-Ethylmaleimide-sensitive Factor Attachment P... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX3 (PMID:26359495). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX3, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:24373201 A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). |
| GO:0005515 protein binding | IPI PMID:26359495 The Q-soluble N-Ethylmaleimide-sensitive Factor Attachment P... | MODIFY | Summary: Interaction of SNAP23 with the R-SNARE VAMP3 (cellubrevin) (PMID:26359495). Reason: VAMP3 is an R-SNARE that zippers with SNAP23 and a syntaxin into the SNARE four-helix bundle. SNARE binding is the informative term. SNAP23-VAMP3 complexes are seen in human cells and in the crystallised heterotetramer. Proposed replacements: SNARE binding Supporting Evidence: PMID:24373201 A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. |
| GO:0005515 protein binding | IPI PMID:30833792 A protein-interaction network of interferon-stimulated genes... | REMOVE | Summary: Interaction of SNAP23 with NAPA (alpha-SNAP) (PMID:30833792). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. NAPA binds assembled SNARE complexes as the NSF adaptor for disassembly; the interaction places SNAP23 in SNARE complexes, which is already captured by the SNARE complex annotations. |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX11 (PMID:32296183). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX11, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX11 (PMID:33961781). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX11, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | REMOVE | Summary: Interaction of SNAP23 with SCGN (secretagogin) (PMID:33961781). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. Secretagogin is a calcium sensor reported to bind SNAP-25 family proteins; no specific molecular function of SNAP23 follows from this interaction. |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | REMOVE | Summary: Interaction of SNAP23 with NAPA (alpha-SNAP) (PMID:33961781). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. NAPA binds assembled SNARE complexes as the NSF adaptor for disassembly; the interaction places SNAP23 in SNARE complexes, which is already captured by the SNARE complex annotations. |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX3 (PMID:33961781). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX3, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:24373201 A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). |
| GO:0005515 protein binding | IPI PMID:35271311 OpenCell: Endogenous tagging for the cartography of human ce... | REMOVE | Summary: Interaction of SNAP23 with NAPA (alpha-SNAP) (PMID:35271311). Reason: Generic protein binding is uninformative under the repository protein-binding policy. Removal does not dispute the reported interaction. NAPA binds assembled SNARE complexes as the NSF adaptor for disassembly; the interaction places SNAP23 in SNARE complexes, which is already captured by the SNARE complex annotations. |
| GO:0005515 protein binding | IPI PMID:35271311 OpenCell: Endogenous tagging for the cartography of human ce... | MODIFY | Summary: Interaction of SNAP23 with the R-SNARE VAMP3 (cellubrevin) (PMID:35271311). Reason: VAMP3 is an R-SNARE that zippers with SNAP23 and a syntaxin into the SNARE four-helix bundle. SNARE binding is the informative term. SNAP23-VAMP3 complexes are seen in human cells and in the crystallised heterotetramer. Proposed replacements: SNARE binding Supporting Evidence: PMID:24373201 A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. |
| GO:0005515 protein binding | IPI PMID:40205054 Multimodal cell maps as a foundation for structural and func... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX11 (PMID:40205054). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX11, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0005515 protein binding | IPI PMID:40205054 Multimodal cell maps as a foundation for structural and func... | MODIFY | Summary: Interaction of SNAP23 with the syntaxin STX3 (PMID:40205054). The SNARE motifs of SNAP23 pair with a syntaxin Qa-SNARE motif in the SNARE complex. Reason: The partner is the syntaxin STX3, a cognate Qa-SNARE, so the informative function is syntaxin binding. This is a defining SNAP23 activity, shown in human proteins and cells independently of this screen. Proposed replacements: syntaxin binding Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:24373201 A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). |
| GO:0005737 cytoplasm | IDA PMID:18457912 Heterogeneous expression of SNARE proteins SNAP-23, SNAP-25,... | KEEP AS NON CORE | Summary: Immunohistochemistry of human parathyroid tissue detected SNAP-23. Reason: SNAP23 is a palmitoyl-anchored peripheral membrane protein on the cytosolic face of the plasma membrane and of intracellular membranes, so it lies within the cytoplasm as GO defines it. Tissue IHC cannot resolve the membrane compartment, so the term is about as precise as this evidence allows, but it is not informative of function. Supporting Evidence: PMID:18457912 SNAP-23 and VAMP were evenly expressed in all studied parathyroid tissues using immunohistochemistry and/or Western blot analysis. |
| GO:0005739 mitochondrion | IDA PMID:26733245 Immunofluorescence microscopy of SNAP23 in human skeletal mu... | MARK AS OVER ANNOTATED | Summary: Confocal immunofluorescence of human vastus lateralis showed punctate intracellular SNAP23 staining that colocalised with cytochrome c oxidase (r = 0.50). Reason: A Pearson coefficient of 0.5 at light-microscopy resolution shows proximity, not that SNAP23 is part of the mitochondrion. There is no fractionation, protease protection or EM evidence for a mitochondrial pool, and SNAP23 has no mitochondrial targeting signal. The observation may reflect SNAP23 at lipid droplet-mitochondria contacts or nearby membranes. Supporting Evidence: PMID:26733245 The intense punctate intracellular staining colocalized primarily with the mitochondrial marker cytochrome C oxidase (r = 0.50 Β± 0.012) and to a lesser extent with LDs |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PAINT node PTN000447752; human SNAP23 is among the donors. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. The plasma membrane is the main site of SNAP23 action and the node placement fits. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; file:human/SNAP23/SNAP23-uniprot.txt CC Lipid-anchor {ECO:0000269|PubMed:21044946}. |
| GO:0005886 plasma membrane | IDA GO_REF:0000052 | ACCEPT | Summary: Human Protein Atlas immunofluorescence localisation to the plasma membrane. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; |
| GO:0005886 plasma membrane | IDA PMID:18253931 Vesicle associated membrane protein (VAMP)-7 and VAMP-8, but... | ACCEPT | Summary: In human mast cells, activated VAMP-7/VAMP-8 translocate to the plasma membrane and bind SNAP-23 and STX4. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005886 plasma membrane | IDA PMID:18457912 Heterogeneous expression of SNARE proteins SNAP-23, SNAP-25,... | ACCEPT | Summary: Immunohistochemistry of SNAP-23 in human parathyroid tissue. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. The abstract reports expression rather than a membrane pattern; the curator read the full text and the localisation agrees with the other evidence. Supporting Evidence: PMID:18457912 SNAP-23 and VAMP were evenly expressed in all studied parathyroid tissues using immunohistochemistry and/or Western blot analysis. file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; |
| GO:0005886 plasma membrane | IDA PMID:26733245 Immunofluorescence microscopy of SNAP23 in human skeletal mu... | ACCEPT | Summary: SNAP23 colocalises with the sarcolemmal marker dystrophin in human skeletal muscle. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: PMID:26733245 showed colocalization of SNAP23 with the plasma membrane marker dystrophin |
| GO:0005886 plasma membrane | IDA PMID:30811271 Syntaxin 11 regulates the stimulus-dependent transport of To... | ACCEPT | Summary: SNAP-23 is a plasma membrane-localised Qbc-SNARE in macrophages (mouse J774 cells). Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Evidence is from a mouse cell line, consistent with direct human localisation data. Supporting Evidence: PMID:30811271 experiment suggested that stx11 interacts with SNAP-23, a plasma membrane-localized SNARE protein, whose depletion also inhibits TLR4 replenishment in LPS-stimulated cells |
| GO:0005886 plasma membrane | IEA GO_REF:0000120 | ACCEPT | Summary: Electronic annotation from UniProt subcellular location (cell membrane) and ortholog transfer. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-376357 | ACCEPT | Summary: Reactome pathway (Reactome:R-HSA-376357) places SNAP23 as the plasma membrane t-SNARE for vesicle or granule fusion. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-376364 | ACCEPT | Summary: Reactome pathway (Reactome:R-HSA-376364) places SNAP23 as the plasma membrane t-SNARE for vesicle or granule fusion. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-376369 | ACCEPT | Summary: Reactome pathway (Reactome:R-HSA-376369) places SNAP23 as the plasma membrane t-SNARE for vesicle or granule fusion. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-6798747 | ACCEPT | Summary: Reactome pathway (Reactome:R-HSA-6798747) places SNAP23 as the plasma membrane t-SNARE for vesicle or granule fusion. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-6799350 | ACCEPT | Summary: Reactome pathway (Reactome:R-HSA-6799350) places SNAP23 as the plasma membrane t-SNARE for vesicle or granule fusion. Reason: SNAP23 is palmitoylated on its central cysteine cluster and anchored to the cytoplasmic face of the plasma membrane, where it acts as the t-SNARE for fusion of exocytic and recycling vesicles. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:30811271}; PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0005912 adherens junction | IDA PMID:25468996 E-cadherin interactome complexity and robustness resolved by... | MARK AS OVER ANNOTATED | Summary: SNAP23 identified among proteins biotinylated by E-cadherin-BirA* (BioID proximity proteomics). Reason: Proximity labelling places a plasma membrane protein near the cadherin tail but does not show residence in adherens junctions; the authors themselves note that many hits localise elsewhere. SNAP23 is spread over the plasma membrane. Supporting Evidence: PMID:25468996 many of the E-cad-BirA* interactome proteins are found in other locations in the cell |
| GO:0005925 focal adhesion | HDA PMID:21423176 Analysis of the myosin-II-responsive focal adhesion proteome... | MARK AS OVER ANNOTATED | Summary: High-throughput focal adhesion proteome (myosin-II-responsive fraction). Reason: Focal adhesion isolates co-purify plasma membrane proteins. No targeted study places SNAP23 in focal adhesions or gives it a role there; this reflects its general plasma membrane residence. |
| GO:0006887 exocytosis | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000447753 with human SNAP23 among the donors. Reason: SNAP23 is the plasma membrane Qbc-SNARE in exocytosis in many non-neuronal cells: mast cell histamine release, cytokine release from synoviocytes, granulocyte mediator release and CTL lytic granule release. It does part of the work, contributing two of the four helices of the fusing SNARE bundle. Supporting Evidence: PMID:18253931 Inhibition of SNAP-23, STX-4, VAMP-7 or VAMP-8, but not VAMP-2 or VAMP-3, resulted in a markedly reduced high-affinity IgE receptor-mediated histamine release. PMID:24373201 Specific knockdown of SNAP-23 or VAMP-3 decreased the exocytosis of IL-6 and TNFΞ± PMID:16677249 Syntaxin-4, but not syntaxin-6, was found to interact with SNAP-23 and was partially involved in mediator secretion from multiple compartments. |
| GO:0006887 exocytosis | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA electronic annotation. Reason: Agrees with the experimental and IBA support for SNAP23 in exocytosis. Supporting Evidence: PMID:18253931 Inhibition of SNAP-23, STX-4, VAMP-7 or VAMP-8, but not VAMP-2 or VAMP-3, resulted in a markedly reduced high-affinity IgE receptor-mediated histamine release. PMID:24373201 Specific knockdown of SNAP-23 or VAMP-3 decreased the exocytosis of IL-6 and TNFΞ± |
| GO:0006906 vesicle fusion | IDA PMID:28265073 SM protein Munc18-2 facilitates transition of Syntaxin 11-me... | ACCEPT | Summary: SNAP23-containing STX11 SNARE complexes drive lipid mixing in a reconstituted cell-cell fusion assay, with Munc18-2 promoting full fusion. Reason: SNAP23 contributes SNARE motifs to the fusing complex, so it takes part directly in vesicle fusion. Abstract-only in cache; deferring to the curator for full-text details. Supporting Evidence: PMID:28265073 lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion PMID:28265073 Munc18-2 is not just a chaperone of STX11 but also directly contributes to complete membrane merging by promoting SNARE complex assembly |
| GO:0006906 vesicle fusion | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA electronic annotation. Reason: Agrees with direct evidence for SNAP23 in SNARE-mediated vesicle fusion. Supporting Evidence: PMID:28265073 lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion |
| GO:0016082 synaptic vesicle priming | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: IBA from PAINT node PTN000447754, seeded only by Drosophila Snap25 (FBgn0011288); human SNAP23 is not a donor. Reason: Synaptic vesicle priming and fusion at the presynaptic active zone are carried out in vertebrate neurons by SNAP25 (and SNAP47), not SNAP23. SNAP23 is the ubiquitously expressed paralog (PTHR19305:SF4), functioning in constitutive and regulated exocytosis in non-neuronal cells; no study in this review shows SNAP23 in presynaptic vesicle cycling. The node lies above the vertebrate SNAP23/SNAP25 duplication, and the synaptic role was retained by SNAP25. The general activity (fusogenic SNARE) is inherited, but the synapse-specific process is an over-propagation to SNAP23. Propagation Review Root cause: PROPAGATION BAD Failure modes: FUNCTIONAL DIVERGENCE CONTEXT OR TISSUE MISMATCH Sources checked: PANTHER:PTN000447754 SUPPORTS SOURCE BUT NOT TARGET Synaptic IBD seeded only by Drosophila Snap25; in vertebrates the neuronal synaptic role sits with SNAP25, while SNAP23 (PTHR19305:SF4) is the ubiquitous non-neuronal paralog. FB:FBgn0011288 Β· Snap25 SUPPORTS SOURCE BUT NOT TARGET Fly Snap25 is the synaptic t-SNARE; its synapse-specific process does not transfer to vertebrate SNAP23. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- TISSUE SPECIFICITY: Ubiquitous. Highest levels where found in placenta. file:human/SNAP23/SNAP23-uniprot.txt DR PANTHER; PTHR19305:SF4; SYNAPTOSOMAL-ASSOCIATED PROTEIN 23; 1. |
| GO:0019905 syntaxin binding | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000447753 with human SNAP23 among the donors. Reason: SNAP23 binds STX4, STX11, STX3 and other syntaxins as part of SNARE complex assembly; shown with human proteins in vitro and in human cells. Supporting Evidence: PMID:8663154 we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/VAMPs in vitro PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. |
| GO:0019905 syntaxin binding | IPI PMID:16677249 A critical role for vesicle-associated membrane protein-7 in... | ACCEPT | Summary: In human eosinophils and neutrophils, SNAP-23 interacts with syntaxin-4 (STX4). Reason: Direct human evidence of syntaxin binding, a core SNAP23 activity. Supporting Evidence: PMID:16677249 Syntaxin-4, but not syntaxin-6, was found to interact with SNAP-23 and was partially involved in mediator secretion from multiple compartments. |
| GO:0030670 phagocytic vesicle membrane | TAS Reactome:R-HSA-8863895 | KEEP AS NON CORE | Summary: Reactome: IKK2 phosphorylates phagosomal SNAP23 (Ser95) after TLR signalling in dendritic cells. Reason: SNAP23 on phagosomes mediates fusion of recycling endosomes carrying MHC-I with phagosomes during cross-presentation. The underlying data are largely from mouse dendritic cells. This is a peripheral location, valid but not the main site of action. Supporting Evidence: Reactome:R-HSA-8863895 SNAP23 phosphorylation may increase SNAP23 binding to SNAREs. Reactome:R-HSA-8863973 Recycling endosome-localized R-SNARE protein like RAB11a, VAMP3, and VAMP8 dock with target phagosome membrane Q-SNARE protein SNAP23. |
| GO:0030670 phagocytic vesicle membrane | TAS Reactome:R-HSA-8863973 | KEEP AS NON CORE | Summary: Reactome: recycling endosome R-SNAREs dock with phagosomal SNAP23. Reason: As above: phagosomal SNAP23 in endocytic recycling compartment-phagosome fusion; a peripheral location. Supporting Evidence: Reactome:R-HSA-8863973 Recycling endosome-localized R-SNARE protein like RAB11a, VAMP3, and VAMP8 dock with target phagosome membrane Q-SNARE protein SNAP23. |
| GO:0031201 SNARE complex | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000447753 with human SNAP23 among the donors. Reason: SNAP23 contributes the Qb and Qc helices to SNARE complexes with syntaxins (STX4, STX11, STX3) and VAMPs (VAMP3, VAMP7, VAMP8). Supporting Evidence: PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. PMID:10036234 syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes |
| GO:0031201 SNARE complex | IDA PMID:18253931 Vesicle associated membrane protein (VAMP)-7 and VAMP-8, but... | ACCEPT | Summary: SNAP-23/STX4/VAMP-7/VAMP-8 complexes form in activated human mast cells. Reason: SNAP23 contributes the Qb and Qc helices to SNARE complexes with syntaxins (STX4, STX11, STX3) and VAMPs (VAMP3, VAMP7, VAMP8). Supporting Evidence: PMID:18253931 VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation |
| GO:0031201 SNARE complex | IDA PMID:30811271 Syntaxin 11 regulates the stimulus-dependent transport of To... | ACCEPT | Summary: FRET probe shows LPS-induced SNARE complex formation by SNAP-23 at the plasma membrane (mouse J774 cells). Reason: SNAP23 contributes the Qb and Qc helices to SNARE complexes with syntaxins (STX4, STX11, STX3) and VAMPs (VAMP3, VAMP7, VAMP8). Evidence is from mouse cells. Supporting Evidence: PMID:30811271 indicating that stx11 is responsible for the structural alteration of SNAP-23 caused by LPS-induced SNARE complex formation on the plasma membrane |
| GO:0031201 SNARE complex | IEA GO_REF:0000120 | ACCEPT | Summary: Electronic annotation (ARBA and ortholog transfer). Reason: SNAP23 contributes the Qb and Qc helices to SNARE complexes with syntaxins (STX4, STX11, STX3) and VAMPs (VAMP3, VAMP7, VAMP8). Supporting Evidence: PMID:12556468 SNAP-23N can assemble spontaneously with the coiled-coil domains from SNAP-23C, syntaxin-4, and VAMP-3 to form a heterotetrameric complex. file:human/SNAP23/SNAP23-uniprot.txt Forms a SNARE complex with VAMP4 and STX11; |
| GO:0031201 SNARE complex | IPI PMID:28265073 SM protein Munc18-2 facilitates transition of Syntaxin 11-me... | ACCEPT | Summary: SNARE complex of SNAP23 with STX11 and VAMP8 in the reconstituted fusion assay. Reason: SNAP23 contributes the Qb and Qc helices to SNARE complexes with syntaxins (STX4, STX11, STX3) and VAMPs (VAMP3, VAMP7, VAMP8). Supporting Evidence: PMID:28265073 Munc18-2 is not just a chaperone of STX11 but also directly contributes to complete membrane merging by promoting SNARE complex assembly |
| GO:0031410 cytoplasmic vesicle | IEA GO_REF:0000107 | KEEP AS NON CORE | Summary: Ensembl Compara transfer from mouse Snap23. Reason: SNAP23 is found on intracellular membranes (granules, phagosomes, endosomes), but its main site is the plasma membrane. Acceptable as a non-core location. Supporting Evidence: Reactome:R-HSA-8863973 Recycling endosome-localized R-SNARE protein like RAB11a, VAMP3, and VAMP8 dock with target phagosome membrane Q-SNARE protein SNAP23. |
| GO:0031629 synaptic vesicle fusion to presynaptic active zone membrane | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: IBA from PAINT node PTN000447754, seeded only by Drosophila Snap25 (FBgn0011288); human SNAP23 is not a donor. Reason: Synaptic vesicle priming and fusion at the presynaptic active zone are carried out in vertebrate neurons by SNAP25 (and SNAP47), not SNAP23. SNAP23 is the ubiquitously expressed paralog (PTHR19305:SF4), functioning in constitutive and regulated exocytosis in non-neuronal cells; no study in this review shows SNAP23 in presynaptic vesicle cycling. The node lies above the vertebrate SNAP23/SNAP25 duplication, and the synaptic role was retained by SNAP25. The general activity (fusogenic SNARE) is inherited, but the synapse-specific process is an over-propagation to SNAP23. Propagation Review Root cause: PROPAGATION BAD Failure modes: FUNCTIONAL DIVERGENCE CONTEXT OR TISSUE MISMATCH Sources checked: PANTHER:PTN000447754 SUPPORTS SOURCE BUT NOT TARGET Synaptic IBD seeded only by Drosophila Snap25; in vertebrates the neuronal synaptic role sits with SNAP25, while SNAP23 (PTHR19305:SF4) is the ubiquitous non-neuronal paralog. FB:FBgn0011288 Β· Snap25 SUPPORTS SOURCE BUT NOT TARGET Fly Snap25 is the synaptic t-SNARE; its synapse-specific process does not transfer to vertebrate SNAP23. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC -!- TISSUE SPECIFICITY: Ubiquitous. Highest levels where found in placenta. file:human/SNAP23/SNAP23-uniprot.txt DR PANTHER; PTHR19305:SF4; SYNAPTOSOMAL-ASSOCIATED PROTEIN 23; 1. |
| GO:0035579 specific granule membrane | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: Neutrophil granule membrane localisation (GO_REF:0000117). Reason: Neutrophil granule proteomics and Reactome place SNAP23 on specific/tertiary granule membranes, which merge with the plasma membrane on exocytosis. Plausible but peripheral to its function as the plasma membrane t-SNARE. |
| GO:0035579 specific granule membrane | TAS Reactome:R-HSA-6799350 | KEEP AS NON CORE | Summary: Neutrophil granule membrane localisation (Reactome:R-HSA-6799350). Reason: Neutrophil granule proteomics and Reactome place SNAP23 on specific/tertiary granule membranes, which merge with the plasma membrane on exocytosis. Plausible but peripheral to its function as the plasma membrane t-SNARE. |
| GO:0042581 specific granule | IDA PMID:18588921 Involvement of Munc18 isoforms in the regulation of granule ... | KEEP AS NON CORE | Summary: Subcellular fractionation/immuno-EM of human neutrophils in a study of Munc18-2/Munc18-3 (PMID:18588921). Reason: The abstract describes Munc18 isoforms and syntaxins on granules but does not mention SNAP23; the full text (not cached) presumably fractionated SNAP23 too, and we defer to the curator. Granule pools of SNAP23 are plausible but secondary to its plasma membrane role. |
| GO:0042582 azurophil granule | IDA PMID:18588921 Involvement of Munc18 isoforms in the regulation of granule ... | KEEP AS NON CORE | Summary: Subcellular fractionation/immuno-EM of human neutrophils in a study of Munc18-2/Munc18-3 (PMID:18588921). Reason: The abstract describes Munc18 isoforms and syntaxins on granules but does not mention SNAP23; the full text (not cached) presumably fractionated SNAP23 too, and we defer to the curator. Granule pools of SNAP23 are plausible but secondary to its plasma membrane role. |
| GO:0043316 cytotoxic T cell degranulation | IMP PMID:28265073 SM protein Munc18-2 facilitates transition of Syntaxin 11-me... | ACCEPT | Summary: CTL degranulation (IMP) in a study of STX11 and Munc18-2 in lytic granule exocytosis. Reason: STX11 with its cognate SNAREs, of which SNAP23 is the plasma membrane Qbc partner, supports lytic granule release by CTLs. The full text is not cached, so the SNAP23 perturbation data are taken from the curator's reading. SNAP23 contributes SNARE motifs to the fusion complex, which is participation, not just requirement. Supporting Evidence: PMID:28265073 facilitate cytolytic granule release by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells PMID:28265073 lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion |
| GO:0070062 extracellular exosome | HDA PMID:19056867 Large-scale proteomics and phosphoproteomics of urinary exos... | KEEP AS NON CORE | Summary: Exosome proteomics (PMID:19056867). Reason: Palmitoylated inner-leaflet plasma membrane proteins are routinely captured in extracellular vesicles. This is a valid HDA location with no known functional role. |
| GO:0070062 extracellular exosome | HDA PMID:20458337 MHC class II-associated proteins in B-cell exosomes and pote... | KEEP AS NON CORE | Summary: Exosome proteomics (PMID:20458337). Reason: Palmitoylated inner-leaflet plasma membrane proteins are routinely captured in extracellular vesicles. This is a valid HDA location with no known functional role. |
| GO:0070821 tertiary granule membrane | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: Neutrophil granule membrane localisation (GO_REF:0000117). Reason: Neutrophil granule proteomics and Reactome place SNAP23 on specific/tertiary granule membranes, which merge with the plasma membrane on exocytosis. Plausible but peripheral to its function as the plasma membrane t-SNARE. |
| GO:0070821 tertiary granule membrane | TAS Reactome:R-HSA-6798747 | KEEP AS NON CORE | Summary: Neutrophil granule membrane localisation (Reactome:R-HSA-6798747). Reason: Neutrophil granule proteomics and Reactome place SNAP23 on specific/tertiary granule membranes, which merge with the plasma membrane on exocytosis. Plausible but peripheral to its function as the plasma membrane t-SNARE. |
| GO:0098562 cytoplasmic side of membrane | IEA GO_REF:0000107 | ACCEPT | Summary: Ensembl Compara transfer from mouse Snap23. Reason: SNAP23 has no transmembrane segment and is attached by palmitoylation to the cytoplasmic leaflet of the plasma membrane and of intracellular membranes. The general term is appropriate because SNAP23 acts on more than one membrane. Supporting Evidence: file:human/SNAP23/SNAP23-uniprot.txt CC Lipid-anchor {ECO:0000269|PubMed:21044946}. PMID:9070898 This region of SNAP-23A has a target sequence for posttranslational fatty acid acylation |
| GO:0098793 presynapse | IEA GO_REF:0000108 | MARK AS OVER ANNOTATED | Summary: Inter-ontology inference from the synaptic vesicle priming IBA. Reason: Derived only from the over-propagated synaptic vesicle priming IBA (see that row). No evidence places SNAP23 in the presynapse. |
| GO:0099638 obsolete endosome to plasma membrane protein transport | IDA PMID:30811271 Syntaxin 11 regulates the stimulus-dependent transport of To... | MODIFY | Summary: SNAP-23 knockdown reduced constitutive and LPS-induced TLR4 delivery from endosomes to the macrophage surface (mouse J774 cells). Reason: GO:0099638 is obsolete; GO merged it into GO:0032456 endocytic recycling because the protein-cargo restriction was unnecessary. SNAP23 does part of the work, as the plasma membrane Qbc-SNARE for fusion of TLR4-carrying recycling carriers. Evidence is from a mouse cell line. Proposed replacements: endocytic recycling Supporting Evidence: PMID:30811271 experiment suggested that stx11 interacts with SNAP-23, a plasma membrane-localized SNARE protein, whose depletion also inhibits TLR4 replenishment in LPS-stimulated cells |
| GO:0140522 fusogenic activity | IDA PMID:28265073 SM protein Munc18-2 facilitates transition of Syntaxin 11-me... | TOO GENERAL | Summary: Fusogenic activity (contributes_to) (PMID:28265073). Reason: True, but GO:0005484 helical-bundle zippering fusogenic activity, accepted elsewhere in this review, is an is_a child of fusogenic activity and states the SNARE mechanism. The contributes_to qualifier correctly reflects that fusogenic activity is a property of the assembled SNARE complex. Supporting Evidence: PMID:28265073 lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion |
| GO:0140522 fusogenic activity | IEA GO_REF:0000107 | TOO GENERAL | Summary: Fusogenic activity (contributes_to) (GO_REF:0000107). Reason: True, but GO:0005484 helical-bundle zippering fusogenic activity, accepted elsewhere in this review, is an is_a child of fusogenic activity and states the SNARE mechanism. The contributes_to qualifier correctly reflects that fusogenic activity is a property of the assembled SNARE complex. Supporting Evidence: PMID:28265073 lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion |
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Download this section (compressed HTML)Q: Does the immunological synapse IDA from PMID:26771955 rest on SNAP23 imaging in a figure or supplement? The cached text discusses only STX11 and Munc18-2.
Q: Should the PTN000447754 synaptic vesicle priming and active-zone fusion terms be pruned from the SNAP23 branch, given that vertebrate SNAP23 is the non-neuronal paralog?
Q: Is there direct evidence in human cells (not mouse J774) that SNAP23 mediates TLR4 or other receptor recycling to the plasma membrane?
Experiment: Knock out SNAP23 in human primary macrophages or THP-1 cells and measure surface TLR4 recovery after LPS-induced internalisation, with rescue by wild-type versus palmitoylation-deficient SNAP23.
Hypothesis: Palmitoyl-anchored SNAP23 is the plasma membrane Qbc-SNARE for TLR4 recycling in human macrophages.
Experiment: Use immuno-EM or proximity biotinylation from an outer mitochondrial membrane bait in human myotubes to test whether SNAP23 resides on mitochondria or only at contact sites.
Hypothesis: The SNAP23 signal near mitochondria in muscle comes from lipid droplet or ER contacts, not from a mitochondrial pool.
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