{"gene":"VAMP4","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":2003,"finding":"The N-terminal 51-residue extension of VAMP4 (containing a di-leucine motif followed by two acidic clusters) is a dominant autonomous targeting signal for the trans-Golgi network (TGN). Swapping this region onto VAMP5 redirects it to the TGN; site-directed mutagenesis confirmed the essential roles of the di-Leu motif and the second acidic cluster.","method":"Chimeric protein swaps, deletion mutagenesis, site-directed mutagenesis, EGFP-tagging and fluorescence microscopy","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (domain swaps, deletion mutants, point mutagenesis) in a single focused study establishing the targeting signal","pmids":["12682051"],"is_preprint":false},{"year":2003,"finding":"VAMP4 binds to the AP-1 adaptor subunit mu1a (but not mu1b or GGAs) via its di-leucine motif (Leu25/26) and Ser20. Phosphorylation of Ser30 in the acidic cluster by casein kinase 2 enhances AP-1 recruitment through PACS-1. Ablation of both the di-leucine motif and Ser30, or expression of dominant-negative PACS-1, causes dramatic VAMP4 mislocalization in the regulated secretory pathway.","method":"Binding assays, site-directed mutagenesis, dominant-negative PACS-1 overexpression, immunofluorescence in AtT20 cells","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (mutagenesis, phosphorylation assay, dominant-negative rescue) with clear functional readout","pmids":["14608369"],"is_preprint":false},{"year":2007,"finding":"VAMP4 cycles from the cell surface to the TGN via clathrin-dependent endocytosis through sorting and then recycling endosomes, followed by direct transport to the TGN without transiting the late endosome. The di-Leu motif is required for internalization, and the acidic cluster is crucial for endosome-to-TGN delivery.","method":"EGFP-antibody uptake assay, pharmacological and thermal perturbation of endosomal trafficking, fluorescence time-course imaging in stable VAMP4-EGFP cells","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal perturbations (pharmacological, thermal, mutagenesis of motifs) with quantitative trafficking assay","pmids":["17327277"],"is_preprint":false},{"year":2008,"finding":"VAMP4 localizes to enlargeosome membranes in PC12-27 cells and is a component of the SNARE machinery (with syntaxin-6 and SNAP-23) mediating fast regulated exocytosis of enlargeosomes. Microinjection of anti-VAMP4 antibody and VAMP4 siRNA knockdown both inhibit enlargeosome exocytosis.","method":"Co-localization imaging, antibody microinjection, siRNA knockdown, capacitance measurements, VAMP4-GFP surface appearance assay","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal perturbations (antibody inhibition + siRNA KD) with electrophysiological and imaging readouts, in two cell types","pmids":["18713833"],"is_preprint":false},{"year":2011,"finding":"VAMP4 co-localizes with lytic granules during cytotoxic NK-cell interactions and is required for cytotoxic granule exocytosis. Knockdown of VAMP4 in both the YTS NK cell line and peripheral NK cells inhibits lytic granule release and severely impairs cytotoxic activity. Unlike VAMP7, VAMP4 is not involved in IFN-γ secretion.","method":"Immunofluorescence co-localization, siRNA knockdown, cytotoxicity assays, IFN-γ secretion assays in NK cells","journal":"European journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA KD with defined functional readout in two cell types, single lab","pmids":["21805468"],"is_preprint":false},{"year":2012,"finding":"VAMP4 selectively maintains Ca2+-dependent asynchronous neurotransmitter release at inhibitory synapses, while synaptobrevin-2/VAMP2 drives synchronous release. VAMP4 forms a stable SNARE complex with syntaxin-1 and SNAP-25 that does not interact with complexin or synaptotagmin-1. VAMP4 and VAMP2 traffic independently with minimal overlap in individual synapses.","method":"Up/downregulation of VAMP4 with electrophysiological recording, biochemical SNARE complex formation assay, optical imaging of individual synapses in mouse neurons","journal":"Nature neuroscience","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (electrophysiology, biochemical complex assay, optical imaging) with bidirectional modulation of VAMP4","pmids":["22406549"],"is_preprint":false},{"year":2013,"finding":"VAMP4 is required to maintain the ribbon structure of the Golgi apparatus. RNAi-mediated depletion of VAMP4 in HeLa cells causes Golgi ribbon fragmentation (shortened stacks remain in juxtanuclear area) without disrupting anterograde trafficking or microtubules. Knockdown of cognate SNARE partners syntaxin 6, syntaxin 16, and Vti1a phenocopies this fragmentation, implicating VAMP4-containing SNARE complexes in retrograde endosome-to-TGN trafficking needed for Golgi integrity.","method":"siRNA knockdown, electron microscopy, immunofluorescence, anterograde trafficking assay in HeLa cells","journal":"Molecular and cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA KD with EM and fluorescence readouts, multiple SNARE partners tested, single lab","pmids":["23677696"],"is_preprint":false},{"year":2015,"finding":"VAMP4 is the first identified cargo specifically retrieved by activity-dependent bulk endocytosis (ADBE) during intense neuronal stimulation. Endogenous VAMP4 is enriched in purified bulk endosomes. VAMP4 is also essential for ADBE to proceed, with the cytoplasmic di-leucine motif being critical for this role.","method":"pHluorin reporter assays for multiple SV cargo proteins, ADBE inhibition, immunoisolation of bulk endosomes, di-leucine motif mutagenesis, neuronal cultures","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple cargo reporters compared, biochemical fractionation of bulk endosomes, and mutagenesis of functional motif, single lab but orthogonal methods","pmids":["26607000"],"is_preprint":false},{"year":2020,"finding":"VAMP4 is required for Ca2+-dependent spontaneous excitatory neurotransmission, with limited role in spontaneous inhibitory transmission. Key residues governing VAMP4 retrieval and clathrin-mediated vesicle trafficking are essential for this role. High-frequency stimulation triggers VAMP4 retrieval and augments Ca2+-sensitive spontaneous release for up to 30 min in a VAMP4-dependent manner, linking asynchronous and spontaneous release.","method":"VAMP4 knockdown/mutant expression, electrophysiological recording, clathrin pathway inhibition in rat hippocampal neurons","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD plus mutant rescue with electrophysiological readout, single lab","pmids":["32532887"],"is_preprint":false},{"year":2021,"finding":"VAMP4 copy number on synaptic vesicles (SVs) regulates release probability (Pr). VAMP4 has reduced ability to form efficient SNARE complexes with canonical plasma membrane SNAREs, and is selectively sorted to endolysosomes during ADBE. Disruption of endolysosomal trafficking increases VAMP4 abundance in the SV pool and inhibits SV fusion, demonstrating that endolysosomal clearance of VAMP4 is the mechanism generating SV heterogeneity.","method":"Modulation of VAMP4 copy number, SNARE complex efficiency assay, endolysosomal trafficking perturbation, SV pool analysis, electrophysiology in neuronal cultures","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — biochemical SNARE complex assay, trafficking perturbation, and functional electrophysiology combined in one study with clear mechanistic outcome","pmids":["33931449"],"is_preprint":false},{"year":2021,"finding":"VAMP4 is the primary vesicular SNARE mediating dendritic recycling endosome exocytosis in neurons. VAMP4 KD decreases transferrin receptor (TfR) recycling while paradoxically increasing AMPA receptor (AMPAR) recycling and synaptic transmission, occluding LTP expression. This reveals that VAMP4 sorts AMPARs and TfRs into separate endosomal populations.","method":"VAMP4 KD, live imaging of vesicle exocytosis, transferrin receptor recycling assay, electrophysiological recording of synaptic transmission and LTP in neuronal cultures","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with multiple functional readouts (recycling assays, electrophysiology), single lab","pmids":["34496238"],"is_preprint":false},{"year":2021,"finding":"In macrophages, VAMP4 on Golgi-derived vesicles forms a trans-SNARE complex with the Q-SNARE complex Stx6/Stx7/Vti1b to mediate transport of MT1-MMP from the Golgi to late endosomes en route to the cell surface. Depletion of VAMP4 or any component of this complex reduces surface MT1-MMP and gelatin degradation.","method":"Fixed and live imaging, siRNA depletion of SNARE components, surface MT1-MMP quantification, gelatin degradation assay in macrophages","journal":"Traffic (Copenhagen, Denmark)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — imaging plus functional depletion assays with degradation readout, single lab","pmids":["34476885"],"is_preprint":false},{"year":2026,"finding":"Under hypoxic conditions in HNSCC, VAMP4 and syntaxin 8 (STX8) mediate the autophagic (mitophagy-dependent) secretion of mitochondria as extracellular vesicles, identified by multivesicular body membrane proteomics and molecular interaction validation.","method":"Multivesicular body membrane proteomics, molecular interaction validation, hypoxia model in HNSCC cells","journal":"Journal of extracellular vesicles","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, limited mechanistic detail on interaction validation in abstract, no reconstitution or mutagenesis described","pmids":["41979085"],"is_preprint":false}],"current_model":"VAMP4 is a TGN-enriched R-SNARE whose N-terminal di-leucine/acidic-cluster motif directs its TGN localization and clathrin-dependent endocytic recycling (modulated by CK2-phosphorylation–dependent PACS-1/AP-1 recruitment); it forms SNARE complexes with syntaxin-6/syntaxin-16/Vti1a for retrograde endosome-to-TGN traffic (maintaining Golgi ribbon structure), with syntaxin-6/SNAP-23 for regulated enlargeosome exocytosis, with syntaxin-1/SNAP-25 for asynchronous and Ca2+-sensitive spontaneous synaptic vesicle fusion (but not synchronous release because it does not engage synaptotagmin-1 or complexin), and with Stx6/Stx7/Vti1b for Golgi-to-late-endosome trafficking of MT1-MMP; at synapses, VAMP4 is selectively retrieved via activity-dependent bulk endocytosis through its di-leucine motif and cleared to endolysosomes, thereby controlling synaptic vesicle release probability by limiting VAMP4 copy number on vesicles; in dendrites VAMP4 mediates recycling-endosome exocytosis and sorts transferrin receptors and AMPARs into distinct endosomal pools, restraining baseline AMPAR-mediated transmission and permitting LTP expression."},"narrative":{"mechanistic_narrative":"VAMP4 is a trans-Golgi network (TGN)-enriched R-SNARE that organizes multiple membrane trafficking pathways by assembling into distinct SNARE complexes whose composition is dictated by its localization [PMID:12682051, PMID:23677696]. Its TGN targeting and cycling are governed by an N-terminal extension containing a di-leucine motif and acidic clusters: this region is an autonomous TGN-targeting signal [PMID:12682051], binds the AP-1 subunit mu1a, and is regulated by CK2 phosphorylation of Ser30 that recruits AP-1 via PACS-1 [PMID:14608369], driving clathrin-dependent endocytic retrieval from the cell surface through endosomes back to the TGN [PMID:17327277]. In the secretory and endosomal systems, VAMP4 partners with syntaxin-6/syntaxin-16/Vti1a to support retrograde endosome-to-TGN transport required to maintain Golgi ribbon integrity [PMID:23677696], with syntaxin-6/SNAP-23 to drive regulated enlargeosome exocytosis [PMID:18713833], and with Stx6/Stx7/Vti1b to traffic MT1-MMP from the Golgi to late endosomes for surface delivery and matrix degradation in macrophages [PMID:34476885]. At synapses, VAMP4 forms a SNARE complex with syntaxin-1 and SNAP-25 that excludes complexin and synaptotagmin-1, supporting Ca2+-dependent asynchronous and spontaneous release rather than fast synchronous fusion [PMID:22406549, PMID:32532887]; it is selectively retrieved by activity-dependent bulk endocytosis through its di-leucine motif and cleared to endolysosomes, and its copy number on synaptic vesicles sets release probability [PMID:26607000, PMID:33931449]. In dendrites VAMP4 mediates recycling-endosome exocytosis and sorts transferrin receptors and AMPA receptors into distinct endosomal pools, thereby restraining basal AMPAR-mediated transmission and enabling LTP [PMID:34496238]. VAMP4 also supports cytotoxic granule exocytosis in NK cells [PMID:21805468].","teleology":[{"year":2003,"claim":"Established the molecular basis of VAMP4's steady-state localization, answering how this R-SNARE is concentrated at the TGN and routed within the regulated secretory pathway.","evidence":"Chimeric domain swaps, deletion and point mutagenesis of the N-terminal di-leucine/acidic-cluster motif, plus AP-1 mu1a binding assays, CK2 phosphorylation, and dominant-negative PACS-1 rescue in cultured cells","pmids":["12682051","14608369"],"confidence":"High","gaps":["Did not resolve which downstream SNARE complexes the localized protein engages","In vivo relevance of CK2/PACS-1 regulation not tested"]},{"year":2007,"claim":"Resolved the trafficking itinerary of VAMP4, showing it cycles from the plasma membrane through sorting and recycling endosomes directly back to the TGN, bypassing late endosomes.","evidence":"Antibody-uptake assays with pharmacological and thermal perturbation of endosomal transport plus motif mutagenesis in stable VAMP4-EGFP cells","pmids":["17327277"],"confidence":"High","gaps":["Did not identify the SNARE partners executing each transport step","Quantitative flux through each compartment not measured"]},{"year":2008,"claim":"Defined a dedicated exocytic role, identifying VAMP4 with syntaxin-6/SNAP-23 as the SNARE machinery for fast regulated enlargeosome exocytosis.","evidence":"Co-localization, anti-VAMP4 antibody microinjection, siRNA knockdown and membrane capacitance measurements in PC12-27 cells","pmids":["18713833"],"confidence":"High","gaps":["Cognate Q-SNARE stoichiometry and trans-complex structure not resolved","Generality beyond enlargeosome-containing cells not addressed"]},{"year":2011,"claim":"Extended VAMP4 function to immune secretion, showing it is required for cytotoxic granule release but not IFN-gamma secretion in NK cells.","evidence":"siRNA knockdown, immunofluorescence co-localization and cytotoxicity/secretion assays in YTS and peripheral NK cells","pmids":["21805468"],"confidence":"Medium","gaps":["SNARE partners for lytic granule fusion not identified","Single lab, no rescue"]},{"year":2012,"claim":"Demonstrated a specialized synaptic function: VAMP4 forms a complexin/synaptotagmin-1-independent SNARE complex with syntaxin-1/SNAP-25 selectively driving Ca2+-dependent asynchronous release.","evidence":"Bidirectional VAMP4 modulation with electrophysiology, biochemical SNARE complex formation assays and single-synapse optical imaging in mouse neurons","pmids":["22406549"],"confidence":"High","gaps":["Calcium sensor for asynchronous release not identified","Structural basis for excluding synaptotagmin-1/complexin unresolved"]},{"year":2013,"claim":"Connected VAMP4-mediated retrograde traffic to organelle architecture, showing its endosome-to-TGN SNARE complex maintains the Golgi ribbon.","evidence":"siRNA depletion of VAMP4 and partners syntaxin-6/syntaxin-16/Vti1a with EM, immunofluorescence and anterograde trafficking assays in HeLa cells","pmids":["23677696"],"confidence":"Medium","gaps":["Direct trans-SNARE assembly with these partners not biochemically reconstituted","Single lab"]},{"year":2015,"claim":"Identified VAMP4 as the first cargo specifically retrieved by activity-dependent bulk endocytosis and as a factor essential for ADBE itself.","evidence":"pHluorin cargo reporters, ADBE inhibition, immunoisolation of bulk endosomes and di-leucine motif mutagenesis in neuronal cultures","pmids":["26607000"],"confidence":"High","gaps":["Molecular machinery recognizing the di-leucine motif during ADBE not defined","Mechanism of VAMP4's requirement for ADBE not resolved"]},{"year":2020,"claim":"Linked VAMP4 retrieval to a distinct release mode, showing it supports Ca2+-dependent spontaneous excitatory transmission and that high-frequency stimulation augments this release VAMP4-dependently.","evidence":"VAMP4 knockdown/mutant expression, clathrin pathway inhibition and electrophysiology in rat hippocampal neurons","pmids":["32532887"],"confidence":"Medium","gaps":["Vesicle pool generating spontaneous events not directly imaged","Single lab"]},{"year":2021,"claim":"Provided the mechanism for synaptic vesicle heterogeneity: endolysosomal clearance of VAMP4 limits its copy number on vesicles and thereby sets release probability.","evidence":"VAMP4 copy-number modulation, SNARE complex efficiency assays, endolysosomal trafficking perturbation and electrophysiology in neuronal cultures","pmids":["33931449"],"confidence":"High","gaps":["Quantitative relationship between VAMP4 number and fusion kinetics not fully resolved","Endolysosomal sorting receptor not identified"]},{"year":2021,"claim":"Established VAMP4 as the dendritic recycling-endosome R-SNARE that sorts AMPARs and transferrin receptors into separate pools, restraining basal AMPAR transmission and permitting LTP.","evidence":"VAMP4 knockdown, live exocytosis imaging, transferrin recycling assays and LTP electrophysiology in neuronal cultures","pmids":["34496238"],"confidence":"Medium","gaps":["Cargo-sorting determinant distinguishing AMPAR from TfR pools unknown","Single lab"]},{"year":2021,"claim":"Defined a macrophage trafficking route, showing VAMP4 pairs with the Stx6/Stx7/Vti1b Q-SNARE complex to deliver MT1-MMP from Golgi to late endosomes for surface matrix degradation.","evidence":"Fixed/live imaging, siRNA depletion of each SNARE component, surface MT1-MMP quantification and gelatin degradation assays in macrophages","pmids":["34476885"],"confidence":"Medium","gaps":["Trans-SNARE complex not reconstituted in vitro","Single lab"]},{"year":2026,"claim":"Implicated VAMP4 in hypoxia-driven secretion of mitochondria as extracellular vesicles via autophagy/mitophagy in cancer cells.","evidence":"Multivesicular body membrane proteomics and interaction validation in a hypoxic HNSCC model","pmids":["41979085"],"confidence":"Low","gaps":["Interaction validation limited; no reconstitution or mutagenesis","Functional contribution of VAMP4 to mitochondrial EV secretion not dissected","Single lab, not independently confirmed"]},{"year":null,"claim":"How VAMP4's distinct SNARE-complex assemblies are spatially and temporally partitioned within a single cell — and how its sorting motifs select the correct partner at each compartment — remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of VAMP4 trans-SNARE complexes","Determinants directing VAMP4 to specific partners (syntaxin-1 vs syntaxin-6 vs syntaxin-7) not defined","Regulation integrating retrograde traffic with synaptic release in vivo unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[5,9,11]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,2]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0,6,11]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[2,7]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[3,5,10]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[2,3,6,11]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[5,7,9,10]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[2,6]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[4]}],"complexes":["VAMP4-syntaxin-1-SNAP-25 SNARE complex","VAMP4-syntaxin-6-syntaxin-16-Vti1a SNARE complex","VAMP4-syntaxin-6-SNAP-23 SNARE complex","VAMP4-Stx6-Stx7-Vti1b SNARE complex"],"partners":["STX1A","SNAP25","STX6","STX16","VTI1A","STX7","VTI1B","AP1M1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O75379","full_name":"Vesicle-associated membrane protein 4","aliases":[],"length_aa":141,"mass_kda":16.4,"function":"Involved in the pathway that functions to remove an inhibitor (probably synaptotagmin-4) of calcium-triggered exocytosis during the maturation of secretory granules. May be a marker for this sorting pathway that is critical for remodeling the secretory response of granule","subcellular_location":"Golgi apparatus, trans-Golgi network membrane","url":"https://www.uniprot.org/uniprotkb/O75379/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/VAMP4","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000117533","cell_line_id":"CID000771","localizations":[{"compartment":"vesicles","grade":3}],"interactors":[{"gene":"VTI1A","stoichiometry":10.0},{"gene":"SNAP29","stoichiometry":4.0},{"gene":"NSF","stoichiometry":4.0},{"gene":"CLTA","stoichiometry":0.2},{"gene":"CSNK2B","stoichiometry":0.2},{"gene":"NAPA","stoichiometry":0.2},{"gene":"STX10","stoichiometry":0.2},{"gene":"STX5","stoichiometry":0.2},{"gene":"STX7","stoichiometry":0.2},{"gene":"STX8","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000771","total_profiled":1310},"omim":[{"mim_id":"620986","title":"T-SNARE DOMAIN-CONTAINING PROTEIN 1; TSNARE1","url":"https://www.omim.org/entry/620986"},{"mim_id":"619659","title":"SYNAPTOSOME-ASSOCIATED PROTEIN 47; SNAP47","url":"https://www.omim.org/entry/619659"},{"mim_id":"619550","title":"RAB40B, MEMBER RAS ONCOGENE FAMILY; RAB40B","url":"https://www.omim.org/entry/619550"},{"mim_id":"615738","title":"VPS51 SUBUNIT OF GARP COMPLEX; VPS51","url":"https://www.omim.org/entry/615738"},{"mim_id":"606909","title":"VESICLE-ASSOCIATED MEMBRANE PROTEIN 4; VAMP4","url":"https://www.omim.org/entry/606909"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/VAMP4"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"O75379","domains":[{"cath_id":"1.20.5","chopping":"51-141","consensus_level":"medium","plddt":91.0362,"start":51,"end":141}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O75379","model_url":"https://alphafold.ebi.ac.uk/files/AF-O75379-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O75379-F1-predicted_aligned_error_v6.png","plddt_mean":81.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=VAMP4","jax_strain_url":"https://www.jax.org/strain/search?query=VAMP4"},"sequence":{"accession":"O75379","fasta_url":"https://rest.uniprot.org/uniprotkb/O75379.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O75379/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O75379"}},"corpus_meta":[{"pmid":"22406549","id":"PMC_22406549","title":"VAMP4 directs synaptic vesicles to a pool that selectively maintains asynchronous neurotransmission.","date":"2012","source":"Nature neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/22406549","citation_count":127,"is_preprint":false},{"pmid":"17327277","id":"PMC_17327277","title":"VAMP4 cycles from the cell surface to the trans-Golgi network via sorting and recycling endosomes.","date":"2007","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/17327277","citation_count":62,"is_preprint":false},{"pmid":"26607000","id":"PMC_26607000","title":"VAMP4 Is an Essential Cargo Molecule for Activity-Dependent Bulk Endocytosis.","date":"2015","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/26607000","citation_count":59,"is_preprint":false},{"pmid":"14608369","id":"PMC_14608369","title":"AP-1 recruitment to VAMP4 is modulated by phosphorylation-dependent binding of PACS-1.","date":"2003","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/14608369","citation_count":55,"is_preprint":false},{"pmid":"18713833","id":"PMC_18713833","title":"The regulated exocytosis of enlargeosomes is mediated by a SNARE machinery that includes VAMP4.","date":"2008","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/18713833","citation_count":50,"is_preprint":false},{"pmid":"15635639","id":"PMC_15635639","title":"Suicide attempt and basic mechanisms in neural conduction: relationships to the SCN8A and VAMP4 genes.","date":"2005","source":"American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15635639","citation_count":41,"is_preprint":false},{"pmid":"12682051","id":"PMC_12682051","title":"The cytoplasmic domain of Vamp4 and Vamp5 is responsible for their correct subcellular targeting: the N-terminal extenSion of VAMP4 contains a dominant autonomous targeting signal for the trans-Golgi network.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12682051","citation_count":39,"is_preprint":false},{"pmid":"21805468","id":"PMC_21805468","title":"VAMP4- and VAMP7-expressing vesicles are both required for cytotoxic granule exocytosis in NK cells.","date":"2011","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/21805468","citation_count":33,"is_preprint":false},{"pmid":"33931449","id":"PMC_33931449","title":"Control of synaptic vesicle release probability via VAMP4 targeting to endolysosomes.","date":"2021","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/33931449","citation_count":31,"is_preprint":false},{"pmid":"23677696","id":"PMC_23677696","title":"VAMP4 is required to maintain the ribbon structure of the Golgi apparatus.","date":"2013","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23677696","citation_count":31,"is_preprint":false},{"pmid":"32532887","id":"PMC_32532887","title":"VAMP4 Maintains a Ca2+-Sensitive Pool of Spontaneously Recycling Synaptic Vesicles.","date":"2020","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/32532887","citation_count":27,"is_preprint":false},{"pmid":"32873436","id":"PMC_32873436","title":"Analysis of DNM3 and VAMP4 as genetic modifiers of LRRK2 Parkinson's disease.","date":"2020","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/32873436","citation_count":22,"is_preprint":false},{"pmid":"34496238","id":"PMC_34496238","title":"The vSNAREs VAMP2 and VAMP4 control recycling and intracellular sorting of post-synaptic receptors in neuronal dendrites.","date":"2021","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/34496238","citation_count":19,"is_preprint":false},{"pmid":"34476885","id":"PMC_34476885","title":"The trans-SNARE complex VAMP4/Stx6/Stx7/Vti1b is a key regulator of Golgi to late endosome MT1-MMP transport in macrophages.","date":"2021","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/34476885","citation_count":12,"is_preprint":false},{"pmid":"41460344","id":"PMC_41460344","title":"VAMP4 in hypoxic adipose stem cell exosomes alleviates ischemia-reperfusion injury.","date":"2025","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/41460344","citation_count":0,"is_preprint":false},{"pmid":"41979085","id":"PMC_41979085","title":"VAMP4/STX8 Mediate the Autophagic Secretion of Mitochondria and Promote TAMs Polarization in HNSCC.","date":"2026","source":"Journal of extracellular vesicles","url":"https://pubmed.ncbi.nlm.nih.gov/41979085","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9475,"output_tokens":3680,"usd":0.041813,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11342,"output_tokens":4393,"usd":0.083267,"stage2_stop_reason":"end_turn"},"total_usd":0.12508,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2003,\n      \"finding\": \"The N-terminal 51-residue extension of VAMP4 (containing a di-leucine motif followed by two acidic clusters) is a dominant autonomous targeting signal for the trans-Golgi network (TGN). Swapping this region onto VAMP5 redirects it to the TGN; site-directed mutagenesis confirmed the essential roles of the di-Leu motif and the second acidic cluster.\",\n      \"method\": \"Chimeric protein swaps, deletion mutagenesis, site-directed mutagenesis, EGFP-tagging and fluorescence microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (domain swaps, deletion mutants, point mutagenesis) in a single focused study establishing the targeting signal\",\n      \"pmids\": [\"12682051\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"VAMP4 binds to the AP-1 adaptor subunit mu1a (but not mu1b or GGAs) via its di-leucine motif (Leu25/26) and Ser20. Phosphorylation of Ser30 in the acidic cluster by casein kinase 2 enhances AP-1 recruitment through PACS-1. Ablation of both the di-leucine motif and Ser30, or expression of dominant-negative PACS-1, causes dramatic VAMP4 mislocalization in the regulated secretory pathway.\",\n      \"method\": \"Binding assays, site-directed mutagenesis, dominant-negative PACS-1 overexpression, immunofluorescence in AtT20 cells\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (mutagenesis, phosphorylation assay, dominant-negative rescue) with clear functional readout\",\n      \"pmids\": [\"14608369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"VAMP4 cycles from the cell surface to the TGN via clathrin-dependent endocytosis through sorting and then recycling endosomes, followed by direct transport to the TGN without transiting the late endosome. The di-Leu motif is required for internalization, and the acidic cluster is crucial for endosome-to-TGN delivery.\",\n      \"method\": \"EGFP-antibody uptake assay, pharmacological and thermal perturbation of endosomal trafficking, fluorescence time-course imaging in stable VAMP4-EGFP cells\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal perturbations (pharmacological, thermal, mutagenesis of motifs) with quantitative trafficking assay\",\n      \"pmids\": [\"17327277\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"VAMP4 localizes to enlargeosome membranes in PC12-27 cells and is a component of the SNARE machinery (with syntaxin-6 and SNAP-23) mediating fast regulated exocytosis of enlargeosomes. Microinjection of anti-VAMP4 antibody and VAMP4 siRNA knockdown both inhibit enlargeosome exocytosis.\",\n      \"method\": \"Co-localization imaging, antibody microinjection, siRNA knockdown, capacitance measurements, VAMP4-GFP surface appearance assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal perturbations (antibody inhibition + siRNA KD) with electrophysiological and imaging readouts, in two cell types\",\n      \"pmids\": [\"18713833\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"VAMP4 co-localizes with lytic granules during cytotoxic NK-cell interactions and is required for cytotoxic granule exocytosis. Knockdown of VAMP4 in both the YTS NK cell line and peripheral NK cells inhibits lytic granule release and severely impairs cytotoxic activity. Unlike VAMP7, VAMP4 is not involved in IFN-γ secretion.\",\n      \"method\": \"Immunofluorescence co-localization, siRNA knockdown, cytotoxicity assays, IFN-γ secretion assays in NK cells\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA KD with defined functional readout in two cell types, single lab\",\n      \"pmids\": [\"21805468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"VAMP4 selectively maintains Ca2+-dependent asynchronous neurotransmitter release at inhibitory synapses, while synaptobrevin-2/VAMP2 drives synchronous release. VAMP4 forms a stable SNARE complex with syntaxin-1 and SNAP-25 that does not interact with complexin or synaptotagmin-1. VAMP4 and VAMP2 traffic independently with minimal overlap in individual synapses.\",\n      \"method\": \"Up/downregulation of VAMP4 with electrophysiological recording, biochemical SNARE complex formation assay, optical imaging of individual synapses in mouse neurons\",\n      \"journal\": \"Nature neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (electrophysiology, biochemical complex assay, optical imaging) with bidirectional modulation of VAMP4\",\n      \"pmids\": [\"22406549\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"VAMP4 is required to maintain the ribbon structure of the Golgi apparatus. RNAi-mediated depletion of VAMP4 in HeLa cells causes Golgi ribbon fragmentation (shortened stacks remain in juxtanuclear area) without disrupting anterograde trafficking or microtubules. Knockdown of cognate SNARE partners syntaxin 6, syntaxin 16, and Vti1a phenocopies this fragmentation, implicating VAMP4-containing SNARE complexes in retrograde endosome-to-TGN trafficking needed for Golgi integrity.\",\n      \"method\": \"siRNA knockdown, electron microscopy, immunofluorescence, anterograde trafficking assay in HeLa cells\",\n      \"journal\": \"Molecular and cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA KD with EM and fluorescence readouts, multiple SNARE partners tested, single lab\",\n      \"pmids\": [\"23677696\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"VAMP4 is the first identified cargo specifically retrieved by activity-dependent bulk endocytosis (ADBE) during intense neuronal stimulation. Endogenous VAMP4 is enriched in purified bulk endosomes. VAMP4 is also essential for ADBE to proceed, with the cytoplasmic di-leucine motif being critical for this role.\",\n      \"method\": \"pHluorin reporter assays for multiple SV cargo proteins, ADBE inhibition, immunoisolation of bulk endosomes, di-leucine motif mutagenesis, neuronal cultures\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple cargo reporters compared, biochemical fractionation of bulk endosomes, and mutagenesis of functional motif, single lab but orthogonal methods\",\n      \"pmids\": [\"26607000\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"VAMP4 is required for Ca2+-dependent spontaneous excitatory neurotransmission, with limited role in spontaneous inhibitory transmission. Key residues governing VAMP4 retrieval and clathrin-mediated vesicle trafficking are essential for this role. High-frequency stimulation triggers VAMP4 retrieval and augments Ca2+-sensitive spontaneous release for up to 30 min in a VAMP4-dependent manner, linking asynchronous and spontaneous release.\",\n      \"method\": \"VAMP4 knockdown/mutant expression, electrophysiological recording, clathrin pathway inhibition in rat hippocampal neurons\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD plus mutant rescue with electrophysiological readout, single lab\",\n      \"pmids\": [\"32532887\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"VAMP4 copy number on synaptic vesicles (SVs) regulates release probability (Pr). VAMP4 has reduced ability to form efficient SNARE complexes with canonical plasma membrane SNAREs, and is selectively sorted to endolysosomes during ADBE. Disruption of endolysosomal trafficking increases VAMP4 abundance in the SV pool and inhibits SV fusion, demonstrating that endolysosomal clearance of VAMP4 is the mechanism generating SV heterogeneity.\",\n      \"method\": \"Modulation of VAMP4 copy number, SNARE complex efficiency assay, endolysosomal trafficking perturbation, SV pool analysis, electrophysiology in neuronal cultures\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — biochemical SNARE complex assay, trafficking perturbation, and functional electrophysiology combined in one study with clear mechanistic outcome\",\n      \"pmids\": [\"33931449\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"VAMP4 is the primary vesicular SNARE mediating dendritic recycling endosome exocytosis in neurons. VAMP4 KD decreases transferrin receptor (TfR) recycling while paradoxically increasing AMPA receptor (AMPAR) recycling and synaptic transmission, occluding LTP expression. This reveals that VAMP4 sorts AMPARs and TfRs into separate endosomal populations.\",\n      \"method\": \"VAMP4 KD, live imaging of vesicle exocytosis, transferrin receptor recycling assay, electrophysiological recording of synaptic transmission and LTP in neuronal cultures\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with multiple functional readouts (recycling assays, electrophysiology), single lab\",\n      \"pmids\": [\"34496238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In macrophages, VAMP4 on Golgi-derived vesicles forms a trans-SNARE complex with the Q-SNARE complex Stx6/Stx7/Vti1b to mediate transport of MT1-MMP from the Golgi to late endosomes en route to the cell surface. Depletion of VAMP4 or any component of this complex reduces surface MT1-MMP and gelatin degradation.\",\n      \"method\": \"Fixed and live imaging, siRNA depletion of SNARE components, surface MT1-MMP quantification, gelatin degradation assay in macrophages\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — imaging plus functional depletion assays with degradation readout, single lab\",\n      \"pmids\": [\"34476885\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Under hypoxic conditions in HNSCC, VAMP4 and syntaxin 8 (STX8) mediate the autophagic (mitophagy-dependent) secretion of mitochondria as extracellular vesicles, identified by multivesicular body membrane proteomics and molecular interaction validation.\",\n      \"method\": \"Multivesicular body membrane proteomics, molecular interaction validation, hypoxia model in HNSCC cells\",\n      \"journal\": \"Journal of extracellular vesicles\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, limited mechanistic detail on interaction validation in abstract, no reconstitution or mutagenesis described\",\n      \"pmids\": [\"41979085\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"VAMP4 is a TGN-enriched R-SNARE whose N-terminal di-leucine/acidic-cluster motif directs its TGN localization and clathrin-dependent endocytic recycling (modulated by CK2-phosphorylation–dependent PACS-1/AP-1 recruitment); it forms SNARE complexes with syntaxin-6/syntaxin-16/Vti1a for retrograde endosome-to-TGN traffic (maintaining Golgi ribbon structure), with syntaxin-6/SNAP-23 for regulated enlargeosome exocytosis, with syntaxin-1/SNAP-25 for asynchronous and Ca2+-sensitive spontaneous synaptic vesicle fusion (but not synchronous release because it does not engage synaptotagmin-1 or complexin), and with Stx6/Stx7/Vti1b for Golgi-to-late-endosome trafficking of MT1-MMP; at synapses, VAMP4 is selectively retrieved via activity-dependent bulk endocytosis through its di-leucine motif and cleared to endolysosomes, thereby controlling synaptic vesicle release probability by limiting VAMP4 copy number on vesicles; in dendrites VAMP4 mediates recycling-endosome exocytosis and sorts transferrin receptors and AMPARs into distinct endosomal pools, restraining baseline AMPAR-mediated transmission and permitting LTP expression.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"VAMP4 is a trans-Golgi network (TGN)-enriched R-SNARE that organizes multiple membrane trafficking pathways by assembling into distinct SNARE complexes whose composition is dictated by its localization [#0, #6]. Its TGN targeting and cycling are governed by an N-terminal extension containing a di-leucine motif and acidic clusters: this region is an autonomous TGN-targeting signal [#0], binds the AP-1 subunit mu1a, and is regulated by CK2 phosphorylation of Ser30 that recruits AP-1 via PACS-1 [#1], driving clathrin-dependent endocytic retrieval from the cell surface through endosomes back to the TGN [#2]. In the secretory and endosomal systems, VAMP4 partners with syntaxin-6/syntaxin-16/Vti1a to support retrograde endosome-to-TGN transport required to maintain Golgi ribbon integrity [#6], with syntaxin-6/SNAP-23 to drive regulated enlargeosome exocytosis [#3], and with Stx6/Stx7/Vti1b to traffic MT1-MMP from the Golgi to late endosomes for surface delivery and matrix degradation in macrophages [#11]. At synapses, VAMP4 forms a SNARE complex with syntaxin-1 and SNAP-25 that excludes complexin and synaptotagmin-1, supporting Ca2+-dependent asynchronous and spontaneous release rather than fast synchronous fusion [#5, #8]; it is selectively retrieved by activity-dependent bulk endocytosis through its di-leucine motif and cleared to endolysosomes, and its copy number on synaptic vesicles sets release probability [#7, #9]. In dendrites VAMP4 mediates recycling-endosome exocytosis and sorts transferrin receptors and AMPA receptors into distinct endosomal pools, thereby restraining basal AMPAR-mediated transmission and enabling LTP [#10]. VAMP4 also supports cytotoxic granule exocytosis in NK cells [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"Established the molecular basis of VAMP4's steady-state localization, answering how this R-SNARE is concentrated at the TGN and routed within the regulated secretory pathway.\",\n      \"evidence\": \"Chimeric domain swaps, deletion and point mutagenesis of the N-terminal di-leucine/acidic-cluster motif, plus AP-1 mu1a binding assays, CK2 phosphorylation, and dominant-negative PACS-1 rescue in cultured cells\",\n      \"pmids\": [\"12682051\", \"14608369\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve which downstream SNARE complexes the localized protein engages\", \"In vivo relevance of CK2/PACS-1 regulation not tested\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Resolved the trafficking itinerary of VAMP4, showing it cycles from the plasma membrane through sorting and recycling endosomes directly back to the TGN, bypassing late endosomes.\",\n      \"evidence\": \"Antibody-uptake assays with pharmacological and thermal perturbation of endosomal transport plus motif mutagenesis in stable VAMP4-EGFP cells\",\n      \"pmids\": [\"17327277\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the SNARE partners executing each transport step\", \"Quantitative flux through each compartment not measured\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defined a dedicated exocytic role, identifying VAMP4 with syntaxin-6/SNAP-23 as the SNARE machinery for fast regulated enlargeosome exocytosis.\",\n      \"evidence\": \"Co-localization, anti-VAMP4 antibody microinjection, siRNA knockdown and membrane capacitance measurements in PC12-27 cells\",\n      \"pmids\": [\"18713833\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cognate Q-SNARE stoichiometry and trans-complex structure not resolved\", \"Generality beyond enlargeosome-containing cells not addressed\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Extended VAMP4 function to immune secretion, showing it is required for cytotoxic granule release but not IFN-gamma secretion in NK cells.\",\n      \"evidence\": \"siRNA knockdown, immunofluorescence co-localization and cytotoxicity/secretion assays in YTS and peripheral NK cells\",\n      \"pmids\": [\"21805468\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"SNARE partners for lytic granule fusion not identified\", \"Single lab, no rescue\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Demonstrated a specialized synaptic function: VAMP4 forms a complexin/synaptotagmin-1-independent SNARE complex with syntaxin-1/SNAP-25 selectively driving Ca2+-dependent asynchronous release.\",\n      \"evidence\": \"Bidirectional VAMP4 modulation with electrophysiology, biochemical SNARE complex formation assays and single-synapse optical imaging in mouse neurons\",\n      \"pmids\": [\"22406549\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Calcium sensor for asynchronous release not identified\", \"Structural basis for excluding synaptotagmin-1/complexin unresolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Connected VAMP4-mediated retrograde traffic to organelle architecture, showing its endosome-to-TGN SNARE complex maintains the Golgi ribbon.\",\n      \"evidence\": \"siRNA depletion of VAMP4 and partners syntaxin-6/syntaxin-16/Vti1a with EM, immunofluorescence and anterograde trafficking assays in HeLa cells\",\n      \"pmids\": [\"23677696\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct trans-SNARE assembly with these partners not biochemically reconstituted\", \"Single lab\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identified VAMP4 as the first cargo specifically retrieved by activity-dependent bulk endocytosis and as a factor essential for ADBE itself.\",\n      \"evidence\": \"pHluorin cargo reporters, ADBE inhibition, immunoisolation of bulk endosomes and di-leucine motif mutagenesis in neuronal cultures\",\n      \"pmids\": [\"26607000\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular machinery recognizing the di-leucine motif during ADBE not defined\", \"Mechanism of VAMP4's requirement for ADBE not resolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked VAMP4 retrieval to a distinct release mode, showing it supports Ca2+-dependent spontaneous excitatory transmission and that high-frequency stimulation augments this release VAMP4-dependently.\",\n      \"evidence\": \"VAMP4 knockdown/mutant expression, clathrin pathway inhibition and electrophysiology in rat hippocampal neurons\",\n      \"pmids\": [\"32532887\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Vesicle pool generating spontaneous events not directly imaged\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Provided the mechanism for synaptic vesicle heterogeneity: endolysosomal clearance of VAMP4 limits its copy number on vesicles and thereby sets release probability.\",\n      \"evidence\": \"VAMP4 copy-number modulation, SNARE complex efficiency assays, endolysosomal trafficking perturbation and electrophysiology in neuronal cultures\",\n      \"pmids\": [\"33931449\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative relationship between VAMP4 number and fusion kinetics not fully resolved\", \"Endolysosomal sorting receptor not identified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Established VAMP4 as the dendritic recycling-endosome R-SNARE that sorts AMPARs and transferrin receptors into separate pools, restraining basal AMPAR transmission and permitting LTP.\",\n      \"evidence\": \"VAMP4 knockdown, live exocytosis imaging, transferrin recycling assays and LTP electrophysiology in neuronal cultures\",\n      \"pmids\": [\"34496238\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cargo-sorting determinant distinguishing AMPAR from TfR pools unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined a macrophage trafficking route, showing VAMP4 pairs with the Stx6/Stx7/Vti1b Q-SNARE complex to deliver MT1-MMP from Golgi to late endosomes for surface matrix degradation.\",\n      \"evidence\": \"Fixed/live imaging, siRNA depletion of each SNARE component, surface MT1-MMP quantification and gelatin degradation assays in macrophages\",\n      \"pmids\": [\"34476885\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Trans-SNARE complex not reconstituted in vitro\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Implicated VAMP4 in hypoxia-driven secretion of mitochondria as extracellular vesicles via autophagy/mitophagy in cancer cells.\",\n      \"evidence\": \"Multivesicular body membrane proteomics and interaction validation in a hypoxic HNSCC model\",\n      \"pmids\": [\"41979085\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Interaction validation limited; no reconstitution or mutagenesis\", \"Functional contribution of VAMP4 to mitochondrial EV secretion not dissected\", \"Single lab, not independently confirmed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How VAMP4's distinct SNARE-complex assemblies are spatially and temporally partitioned within a single cell — and how its sorting motifs select the correct partner at each compartment — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of VAMP4 trans-SNARE complexes\", \"Determinants directing VAMP4 to specific partners (syntaxin-1 vs syntaxin-6 vs syntaxin-7) not defined\", \"Regulation integrating retrograde traffic with synaptic release in vivo unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [5, 9, 11]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0, 6, 11]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [2, 7]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [3, 5, 10]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [2, 3, 6, 11]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [5, 7, 9, 10]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [2, 6]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [\n      \"VAMP4-syntaxin-1-SNAP-25 SNARE complex\",\n      \"VAMP4-syntaxin-6-syntaxin-16-Vti1a SNARE complex\",\n      \"VAMP4-syntaxin-6-SNAP-23 SNARE complex\",\n      \"VAMP4-Stx6-Stx7-Vti1b SNARE complex\"\n    ],\n    \"partners\": [\n      \"STX1A\",\n      \"SNAP25\",\n      \"STX6\",\n      \"STX16\",\n      \"VTI1A\",\n      \"STX7\",\n      \"VTI1B\",\n      \"AP1M1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}