{"gene":"RAB3C","run_date":"2026-04-28T19:45:45","timeline":{"discoveries":[{"year":1994,"finding":"RAB3C is localized on synaptic vesicles in neurons and dissociates from synaptic vesicle and/or recycling membranes upon stimulation of neurotransmitter release, cycling on and off the membrane in parallel with exocytotic release, mirroring RAB3A behavior. Co-immunoisolation with anti-RAB3A antibodies demonstrated co-localization of RAB3A and RAB3C on the same organelle.","method":"Synaptic vesicle immunoisolation with monoclonal anti-RAB3A antibodies, subcellular fractionation of isolated nerve terminals after stimulation, Western blotting","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-isolation, functional stimulation assay, replicated across multiple approaches in a highly-cited study","pmids":["8157621"],"is_preprint":false},{"year":1997,"finding":"RAB3C expressed in bovine chromaffin cells exhibits a distinct nucleotide-binding affinity (Kd for GTPγS ~204 nM) compared to RAB3A and RAB3B; truncation of the C-terminal 31 residues decreases GTPγS binding affinity, and replacing the RAB3C C-terminus with that of RAB3A further decreases affinity. RAB3C localizes to vesicle-like structures (distinct from RAB3B plasma membrane localization), and its intrinsic GTPase activity is stimulated ~3-fold by chromaffin cell lysate.","method":"In vitro GTP binding and GTPase activity assays with recombinant truncation and chimeric mutants; immunostaining of chromaffin cells","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 — in vitro biochemical assays with mutagenesis plus direct localization imaging","pmids":["9164844"],"is_preprint":false},{"year":1995,"finding":"RAB3C undergoes insulin-dependent translocation from microsomal membranes to plasma membranes in cardiac muscle of lean rats, an effect abolished in insulin-resistant obese Zucker rats, implicating RAB3C in insulin-regulated vesicle trafficking in cardiac muscle.","method":"Subcellular fractionation and Western blotting of cardiac muscle after in vivo insulin stimulation","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 — subcellular fractionation with functional perturbation (insulin stimulation and insulin-resistant model), single study","pmids":["8543030"],"is_preprint":false},{"year":2008,"finding":"Zwint-1 was identified as a RAB3C-specific binding partner; a unique residue in RAB3C determines preferential binding to Zwint-1 (over RAB3A, RAB3B, RAB3D), and this residue is not required for rabphilin-3A interaction. RAB3C and Zwint-1 co-localize in primary hippocampal neurons. SNAP25 binds the same region of Zwint-1 as RAB3C, suggesting a presynaptic role for this interaction.","method":"Binding partner screen, co-immunoprecipitation, site-directed mutagenesis of RAB3C, immunofluorescence co-localization in primary hippocampal neurons, pull-down assays","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2-3 — pulldown/Co-IP plus mutagenesis and co-localization, single lab study","pmids":["18625232"],"is_preprint":false},{"year":2022,"finding":"RAB3C localizes to the manchette structure during spermatid head shaping and to the sperm tail in murine spermatids; in human spermatozoa it is concentrated in the postacrosomal region, neck, and midpiece. In human sperm carrying SEPT14 mutations, RAB3C signals are delocalized and accompanied by defective head and tail morphology, suggesting RAB3C localization depends on SEPT14 and is associated with sperm morphogenesis.","method":"Immunofluorescence of murine testicular tissue, isolated elongated spermatids, and human spermatozoa; comparison with SEPT14 mutant patient samples","journal":"Medicina (Kaunas, Lithuania)","confidence":"Low","confidence_rationale":"Tier 3 — localization study with disease correlation but no functional rescue or direct mechanistic dissection","pmids":["36295569"],"is_preprint":false},{"year":2024,"finding":"Citrulline was reported to bind RAB3C protein and activate the IL-6/STAT3 signaling pathway in lung cancer cells, promoting glycolysis, proliferation, migration, and invasion.","method":"RNA-seq, molecular docking, Western blotting of IL-6/STAT3 pathway components, in vivo mouse tumor model","journal":"Environmental toxicology","confidence":"Low","confidence_rationale":"Tier 3-4 — molecular docking (computational) plus Western blot correlation; no direct binding validation or RAB3C loss-of-function rescue","pmids":["38770826"],"is_preprint":false}],"current_model":"RAB3C is a vesicle-associated small GTPase of the RAB3 subfamily that localizes to synaptic vesicles and secretory vesicles in neuroendocrine cells, cycles on and off vesicle membranes in concert with stimulated exocytosis, possesses intrinsic GTPase activity stimulated by cytosolic factors, undergoes insulin-dependent translocation in cardiac muscle, and interacts with the kinetochore/presynaptic protein Zwint-1 via a unique residue that also influences SNAP25 binding, collectively placing RAB3C as a regulated effector of exocytotic membrane dynamics."},"narrative":{"teleology":[{"year":1994,"claim":"Establishing that RAB3C, like RAB3A, resides on synaptic vesicles and cycles off during exocytosis resolved whether RAB3C participates in the same stimulus-coupled vesicle dynamics as its paralog.","evidence":"Synaptic vesicle co-immunoisolation with anti-RAB3A antibodies and subcellular fractionation of nerve terminals after stimulation of neurotransmitter release","pmids":["8157621"],"confidence":"High","gaps":["Whether RAB3C has non-redundant functions distinct from RAB3A on the same vesicle","Identity of RAB3C-specific effectors at the synapse","No loss-of-function analysis to test requirement for exocytosis"]},{"year":1995,"claim":"Demonstrating insulin-dependent translocation of RAB3C in cardiac muscle extended the functional scope of RAB3C beyond neurons and linked it to metabolic regulation of vesicle trafficking.","evidence":"Subcellular fractionation and Western blotting of lean vs. insulin-resistant obese Zucker rat cardiac muscle after in vivo insulin stimulation","pmids":["8543030"],"confidence":"Medium","gaps":["The cargo or vesicle population governed by RAB3C in cardiac muscle is unknown","Single study with no genetic perturbation of RAB3C itself","Mechanism linking insulin signaling to RAB3C membrane recruitment is uncharacterized"]},{"year":1997,"claim":"Biochemical characterization of RAB3C GTP binding and GTPase activity, including C-terminal truncation and chimera analysis, established that the C-terminus dictates nucleotide affinity and vesicle targeting specificity distinct from other RAB3 paralogs.","evidence":"In vitro GTP-binding and GTPase assays with recombinant wild-type, truncated, and chimeric RAB3C proteins; immunostaining in bovine chromaffin cells","pmids":["9164844"],"confidence":"High","gaps":["The cytosolic GAP(s) responsible for stimulating RAB3C GTPase activity were not identified","Whether C-terminal differences among RAB3 paralogs determine distinct effector recruitment in vivo"]},{"year":2008,"claim":"Identification of Zwint-1 as a RAB3C-specific effector, with a unique RAB3C residue determining binding selectivity and SNAP25 competing for the same Zwint-1 interface, provided the first molecular basis for paralog-specific function at the presynapse.","evidence":"Binding partner screen, co-immunoprecipitation, site-directed mutagenesis, and co-localization in primary hippocampal neurons","pmids":["18625232"],"confidence":"Medium","gaps":["Functional consequence of disrupting RAB3C–Zwint-1 interaction on neurotransmitter release is untested","Single-lab finding without independent replication","Whether Zwint-1 acts as a vesicle tether, fusion regulator, or scaffolding factor in this context is unknown"]},{"year":2022,"claim":"Localization of RAB3C to the manchette and sperm tail during spermiogenesis, with delocalization in SEPT14-mutant sperm, suggested a role in membrane trafficking during sperm morphogenesis.","evidence":"Immunofluorescence of murine spermatids and human spermatozoa, including SEPT14-mutant patient samples","pmids":["36295569"],"confidence":"Low","gaps":["No functional perturbation of RAB3C itself was performed; causality not established","Whether RAB3C delocalization is a direct consequence of SEPT14 loss or secondary to structural disorganization is unclear","No rescue or knockdown experiments"]},{"year":null,"claim":"Key unresolved questions include the identity of RAB3C-specific GTPase-activating proteins, the functional consequence of RAB3C loss-of-function in neurons and other tissues, and whether RAB3C–Zwint-1 interaction directly regulates vesicle fusion or docking.","evidence":"","pmids":[],"confidence":"High","gaps":["No genetic knockout or knockdown phenotype has been reported for RAB3C in any organism","No structural model of the RAB3C–Zwint-1 or RAB3C–effector complex exists","The specific cargo(s) regulated by RAB3C in non-neuronal tissues remain unidentified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003924","term_label":"GTPase activity","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,1]},{"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":[0,1,2]}],"complexes":[],"partners":["ZWINT-1","RAB3A","SNAP25"],"other_free_text":[]},"mechanistic_narrative":"RAB3C is a small GTPase of the RAB3 subfamily that localizes to synaptic vesicles and secretory vesicles in neurons and neuroendocrine cells, cycling on and off vesicle membranes in concert with stimulated exocytosis [PMID:8157621]. Its intrinsic GTPase activity is stimulated by cytosolic factors, and the C-terminal domain modulates nucleotide-binding affinity and vesicle targeting [PMID:9164844]. RAB3C selectively binds Zwint-1 through a unique residue not shared by other RAB3 paralogs, and Zwint-1 in turn contacts SNAP25, linking RAB3C to the presynaptic vesicle fusion machinery in hippocampal neurons [PMID:18625232]. RAB3C also undergoes insulin-dependent translocation from microsomal to plasma membranes in cardiac muscle, indicating a broader role in regulated vesicle trafficking beyond the nervous system [PMID:8543030]."},"prefetch_data":{"uniprot":{"accession":"Q96E17","full_name":"Ras-related protein Rab-3C","aliases":[],"length_aa":227,"mass_kda":26.0,"function":"The small GTPases Rab are key regulators of intracellular membrane trafficking, from the formation of transport vesicles to their fusion with membranes. Rabs cycle between an inactive GDP-bound form and an active GTP-bound form that is able to recruit to membranes different sets of downstream effectors directly responsible for vesicle formation, movement, tethering and fusion","subcellular_location":"Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q96E17/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RAB3C","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RAB3C","total_profiled":1310},"omim":[{"mim_id":"612829","title":"RAS-ASSOCIATED PROTEIN RAB3C; RAB3C","url":"https://www.omim.org/entry/612829"},{"mim_id":"606630","title":"PROTEIN REGULATING SYNAPTIC MEMBRANE EXOCYTOSIS 2; RIMS2","url":"https://www.omim.org/entry/606630"},{"mim_id":"604350","title":"RAS-ASSOCIATED PROTEIN RAB3D; RAB3D","url":"https://www.omim.org/entry/604350"},{"mim_id":"601554","title":"DYNEIN, LIGHT CHAIN, TCTEX TYPE, 1; DYNLT1","url":"https://www.omim.org/entry/601554"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"adrenal gland","ntpm":8.5},{"tissue":"brain","ntpm":31.9}],"url":"https://www.proteinatlas.org/search/RAB3C"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q96E17","domains":[{"cath_id":"3.40.50.300","chopping":"26-198","consensus_level":"high","plddt":94.0352,"start":26,"end":198}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96E17","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96E17-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96E17-F1-predicted_aligned_error_v6.png","plddt_mean":82.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RAB3C","jax_strain_url":"https://www.jax.org/strain/search?query=RAB3C"},"sequence":{"accession":"Q96E17","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96E17.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96E17/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96E17"}},"corpus_meta":[{"pmid":"8157621","id":"PMC_8157621","title":"Rab3C is a synaptic vesicle protein that dissociates from synaptic vesicles after stimulation of exocytosis.","date":"1994","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/8157621","citation_count":133,"is_preprint":false},{"pmid":"18625232","id":"PMC_18625232","title":"A unique residue in rab3c determines the interaction with novel binding protein Zwint-1.","date":"2008","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/18625232","citation_count":26,"is_preprint":false},{"pmid":"8185573","id":"PMC_8185573","title":"Distribution and regulation of rab3C, a small molecular weight GTP-binding protein.","date":"1994","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/8185573","citation_count":15,"is_preprint":false},{"pmid":"8543030","id":"PMC_8543030","title":"Insulin-dependent translocation of the small GTP-binding protein rab3C in cardiac muscle: studies on insulin-resistant Zucker rats.","date":"1995","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/8543030","citation_count":12,"is_preprint":false},{"pmid":"9164844","id":"PMC_9164844","title":"Characterization of Rab3A, Rab3B and Rab3C: different biochemical properties and intracellular localization in bovine chromaffin cells.","date":"1997","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/9164844","citation_count":11,"is_preprint":false},{"pmid":"12296628","id":"PMC_12296628","title":"Cloning, mapping, and characterization of the human Rab3C gene.","date":"2002","source":"Biochemical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/12296628","citation_count":4,"is_preprint":false},{"pmid":"11573517","id":"PMC_11573517","title":"Molecular cloning of the mouse homologue of Rab3c.","date":"2001","source":"Journal of molecular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/11573517","citation_count":4,"is_preprint":false},{"pmid":"38770826","id":"PMC_38770826","title":"Citrulline facilitates the glycolysis, proliferation, and metastasis of lung cancer cells by regulating RAB3C.","date":"2024","source":"Environmental toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/38770826","citation_count":3,"is_preprint":false},{"pmid":"36295569","id":"PMC_36295569","title":"Localization Patterns of RAB3C Are Associated with Murine and Human Sperm Formation.","date":"2022","source":"Medicina (Kaunas, Lithuania)","url":"https://pubmed.ncbi.nlm.nih.gov/36295569","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.08.18.670791","title":"Aberrant epithelialization: A plausible factor for the development of endometrial polyps","date":"2025-08-22","source":"bioRxiv","url":"https://doi.org/10.1101/2025.08.18.670791","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":5544,"output_tokens":1626,"usd":0.020511},"stage2":{"model":"claude-opus-4-6","input_tokens":4869,"output_tokens":1718,"usd":0.100943},"total_usd":0.121454,"stage1_batch_id":"msgbatch_01SUR8NDzVrNmyszWyJeCct7","stage2_batch_id":"msgbatch_01G7Yfutko3cDWzejrwH5AMx","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1994,\n      \"finding\": \"RAB3C is localized on synaptic vesicles in neurons and dissociates from synaptic vesicle and/or recycling membranes upon stimulation of neurotransmitter release, cycling on and off the membrane in parallel with exocytotic release, mirroring RAB3A behavior. Co-immunoisolation with anti-RAB3A antibodies demonstrated co-localization of RAB3A and RAB3C on the same organelle.\",\n      \"method\": \"Synaptic vesicle immunoisolation with monoclonal anti-RAB3A antibodies, subcellular fractionation of isolated nerve terminals after stimulation, Western blotting\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-isolation, functional stimulation assay, replicated across multiple approaches in a highly-cited study\",\n      \"pmids\": [\"8157621\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"RAB3C expressed in bovine chromaffin cells exhibits a distinct nucleotide-binding affinity (Kd for GTPγS ~204 nM) compared to RAB3A and RAB3B; truncation of the C-terminal 31 residues decreases GTPγS binding affinity, and replacing the RAB3C C-terminus with that of RAB3A further decreases affinity. RAB3C localizes to vesicle-like structures (distinct from RAB3B plasma membrane localization), and its intrinsic GTPase activity is stimulated ~3-fold by chromaffin cell lysate.\",\n      \"method\": \"In vitro GTP binding and GTPase activity assays with recombinant truncation and chimeric mutants; immunostaining of chromaffin cells\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro biochemical assays with mutagenesis plus direct localization imaging\",\n      \"pmids\": [\"9164844\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"RAB3C undergoes insulin-dependent translocation from microsomal membranes to plasma membranes in cardiac muscle of lean rats, an effect abolished in insulin-resistant obese Zucker rats, implicating RAB3C in insulin-regulated vesicle trafficking in cardiac muscle.\",\n      \"method\": \"Subcellular fractionation and Western blotting of cardiac muscle after in vivo insulin stimulation\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — subcellular fractionation with functional perturbation (insulin stimulation and insulin-resistant model), single study\",\n      \"pmids\": [\"8543030\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Zwint-1 was identified as a RAB3C-specific binding partner; a unique residue in RAB3C determines preferential binding to Zwint-1 (over RAB3A, RAB3B, RAB3D), and this residue is not required for rabphilin-3A interaction. RAB3C and Zwint-1 co-localize in primary hippocampal neurons. SNAP25 binds the same region of Zwint-1 as RAB3C, suggesting a presynaptic role for this interaction.\",\n      \"method\": \"Binding partner screen, co-immunoprecipitation, site-directed mutagenesis of RAB3C, immunofluorescence co-localization in primary hippocampal neurons, pull-down assays\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — pulldown/Co-IP plus mutagenesis and co-localization, single lab study\",\n      \"pmids\": [\"18625232\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"RAB3C localizes to the manchette structure during spermatid head shaping and to the sperm tail in murine spermatids; in human spermatozoa it is concentrated in the postacrosomal region, neck, and midpiece. In human sperm carrying SEPT14 mutations, RAB3C signals are delocalized and accompanied by defective head and tail morphology, suggesting RAB3C localization depends on SEPT14 and is associated with sperm morphogenesis.\",\n      \"method\": \"Immunofluorescence of murine testicular tissue, isolated elongated spermatids, and human spermatozoa; comparison with SEPT14 mutant patient samples\",\n      \"journal\": \"Medicina (Kaunas, Lithuania)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — localization study with disease correlation but no functional rescue or direct mechanistic dissection\",\n      \"pmids\": [\"36295569\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Citrulline was reported to bind RAB3C protein and activate the IL-6/STAT3 signaling pathway in lung cancer cells, promoting glycolysis, proliferation, migration, and invasion.\",\n      \"method\": \"RNA-seq, molecular docking, Western blotting of IL-6/STAT3 pathway components, in vivo mouse tumor model\",\n      \"journal\": \"Environmental toxicology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3-4 — molecular docking (computational) plus Western blot correlation; no direct binding validation or RAB3C loss-of-function rescue\",\n      \"pmids\": [\"38770826\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RAB3C is a vesicle-associated small GTPase of the RAB3 subfamily that localizes to synaptic vesicles and secretory vesicles in neuroendocrine cells, cycles on and off vesicle membranes in concert with stimulated exocytosis, possesses intrinsic GTPase activity stimulated by cytosolic factors, undergoes insulin-dependent translocation in cardiac muscle, and interacts with the kinetochore/presynaptic protein Zwint-1 via a unique residue that also influences SNAP25 binding, collectively placing RAB3C as a regulated effector of exocytotic membrane dynamics.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"RAB3C is a small GTPase of the RAB3 subfamily that localizes to synaptic vesicles and secretory vesicles in neurons and neuroendocrine cells, cycling on and off vesicle membranes in concert with stimulated exocytosis [PMID:8157621]. Its intrinsic GTPase activity is stimulated by cytosolic factors, and the C-terminal domain modulates nucleotide-binding affinity and vesicle targeting [PMID:9164844]. RAB3C selectively binds Zwint-1 through a unique residue not shared by other RAB3 paralogs, and Zwint-1 in turn contacts SNAP25, linking RAB3C to the presynaptic vesicle fusion machinery in hippocampal neurons [PMID:18625232]. RAB3C also undergoes insulin-dependent translocation from microsomal to plasma membranes in cardiac muscle, indicating a broader role in regulated vesicle trafficking beyond the nervous system [PMID:8543030].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Establishing that RAB3C, like RAB3A, resides on synaptic vesicles and cycles off during exocytosis resolved whether RAB3C participates in the same stimulus-coupled vesicle dynamics as its paralog.\",\n      \"evidence\": \"Synaptic vesicle co-immunoisolation with anti-RAB3A antibodies and subcellular fractionation of nerve terminals after stimulation of neurotransmitter release\",\n      \"pmids\": [\"8157621\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether RAB3C has non-redundant functions distinct from RAB3A on the same vesicle\",\n        \"Identity of RAB3C-specific effectors at the synapse\",\n        \"No loss-of-function analysis to test requirement for exocytosis\"\n      ]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Demonstrating insulin-dependent translocation of RAB3C in cardiac muscle extended the functional scope of RAB3C beyond neurons and linked it to metabolic regulation of vesicle trafficking.\",\n      \"evidence\": \"Subcellular fractionation and Western blotting of lean vs. insulin-resistant obese Zucker rat cardiac muscle after in vivo insulin stimulation\",\n      \"pmids\": [\"8543030\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The cargo or vesicle population governed by RAB3C in cardiac muscle is unknown\",\n        \"Single study with no genetic perturbation of RAB3C itself\",\n        \"Mechanism linking insulin signaling to RAB3C membrane recruitment is uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Biochemical characterization of RAB3C GTP binding and GTPase activity, including C-terminal truncation and chimera analysis, established that the C-terminus dictates nucleotide affinity and vesicle targeting specificity distinct from other RAB3 paralogs.\",\n      \"evidence\": \"In vitro GTP-binding and GTPase assays with recombinant wild-type, truncated, and chimeric RAB3C proteins; immunostaining in bovine chromaffin cells\",\n      \"pmids\": [\"9164844\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The cytosolic GAP(s) responsible for stimulating RAB3C GTPase activity were not identified\",\n        \"Whether C-terminal differences among RAB3 paralogs determine distinct effector recruitment in vivo\"\n      ]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Identification of Zwint-1 as a RAB3C-specific effector, with a unique RAB3C residue determining binding selectivity and SNAP25 competing for the same Zwint-1 interface, provided the first molecular basis for paralog-specific function at the presynapse.\",\n      \"evidence\": \"Binding partner screen, co-immunoprecipitation, site-directed mutagenesis, and co-localization in primary hippocampal neurons\",\n      \"pmids\": [\"18625232\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Functional consequence of disrupting RAB3C–Zwint-1 interaction on neurotransmitter release is untested\",\n        \"Single-lab finding without independent replication\",\n        \"Whether Zwint-1 acts as a vesicle tether, fusion regulator, or scaffolding factor in this context is unknown\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Localization of RAB3C to the manchette and sperm tail during spermiogenesis, with delocalization in SEPT14-mutant sperm, suggested a role in membrane trafficking during sperm morphogenesis.\",\n      \"evidence\": \"Immunofluorescence of murine spermatids and human spermatozoa, including SEPT14-mutant patient samples\",\n      \"pmids\": [\"36295569\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No functional perturbation of RAB3C itself was performed; causality not established\",\n        \"Whether RAB3C delocalization is a direct consequence of SEPT14 loss or secondary to structural disorganization is unclear\",\n        \"No rescue or knockdown experiments\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the identity of RAB3C-specific GTPase-activating proteins, the functional consequence of RAB3C loss-of-function in neurons and other tissues, and whether RAB3C–Zwint-1 interaction directly regulates vesicle fusion or docking.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No genetic knockout or knockdown phenotype has been reported for RAB3C in any organism\",\n        \"No structural model of the RAB3C–Zwint-1 or RAB3C–effector complex exists\",\n        \"The specific cargo(s) regulated by RAB3C in non-neuronal tissues remain unidentified\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003924\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"Zwint-1\",\n      \"RAB3A\",\n      \"SNAP25\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}