{"gene":"SCAMP2","run_date":"2026-06-10T07:46:29","timeline":{"discoveries":[{"year":2005,"finding":"SCAMP2 physically associates with Arf6 and phospholipase D1 (PLD1) at the cell surface of PC12 cells, as demonstrated by co-immunoprecipitation. Association with Arf6 is enhanced after cell depolarization and in the presence of GTPγS, and is disrupted by the SCAMP2 E peptide. SCAMP2 couples Arf6-stimulated PLD1 activity to exocytosis and links this process to fusion pore formation and dilation.","method":"Co-immunoprecipitation, amperometry, point-mutant overexpression, inhibitory peptide competition","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP with functional validation by amperometry and multiple mutants in a single focused study","pmids":["16030257"],"is_preprint":false},{"year":2002,"finding":"A synthetic peptide (E peptide: CWYRPIYKAFR) derived from the cytoplasmic loop between transmembrane spans 2 and 3 of SCAMP2 potently inhibits a very late step of exocytosis (beyond docking, Ca2+/ATP-dependent SNAP-23 relocation, and ATP-dependent priming) in permeabilized mast cells. SCAMP2 partially colocalizes and co-immunoprecipitates with SNARE proteins SNAP-23 and syntaxin 4 at the plasma membrane.","method":"Streptolysin O permeabilization exocytosis assay, co-immunoprecipitation, kinetic ordering with inhibitors, E peptide structure-activity analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (CoIP, functional peptide assay with structure-activity analysis, kinetic ordering) in a focused study","pmids":["12124380"],"is_preprint":false},{"year":2002,"finding":"SCAMP2 localizes to plasma membranes at putative docking/fusion sites enriched in syntaxin1 and complexin in PC12 cells, and is absent from large dense-core vesicles. Overexpression of point mutants within the E peptide of SCAMP2 (but not wild-type SCAMP2) dose-dependently inhibits depolarization- and calcium-stimulated secretion; inhibition is largely reversed by exogenous lysophosphatidylcholine, implicating the E peptide in membrane fusion through a lipid-dependent mechanism.","method":"Immunofluorescence localization, regulated overexpression of point mutants, radiometric secretion assay (35S-secretogranin), lysophosphatidylcholine rescue","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct localization with functional consequence, multiple mutants, pharmacological rescue in a focused study","pmids":["12475951"],"is_preprint":false},{"year":2007,"finding":"The E peptide of SCAMP2 binds phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) within membranes through an electrostatic mechanism; residue R4 (R204 in full-length SCAMP2) is critical for PIP2 binding as determined by EPR spin-label analysis. Full-length SCAMP2 point mutant SC2-R204A inhibits fusion pore opening probability and stability in PC12 cells, establishing that SCAMP2–PIP2 interaction regulates fusion pore formation.","method":"Electron paramagnetic resonance (EPR) of spin-labeled PIP2 in liposomes, alanine-substitution mutagenesis, amperometry, human growth hormone and noradrenalin secretion assays","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro biophysical reconstitution (EPR + liposomes) combined with mutagenesis and amperometric functional readout in a single study","pmids":["17713930"],"is_preprint":false},{"year":2022,"finding":"SCAMP2 interacts with Cav3.2 T-type calcium channels (identified by co-expression and co-immunoprecipitation) and reduces their surface expression, causing near-complete loss of whole-cell T-type current without decreasing total Cav3.2 protein. Loss of intramembrane charge movement confirms reduced surface trafficking. This effect is partly reversed by point mutations in the SCAMP2 E peptide, implicating the E peptide domain in regulating channel surface delivery.","method":"Co-immunoprecipitation, whole-cell patch-clamp electrophysiology, intramembrane charge movement measurement, E-peptide point mutagenesis, surface expression assay","journal":"Molecular brain","confidence":"High","confidence_rationale":"Tier 2 / Strong — CoIP plus multiple orthogonal functional readouts (current, charge movement, mutant rescue) in a single focused study","pmids":["34980194"],"is_preprint":false},{"year":2023,"finding":"SCAMP2 was identified as an interacting protein of the sodium-dependent vitamin C transporter hSVCT1 by affinity-tag proteomics and validated by co-immunoprecipitation. SCAMP2 and hSVCT1 co-localize in intracellular structures and at the plasma membrane. Overexpression of SCAMP2 potentiated 14C-ascorbic acid uptake, whereas silencing endogenous SCAMP2 decreased uptake, establishing SCAMP2 as a regulator of hSVCT1 surface expression and transport activity.","method":"One-STrEP affinity pull-down with proteomics, co-immunoprecipitation, co-localization imaging, 14C-ascorbic acid uptake assay, siRNA knockdown","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal CoIP and functional transport assay in a single lab, two orthogonal methods","pmids":["36632962"],"is_preprint":false},{"year":2026,"finding":"SCAMP2 orchestrates metabolic reprogramming in glioblastoma by regulating aspartate transporters SLC1A3 and SLC25A12 and asparagine synthetase, thereby sustaining intracellular aspartate flux. The natural product auxarconjugatin B (AUX-B) covalently targets SCAMP2, and AUX-B-mediated reduction of SCAMP2 disrupts aspartate metabolism and inhibits GBM growth.","method":"Chemical biology/covalent target identification, in vitro and in vivo GBM models, metabolic profiling (aspartate levels), mechanistic analysis of transporter/enzyme regulation","journal":"Acta pharmaceutica Sinica. B","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — covalent target ID and functional metabolic readout from a single lab; abstract does not detail all orthogonal validation methods","pmids":["42180528"],"is_preprint":false}],"current_model":"SCAMP2 is a four-transmembrane recycling vesicle protein that acts at a late stage of calcium-regulated exocytosis by localizing to plasma-membrane fusion sites, where its conserved cytoplasmic E peptide (CWYRPIYKAFR) interacts with PI(4,5)P2 and couples Arf6-stimulated PLD1 activity to fusion pore formation and dilation; beyond exocytosis, SCAMP2 also regulates the surface trafficking of Cav3.2 T-type calcium channels and hSVCT1 vitamin C transporters via its E peptide domain, and in glioblastoma cells controls aspartate metabolic flux by modulating aspartate transporters and asparagine synthetase."},"narrative":{"mechanistic_narrative":"SCAMP2 is a four-transmembrane recycling-vesicle protein that acts at a late, post-docking step of calcium-regulated exocytosis, operating at plasma-membrane fusion sites to control fusion-pore formation and dilation [PMID:12124380, PMID:12475951]. It localizes to putative docking/fusion sites enriched in syntaxin and complexin and physically associates with the SNARE proteins SNAP-23 and syntaxin 4, while a synthetic peptide derived from its cytoplasmic loop between transmembrane spans 2 and 3 (the E peptide, CWYRPIYKAFR) potently blocks exocytosis downstream of docking and priming [PMID:12124380, PMID:12475951]. The mechanistic basis of E-peptide action is lipid-dependent: the E peptide binds PI(4,5)P2 in membranes through an electrostatic mechanism requiring residue R204, and the SC2-R204A mutant impairs fusion-pore opening probability and stability [PMID:17713930]. SCAMP2 also couples this machinery to lipid signaling by associating with Arf6 and phospholipase D1 at the cell surface in a depolarization- and GTP-enhanced manner, linking Arf6-stimulated PLD1 activity to fusion [PMID:16030257]. Beyond exocytosis, SCAMP2 functions as a regulator of membrane-protein surface trafficking, reducing surface delivery of Cav3.2 T-type calcium channels and modulating hSVCT1 vitamin C transporter surface expression and ascorbate uptake, with the channel effect mapped to the E-peptide domain [PMID:34980194, PMID:36632962]. In glioblastoma, SCAMP2 sustains intracellular aspartate flux by regulating aspartate transporters SLC1A3 and SLC25A12 and asparagine synthetase, and is a covalent target of auxarconjugatin B [PMID:42180528].","teleology":[{"year":2002,"claim":"Established that SCAMP2 acts at a very late step of exocytosis through its cytoplasmic E peptide, defining where in the secretory pathway it functions and linking it to the SNARE fusion machinery.","evidence":"Streptolysin O permeabilized mast cell exocytosis assay with E-peptide structure-activity analysis, kinetic ordering, and co-immunoprecipitation with SNAP-23 and syntaxin 4","pmids":["12124380"],"confidence":"High","gaps":["Did not define the molecular mechanism by which the E peptide acts at the fusion step","Synthetic peptide inhibition does not establish the endogenous interaction surface"]},{"year":2002,"claim":"Showed that SCAMP2 resides at plasma-membrane docking/fusion sites and that E-peptide mutants inhibit secretion via a lipid-dependent mechanism, implicating membrane lipid handling in fusion.","evidence":"Immunofluorescence localization, regulated point-mutant overexpression, radiometric secretogranin secretion assay, lysophosphatidylcholine rescue in PC12 cells","pmids":["12475951"],"confidence":"High","gaps":["The specific lipid partner of the E peptide was not yet identified","How LPC rescue relates to the physiological mechanism was unresolved"]},{"year":2005,"claim":"Identified Arf6 and PLD1 as cell-surface partners of SCAMP2, connecting SCAMP2 to a lipid-signaling pathway that promotes fusion pore formation and dilation.","evidence":"Co-immunoprecipitation (GTPgammaS- and depolarization-dependent), amperometry, point mutants, and E-peptide competition in PC12 cells","pmids":["16030257"],"confidence":"High","gaps":["Did not resolve whether SCAMP2 directly binds Arf6/PLD1 or scaffolds them indirectly","The PLD1 lipid product mediating fusion was not directly traced"]},{"year":2007,"claim":"Defined the biophysical mechanism of E-peptide action by showing direct electrostatic PI(4,5)P2 binding via R204, linking SCAMP2-lipid interaction to fusion-pore regulation.","evidence":"EPR of spin-labeled PIP2 in liposomes, alanine mutagenesis, amperometry, and hGH/noradrenalin secretion assays","pmids":["17713930"],"confidence":"High","gaps":["Did not establish the stoichiometry or kinetics of PIP2 binding at fusion sites in vivo","Relationship between PIP2 binding and Arf6/PLD1 coupling not directly reconstituted"]},{"year":2022,"claim":"Extended SCAMP2 function beyond exocytosis to membrane-protein trafficking by showing it suppresses Cav3.2 T-type channel surface expression through its E-peptide domain.","evidence":"Co-immunoprecipitation, whole-cell patch clamp, intramembrane charge movement, surface expression assay, and E-peptide mutagenesis","pmids":["34980194"],"confidence":"High","gaps":["Mechanism of how SCAMP2 diverts Cav3.2 from the surface not defined","Physiological context of this regulation in neurons not established"]},{"year":2023,"claim":"Showed SCAMP2 positively regulates a transporter (hSVCT1), broadening its trafficking role to include promotion of surface delivery and transport activity.","evidence":"Affinity-tag proteomics, reciprocal co-immunoprecipitation, co-localization imaging, 14C-ascorbate uptake, and siRNA knockdown","pmids":["36632962"],"confidence":"Medium","gaps":["Single-lab validation with two orthogonal methods","Opposite directionality from Cav3.2 regulation not mechanistically reconciled"]},{"year":2026,"claim":"Implicated SCAMP2 in cancer metabolism by linking it to aspartate transporter/enzyme regulation in glioblastoma and identifying it as a druggable covalent target.","evidence":"Covalent target identification with auxarconjugatin B, in vitro/in vivo GBM models, and aspartate metabolic profiling","pmids":["42180528"],"confidence":"Medium","gaps":["How SCAMP2 mechanistically regulates SLC1A3, SLC25A12, and asparagine synthetase is not detailed","Full orthogonal validation of the covalent target not described in the abstract"]},{"year":null,"claim":"Whether SCAMP2's lipid-coupled exocytic role and its diverse surface-trafficking/metabolic functions share a unified molecular mechanism remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of SCAMP2 with its partners","Unclear whether E-peptide PIP2 binding underlies all trafficking roles or only fusion","Directionality of trafficking effects (suppress vs. promote surface delivery) unexplained"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[2,3]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,5]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,1,2]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[4,5]}],"complexes":[],"partners":["ARF6","PLD1","SNAP23","STX4","CACNA1H","SLC23A1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O15127","full_name":"Secretory carrier-associated membrane protein 2","aliases":[],"length_aa":329,"mass_kda":36.6,"function":"Functions in post-Golgi recycling pathways. Acts as a recycling carrier to the cell surface","subcellular_location":"Golgi apparatus, trans-Golgi network membrane; Recycling endosome membrane","url":"https://www.uniprot.org/uniprotkb/O15127/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SCAMP2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000140497","cell_line_id":"CID000080","localizations":[{"compartment":"golgi","grade":3},{"compartment":"vesicles","grade":3},{"compartment":"membrane","grade":1}],"interactors":[{"gene":"TFRC","stoichiometry":10.0},{"gene":"SCAMP3","stoichiometry":10.0},{"gene":"NSF","stoichiometry":10.0},{"gene":"SCAMP1","stoichiometry":10.0},{"gene":"RAB11FIP5","stoichiometry":10.0},{"gene":"PDCD6IP","stoichiometry":10.0},{"gene":"RAB21","stoichiometry":10.0},{"gene":"RAB5B","stoichiometry":10.0},{"gene":"RAB2A","stoichiometry":10.0},{"gene":"WDFY1","stoichiometry":10.0}],"url":"https://opencell.sf.czbiohub.org/target/CID000080","total_profiled":1310},"omim":[{"mim_id":"606913","title":"SECRETORY CARRIER MEMBRANE PROTEIN 3; SCAMP3","url":"https://www.omim.org/entry/606913"},{"mim_id":"606912","title":"SECRETORY CARRIER MEMBRANE PROTEIN 2; SCAMP2","url":"https://www.omim.org/entry/606912"},{"mim_id":"606911","title":"SECRETORY CARRIER MEMBRANE PROTEIN 1; SCAMP1","url":"https://www.omim.org/entry/606911"},{"mim_id":"600761","title":"SODIUM CHANNEL, EPITHELIAL 1, GAMMA SUBUNIT; SCNN1G","url":"https://www.omim.org/entry/600761"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Golgi apparatus","reliability":"Supported"},{"location":"Vesicles","reliability":"Supported"},{"location":"Mid piece","reliability":"Additional"},{"location":"Principal piece","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SCAMP2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"O15127","domains":[{"cath_id":"1.20.120","chopping":"144-294","consensus_level":"high","plddt":94.3654,"start":144,"end":294}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O15127","model_url":"https://alphafold.ebi.ac.uk/files/AF-O15127-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O15127-F1-predicted_aligned_error_v6.png","plddt_mean":76.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SCAMP2","jax_strain_url":"https://www.jax.org/strain/search?query=SCAMP2"},"sequence":{"accession":"O15127","fasta_url":"https://rest.uniprot.org/uniprotkb/O15127.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O15127/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O15127"}},"corpus_meta":[{"pmid":"16030257","id":"PMC_16030257","title":"SCAMP2 interacts with Arf6 and phospholipase D1 and links their function to exocytotic fusion pore formation in PC12 cells.","date":"2005","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/16030257","citation_count":55,"is_preprint":false},{"pmid":"12124380","id":"PMC_12124380","title":"Perturbation of a very late step of regulated exocytosis by a secretory carrier membrane protein (SCAMP2)-derived peptide.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12124380","citation_count":52,"is_preprint":false},{"pmid":"12475951","id":"PMC_12475951","title":"Role of secretory carrier membrane protein SCAMP2 in granule exocytosis.","date":"2002","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/12475951","citation_count":46,"is_preprint":false},{"pmid":"17713930","id":"PMC_17713930","title":"Secretory carrier membrane protein SCAMP2 and phosphatidylinositol 4,5-bisphosphate interactions in the regulation of dense core vesicle exocytosis.","date":"2007","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17713930","citation_count":33,"is_preprint":false},{"pmid":"20514246","id":"PMC_20514246","title":"Exo- and endocytotic trafficking of SCAMP2.","date":"2009","source":"Plant signaling & behavior","url":"https://pubmed.ncbi.nlm.nih.gov/20514246","citation_count":13,"is_preprint":false},{"pmid":"34980194","id":"PMC_34980194","title":"Secretory carrier-associated membrane protein 2 (SCAMP2) regulates cell surface expression of T-type calcium channels.","date":"2022","source":"Molecular brain","url":"https://pubmed.ncbi.nlm.nih.gov/34980194","citation_count":10,"is_preprint":false},{"pmid":"36632962","id":"PMC_36632962","title":"Vitamin C transport in neurons and epithelia is regulated by secretory carrier-associated membrane protein-2 (SCAMP2).","date":"2023","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/36632962","citation_count":0,"is_preprint":false},{"pmid":"42180528","id":"PMC_42180528","title":"Targeting SCAMP2 by a natural product auxarconjugatin B for glioblastoma therapy via restoring aspartate metabolic flux.","date":"2026","source":"Acta pharmaceutica Sinica. B","url":"https://pubmed.ncbi.nlm.nih.gov/42180528","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":5973,"output_tokens":2168,"usd":0.025219,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9166,"output_tokens":2927,"usd":0.059502,"stage2_stop_reason":"end_turn"},"total_usd":0.084721,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2005,\n      \"finding\": \"SCAMP2 physically associates with Arf6 and phospholipase D1 (PLD1) at the cell surface of PC12 cells, as demonstrated by co-immunoprecipitation. Association with Arf6 is enhanced after cell depolarization and in the presence of GTPγS, and is disrupted by the SCAMP2 E peptide. SCAMP2 couples Arf6-stimulated PLD1 activity to exocytosis and links this process to fusion pore formation and dilation.\",\n      \"method\": \"Co-immunoprecipitation, amperometry, point-mutant overexpression, inhibitory peptide competition\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP with functional validation by amperometry and multiple mutants in a single focused study\",\n      \"pmids\": [\"16030257\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"A synthetic peptide (E peptide: CWYRPIYKAFR) derived from the cytoplasmic loop between transmembrane spans 2 and 3 of SCAMP2 potently inhibits a very late step of exocytosis (beyond docking, Ca2+/ATP-dependent SNAP-23 relocation, and ATP-dependent priming) in permeabilized mast cells. SCAMP2 partially colocalizes and co-immunoprecipitates with SNARE proteins SNAP-23 and syntaxin 4 at the plasma membrane.\",\n      \"method\": \"Streptolysin O permeabilization exocytosis assay, co-immunoprecipitation, kinetic ordering with inhibitors, E peptide structure-activity analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (CoIP, functional peptide assay with structure-activity analysis, kinetic ordering) in a focused study\",\n      \"pmids\": [\"12124380\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"SCAMP2 localizes to plasma membranes at putative docking/fusion sites enriched in syntaxin1 and complexin in PC12 cells, and is absent from large dense-core vesicles. Overexpression of point mutants within the E peptide of SCAMP2 (but not wild-type SCAMP2) dose-dependently inhibits depolarization- and calcium-stimulated secretion; inhibition is largely reversed by exogenous lysophosphatidylcholine, implicating the E peptide in membrane fusion through a lipid-dependent mechanism.\",\n      \"method\": \"Immunofluorescence localization, regulated overexpression of point mutants, radiometric secretion assay (35S-secretogranin), lysophosphatidylcholine rescue\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct localization with functional consequence, multiple mutants, pharmacological rescue in a focused study\",\n      \"pmids\": [\"12475951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"The E peptide of SCAMP2 binds phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) within membranes through an electrostatic mechanism; residue R4 (R204 in full-length SCAMP2) is critical for PIP2 binding as determined by EPR spin-label analysis. Full-length SCAMP2 point mutant SC2-R204A inhibits fusion pore opening probability and stability in PC12 cells, establishing that SCAMP2–PIP2 interaction regulates fusion pore formation.\",\n      \"method\": \"Electron paramagnetic resonance (EPR) of spin-labeled PIP2 in liposomes, alanine-substitution mutagenesis, amperometry, human growth hormone and noradrenalin secretion assays\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro biophysical reconstitution (EPR + liposomes) combined with mutagenesis and amperometric functional readout in a single study\",\n      \"pmids\": [\"17713930\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SCAMP2 interacts with Cav3.2 T-type calcium channels (identified by co-expression and co-immunoprecipitation) and reduces their surface expression, causing near-complete loss of whole-cell T-type current without decreasing total Cav3.2 protein. Loss of intramembrane charge movement confirms reduced surface trafficking. This effect is partly reversed by point mutations in the SCAMP2 E peptide, implicating the E peptide domain in regulating channel surface delivery.\",\n      \"method\": \"Co-immunoprecipitation, whole-cell patch-clamp electrophysiology, intramembrane charge movement measurement, E-peptide point mutagenesis, surface expression assay\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — CoIP plus multiple orthogonal functional readouts (current, charge movement, mutant rescue) in a single focused study\",\n      \"pmids\": [\"34980194\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SCAMP2 was identified as an interacting protein of the sodium-dependent vitamin C transporter hSVCT1 by affinity-tag proteomics and validated by co-immunoprecipitation. SCAMP2 and hSVCT1 co-localize in intracellular structures and at the plasma membrane. Overexpression of SCAMP2 potentiated 14C-ascorbic acid uptake, whereas silencing endogenous SCAMP2 decreased uptake, establishing SCAMP2 as a regulator of hSVCT1 surface expression and transport activity.\",\n      \"method\": \"One-STrEP affinity pull-down with proteomics, co-immunoprecipitation, co-localization imaging, 14C-ascorbic acid uptake assay, siRNA knockdown\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal CoIP and functional transport assay in a single lab, two orthogonal methods\",\n      \"pmids\": [\"36632962\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"SCAMP2 orchestrates metabolic reprogramming in glioblastoma by regulating aspartate transporters SLC1A3 and SLC25A12 and asparagine synthetase, thereby sustaining intracellular aspartate flux. The natural product auxarconjugatin B (AUX-B) covalently targets SCAMP2, and AUX-B-mediated reduction of SCAMP2 disrupts aspartate metabolism and inhibits GBM growth.\",\n      \"method\": \"Chemical biology/covalent target identification, in vitro and in vivo GBM models, metabolic profiling (aspartate levels), mechanistic analysis of transporter/enzyme regulation\",\n      \"journal\": \"Acta pharmaceutica Sinica. B\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — covalent target ID and functional metabolic readout from a single lab; abstract does not detail all orthogonal validation methods\",\n      \"pmids\": [\"42180528\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SCAMP2 is a four-transmembrane recycling vesicle protein that acts at a late stage of calcium-regulated exocytosis by localizing to plasma-membrane fusion sites, where its conserved cytoplasmic E peptide (CWYRPIYKAFR) interacts with PI(4,5)P2 and couples Arf6-stimulated PLD1 activity to fusion pore formation and dilation; beyond exocytosis, SCAMP2 also regulates the surface trafficking of Cav3.2 T-type calcium channels and hSVCT1 vitamin C transporters via its E peptide domain, and in glioblastoma cells controls aspartate metabolic flux by modulating aspartate transporters and asparagine synthetase.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SCAMP2 is a four-transmembrane recycling-vesicle protein that acts at a late, post-docking step of calcium-regulated exocytosis, operating at plasma-membrane fusion sites to control fusion-pore formation and dilation [#1, #2]. It localizes to putative docking/fusion sites enriched in syntaxin and complexin and physically associates with the SNARE proteins SNAP-23 and syntaxin 4, while a synthetic peptide derived from its cytoplasmic loop between transmembrane spans 2 and 3 (the E peptide, CWYRPIYKAFR) potently blocks exocytosis downstream of docking and priming [#1, #2]. The mechanistic basis of E-peptide action is lipid-dependent: the E peptide binds PI(4,5)P2 in membranes through an electrostatic mechanism requiring residue R204, and the SC2-R204A mutant impairs fusion-pore opening probability and stability [#3]. SCAMP2 also couples this machinery to lipid signaling by associating with Arf6 and phospholipase D1 at the cell surface in a depolarization- and GTP-enhanced manner, linking Arf6-stimulated PLD1 activity to fusion [#0]. Beyond exocytosis, SCAMP2 functions as a regulator of membrane-protein surface trafficking, reducing surface delivery of Cav3.2 T-type calcium channels and modulating hSVCT1 vitamin C transporter surface expression and ascorbate uptake, with the channel effect mapped to the E-peptide domain [#4, #5]. In glioblastoma, SCAMP2 sustains intracellular aspartate flux by regulating aspartate transporters SLC1A3 and SLC25A12 and asparagine synthetase, and is a covalent target of auxarconjugatin B [#6].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established that SCAMP2 acts at a very late step of exocytosis through its cytoplasmic E peptide, defining where in the secretory pathway it functions and linking it to the SNARE fusion machinery.\",\n      \"evidence\": \"Streptolysin O permeabilized mast cell exocytosis assay with E-peptide structure-activity analysis, kinetic ordering, and co-immunoprecipitation with SNAP-23 and syntaxin 4\",\n      \"pmids\": [\"12124380\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the molecular mechanism by which the E peptide acts at the fusion step\", \"Synthetic peptide inhibition does not establish the endogenous interaction surface\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Showed that SCAMP2 resides at plasma-membrane docking/fusion sites and that E-peptide mutants inhibit secretion via a lipid-dependent mechanism, implicating membrane lipid handling in fusion.\",\n      \"evidence\": \"Immunofluorescence localization, regulated point-mutant overexpression, radiometric secretogranin secretion assay, lysophosphatidylcholine rescue in PC12 cells\",\n      \"pmids\": [\"12475951\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The specific lipid partner of the E peptide was not yet identified\", \"How LPC rescue relates to the physiological mechanism was unresolved\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identified Arf6 and PLD1 as cell-surface partners of SCAMP2, connecting SCAMP2 to a lipid-signaling pathway that promotes fusion pore formation and dilation.\",\n      \"evidence\": \"Co-immunoprecipitation (GTPgammaS- and depolarization-dependent), amperometry, point mutants, and E-peptide competition in PC12 cells\",\n      \"pmids\": [\"16030257\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve whether SCAMP2 directly binds Arf6/PLD1 or scaffolds them indirectly\", \"The PLD1 lipid product mediating fusion was not directly traced\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined the biophysical mechanism of E-peptide action by showing direct electrostatic PI(4,5)P2 binding via R204, linking SCAMP2-lipid interaction to fusion-pore regulation.\",\n      \"evidence\": \"EPR of spin-labeled PIP2 in liposomes, alanine mutagenesis, amperometry, and hGH/noradrenalin secretion assays\",\n      \"pmids\": [\"17713930\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish the stoichiometry or kinetics of PIP2 binding at fusion sites in vivo\", \"Relationship between PIP2 binding and Arf6/PLD1 coupling not directly reconstituted\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Extended SCAMP2 function beyond exocytosis to membrane-protein trafficking by showing it suppresses Cav3.2 T-type channel surface expression through its E-peptide domain.\",\n      \"evidence\": \"Co-immunoprecipitation, whole-cell patch clamp, intramembrane charge movement, surface expression assay, and E-peptide mutagenesis\",\n      \"pmids\": [\"34980194\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of how SCAMP2 diverts Cav3.2 from the surface not defined\", \"Physiological context of this regulation in neurons not established\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showed SCAMP2 positively regulates a transporter (hSVCT1), broadening its trafficking role to include promotion of surface delivery and transport activity.\",\n      \"evidence\": \"Affinity-tag proteomics, reciprocal co-immunoprecipitation, co-localization imaging, 14C-ascorbate uptake, and siRNA knockdown\",\n      \"pmids\": [\"36632962\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab validation with two orthogonal methods\", \"Opposite directionality from Cav3.2 regulation not mechanistically reconciled\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Implicated SCAMP2 in cancer metabolism by linking it to aspartate transporter/enzyme regulation in glioblastoma and identifying it as a druggable covalent target.\",\n      \"evidence\": \"Covalent target identification with auxarconjugatin B, in vitro/in vivo GBM models, and aspartate metabolic profiling\",\n      \"pmids\": [\"42180528\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How SCAMP2 mechanistically regulates SLC1A3, SLC25A12, and asparagine synthetase is not detailed\", \"Full orthogonal validation of the covalent target not described in the abstract\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether SCAMP2's lipid-coupled exocytic role and its diverse surface-trafficking/metabolic functions share a unified molecular mechanism remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of SCAMP2 with its partners\", \"Unclear whether E-peptide PIP2 binding underlies all trafficking roles or only fusion\", \"Directionality of trafficking effects (suppress vs. promote surface delivery) unexplained\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"ARF6\", \"PLD1\", \"SNAP23\", \"STX4\", \"CACNA1H\", \"SLC23A1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}