{"gene":"SEC16A","run_date":"2026-04-28T20:42:07","timeline":{"discoveries":[{"year":2007,"finding":"Mammalian SEC16A (KIAA0310p/p250) is a homologue of yeast Sec16 that localizes to ER exit sites (ERES) and is recruited from the cytosol to ER membranes in a Sar1-dependent manner. It interacts with both the inner COPII layer (Sec23-Sec24) and outer layer (Sec13-Sec31) complexes. Depletion causes disorganization of ERES and delayed ER-to-Golgi protein transport.","method":"Subcellular fractionation, binding experiments, siRNA knockdown, fluorescence microscopy","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (fractionation, binding assays, KD phenotype) in a single study establishing localization, binding partners, and functional role","pmids":["17428803"],"is_preprint":false},{"year":2014,"finding":"LRRK2 interacts and co-localizes with SEC16A and anchors it at ERES. Loss of LRRK2 disperses SEC16A from ERES and impairs ER export. In neurons, LRRK2 and SEC16A co-localize at dendritic ERES and regulate activity-dependent surface targeting of glutamate receptors. The PD-associated LRRK2 R1441C GTPase-domain mutation disrupts the LRRK2-SEC16A interaction and impairs ER-Golgi transport; LRRK2 kinase activity is not required.","method":"Co-immunoprecipitation, co-localization imaging, siRNA knockdown, domain-mutant analysis, neuronal surface receptor trafficking assays","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP, multiple cell types including neurons, functional rescue and mutant dissection across orthogonal assays","pmids":["25201882"],"is_preprint":false},{"year":2016,"finding":"SEC16A is a RAB10 effector required for insulin-stimulated GLUT4 translocation to the plasma membrane in adipocytes. Insulin augments colocalization of SEC16A with RAB10 at a perinuclear recycling endosome/TGN compartment, and SEC16A knockdown phenocopies RAB10 knockdown. This function is independent of canonical COPII coat assembly (SEC13, SEC23B, SEC31 not required), but SEC23A is involved, suggesting a non-canonical COPII subcomplex role.","method":"siRNA knockdown, co-localization imaging, GLUT4 translocation assay, insulin stimulation, epistasis with COPII component knockdowns","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — clean KD phenotype with defined molecular readout, epistasis with multiple COPII components, and identification of a novel binding partner (RAB10)","pmids":["27354378"],"is_preprint":false},{"year":2017,"finding":"SEC16A plays a critical role in unconventional (Golgi-bypassing) secretion of CFTR and ΔF508-CFTR. During ER-to-Golgi blockade or ER stress, SEC16A is redistributed to the cell periphery and associates with GRASP55. IRE1α-mediated signaling acts as an upstream regulator of SEC16A redistribution during unconventional secretion. Knockdown of SEC16A, but not other COPII components, abolishes this unconventional pathway.","method":"siRNA knockdown screen, co-immunoprecipitation, immunofluorescence, CFTR secretion assay, IRE1α inhibition","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 — functional KD screen with defined cargo readout, co-IP of novel partner (GRASP55), upstream pathway placement via IRE1α","pmids":["28067262"],"is_preprint":false},{"year":2017,"finding":"SEC16A was identified as an interactor of the scaffolding protein Nbeal2 in platelets/megakaryocytes, validated by reverse immunoprecipitation and proximity ligation assay.","method":"Affinity purification mass spectrometry (interactome), reverse immunoprecipitation, proximity ligation assay","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP validated by PLA but functional consequence of SEC16A-Nbeal2 interaction not dissected","pmids":["29187380"],"is_preprint":false},{"year":2018,"finding":"SEC16A interacts with the ubiquitin ligase RNF183 through its central conserved domain (CCD). SEC16A is not a substrate for RNF183 but stabilizes RNF183 against ERAD-mediated degradation. SEC16A similarly stabilizes the lysosomal ubiquitin ligase RNF152, indicating a broader role in regulating ubiquitin ligase protein stability and localization.","method":"Co-immunoprecipitation, domain deletion mapping, degradation assays, co-localization imaging","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2-3 — Co-IP with domain mapping and functional degradation assay, single lab","pmids":["29300766"],"is_preprint":false},{"year":2024,"finding":"Loss-of-function SEC16A variants (including frameshift and missense) disrupt COPII complex formation, impede secretory protein vesicle trafficking from the ER, and induce ER stress due to protein overload, as shown in CRISPR/Cas9-edited HEK293T cells. Sec16a+/- mice show impaired zymogen secretion, exacerbated ER stress, and heightened pancreatic inflammation and fibrosis upon cerulein challenge.","method":"CRISPR/Cas9 knockout cell lines, COPII assembly assay, secretion trafficking assay, ER stress markers, mouse model with pancreatitis challenge","journal":"Advanced science","confidence":"High","confidence_rationale":"Tier 1-2 — multiple CRISPR-edited cell lines plus in vivo mouse model with orthogonal mechanistic readouts","pmids":["39119875"],"is_preprint":false},{"year":2025,"finding":"SEC16A is depleted of VLC-ceramide trafficking from the ER to the Golgi upon cholesterol depletion. Depletion of SEC16A abolishes the increased synthesis of very-long-chain sphingomyelin that is induced by cholesterol depletion, establishing SEC16A/COPII as a rate-limiting node in ER-to-Golgi ceramide transport and organelle membrane homeostasis.","method":"siRNA knockdown of SEC16A, sphingolipid metabolic flux analysis, sphingolipid trafficking assay","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — KD with defined metabolic flux readout, but preprint and single lab","pmids":["bio_10.1101_2025.02.12.637879"],"is_preprint":true},{"year":2025,"finding":"The head domain of the Golgi vesicle tether p115 (USO1) binds directly to a conserved motif in the unstructured N-terminal region of SEC16A. Structural prediction and deletion mapping define the interaction surface, and p115 mutations that block this motif reduce secretion efficiency, suggesting p115 bridges early Golgi to ERES via SEC16A.","method":"Direct binding assay, deletion mapping, structural prediction, secretion efficiency assay with p115 mutants","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — direct binding with deletion mapping and functional mutant validation, but preprint","pmids":["bio_10.1101_2025.10.16.682774"],"is_preprint":true},{"year":2025,"finding":"A knock-in mouse model carrying the Sec16a L1551V mutation (corresponding to human L1536V in the conserved central core domain involved in COPII assembly) displays neurological impairment: homozygous mice show deficits in novel object recognition and fear-conditioned learning/memory, and limb clasping behavior associated with neurodegeneration.","method":"CRISPR/Cas9 knock-in mouse model, behavioral testing (novel object recognition, cued fear conditioning, tail suspension)","journal":"Animal models and experimental medicine","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo model with defined phenotypic readouts, but mechanistic link between CCD mutation and neurological phenotype not fully elucidated","pmids":["41104514"],"is_preprint":false}],"current_model":"SEC16A is a large scaffolding protein that organizes ER exit sites (ERES) by interacting with both inner (Sec23-Sec24) and outer (Sec13-Sec31) COPII coat complexes in a Sar1-dependent manner; it is anchored at ERES by LRRK2, acts as a RAB10 effector to drive insulin-stimulated GLUT4 vesicle biogenesis via a non-canonical COPII subcomplex, mediates unconventional GRASP55-dependent secretion downstream of IRE1α during ER stress, stabilizes ER-associated ubiquitin ligases (RNF183, RNF152) through its central conserved domain, and is directly tethered to the early Golgi via binding of the p115/USO1 head domain to its unstructured N-terminus, collectively positioning SEC16A as a master organizer of anterograde ER-to-Golgi traffic with additional roles in non-canonical secretory routes."},"narrative":{"teleology":[{"year":2007,"claim":"Establishing SEC16A as the mammalian ERES scaffold resolved how the two-layered COPII coat is spatially organized on ER membranes, showing that a single protein interacts with both inner and outer coat and that its loss disorganizes exit sites.","evidence":"Subcellular fractionation, binding assays with COPII components, siRNA knockdown and fluorescence microscopy in mammalian cells","pmids":["17428803"],"confidence":"High","gaps":["Mechanism by which SEC16A is initially targeted to specific ER membrane domains remains unclear","Structural basis of SEC16A interactions with Sec23–Sec24 and Sec13–Sec31 not resolved","Whether SEC16A has catalytic activity or functions purely as a scaffold was not addressed"]},{"year":2014,"claim":"Demonstrating that LRRK2 anchors SEC16A at ERES and that the PD-associated R1441C mutation disrupts this interaction linked ERES organization to neurodegeneration and revealed how SEC16A retention at exit sites is regulated upstream.","evidence":"Reciprocal co-immunoprecipitation, co-localization imaging, domain-mutant analysis, and neuronal surface receptor trafficking assays","pmids":["25201882"],"confidence":"High","gaps":["Direct binding interface between LRRK2 and SEC16A not mapped at residue level","Whether other kinases or GTPases can substitute for LRRK2 in anchoring SEC16A is unknown"]},{"year":2016,"claim":"Identifying SEC16A as a RAB10 effector for insulin-stimulated GLUT4 translocation revealed a non-canonical COPII function independent of the full canonical coat, broadening SEC16A's role beyond classical ER export.","evidence":"siRNA epistasis with individual COPII components, GLUT4 translocation assay, and co-localization imaging in adipocytes","pmids":["27354378"],"confidence":"High","gaps":["Composition of the non-canonical SEC16A–SEC23A subcomplex not fully defined","Whether RAB10–SEC16A interaction is direct or mediated through an adaptor is unresolved"]},{"year":2017,"claim":"Showing that SEC16A mediates GRASP55-dependent unconventional secretion of CFTR downstream of IRE1α established SEC16A as a bifunctional scaffold operating in both canonical and Golgi-bypassing secretory routes during ER stress.","evidence":"siRNA knockdown screen, co-immunoprecipitation with GRASP55, CFTR secretion assay, and IRE1α inhibition","pmids":["28067262"],"confidence":"High","gaps":["Cargo selectivity of the unconventional pathway beyond CFTR not characterized","Mechanism by which IRE1α signaling triggers SEC16A redistribution to the cell periphery is unknown"]},{"year":2018,"claim":"Mapping the central conserved domain (CCD) as the interface for stabilizing ER-associated ubiquitin ligases RNF183 and RNF152 extended SEC16A's function beyond vesicle coat organization to proteostasis regulation.","evidence":"Co-immunoprecipitation, domain deletion mapping, and degradation assays","pmids":["29300766"],"confidence":"Medium","gaps":["Mechanism by which SEC16A shields these ligases from ERAD is not defined","Whether additional E3 ligases are stabilized by SEC16A's CCD is untested","Finding from a single laboratory awaits independent confirmation"]},{"year":2024,"claim":"Demonstrating that SEC16A loss-of-function variants impede COPII assembly and cause ER stress, and that Sec16a haploinsufficiency in mice exacerbates pancreatic inflammation and fibrosis, provided the first in vivo disease-relevant model linking SEC16A deficiency to organ pathology.","evidence":"CRISPR/Cas9-edited HEK293T cells, COPII assembly and secretion assays, ER stress markers, Sec16a+/- mouse model with cerulein-induced pancreatitis","pmids":["39119875"],"confidence":"High","gaps":["Whether SEC16A variants contribute to human pancreatitis susceptibility requires clinical genetic studies","Cell-type-specific consequences of SEC16A deficiency beyond pancreatic acinar cells not explored"]},{"year":2025,"claim":"A knock-in mouse carrying a CCD missense mutation (L1551V) displayed neurological deficits including impaired learning/memory and neurodegeneration-associated clasping, establishing that even subtle disruption of the COPII-interacting domain has consequences for CNS function.","evidence":"CRISPR/Cas9 knock-in mouse model with behavioral testing (novel object recognition, fear conditioning, tail suspension)","pmids":["41104514"],"confidence":"Medium","gaps":["Cellular mechanism linking CCD mutation to neurodegeneration not elucidated","Whether this mutation affects COPII assembly, ubiquitin ligase stabilization, or both is untested","Findings from a single mouse model line"]},{"year":null,"claim":"How SEC16A coordinates its multiple scaffolding roles — canonical COPII assembly, non-canonical vesicle biogenesis, unconventional secretion, and ubiquitin ligase stabilization — through its distinct domains, and whether these functions are mutually exclusive or concurrent at the same ERES, remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of full-length SEC16A or its domain complexes exists","Post-translational modifications regulating switching between canonical and non-canonical functions are uncharacterized","In vivo tissue-specific requirements for SEC16A beyond pancreas and brain are largely unexplored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,2,3]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,6]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[0,1,6]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,2]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[2,3]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,1,2,3,6]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0,2,6]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,6]}],"complexes":["COPII coat"],"partners":["SEC23A","SEC24","SEC13","SEC31","LRRK2","RAB10","GRASP55","RNF183"],"other_free_text":[]},"mechanistic_narrative":"SEC16A is a large scaffolding protein that organizes endoplasmic reticulum exit sites (ERES) and serves as a master regulator of anterograde ER-to-Golgi transport. It is recruited to ER membranes in a Sar1-dependent manner and interacts with both inner (Sec23–Sec24) and outer (Sec13–Sec31) COPII coat complexes; depletion disorganizes ERES and delays secretory trafficking, while loss-of-function variants impede COPII assembly, induce ER stress, and in mice exacerbate cerulein-induced pancreatic inflammation and fibrosis [PMID:17428803, PMID:39119875]. Beyond canonical COPII-dependent export, SEC16A functions as a RAB10 effector driving insulin-stimulated GLUT4 translocation via a non-canonical COPII subcomplex [PMID:27354378], mediates GRASP55-dependent unconventional secretion of CFTR downstream of IRE1α during ER stress [PMID:28067262], and is anchored at ERES by LRRK2, whose Parkinson's-disease-associated R1441C mutation disrupts this interaction and impairs ER-Golgi transport in neurons [PMID:25201882]. SEC16A additionally stabilizes ER-associated ubiquitin ligases RNF183 and RNF152 through its central conserved domain, and a missense mutation in this domain causes neurological impairment in mice [PMID:29300766, PMID:41104514]."},"prefetch_data":{"uniprot":{"accession":"O15027","full_name":"Protein transport protein Sec16A","aliases":["SEC16 homolog A","p250"],"length_aa":2357,"mass_kda":251.9,"function":"Acts as a molecular scaffold that plays a key role in the organization of the endoplasmic reticulum exit sites (ERES), also known as transitional endoplasmic reticulum (tER). SAR1A-GTP-dependent assembly of SEC16A on the ER membrane forms an organized scaffold defining an ERES. Required for secretory cargo traffic from the endoplasmic reticulum to the Golgi apparatus (PubMed:17005010, PubMed:17192411, PubMed:17428803, PubMed:21768384, PubMed:22355596). Mediates the recruitment of MIA3/TANGO to ERES (PubMed:28442536). Regulates both conventional (ER/Golgi-dependent) and GORASP2-mediated unconventional (ER/Golgi-independent) trafficking of CFTR to cell membrane (PubMed:28067262). Positively regulates the protein stability of E3 ubiquitin-protein ligases RNF152 and RNF183 and the ER localization of RNF183 (PubMed:29300766). Acts as a RAB10 effector in the regulation of insulin-induced SLC2A4/GLUT4 glucose transporter-enriched vesicles delivery to the cell membrane in adipocytes (By similarity)","subcellular_location":"Endoplasmic reticulum membrane; Golgi apparatus membrane; Cytoplasm, perinuclear region; Cytoplasm, cytosol; Microsome membrane","url":"https://www.uniprot.org/uniprotkb/O15027/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/SEC16A","classification":"Common Essential","n_dependent_lines":878,"n_total_lines":1208,"dependency_fraction":0.7268211920529801},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000148396","cell_line_id":"CID000831","localizations":[{"compartment":"vesicles","grade":3}],"interactors":[{"gene":"CSNK1A1","stoichiometry":10.0},{"gene":"SEC13","stoichiometry":10.0},{"gene":"CLINT1","stoichiometry":4.0},{"gene":"ARHGAP18","stoichiometry":0.2},{"gene":"CLTA","stoichiometry":0.2},{"gene":"CLTB","stoichiometry":0.2},{"gene":"DCP1B","stoichiometry":0.2},{"gene":"DNAJC7","stoichiometry":0.2},{"gene":"HNRNPA2B1","stoichiometry":0.2},{"gene":"RBM14","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000831","total_profiled":1310},"omim":[{"mim_id":"621029","title":"RING FINGER PROTEIN 183; RNF183","url":"https://www.omim.org/entry/621029"},{"mim_id":"617208","title":"MAM DOMAIN-CONTAINING PROTEIN 4; MAMDC4","url":"https://www.omim.org/entry/617208"},{"mim_id":"612855","title":"SEC16 HOMOLOG B, ENDOPLASMIC RETICULUM EXPORT FACTOR; SEC16B","url":"https://www.omim.org/entry/612855"},{"mim_id":"612854","title":"SEC16 HOMOLOG A, ENDOPLASMIC RETICULUM EXPORT FACTOR; SEC16A","url":"https://www.omim.org/entry/612854"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Golgi apparatus","reliability":"Supported"},{"location":"Endoplasmic reticulum","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SEC16A"},"hgnc":{"alias_symbol":["p250","Sec16L"],"prev_symbol":["KIAA0310"]},"alphafold":{"accession":"O15027","domains":[{"cath_id":"-","chopping":"1511-1570_1686-1797","consensus_level":"medium","plddt":88.4413,"start":1511,"end":1797},{"cath_id":"1.20.58","chopping":"1613-1670","consensus_level":"medium","plddt":91.0359,"start":1613,"end":1670},{"cath_id":"-","chopping":"1801-1866_1874-1889","consensus_level":"medium","plddt":89.6361,"start":1801,"end":1889}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O15027","model_url":"https://alphafold.ebi.ac.uk/files/AF-O15027-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O15027-F1-predicted_aligned_error_v6.png","plddt_mean":40.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SEC16A","jax_strain_url":"https://www.jax.org/strain/search?query=SEC16A"},"sequence":{"accession":"O15027","fasta_url":"https://rest.uniprot.org/uniprotkb/O15027.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O15027/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O15027"}},"corpus_meta":[{"pmid":"8450888","id":"PMC_8450888","title":"The 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It binds both the inner COPII coat complex (Sec23-Sec24) and the outer layer complex (Sec13-Sec31), and its depletion causes disorganization of ER exit sites and delays protein transport from the ER.\",\n      \"method\": \"Subcellular fractionation, binding experiments, siRNA knockdown, fluorescence microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (fractionation, binding assays, knockdown with defined trafficking phenotype) in a single study\",\n      \"pmids\": [\"17428803\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"LRRK2 interacts with SEC16A and anchors it at ER exit sites (ERES) to support anterograde ER-Golgi transport; loss of Lrrk2 disperses SEC16A from ERES and impairs ER export, while the PD-associated LRRK2 R1441C mutation disrupts the LRRK2–SEC16A interaction. LRRK2 kinase activity is not required for this function.\",\n      \"method\": \"Co-immunoprecipitation, co-localization (confocal microscopy), siRNA knockdown, ER-Golgi transport assays, disease-mutation analysis\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, co-localization, KD phenotype, and mutation-specific interaction disruption, all in one study\",\n      \"pmids\": [\"25201882\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"SEC16A is a RAB10 effector required for insulin-stimulated GLUT4 trafficking to the plasma membrane in adipocytes. SEC16A co-localizes with RAB10 in a manner augmented by insulin, and SEC16A knockdown phenocopies RAB10 knockdown. This function is independent of canonical COPII coat components (SEC13, SEC23B, SEC31) but involves SEC23A, and operates at a perinuclear recycling endosome/TGN compartment distinct from canonical ERES.\",\n      \"method\": \"siRNA knockdown, co-localization microscopy, GLUT4 translocation assay, GTPase effector binding\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal functional epistasis (KD phenocopying), effector relationship established, independent of COPII function shown by selective component KD\",\n      \"pmids\": [\"27354378\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SEC16A is required for both conventional ER-to-Golgi secretion and IRE1α-mediated unconventional (GRASP55-dependent, Golgi-bypassing) secretion of CFTR. During unconventional secretion, SEC16A redistributes to the cell periphery and associates with GRASP55; knockdown of SEC16A, but not of other COPII components, abolishes unconventional CFTR secretion.\",\n      \"method\": \"siRNA gene silencing screen, immunoprecipitation, fluorescence microscopy, CFTR trafficking assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — selective KD screen among multiple COPII components identifies SEC16A uniquely, Co-IP with GRASP55, localization change during stress\",\n      \"pmids\": [\"28067262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"SEC16A interacts with the ubiquitin ligase RNF183 through the central conserved domain (CCD) of SEC16A, stabilizing RNF183 against ERAD-mediated degradation. SEC16A similarly stabilizes the lysosomal ubiquitin ligase RNF152. SEC16A is not a substrate for RNF183.\",\n      \"method\": \"Co-immunoprecipitation, co-localization, protein stability/degradation assays, domain mapping\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP with domain mapping and functional stability readout, single lab\",\n      \"pmids\": [\"29300766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SEC16A was identified as an interactor of the scaffolding protein Nbeal2 by mass spectrometry interactome analysis, with interaction validated by reverse immunoprecipitation in platelets/megakaryocytes.\",\n      \"method\": \"Mass spectrometry interactome, reverse Co-IP, proximity ligation assay\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — MS interactome with reverse IP validation, but functional consequence of SEC16A–Nbeal2 interaction not directly tested\",\n      \"pmids\": [\"29187380\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Loss-of-function SEC16A variants disrupt COPII complex formation, impede secretory protein vesicle trafficking from the ER, and induce ER stress due to protein overload. Sec16a+/- mice show impaired zymogen secretion, exacerbated ER stress, and heightened pancreatic inflammation in cerulein-induced pancreatitis.\",\n      \"method\": \"CRISPR/Cas9 knockout cell lines, COPII assembly assays, ER stress markers, mouse model with cerulein pancreatitis challenge\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple CRISPR-edited cell lines plus in vivo mouse model with defined molecular and phenotypic readouts\",\n      \"pmids\": [\"39119875\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The head domain of the Golgi vesicle tether p115/USO1 binds directly to a conserved motif within the unstructured N-terminal region of SEC16A. Structural prediction and deletion mapping defined the interaction site, and p115 mutations blocking this motif reduce secretion efficiency, suggesting this interaction contributes to organization of the early secretory pathway.\",\n      \"method\": \"In vitro binding assay, deletion mapping, structural prediction (AlphaFold), mutagenesis, secretion efficiency assay\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1/2 — direct in vitro binding with deletion mapping and mutagenesis, but preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.10.16.682774\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Depletion of SEC16A abolishes cholesterol depletion-induced very-long-chain sphingomyelin synthesis by blocking COPII-dependent ER-to-Golgi trafficking of VLC-ceramide, establishing SEC16A as a required component of this lipid homeostasis pathway.\",\n      \"method\": \"Sphingolipid metabolic flux analysis, siRNA depletion of SEC16A, ceramide trafficking assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — metabolic flux combined with specific KD phenotype, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.02.12.637879\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"SEC16A is a large scaffolding protein that organizes ER exit sites (ERES) by interacting with both inner (Sec23-Sec24) and outer (Sec13-Sec31) COPII coat complexes in a Sar1-dependent manner, and is anchored at ERES by LRRK2; beyond canonical COPII vesicle biogenesis, SEC16A also functions as a RAB10 effector in insulin-stimulated GLUT4 trafficking (independently of most COPII components), is redistributed and associates with GRASP55 to mediate unconventional IRE1α-dependent secretion under ER stress, directly binds the Golgi tether p115/USO1 to help organize the early secretory pathway, and stabilizes certain ER/lysosomal ubiquitin ligases through its central conserved domain.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2007,\n      \"finding\": \"Mammalian SEC16A (KIAA0310p/p250) is a homologue of yeast Sec16 that localizes to ER exit sites (ERES) and is recruited from the cytosol to ER membranes in a Sar1-dependent manner. It interacts with both the inner COPII layer (Sec23-Sec24) and outer layer (Sec13-Sec31) complexes. Depletion causes disorganization of ERES and delayed ER-to-Golgi protein transport.\",\n      \"method\": \"Subcellular fractionation, binding experiments, siRNA knockdown, fluorescence microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (fractionation, binding assays, KD phenotype) in a single study establishing localization, binding partners, and functional role\",\n      \"pmids\": [\"17428803\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"LRRK2 interacts and co-localizes with SEC16A and anchors it at ERES. Loss of LRRK2 disperses SEC16A from ERES and impairs ER export. In neurons, LRRK2 and SEC16A co-localize at dendritic ERES and regulate activity-dependent surface targeting of glutamate receptors. The PD-associated LRRK2 R1441C GTPase-domain mutation disrupts the LRRK2-SEC16A interaction and impairs ER-Golgi transport; LRRK2 kinase activity is not required.\",\n      \"method\": \"Co-immunoprecipitation, co-localization imaging, siRNA knockdown, domain-mutant analysis, neuronal surface receptor trafficking assays\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, multiple cell types including neurons, functional rescue and mutant dissection across orthogonal assays\",\n      \"pmids\": [\"25201882\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"SEC16A is a RAB10 effector required for insulin-stimulated GLUT4 translocation to the plasma membrane in adipocytes. Insulin augments colocalization of SEC16A with RAB10 at a perinuclear recycling endosome/TGN compartment, and SEC16A knockdown phenocopies RAB10 knockdown. This function is independent of canonical COPII coat assembly (SEC13, SEC23B, SEC31 not required), but SEC23A is involved, suggesting a non-canonical COPII subcomplex role.\",\n      \"method\": \"siRNA knockdown, co-localization imaging, GLUT4 translocation assay, insulin stimulation, epistasis with COPII component knockdowns\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KD phenotype with defined molecular readout, epistasis with multiple COPII components, and identification of a novel binding partner (RAB10)\",\n      \"pmids\": [\"27354378\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SEC16A plays a critical role in unconventional (Golgi-bypassing) secretion of CFTR and ΔF508-CFTR. During ER-to-Golgi blockade or ER stress, SEC16A is redistributed to the cell periphery and associates with GRASP55. IRE1α-mediated signaling acts as an upstream regulator of SEC16A redistribution during unconventional secretion. Knockdown of SEC16A, but not other COPII components, abolishes this unconventional pathway.\",\n      \"method\": \"siRNA knockdown screen, co-immunoprecipitation, immunofluorescence, CFTR secretion assay, IRE1α inhibition\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — functional KD screen with defined cargo readout, co-IP of novel partner (GRASP55), upstream pathway placement via IRE1α\",\n      \"pmids\": [\"28067262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SEC16A was identified as an interactor of the scaffolding protein Nbeal2 in platelets/megakaryocytes, validated by reverse immunoprecipitation and proximity ligation assay.\",\n      \"method\": \"Affinity purification mass spectrometry (interactome), reverse immunoprecipitation, proximity ligation assay\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP validated by PLA but functional consequence of SEC16A-Nbeal2 interaction not dissected\",\n      \"pmids\": [\"29187380\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"SEC16A interacts with the ubiquitin ligase RNF183 through its central conserved domain (CCD). SEC16A is not a substrate for RNF183 but stabilizes RNF183 against ERAD-mediated degradation. SEC16A similarly stabilizes the lysosomal ubiquitin ligase RNF152, indicating a broader role in regulating ubiquitin ligase protein stability and localization.\",\n      \"method\": \"Co-immunoprecipitation, domain deletion mapping, degradation assays, co-localization imaging\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — Co-IP with domain mapping and functional degradation assay, single lab\",\n      \"pmids\": [\"29300766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Loss-of-function SEC16A variants (including frameshift and missense) disrupt COPII complex formation, impede secretory protein vesicle trafficking from the ER, and induce ER stress due to protein overload, as shown in CRISPR/Cas9-edited HEK293T cells. Sec16a+/- mice show impaired zymogen secretion, exacerbated ER stress, and heightened pancreatic inflammation and fibrosis upon cerulein challenge.\",\n      \"method\": \"CRISPR/Cas9 knockout cell lines, COPII assembly assay, secretion trafficking assay, ER stress markers, mouse model with pancreatitis challenge\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple CRISPR-edited cell lines plus in vivo mouse model with orthogonal mechanistic readouts\",\n      \"pmids\": [\"39119875\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SEC16A is depleted of VLC-ceramide trafficking from the ER to the Golgi upon cholesterol depletion. Depletion of SEC16A abolishes the increased synthesis of very-long-chain sphingomyelin that is induced by cholesterol depletion, establishing SEC16A/COPII as a rate-limiting node in ER-to-Golgi ceramide transport and organelle membrane homeostasis.\",\n      \"method\": \"siRNA knockdown of SEC16A, sphingolipid metabolic flux analysis, sphingolipid trafficking assay\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KD with defined metabolic flux readout, but preprint and single lab\",\n      \"pmids\": [\"bio_10.1101_2025.02.12.637879\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The head domain of the Golgi vesicle tether p115 (USO1) binds directly to a conserved motif in the unstructured N-terminal region of SEC16A. Structural prediction and deletion mapping define the interaction surface, and p115 mutations that block this motif reduce secretion efficiency, suggesting p115 bridges early Golgi to ERES via SEC16A.\",\n      \"method\": \"Direct binding assay, deletion mapping, structural prediction, secretion efficiency assay with p115 mutants\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct binding with deletion mapping and functional mutant validation, but preprint\",\n      \"pmids\": [\"bio_10.1101_2025.10.16.682774\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A knock-in mouse model carrying the Sec16a L1551V mutation (corresponding to human L1536V in the conserved central core domain involved in COPII assembly) displays neurological impairment: homozygous mice show deficits in novel object recognition and fear-conditioned learning/memory, and limb clasping behavior associated with neurodegeneration.\",\n      \"method\": \"CRISPR/Cas9 knock-in mouse model, behavioral testing (novel object recognition, cued fear conditioning, tail suspension)\",\n      \"journal\": \"Animal models and experimental medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo model with defined phenotypic readouts, but mechanistic link between CCD mutation and neurological phenotype not fully elucidated\",\n      \"pmids\": [\"41104514\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SEC16A is a large scaffolding protein that organizes ER exit sites (ERES) by interacting with both inner (Sec23-Sec24) and outer (Sec13-Sec31) COPII coat complexes in a Sar1-dependent manner; it is anchored at ERES by LRRK2, acts as a RAB10 effector to drive insulin-stimulated GLUT4 vesicle biogenesis via a non-canonical COPII subcomplex, mediates unconventional GRASP55-dependent secretion downstream of IRE1α during ER stress, stabilizes ER-associated ubiquitin ligases (RNF183, RNF152) through its central conserved domain, and is directly tethered to the early Golgi via binding of the p115/USO1 head domain to its unstructured N-terminus, collectively positioning SEC16A as a master organizer of anterograde ER-to-Golgi traffic with additional roles in non-canonical secretory routes.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"SEC16A is a large scaffolding protein that organizes ER exit sites (ERES) and coordinates multiple secretory trafficking pathways. It is recruited to ER membranes in a Sar1-dependent manner and binds both the inner (Sec23–Sec24) and outer (Sec13–Sec31) COPII coat subcomplexes; its depletion disorganizes ERES, delays ER-to-Golgi transport, disrupts COPII complex formation, and induces ER stress from protein overload [PMID:17428803, PMID:39119875]. LRRK2 anchors SEC16A at ERES to support anterograde transport, and the Parkinson disease–associated LRRK2 R1441C mutation disrupts this interaction [PMID:25201882]. Beyond canonical COPII-mediated export, SEC16A functions as a RAB10 effector in insulin-stimulated GLUT4 translocation independently of most COPII components [PMID:27354378], and during ER stress it redistributes to associate with GRASP55 to mediate unconventional, Golgi-bypassing secretion of CFTR [PMID:28067262].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Establishing that mammalian SEC16A is a bona fide ERES scaffold resolved how COPII coat assembly is spatially organized: SEC16A localizes to ERES in a Sar1-dependent manner, binds both inner and outer COPII coat subcomplexes, and is required for ERES integrity and ER export.\",\n      \"evidence\": \"Subcellular fractionation, direct binding assays, siRNA knockdown with fluorescence microscopy and trafficking readouts in mammalian cells\",\n      \"pmids\": [\"17428803\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"How SEC16A is retained at ERES membranes independently of Sar1 cycling was not determined\",\n        \"The precise stoichiometry and structural basis of SEC16A–coat interactions remained unknown\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identifying LRRK2 as the upstream anchor of SEC16A at ERES explained how a Parkinson disease–linked kinase regulates the secretory pathway: LRRK2 physically interacts with SEC16A, and the PD-associated R1441C mutation disrupts this interaction, dispersing SEC16A from ERES.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, confocal co-localization, siRNA knockdown with ER-Golgi transport assays, disease-mutation analysis\",\n      \"pmids\": [\"25201882\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether other PD-associated LRRK2 mutations similarly affect SEC16A anchoring was not tested\",\n        \"The domain on SEC16A recognized by LRRK2 was not mapped\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrating that SEC16A is a RAB10 effector required for insulin-stimulated GLUT4 translocation revealed a COPII-independent function at perinuclear recycling endosomes, separating SEC16A's trafficking roles from its canonical ERES scaffold activity.\",\n      \"evidence\": \"siRNA knockdown phenocopying RAB10 depletion, co-localization microscopy, GLUT4 translocation assay in adipocytes, selective COPII component knockdowns\",\n      \"pmids\": [\"27354378\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The molecular basis of SEC16A recruitment by GTP-bound RAB10 was not structurally defined\",\n        \"Whether SEC16A participates in RAB10-dependent trafficking of cargoes other than GLUT4 is unknown\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showing that SEC16A redistributes and associates with GRASP55 during ER stress to uniquely support unconventional CFTR secretion established SEC16A as a dual-mode trafficking factor operating in both conventional and Golgi-bypassing pathways.\",\n      \"evidence\": \"siRNA screen of multiple COPII components, co-immunoprecipitation with GRASP55, fluorescence microscopy, CFTR trafficking assays\",\n      \"pmids\": [\"28067262\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The signal that triggers SEC16A redistribution during ER stress is uncharacterized\",\n        \"Whether this unconventional pathway operates for cargoes beyond CFTR was not tested\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Mapping the interaction of the SEC16A central conserved domain with ubiquitin ligases RNF183 and RNF152 uncovered a non-trafficking role for SEC16A in stabilizing these ligases against ERAD-mediated degradation.\",\n      \"evidence\": \"Co-immunoprecipitation, domain deletion mapping, protein stability/degradation assays\",\n      \"pmids\": [\"29300766\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Validated in a single lab without independent replication\",\n        \"Functional consequences of RNF183/RNF152 stabilization on downstream ubiquitination targets were not examined\",\n        \"Whether SEC16A stabilizes other ERAD substrates through its CCD is unknown\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrating that SEC16A loss-of-function disrupts COPII assembly, induces ER stress, and exacerbates pancreatitis in vivo linked the scaffolding role to organ-level pathophysiology and showed that partial SEC16A deficiency is sufficient to compromise secretory tissue homeostasis.\",\n      \"evidence\": \"CRISPR/Cas9 knockout cell lines with COPII assembly assays, ER stress markers, Sec16a+/- mouse model challenged with cerulein-induced pancreatitis\",\n      \"pmids\": [\"39119875\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether SEC16A variants cause human pancreatitis or other secretory diseases is not established\",\n        \"Contribution of unconventional secretion defects versus canonical COPII defects to the in vivo phenotype was not dissected\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"A full structural model of SEC16A at ERES — including how its multiple interaction surfaces simultaneously engage COPII coats, LRRK2, RAB10, GRASP55, and p115 — remains unresolved, as does the mechanism by which SEC16A switches between conventional and unconventional trafficking modes.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No high-resolution structure of SEC16A or its complexes exists\",\n        \"The signal-dependent switching mechanism between ERES scaffolding and unconventional secretion roles is unknown\",\n        \"Whether SEC16A's RAB10-effector and COPII-scaffold functions are mutually exclusive or coexist on the same molecule is not determined\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 2, 3]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0, 1, 6]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1, 2, 3, 6]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 2, 6]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [3, 6]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [\n      \"COPII coat\"\n    ],\n    \"partners\": [\n      \"SEC23A\",\n      \"SEC24\",\n      \"SEC13\",\n      \"SEC31\",\n      \"LRRK2\",\n      \"RAB10\",\n      \"GRASP55\",\n      \"RNF183\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"SEC16A is a large scaffolding protein that organizes endoplasmic reticulum exit sites (ERES) and serves as a master regulator of anterograde ER-to-Golgi transport. It is recruited to ER membranes in a Sar1-dependent manner and interacts with both inner (Sec23–Sec24) and outer (Sec13–Sec31) COPII coat complexes; depletion disorganizes ERES and delays secretory trafficking, while loss-of-function variants impede COPII assembly, induce ER stress, and in mice exacerbate cerulein-induced pancreatic inflammation and fibrosis [PMID:17428803, PMID:39119875]. Beyond canonical COPII-dependent export, SEC16A functions as a RAB10 effector driving insulin-stimulated GLUT4 translocation via a non-canonical COPII subcomplex [PMID:27354378], mediates GRASP55-dependent unconventional secretion of CFTR downstream of IRE1α during ER stress [PMID:28067262], and is anchored at ERES by LRRK2, whose Parkinson's-disease-associated R1441C mutation disrupts this interaction and impairs ER-Golgi transport in neurons [PMID:25201882]. SEC16A additionally stabilizes ER-associated ubiquitin ligases RNF183 and RNF152 through its central conserved domain, and a missense mutation in this domain causes neurological impairment in mice [PMID:29300766, PMID:41104514].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Establishing SEC16A as the mammalian ERES scaffold resolved how the two-layered COPII coat is spatially organized on ER membranes, showing that a single protein interacts with both inner and outer coat and that its loss disorganizes exit sites.\",\n      \"evidence\": \"Subcellular fractionation, binding assays with COPII components, siRNA knockdown and fluorescence microscopy in mammalian cells\",\n      \"pmids\": [\"17428803\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Mechanism by which SEC16A is initially targeted to specific ER membrane domains remains unclear\",\n        \"Structural basis of SEC16A interactions with Sec23–Sec24 and Sec13–Sec31 not resolved\",\n        \"Whether SEC16A has catalytic activity or functions purely as a scaffold was not addressed\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrating that LRRK2 anchors SEC16A at ERES and that the PD-associated R1441C mutation disrupts this interaction linked ERES organization to neurodegeneration and revealed how SEC16A retention at exit sites is regulated upstream.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, co-localization imaging, domain-mutant analysis, and neuronal surface receptor trafficking assays\",\n      \"pmids\": [\"25201882\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct binding interface between LRRK2 and SEC16A not mapped at residue level\",\n        \"Whether other kinases or GTPases can substitute for LRRK2 in anchoring SEC16A is unknown\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identifying SEC16A as a RAB10 effector for insulin-stimulated GLUT4 translocation revealed a non-canonical COPII function independent of the full canonical coat, broadening SEC16A's role beyond classical ER export.\",\n      \"evidence\": \"siRNA epistasis with individual COPII components, GLUT4 translocation assay, and co-localization imaging in adipocytes\",\n      \"pmids\": [\"27354378\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Composition of the non-canonical SEC16A–SEC23A subcomplex not fully defined\",\n        \"Whether RAB10–SEC16A interaction is direct or mediated through an adaptor is unresolved\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showing that SEC16A mediates GRASP55-dependent unconventional secretion of CFTR downstream of IRE1α established SEC16A as a bifunctional scaffold operating in both canonical and Golgi-bypassing secretory routes during ER stress.\",\n      \"evidence\": \"siRNA knockdown screen, co-immunoprecipitation with GRASP55, CFTR secretion assay, and IRE1α inhibition\",\n      \"pmids\": [\"28067262\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Cargo selectivity of the unconventional pathway beyond CFTR not characterized\",\n        \"Mechanism by which IRE1α signaling triggers SEC16A redistribution to the cell periphery is unknown\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Mapping the central conserved domain (CCD) as the interface for stabilizing ER-associated ubiquitin ligases RNF183 and RNF152 extended SEC16A's function beyond vesicle coat organization to proteostasis regulation.\",\n      \"evidence\": \"Co-immunoprecipitation, domain deletion mapping, and degradation assays\",\n      \"pmids\": [\"29300766\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism by which SEC16A shields these ligases from ERAD is not defined\",\n        \"Whether additional E3 ligases are stabilized by SEC16A's CCD is untested\",\n        \"Finding from a single laboratory awaits independent confirmation\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrating that SEC16A loss-of-function variants impede COPII assembly and cause ER stress, and that Sec16a haploinsufficiency in mice exacerbates pancreatic inflammation and fibrosis, provided the first in vivo disease-relevant model linking SEC16A deficiency to organ pathology.\",\n      \"evidence\": \"CRISPR/Cas9-edited HEK293T cells, COPII assembly and secretion assays, ER stress markers, Sec16a+/- mouse model with cerulein-induced pancreatitis\",\n      \"pmids\": [\"39119875\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether SEC16A variants contribute to human pancreatitis susceptibility requires clinical genetic studies\",\n        \"Cell-type-specific consequences of SEC16A deficiency beyond pancreatic acinar cells not explored\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A knock-in mouse carrying a CCD missense mutation (L1551V) displayed neurological deficits including impaired learning/memory and neurodegeneration-associated clasping, establishing that even subtle disruption of the COPII-interacting domain has consequences for CNS function.\",\n      \"evidence\": \"CRISPR/Cas9 knock-in mouse model with behavioral testing (novel object recognition, fear conditioning, tail suspension)\",\n      \"pmids\": [\"41104514\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Cellular mechanism linking CCD mutation to neurodegeneration not elucidated\",\n        \"Whether this mutation affects COPII assembly, ubiquitin ligase stabilization, or both is untested\",\n        \"Findings from a single mouse model line\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SEC16A coordinates its multiple scaffolding roles — canonical COPII assembly, non-canonical vesicle biogenesis, unconventional secretion, and ubiquitin ligase stabilization — through its distinct domains, and whether these functions are mutually exclusive or concurrent at the same ERES, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No high-resolution structure of full-length SEC16A or its domain complexes exists\",\n        \"Post-translational modifications regulating switching between canonical and non-canonical functions are uncharacterized\",\n        \"In vivo tissue-specific requirements for SEC16A beyond pancreas and brain are largely unexplored\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 2, 3]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0, 1, 6]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1, 2, 3, 6]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 2, 6]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"complexes\": [\n      \"COPII coat\"\n    ],\n    \"partners\": [\n      \"SEC23A\",\n      \"SEC24\",\n      \"SEC13\",\n      \"SEC31\",\n      \"LRRK2\",\n      \"RAB10\",\n      \"GRASP55\",\n      \"RNF183\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}