{"gene":"TRAPPC11","run_date":"2026-04-28T21:42:59","timeline":{"discoveries":[{"year":2013,"finding":"TRAPPC11 mutations (p.Gly980Arg in the gryzun domain and p.Ala372_Ser429del in the foie gras domain) impair binding of TRAPPC11 to other TRAPP complex components and disrupt Golgi apparatus architecture; the foie gras domain deletion causes normal ER-to-Golgi trafficking but dramatically delayed exit from the Golgi to the cell surface, and leads to alterations of lysosomal membrane glycoproteins LAMP1 and LAMP2.","method":"Co-immunoprecipitation, marker trafficking experiments, immunofluorescence of Golgi markers, western blotting of LAMP1/LAMP2 in patient fibroblasts with defined mutations","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (Co-IP, trafficking assays, Golgi morphology, glycoprotein analysis) in patient-derived cells with defined mutations","pmids":["23830518"],"is_preprint":false},{"year":2016,"finding":"TRAPPC11 is required for lipid-linked oligosaccharide (LLO) biosynthesis and protein N-glycosylation; depletion of TRAPPC11 (but not other TRAPP components) in human cells causes protein hypoglycosylation associated with reduced LLO levels and compensatory upregulation of the terpenoid/dolichol biosynthetic pathway, leading to a stressed unfolded protein response and lipid droplet accumulation.","method":"Zebrafish trappc11 mutant analysis, siRNA knockdown of TRAPPC11 in human cells, LLO level measurement, UPR reporter assays, pharmacological inhibition of terpenoid/LLO synthesis, patient fibroblast analysis","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1-2 — biochemical LLO measurement, genetic rescue, pharmacological phenocopy, human cell knockdown, replicated across zebrafish and human systems","pmids":["26912795"],"is_preprint":false},{"year":2016,"finding":"A TRAPPC11 splice mutation (c.1893+3A>G) causes incomplete exon skipping, dramatic reduction of full-length TRAPPC11 protein, hypoglycosylation of LAMP1, delayed arrival of marker proteins at the Golgi, and delayed release from the Golgi to the plasma membrane in patient fibroblasts.","method":"Western blotting, membrane trafficking assays with fluorescent cargo markers in patient fibroblasts, mRNA analysis","journal":"Journal of medical genetics","confidence":"Medium","confidence_rationale":"Tier 2 — multiple trafficking assays and glycosylation readout in patient cells, single lab","pmids":["27707803"],"is_preprint":false},{"year":2015,"finding":"TRAPPC11 is a component of the multiprotein TRAPP complex involved in endoplasmic reticulum-to-Golgi trafficking; loss of full-length TRAPPC11 protein (due to compound heterozygous mutations including a novel splice-site mutation causing frameshift/truncation) causes congenital muscular dystrophy with steatosis, demonstrating a physiological role in multiple tissues.","method":"Immunoblotting showing absence of full-length TRAPPC11, mRNA splicing analysis, muscle and liver biopsy histology","journal":"Skeletal muscle","confidence":"Medium","confidence_rationale":"Tier 2-3 — biochemical confirmation of protein loss with pathological consequence, single lab","pmids":["26322222"],"is_preprint":false},{"year":2018,"finding":"TRAPPC11 mutations are associated with hypoglycosylation of α-dystroglycan; compound heterozygous TRAPPC11 mutations (c.851A>C and c.965+5G>T) cause abnormal membrane trafficking in patient fibroblasts, linking membrane trafficking defects to dystroglycanopathy for the first time.","method":"Immunofluorescence and western blotting for α-dystroglycan glycosylation, live cell membrane trafficking analysis in patient fibroblasts","journal":"Skeletal muscle","confidence":"Medium","confidence_rationale":"Tier 2 — multiple methods (IF, WB, live trafficking) in patient-derived cells, single lab","pmids":["29855340"],"is_preprint":false},{"year":2019,"finding":"TRAPPC11 functions in membrane trafficking and autophagy as a component of TRAPP III; variants affecting the carboxy terminus (frameshift p.Asp1127Valfs*47) cause defects in ER-to-Golgi transport, Golgi exit, and glycosylation of an ER-resident glycoprotein, while the compound heterozygous (foie gras deletion + C-terminal frameshift) combination additionally causes autophagic flux defects not seen with the missense variant alone, highlighting the critical role of the extreme carboxy terminus.","method":"Membrane trafficking assays, glycosylation assays (ER-resident glycoprotein), autophagic flux assay in patient fibroblasts with defined bi-allelic variants","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal functional assays in patient cells with genotype-phenotype correlation, single lab","pmids":["31575891"],"is_preprint":false},{"year":2021,"finding":"TRAPPC11 is important for complex integrity and anterograde membrane transport from the ER to the ER-Golgi intermediate compartment; mutations cause universal hypoglycosylation of α-dystroglycan in skeletal muscle and brain (including Purkinje cells and dentate neurons), with neuropathology resembling N-linked congenital disorders of glycosylation.","method":"Membrane trafficking assays in patient fibroblasts, immunofluorescence with IIH6 antibody for α-dystroglycan glycosylation in muscle and post-mortem brain, neuropathological examination","journal":"Neuropathology and applied neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 — trafficking assays plus histopathological glycosylation analysis across multiple tissues, single series","pmids":["34648194"],"is_preprint":false},{"year":2023,"finding":"TRAPPC11 deficiency impairs mitochondrial function: patient fibroblasts/muscle from individuals with the c.1287+5G>A founder variant show decreased mitochondrial ATP production capacity and alterations in mitochondrial network architecture.","method":"Mitochondrial ATP production assays and mitochondrial network morphology analysis in patient-derived cells","journal":"Journal of medical genetics","confidence":"Low","confidence_rationale":"Tier 3 — single lab, functional assay but not mechanistically linked to TRAPPC11's known trafficking role","pmids":["37197784"],"is_preprint":false},{"year":2024,"finding":"TRAPPC11 mutations cause defective ER-to-Golgi transport and decreased expression of LAMP2 and ICAM-1 glycoproteins, further supporting TRAPPC11-opathy as a congenital disorder of glycosylation (CDG) with muscular dystrophy.","method":"Membrane trafficking assays and western blotting for glycoprotein expression in patient fibroblasts","journal":"Molecular genetics and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 — trafficking and glycosylation assays consistent across multiple reported cases","pmids":["38564972"],"is_preprint":false}],"current_model":"TRAPPC11 is a subunit of the TRAPP III complex that is required for anterograde membrane trafficking (ER-to-Golgi and Golgi-to-plasma membrane), lipid-linked oligosaccharide (LLO) biosynthesis, and protein N-glycosylation (including α-dystroglycan); mutations in its foie gras or gryzun domains disrupt binding to other TRAPP subunits, impair Golgi architecture and exit kinetics, and cause hypoglycosylation of multiple glycoproteins (LAMP1, LAMP2, α-dystroglycan), leading to a stressed unfolded protein response, lipid accumulation, and secondarily to autophagic flux defects when the carboxy terminus is also disrupted."},"narrative":{"teleology":[{"year":2013,"claim":"Establishing that TRAPPC11 is required for TRAPP complex integrity and post-Golgi membrane trafficking answered whether this large subunit has a discrete role beyond ER-to-Golgi transport, revealing that foie gras domain mutations specifically delay Golgi exit and alter LAMP1/LAMP2 glycosylation.","evidence":"Co-immunoprecipitation, cargo trafficking kinetics, and glycoprotein blotting in patient fibroblasts carrying defined foie gras or gryzun domain mutations","pmids":["23830518"],"confidence":"High","gaps":["Whether TRAPPC11's trafficking role is separable from a direct glycosylation function was unknown","Structural basis for foie gras versus gryzun domain contributions to TRAPP binding unresolved","Whether Golgi exit delay is the primary cause of glycoprotein alterations or a secondary effect was not determined"]},{"year":2015,"claim":"Demonstrating that loss of full-length TRAPPC11 causes congenital muscular dystrophy with hepatic steatosis established TRAPPC11 as a disease gene with multi-organ physiological consequences.","evidence":"Immunoblotting confirming protein absence, mRNA splicing analysis, and muscle/liver biopsy histology in patients with compound heterozygous mutations","pmids":["26322222"],"confidence":"Medium","gaps":["Mechanism linking TRAPPC11 loss to lipid accumulation in liver was not resolved","Whether steatosis results from trafficking defects or glycosylation defects was unclear"]},{"year":2016,"claim":"Revealing that TRAPPC11 is required for LLO biosynthesis—independent of other TRAPP subunits—resolved the question of whether TRAPPC11 has a glycosylation-specific function beyond vesicle trafficking, showing that its loss reduces LLO pools, triggers the UPR, and promotes lipid droplet accumulation.","evidence":"siRNA knockdown in human cells with LLO quantification, UPR reporter assays, pharmacological phenocopy of terpenoid pathway inhibition, and zebrafish trappc11 mutant analysis","pmids":["26912795"],"confidence":"High","gaps":["Direct molecular mechanism by which TRAPPC11 controls LLO synthesis (enzymatic target or membrane platform) was not identified","Whether the UPR is a cause or consequence of lipid droplet accumulation was not distinguished"]},{"year":2016,"claim":"A splice mutation reducing full-length TRAPPC11 confirmed that both ER-to-Golgi arrival and Golgi exit are TRAPPC11-dependent, extending the trafficking defect model to both anterograde steps.","evidence":"Fluorescent cargo trafficking assays and LAMP1 glycosylation analysis in patient fibroblasts","pmids":["27707803"],"confidence":"Medium","gaps":["Whether residual truncated protein retains partial function was not assessed","Contribution of each trafficking step to overall glycosylation impairment not quantified"]},{"year":2018,"claim":"Linking TRAPPC11 mutations to α-dystroglycan hypoglycosylation established TRAPPC11-opathy as a dystroglycanopathy, answering whether the glycosylation defect extends to the functionally critical O-mannosyl glycans of α-dystroglycan.","evidence":"IIH6 immunofluorescence and western blotting for glycosylated α-dystroglycan combined with live-cell trafficking assays in patient fibroblasts","pmids":["29855340"],"confidence":"Medium","gaps":["Whether α-dystroglycan hypoglycosylation is secondary to N-glycosylation/LLO defects or reflects an independent pathway was not resolved","Quantitative relationship between trafficking delay severity and degree of α-dystroglycan glycosylation loss not established"]},{"year":2019,"claim":"Demonstrating that carboxy-terminal truncation of TRAPPC11 causes autophagic flux defects—not seen with the gryzun missense variant alone—revealed a domain-specific role for the C-terminus in autophagy, separable from its trafficking and glycosylation functions.","evidence":"Autophagic flux assays, ER-to-Golgi and Golgi exit assays, and ER-resident glycoprotein glycosylation in fibroblasts with defined bi-allelic variant combinations","pmids":["31575891"],"confidence":"Medium","gaps":["Whether the autophagy defect is mediated through TRAPP III's known role in autophagosome formation or an independent mechanism was not resolved","Identity of C-terminal interaction partners mediating autophagy function unknown"]},{"year":2021,"claim":"Showing universal α-dystroglycan hypoglycosylation in skeletal muscle, Purkinje cells, and dentate neurons in TRAPPC11-mutant patients established that the glycosylation defect is not tissue-restricted, explaining the neurological phenotype as a central glycosylation disorder.","evidence":"IIH6 immunofluorescence on post-mortem brain and muscle tissue, membrane trafficking assays in fibroblasts, neuropathological examination","pmids":["34648194"],"confidence":"Medium","gaps":["Whether neuronal degeneration is cell-autonomous or secondary to extracellular matrix dysfunction was not determined","Whether other glycoproteins beyond α-dystroglycan contribute to the CNS phenotype remains unknown"]},{"year":2024,"claim":"Confirming defective ER-to-Golgi transport and decreased expression of LAMP2 and ICAM-1 across additional TRAPPC11 mutations consolidated the classification of TRAPPC11-opathy as a congenital disorder of glycosylation (CDG) with broad glycoprotein impact.","evidence":"Membrane trafficking assays and western blotting for glycoproteins in patient fibroblasts","pmids":["38564972"],"confidence":"Medium","gaps":["Full glycoproteomic characterization of hypoglycosylation targets has not been performed","Whether glycosylation correction rescues the trafficking phenotype (or vice versa) is untested"]},{"year":null,"claim":"The direct molecular mechanism by which TRAPPC11 controls LLO biosynthesis—whether through organizing dolichol-pathway enzymes at ER membranes, modulating terpenoid flux, or another mechanism—remains unresolved, and the structural basis for domain-specific contributions of the foie gras, gryzun, and C-terminal regions to trafficking, glycosylation, and autophagy has not been determined.","evidence":"","pmids":[],"confidence":"High","gaps":["No enzymatic target or direct binding partner for LLO pathway regulation identified","No high-resolution structure of TRAPPC11 within the TRAPP III complex","Causal hierarchy between trafficking defects and glycosylation defects not experimentally separated"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,5]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0,2,6]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[1,5]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,2,5,6,8]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[1,4,6]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[5]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[3,4,6]}],"complexes":["TRAPP III"],"partners":[],"other_free_text":[]},"mechanistic_narrative":"TRAPPC11 is a subunit of the TRAPP III complex that functions in anterograde membrane trafficking, lipid-linked oligosaccharide (LLO) biosynthesis, and protein N-glycosylation. Its foie gras and gryzun domains mediate binding to other TRAPP subunits; mutations in these domains disrupt Golgi architecture, delay ER-to-Golgi and Golgi-to-plasma membrane transport, and cause hypoglycosylation of multiple glycoproteins including LAMP1, LAMP2, ICAM-1, and α-dystroglycan [PMID:23830518, PMID:26912795, PMID:38564972]. TRAPPC11 depletion independently reduces LLO levels and triggers an unfolded protein response and lipid droplet accumulation, while disruption of its carboxy terminus additionally impairs autophagic flux [PMID:26912795, PMID:31575891]. Biallelic loss-of-function mutations cause a congenital disorder of glycosylation manifesting as muscular dystrophy (dystroglycanopathy), hepatic steatosis, and neurodegeneration [PMID:26322222, PMID:34648194]."},"prefetch_data":{"uniprot":{"accession":"Q7Z392","full_name":"Trafficking protein particle complex subunit 11","aliases":[],"length_aa":1133,"mass_kda":128.9,"function":"Involved in endoplasmic reticulum to Golgi apparatus trafficking at a very early stage","subcellular_location":"Golgi apparatus; Golgi apparatus, cis-Golgi network","url":"https://www.uniprot.org/uniprotkb/Q7Z392/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/TRAPPC11","classification":"Common Essential","n_dependent_lines":1174,"n_total_lines":1208,"dependency_fraction":0.9718543046357616},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000168538","cell_line_id":"CID000471","localizations":[{"compartment":"golgi","grade":3},{"compartment":"vesicles","grade":3},{"compartment":"cytoplasmic","grade":1}],"interactors":[{"gene":"TRAPPC2B;TRAPPC2","stoichiometry":10.0},{"gene":"TRAPPC13","stoichiometry":10.0},{"gene":"TRAPPC3","stoichiometry":10.0},{"gene":"TRAPPC8","stoichiometry":10.0},{"gene":"TRAPPC6B","stoichiometry":10.0},{"gene":"TRAPPC2","stoichiometry":10.0},{"gene":"ARL6IP6","stoichiometry":0.2},{"gene":"TRAPPC1","stoichiometry":0.2},{"gene":"YWHAB","stoichiometry":0.2},{"gene":"PYGL","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000471","total_profiled":1310},"omim":[{"mim_id":"620166","title":"MUSCULAR DYSTROPHY, CONGENITAL, WITH OR WITHOUT SEIZURES; MYOS","url":"https://www.omim.org/entry/620166"},{"mim_id":"615356","title":"MUSCULAR DYSTROPHY, LIMB-GIRDLE, AUTOSOMAL RECESSIVE 18; LGMDR18","url":"https://www.omim.org/entry/615356"},{"mim_id":"614781","title":"TECTONIN BETA-PROPELLER REPEAT-CONTAINING 1; TECPR1","url":"https://www.omim.org/entry/614781"},{"mim_id":"614138","title":"TRAFFICKING PROTEIN PARTICLE COMPLEX, SUBUNIT 11; TRAPPC11","url":"https://www.omim.org/entry/614138"},{"mim_id":"604027","title":"GOLGI SNAP RECEPTOR COMPLEX MEMBER 2; GOSR2","url":"https://www.omim.org/entry/604027"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Cytosol","reliability":"Uncertain"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TRAPPC11"},"hgnc":{"alias_symbol":["FLJ12716","gry","foigr"],"prev_symbol":["C4orf41"]},"alphafold":{"accession":"Q7Z392","domains":[{"cath_id":"3.40.50","chopping":"2-216","consensus_level":"medium","plddt":88.0941,"start":2,"end":216},{"cath_id":"-","chopping":"302-324_339-400_407-467","consensus_level":"medium","plddt":90.0978,"start":302,"end":467},{"cath_id":"-","chopping":"473-574","consensus_level":"high","plddt":90.4261,"start":473,"end":574},{"cath_id":"2.60.40.10","chopping":"581-644_653-749","consensus_level":"high","plddt":84.4404,"start":581,"end":749},{"cath_id":"2.60.40.10","chopping":"755-869","consensus_level":"high","plddt":88.7441,"start":755,"end":869},{"cath_id":"2.60.40.10","chopping":"889-1011","consensus_level":"high","plddt":87.4505,"start":889,"end":1011},{"cath_id":"2.60.40.10","chopping":"1015-1120","consensus_level":"high","plddt":87.8677,"start":1015,"end":1120}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q7Z392","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q7Z392-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q7Z392-F1-predicted_aligned_error_v6.png","plddt_mean":87.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TRAPPC11","jax_strain_url":"https://www.jax.org/strain/search?query=TRAPPC11"},"sequence":{"accession":"Q7Z392","fasta_url":"https://rest.uniprot.org/uniprotkb/Q7Z392.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q7Z392/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q7Z392"}},"corpus_meta":[{"pmid":"11773003","id":"PMC_11773003","title":"Specific interaction of Smn, the spinal muscular atrophy determining gene product, with hnRNP-R and gry-rbp/hnRNP-Q: a role for Smn in RNA processing in motor axons?","date":"2002","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11773003","citation_count":241,"is_preprint":false},{"pmid":"23830518","id":"PMC_23830518","title":"Recessive TRAPPC11 mutations cause a disease spectrum of limb girdle muscular dystrophy and myopathy with movement disorder and intellectual disability.","date":"2013","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23830518","citation_count":89,"is_preprint":false},{"pmid":"11134005","id":"PMC_11134005","title":"Identification of GRY-RBP as an apolipoprotein B RNA-binding protein that interacts with both apobec-1 and apobec-1 complementation factor to modulate C to U editing.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11134005","citation_count":85,"is_preprint":false},{"pmid":"29855340","id":"PMC_29855340","title":"TRAPPC11 and GOSR2 mutations associate with hypoglycosylation of α-dystroglycan and muscular dystrophy.","date":"2018","source":"Skeletal muscle","url":"https://pubmed.ncbi.nlm.nih.gov/29855340","citation_count":48,"is_preprint":false},{"pmid":"26322222","id":"PMC_26322222","title":"Congenital muscular dystrophy with fatty liver and infantile-onset cataract caused by TRAPPC11 mutations: broadening of the phenotype.","date":"2015","source":"Skeletal muscle","url":"https://pubmed.ncbi.nlm.nih.gov/26322222","citation_count":43,"is_preprint":false},{"pmid":"27707803","id":"PMC_27707803","title":"A novel TRAPPC11 mutation in two Turkish families associated with cerebral atrophy, global retardation, scoliosis, achalasia and alacrima.","date":"2016","source":"Journal of medical 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disease","url":"https://pubmed.ncbi.nlm.nih.gov/28827486","citation_count":22,"is_preprint":false},{"pmid":"34648194","id":"PMC_34648194","title":"TRAPPC11-related muscular dystrophy with hypoglycosylation of alpha-dystroglycan in skeletal muscle and brain.","date":"2021","source":"Neuropathology and applied neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/34648194","citation_count":18,"is_preprint":false},{"pmid":"31575891","id":"PMC_31575891","title":"Characterization of three TRAPPC11 variants suggests a critical role for the extreme carboxy terminus of the protein.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31575891","citation_count":14,"is_preprint":false},{"pmid":"37197784","id":"PMC_37197784","title":"Expanding the phenotypic spectrum of TRAPPC11-related muscular dystrophy: 25 Roma individuals carrying a founder variant.","date":"2023","source":"Journal of medical 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reports","url":"https://pubmed.ncbi.nlm.nih.gov/33173071","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10968,"output_tokens":2297,"usd":0.03368},"stage2":{"model":"claude-opus-4-6","input_tokens":5610,"output_tokens":2523,"usd":0.136687},"total_usd":0.170367,"stage1_batch_id":"msgbatch_01RPbVc9PDH9zQmYK5Hs6srm","stage2_batch_id":"msgbatch_01JVbVLzeKN2yVrsGp3zC8aM","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"TRAPPC11 mutations (p.Gly980Arg in the gryzun domain and p.Ala372_Ser429del in the foie gras domain) impair binding of TRAPPC11 to other TRAPP complex components and disrupt Golgi apparatus architecture; the foie gras domain deletion causes normal ER-to-Golgi trafficking but dramatically delayed exit from the Golgi to the cell surface, and leads to alterations of lysosomal membrane glycoproteins LAMP1 and LAMP2.\",\n      \"method\": \"Co-immunoprecipitation, marker trafficking experiments, immunofluorescence of Golgi markers, western blotting of LAMP1/LAMP2 in patient fibroblasts with defined mutations\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (Co-IP, trafficking assays, Golgi morphology, glycoprotein analysis) in patient-derived cells with defined mutations\",\n      \"pmids\": [\"23830518\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"TRAPPC11 is required for lipid-linked oligosaccharide (LLO) biosynthesis and protein N-glycosylation; depletion of TRAPPC11 (but not other TRAPP components) in human cells causes protein hypoglycosylation associated with reduced LLO levels and compensatory upregulation of the terpenoid/dolichol biosynthetic pathway, leading to a stressed unfolded protein response and lipid droplet accumulation.\",\n      \"method\": \"Zebrafish trappc11 mutant analysis, siRNA knockdown of TRAPPC11 in human cells, LLO level measurement, UPR reporter assays, pharmacological inhibition of terpenoid/LLO synthesis, patient fibroblast analysis\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — biochemical LLO measurement, genetic rescue, pharmacological phenocopy, human cell knockdown, replicated across zebrafish and human systems\",\n      \"pmids\": [\"26912795\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"A TRAPPC11 splice mutation (c.1893+3A>G) causes incomplete exon skipping, dramatic reduction of full-length TRAPPC11 protein, hypoglycosylation of LAMP1, delayed arrival of marker proteins at the Golgi, and delayed release from the Golgi to the plasma membrane in patient fibroblasts.\",\n      \"method\": \"Western blotting, membrane trafficking assays with fluorescent cargo markers in patient fibroblasts, mRNA analysis\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple trafficking assays and glycosylation readout in patient cells, single lab\",\n      \"pmids\": [\"27707803\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"TRAPPC11 is a component of the multiprotein TRAPP complex involved in endoplasmic reticulum-to-Golgi trafficking; loss of full-length TRAPPC11 protein (due to compound heterozygous mutations including a novel splice-site mutation causing frameshift/truncation) causes congenital muscular dystrophy with steatosis, demonstrating a physiological role in multiple tissues.\",\n      \"method\": \"Immunoblotting showing absence of full-length TRAPPC11, mRNA splicing analysis, muscle and liver biopsy histology\",\n      \"journal\": \"Skeletal muscle\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — biochemical confirmation of protein loss with pathological consequence, single lab\",\n      \"pmids\": [\"26322222\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TRAPPC11 mutations are associated with hypoglycosylation of α-dystroglycan; compound heterozygous TRAPPC11 mutations (c.851A>C and c.965+5G>T) cause abnormal membrane trafficking in patient fibroblasts, linking membrane trafficking defects to dystroglycanopathy for the first time.\",\n      \"method\": \"Immunofluorescence and western blotting for α-dystroglycan glycosylation, live cell membrane trafficking analysis in patient fibroblasts\",\n      \"journal\": \"Skeletal muscle\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple methods (IF, WB, live trafficking) in patient-derived cells, single lab\",\n      \"pmids\": [\"29855340\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"TRAPPC11 functions in membrane trafficking and autophagy as a component of TRAPP III; variants affecting the carboxy terminus (frameshift p.Asp1127Valfs*47) cause defects in ER-to-Golgi transport, Golgi exit, and glycosylation of an ER-resident glycoprotein, while the compound heterozygous (foie gras deletion + C-terminal frameshift) combination additionally causes autophagic flux defects not seen with the missense variant alone, highlighting the critical role of the extreme carboxy terminus.\",\n      \"method\": \"Membrane trafficking assays, glycosylation assays (ER-resident glycoprotein), autophagic flux assay in patient fibroblasts with defined bi-allelic variants\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal functional assays in patient cells with genotype-phenotype correlation, single lab\",\n      \"pmids\": [\"31575891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"TRAPPC11 is important for complex integrity and anterograde membrane transport from the ER to the ER-Golgi intermediate compartment; mutations cause universal hypoglycosylation of α-dystroglycan in skeletal muscle and brain (including Purkinje cells and dentate neurons), with neuropathology resembling N-linked congenital disorders of glycosylation.\",\n      \"method\": \"Membrane trafficking assays in patient fibroblasts, immunofluorescence with IIH6 antibody for α-dystroglycan glycosylation in muscle and post-mortem brain, neuropathological examination\",\n      \"journal\": \"Neuropathology and applied neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — trafficking assays plus histopathological glycosylation analysis across multiple tissues, single series\",\n      \"pmids\": [\"34648194\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"TRAPPC11 deficiency impairs mitochondrial function: patient fibroblasts/muscle from individuals with the c.1287+5G>A founder variant show decreased mitochondrial ATP production capacity and alterations in mitochondrial network architecture.\",\n      \"method\": \"Mitochondrial ATP production assays and mitochondrial network morphology analysis in patient-derived cells\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, functional assay but not mechanistically linked to TRAPPC11's known trafficking role\",\n      \"pmids\": [\"37197784\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TRAPPC11 mutations cause defective ER-to-Golgi transport and decreased expression of LAMP2 and ICAM-1 glycoproteins, further supporting TRAPPC11-opathy as a congenital disorder of glycosylation (CDG) with muscular dystrophy.\",\n      \"method\": \"Membrane trafficking assays and western blotting for glycoprotein expression in patient fibroblasts\",\n      \"journal\": \"Molecular genetics and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — trafficking and glycosylation assays consistent across multiple reported cases\",\n      \"pmids\": [\"38564972\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TRAPPC11 is a subunit of the TRAPP III complex that is required for anterograde membrane trafficking (ER-to-Golgi and Golgi-to-plasma membrane), lipid-linked oligosaccharide (LLO) biosynthesis, and protein N-glycosylation (including α-dystroglycan); mutations in its foie gras or gryzun domains disrupt binding to other TRAPP subunits, impair Golgi architecture and exit kinetics, and cause hypoglycosylation of multiple glycoproteins (LAMP1, LAMP2, α-dystroglycan), leading to a stressed unfolded protein response, lipid accumulation, and secondarily to autophagic flux defects when the carboxy terminus is also disrupted.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TRAPPC11 is a subunit of the TRAPP III complex that functions in anterograde membrane trafficking, lipid-linked oligosaccharide (LLO) biosynthesis, and protein N-glycosylation. Its foie gras and gryzun domains mediate binding to other TRAPP subunits; mutations in these domains disrupt Golgi architecture, delay ER-to-Golgi and Golgi-to-plasma membrane transport, and cause hypoglycosylation of multiple glycoproteins including LAMP1, LAMP2, ICAM-1, and α-dystroglycan [PMID:23830518, PMID:26912795, PMID:38564972]. TRAPPC11 depletion independently reduces LLO levels and triggers an unfolded protein response and lipid droplet accumulation, while disruption of its carboxy terminus additionally impairs autophagic flux [PMID:26912795, PMID:31575891]. Biallelic loss-of-function mutations cause a congenital disorder of glycosylation manifesting as muscular dystrophy (dystroglycanopathy), hepatic steatosis, and neurodegeneration [PMID:26322222, PMID:34648194].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Establishing that TRAPPC11 is required for TRAPP complex integrity and post-Golgi membrane trafficking answered whether this large subunit has a discrete role beyond ER-to-Golgi transport, revealing that foie gras domain mutations specifically delay Golgi exit and alter LAMP1/LAMP2 glycosylation.\",\n      \"evidence\": \"Co-immunoprecipitation, cargo trafficking kinetics, and glycoprotein blotting in patient fibroblasts carrying defined foie gras or gryzun domain mutations\",\n      \"pmids\": [\"23830518\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TRAPPC11's trafficking role is separable from a direct glycosylation function was unknown\",\n        \"Structural basis for foie gras versus gryzun domain contributions to TRAPP binding unresolved\",\n        \"Whether Golgi exit delay is the primary cause of glycoprotein alterations or a secondary effect was not determined\"\n      ]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrating that loss of full-length TRAPPC11 causes congenital muscular dystrophy with hepatic steatosis established TRAPPC11 as a disease gene with multi-organ physiological consequences.\",\n      \"evidence\": \"Immunoblotting confirming protein absence, mRNA splicing analysis, and muscle/liver biopsy histology in patients with compound heterozygous mutations\",\n      \"pmids\": [\"26322222\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism linking TRAPPC11 loss to lipid accumulation in liver was not resolved\",\n        \"Whether steatosis results from trafficking defects or glycosylation defects was unclear\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Revealing that TRAPPC11 is required for LLO biosynthesis—independent of other TRAPP subunits—resolved the question of whether TRAPPC11 has a glycosylation-specific function beyond vesicle trafficking, showing that its loss reduces LLO pools, triggers the UPR, and promotes lipid droplet accumulation.\",\n      \"evidence\": \"siRNA knockdown in human cells with LLO quantification, UPR reporter assays, pharmacological phenocopy of terpenoid pathway inhibition, and zebrafish trappc11 mutant analysis\",\n      \"pmids\": [\"26912795\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct molecular mechanism by which TRAPPC11 controls LLO synthesis (enzymatic target or membrane platform) was not identified\",\n        \"Whether the UPR is a cause or consequence of lipid droplet accumulation was not distinguished\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"A splice mutation reducing full-length TRAPPC11 confirmed that both ER-to-Golgi arrival and Golgi exit are TRAPPC11-dependent, extending the trafficking defect model to both anterograde steps.\",\n      \"evidence\": \"Fluorescent cargo trafficking assays and LAMP1 glycosylation analysis in patient fibroblasts\",\n      \"pmids\": [\"27707803\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether residual truncated protein retains partial function was not assessed\",\n        \"Contribution of each trafficking step to overall glycosylation impairment not quantified\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Linking TRAPPC11 mutations to α-dystroglycan hypoglycosylation established TRAPPC11-opathy as a dystroglycanopathy, answering whether the glycosylation defect extends to the functionally critical O-mannosyl glycans of α-dystroglycan.\",\n      \"evidence\": \"IIH6 immunofluorescence and western blotting for glycosylated α-dystroglycan combined with live-cell trafficking assays in patient fibroblasts\",\n      \"pmids\": [\"29855340\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether α-dystroglycan hypoglycosylation is secondary to N-glycosylation/LLO defects or reflects an independent pathway was not resolved\",\n        \"Quantitative relationship between trafficking delay severity and degree of α-dystroglycan glycosylation loss not established\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrating that carboxy-terminal truncation of TRAPPC11 causes autophagic flux defects—not seen with the gryzun missense variant alone—revealed a domain-specific role for the C-terminus in autophagy, separable from its trafficking and glycosylation functions.\",\n      \"evidence\": \"Autophagic flux assays, ER-to-Golgi and Golgi exit assays, and ER-resident glycoprotein glycosylation in fibroblasts with defined bi-allelic variant combinations\",\n      \"pmids\": [\"31575891\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether the autophagy defect is mediated through TRAPP III's known role in autophagosome formation or an independent mechanism was not resolved\",\n        \"Identity of C-terminal interaction partners mediating autophagy function unknown\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Showing universal α-dystroglycan hypoglycosylation in skeletal muscle, Purkinje cells, and dentate neurons in TRAPPC11-mutant patients established that the glycosylation defect is not tissue-restricted, explaining the neurological phenotype as a central glycosylation disorder.\",\n      \"evidence\": \"IIH6 immunofluorescence on post-mortem brain and muscle tissue, membrane trafficking assays in fibroblasts, neuropathological examination\",\n      \"pmids\": [\"34648194\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether neuronal degeneration is cell-autonomous or secondary to extracellular matrix dysfunction was not determined\",\n        \"Whether other glycoproteins beyond α-dystroglycan contribute to the CNS phenotype remains unknown\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Confirming defective ER-to-Golgi transport and decreased expression of LAMP2 and ICAM-1 across additional TRAPPC11 mutations consolidated the classification of TRAPPC11-opathy as a congenital disorder of glycosylation (CDG) with broad glycoprotein impact.\",\n      \"evidence\": \"Membrane trafficking assays and western blotting for glycoproteins in patient fibroblasts\",\n      \"pmids\": [\"38564972\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Full glycoproteomic characterization of hypoglycosylation targets has not been performed\",\n        \"Whether glycosylation correction rescues the trafficking phenotype (or vice versa) is untested\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct molecular mechanism by which TRAPPC11 controls LLO biosynthesis—whether through organizing dolichol-pathway enzymes at ER membranes, modulating terpenoid flux, or another mechanism—remains unresolved, and the structural basis for domain-specific contributions of the foie gras, gryzun, and C-terminal regions to trafficking, glycosylation, and autophagy has not been determined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No enzymatic target or direct binding partner for LLO pathway regulation identified\",\n        \"No high-resolution structure of TRAPPC11 within the TRAPP III complex\",\n        \"Causal hierarchy between trafficking defects and glycosylation defects not experimentally separated\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0, 2, 6]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 2, 5, 6, 8]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [1, 4, 6]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [3, 4, 6]}\n    ],\n    \"complexes\": [\n      \"TRAPP III\"\n    ],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}\n```"}