{"gene":"TMED5","run_date":"2026-06-10T10:51:55","timeline":{"discoveries":[{"year":2014,"finding":"The α-helical region (membrane-adjacent) of p24γ2 (TMED5), but not its GOLD domain, is required for recognition and transport of GPI-anchored proteins (GPI-APs) from the ER to the Golgi. Knockdown of p24γ2 impaired GPI-AP transport, and chimeric constructs between p24γ2 and p24γ1 mapped the functional specificity to the α-helical region, implicating this domain in GPI-AP incorporation into COPII-coated vesicles.","method":"siRNA knockdown, chimeric construct rescue assay, GPI-AP transport reporter assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean knockdown with defined transport phenotype, domain-swap rescue with chimeric constructs, two orthogonal methods in a single study","pmids":["24778190"],"is_preprint":false},{"year":2017,"finding":"The crystal structure of the mouse p24γ2 (TMED5) GOLD domain was determined at 2.8 Å resolution, revealing a β-sandwich fold. The GOLD domain crystallizes as a dimer assisted by a short C-terminal α-helix, suggesting a role for GOLD domain dimerization in p24 complex formation.","method":"X-ray crystallography (single anomalous diffraction using intrinsic sulfur atoms)","journal":"Proteins","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — crystal structure from a single study; functional consequences of dimerization not experimentally validated in cells","pmids":["28066915"],"is_preprint":false},{"year":2010,"finding":"In Xenopus melanotrope cells, p24γ2 (TMED5 ortholog) plays a distinct and non-redundant role in the transport, glycosylation, sulfation, and cleavage of the secretory cargo POMC compared to its subfamily relative p24γ3, demonstrating that p24 proteins from the same subfamily have distinct functions.","method":"Melanotrope-specific transgene expression in Xenopus, biochemical analysis of POMC processing (glycosylation, sulfation, cleavage)","journal":"Biochimie","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — functional transgene expression in a physiological model with multiple biochemical readouts, single lab","pmids":["21118709"],"is_preprint":false},{"year":2018,"finding":"TMED5 interacts with WNT7B and activates the canonical WNT-CTNNB1/β-catenin signaling pathway in cervical cancer cells, as established by co-immunoprecipitation.","method":"Co-immunoprecipitation (IP), western blot, cell-based functional assays","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 3 / Weak — single Co-IP demonstrating TMED5-WNT7B interaction; pathway activation measured by downstream readouts in a single lab","pmids":["30394198"],"is_preprint":false},{"year":2025,"finding":"TMED5 accumulates in lysosomes in APOE4-expressing neuronal cells, and this lysosomal accumulation contributes to lysosomal alkalinization and impaired lysosomal function. Targeting lysosomal TMED5 levels modulated lysosomal function, validating TMED5 as a functional driver of APOE4-associated lysosomal dysfunction.","method":"Quantitative lysosomal proteome profiling (LysoIP + mass spectrometry), siRNA knockdown/overexpression with lysosomal pH and function assays","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — lysosomal proteomics with functional validation via targeted perturbation; two independent publications (preprint and peer-reviewed) reporting the same result","pmids":["41103078","37873080"],"is_preprint":false},{"year":2023,"finding":"Silencing of TMED5 in hepatocellular carcinoma cells (SMMC-7721 and Hep3B) suppressed cell proliferation, migration, and invasion, and enhanced apoptosis, implicating TMED5 in regulation of the cell cycle, mTOR signaling, and TGF-β signaling pathways.","method":"siRNA knockdown, cell proliferation assay (CCK-8), flow cytometry (apoptosis/cell cycle), Transwell migration/invasion assay","journal":"Advances in clinical and experimental medicine","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, phenotypic readouts without direct mechanistic pathway validation for TMED5 specifically","pmids":["36530030"],"is_preprint":false}],"current_model":"TMED5 (p24γ2) is a p24 family cargo receptor in the early secretory pathway whose membrane-adjacent α-helical region mediates selective recognition and COPII-dependent ER-to-Golgi transport of GPI-anchored proteins; its GOLD domain adopts a β-sandwich fold and forms dimers; it is functionally non-redundant with other p24γ subfamily members; in cancer cells it interacts with WNT7B to activate canonical WNT/β-catenin signaling; and it accumulates in lysosomes under APOE4 expression, contributing to lysosomal alkalinization."},"narrative":{"mechanistic_narrative":"TMED5 (p24γ2) is a p24-family cargo receptor of the early secretory pathway that mediates selective ER-to-Golgi transport of secretory and GPI-anchored proteins [PMID:24778190, PMID:21118709]. Cargo selectivity for GPI-anchored proteins is conferred by its membrane-adjacent α-helical region rather than its luminal GOLD domain, which is required for incorporation of GPI-APs into COPII-coated vesicles [PMID:24778190]. The GOLD domain itself adopts a β-sandwich fold and crystallizes as a dimer assisted by a short C-terminal α-helix, consistent with a role in p24 complex assembly [PMID:28066915]. Within the p24γ subfamily TMED5 is functionally non-redundant, supporting distinct cargo-processing roles such as the transport, glycosylation, sulfation, and cleavage of POMC compared to p24γ3 [PMID:21118709]. Beyond its core trafficking function, TMED5 interacts with WNT7B to activate canonical WNT/β-catenin signaling in cervical cancer cells [PMID:30394198], and it accumulates in lysosomes under APOE4 expression where it drives lysosomal alkalinization and impaired lysosomal function [PMID:41103078, PMID:37873080].","teleology":[{"year":2010,"claim":"Established that p24 proteins within a single subfamily are functionally distinct, addressing whether p24γ2 simply substitutes for related subunits in cargo handling.","evidence":"Melanotrope-specific transgene expression in Xenopus with biochemical analysis of POMC glycosylation, sulfation, and cleavage","pmids":["21118709"],"confidence":"Medium","gaps":["Mechanistic basis for the distinct roles of p24γ2 vs p24γ3 not defined","Direct cargo-binding interface for POMC not mapped","Single physiological model and lab"]},{"year":2014,"claim":"Identified the membrane-adjacent α-helical region as the determinant of GPI-anchored protein recognition, localizing cargo selectivity to a specific domain rather than the GOLD domain.","evidence":"siRNA knockdown plus chimeric p24γ2/p24γ1 domain-swap rescue with a GPI-AP transport reporter","pmids":["24778190"],"confidence":"High","gaps":["Direct physical contact between the α-helical region and GPI-AP cargo not demonstrated","How the α-helix couples cargo to the COPII machinery not resolved"]},{"year":2017,"claim":"Provided the first structural model of the TMED5 GOLD domain and proposed dimerization as a basis for p24 complex formation.","evidence":"X-ray crystallography of the mouse p24γ2 GOLD domain at 2.8 Å (sulfur SAD)","pmids":["28066915"],"confidence":"Medium","gaps":["Functional consequence of GOLD dimerization not validated in cells","Full-length structure including the cargo-selective α-helical region absent","Partner subunit interfaces not structurally defined"]},{"year":2018,"claim":"Connected TMED5 to oncogenic signaling by showing physical interaction with WNT7B and activation of canonical WNT/β-catenin signaling in cancer cells.","evidence":"Co-immunoprecipitation, western blot, and cell-based pathway readouts in cervical cancer cells","pmids":["30394198"],"confidence":"Medium","gaps":["Single Co-IP without reciprocal validation","Whether the interaction reflects secretory trafficking of WNT7B or a direct signaling role is unclear","Interaction not confirmed in independent systems"]},{"year":2023,"claim":"Linked TMED5 to hepatocellular carcinoma cell behavior, implicating it in proliferation, migration, invasion, and apoptosis control.","evidence":"siRNA knockdown with CCK-8 proliferation, flow cytometry, and Transwell assays in HCC cell lines","pmids":["36530030"],"confidence":"Low","gaps":["No direct mechanistic validation that TMED5 acts through cell cycle, mTOR, or TGF-β pathways","Single lab and phenotypic-only readouts","In vivo relevance not tested"]},{"year":2025,"claim":"Revealed a non-secretory disease-relevant role by showing TMED5 accumulates in lysosomes under APOE4 expression and drives lysosomal alkalinization and dysfunction.","evidence":"LysoIP-mass spectrometry lysosomal proteomics with siRNA/overexpression and lysosomal pH and function assays in neuronal cells","pmids":["41103078","37873080"],"confidence":"Medium","gaps":["Mechanism of TMED5 lysosomal mistargeting under APOE4 not defined","Molecular cause of alkalinization downstream of TMED5 accumulation unknown","Relationship to its secretory-pathway function unresolved"]},{"year":null,"claim":"How TMED5's defined ER-to-Golgi cargo receptor activity mechanistically connects to its reported roles in WNT signaling, cancer cell phenotypes, and APOE4-driven lysosomal dysfunction remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No unifying mechanism linking secretory trafficking to signaling and lysosomal roles","Direct cargo and partner interfaces largely unmapped at atomic resolution"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[0]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0]}],"complexes":[],"partners":["WNT7B"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9Y3A6","full_name":"Transmembrane emp24 domain-containing protein 5","aliases":["p24 family protein gamma-2","p24gamma2","p28"],"length_aa":229,"mass_kda":26.0,"function":"Potential role in vesicular protein trafficking, mainly in the early secretory pathway. Required for the maintenance of the Golgi apparatus; involved in protein exchange between Golgi stacks during assembly. Probably not required for COPI-vesicle-mediated retrograde transport","subcellular_location":"Endoplasmic reticulum membrane; Golgi apparatus, cis-Golgi network membrane; Endoplasmic reticulum-Golgi intermediate compartment membrane","url":"https://www.uniprot.org/uniprotkb/Q9Y3A6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TMED5","classification":"Not Classified","n_dependent_lines":41,"n_total_lines":1208,"dependency_fraction":0.03394039735099338},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"MYBBP1A","stoichiometry":4.0},{"gene":"CANX","stoichiometry":0.2},{"gene":"CLTA","stoichiometry":0.2},{"gene":"COPA","stoichiometry":0.2},{"gene":"COPB2","stoichiometry":0.2},{"gene":"COPE","stoichiometry":0.2},{"gene":"TMED10","stoichiometry":0.2},{"gene":"TMED2","stoichiometry":0.2},{"gene":"VAPA","stoichiometry":0.2},{"gene":"YIPF5","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/TMED5","total_profiled":1310},"omim":[{"mim_id":"616876","title":"TRANSMEMBRANE p24 TRAFFICKING PROTEIN 5; TMED5","url":"https://www.omim.org/entry/616876"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TMED5"},"hgnc":{"alias_symbol":["CGI-100","p24g2","p24gamma2"],"prev_symbol":[]},"alphafold":{"accession":"Q9Y3A6","domains":[{"cath_id":"2.60.120.380","chopping":"31-131","consensus_level":"medium","plddt":91.9491,"start":31,"end":131},{"cath_id":"1.20.5","chopping":"134-223","consensus_level":"medium","plddt":84.0133,"start":134,"end":223}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y3A6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y3A6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y3A6-F1-predicted_aligned_error_v6.png","plddt_mean":82.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TMED5","jax_strain_url":"https://www.jax.org/strain/search?query=TMED5"},"sequence":{"accession":"Q9Y3A6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y3A6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y3A6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y3A6"}},"corpus_meta":[{"pmid":"21994415","id":"PMC_21994415","title":"Mapping of chromosome 1p deletions in myeloma identifies FAM46C at 1p12 and CDKN2C at 1p32.3 as being genes in regions associated with adverse survival.","date":"2011","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/21994415","citation_count":153,"is_preprint":false},{"pmid":"30394198","id":"PMC_30394198","title":"GRSF1-mediated MIR-G-1 promotes malignant behavior and nuclear autophagy by directly upregulating TMED5 and LMNB1 in cervical cancer cells.","date":"2018","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/30394198","citation_count":73,"is_preprint":false},{"pmid":"24778190","id":"PMC_24778190","title":"The α-helical region in p24γ2 subunit of p24 protein cargo receptor is pivotal for the recognition and transport of glycosylphosphatidylinositol-anchored proteins.","date":"2014","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24778190","citation_count":28,"is_preprint":false},{"pmid":"28066915","id":"PMC_28066915","title":"Crystallographic analysis of murine p24γ2 Golgi dynamics domain.","date":"2017","source":"Proteins","url":"https://pubmed.ncbi.nlm.nih.gov/28066915","citation_count":12,"is_preprint":false},{"pmid":"36160019","id":"PMC_36160019","title":"Exploration of differentially expressed mRNAs and miRNAs for pediatric acute myeloid leukemia.","date":"2022","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36160019","citation_count":11,"is_preprint":false},{"pmid":"34404391","id":"PMC_34404391","title":"Identification of a novel circ_0018289/miR-183-5p/TMED5 regulatory network in cervical cancer development.","date":"2021","source":"World journal of surgical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/34404391","citation_count":10,"is_preprint":false},{"pmid":"35281863","id":"PMC_35281863","title":"TP73-AS1 promotes gastric cancer proliferation and invasion by regulation miR-27b-3p/TMED5 axis.","date":"2022","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/35281863","citation_count":8,"is_preprint":false},{"pmid":"36657061","id":"PMC_36657061","title":"Promoting action of long non-coding RNA small nucleolar RNA host gene 4 in ovarian cancer.","date":"2023","source":"Acta biochimica Polonica","url":"https://pubmed.ncbi.nlm.nih.gov/36657061","citation_count":8,"is_preprint":false},{"pmid":"37873080","id":"PMC_37873080","title":"Lysosomal proteomics reveals mechanisms of neuronal apoE4-associated lysosomal dysfunction.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/37873080","citation_count":7,"is_preprint":false},{"pmid":"41103078","id":"PMC_41103078","title":"Lysosomal proteomics reveals mechanisms of neuronal APOE4-associated lysosomal dysfunction.","date":"2025","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/41103078","citation_count":6,"is_preprint":false},{"pmid":"25135188","id":"PMC_25135188","title":"Mapping of the chromosomal amplification 1p21-22 in bladder cancer.","date":"2014","source":"BMC research notes","url":"https://pubmed.ncbi.nlm.nih.gov/25135188","citation_count":6,"is_preprint":false},{"pmid":"21118709","id":"PMC_21118709","title":"p24 Proteins from the same subfamily are functionally nonredundant.","date":"2010","source":"Biochimie","url":"https://pubmed.ncbi.nlm.nih.gov/21118709","citation_count":5,"is_preprint":false},{"pmid":"36530030","id":"PMC_36530030","title":"Silencing of TMED5 inhibits proliferation, migration and invasion, and enhances apoptosis of hepatocellular carcinoma cells.","date":"2023","source":"Advances in clinical and experimental medicine : official organ Wroclaw Medical University","url":"https://pubmed.ncbi.nlm.nih.gov/36530030","citation_count":4,"is_preprint":false},{"pmid":"37065602","id":"PMC_37065602","title":"SNHG 12 and hsa-miR-140-5P may play an important role in the ceRNA network related to hypertrophic cardiomyopathy.","date":"2023","source":"Journal of thoracic disease","url":"https://pubmed.ncbi.nlm.nih.gov/37065602","citation_count":2,"is_preprint":false},{"pmid":"38147997","id":"PMC_38147997","title":"[Analyzing the evolution of insect TMED gene and the expression pattern of silkworm TMED gene].","date":"2023","source":"Sheng wu gong cheng xue bao = Chinese journal of biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/38147997","citation_count":1,"is_preprint":false},{"pmid":"40011411","id":"PMC_40011411","title":"Lamb Performance and Meat Quality: The Impact of Chromium in High-Concentrate Diets and Its Molecular Effects on Skeletal Muscle During Finishing Phase.","date":"2025","source":"Biological trace element research","url":"https://pubmed.ncbi.nlm.nih.gov/40011411","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11215,"output_tokens":1539,"usd":0.028365,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8322,"output_tokens":2397,"usd":0.050768,"stage2_stop_reason":"end_turn"},"total_usd":0.079133,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2014,\n      \"finding\": \"The α-helical region (membrane-adjacent) of p24γ2 (TMED5), but not its GOLD domain, is required for recognition and transport of GPI-anchored proteins (GPI-APs) from the ER to the Golgi. Knockdown of p24γ2 impaired GPI-AP transport, and chimeric constructs between p24γ2 and p24γ1 mapped the functional specificity to the α-helical region, implicating this domain in GPI-AP incorporation into COPII-coated vesicles.\",\n      \"method\": \"siRNA knockdown, chimeric construct rescue assay, GPI-AP transport reporter assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean knockdown with defined transport phenotype, domain-swap rescue with chimeric constructs, two orthogonal methods in a single study\",\n      \"pmids\": [\"24778190\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The crystal structure of the mouse p24γ2 (TMED5) GOLD domain was determined at 2.8 Å resolution, revealing a β-sandwich fold. The GOLD domain crystallizes as a dimer assisted by a short C-terminal α-helix, suggesting a role for GOLD domain dimerization in p24 complex formation.\",\n      \"method\": \"X-ray crystallography (single anomalous diffraction using intrinsic sulfur atoms)\",\n      \"journal\": \"Proteins\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — crystal structure from a single study; functional consequences of dimerization not experimentally validated in cells\",\n      \"pmids\": [\"28066915\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"In Xenopus melanotrope cells, p24γ2 (TMED5 ortholog) plays a distinct and non-redundant role in the transport, glycosylation, sulfation, and cleavage of the secretory cargo POMC compared to its subfamily relative p24γ3, demonstrating that p24 proteins from the same subfamily have distinct functions.\",\n      \"method\": \"Melanotrope-specific transgene expression in Xenopus, biochemical analysis of POMC processing (glycosylation, sulfation, cleavage)\",\n      \"journal\": \"Biochimie\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — functional transgene expression in a physiological model with multiple biochemical readouts, single lab\",\n      \"pmids\": [\"21118709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TMED5 interacts with WNT7B and activates the canonical WNT-CTNNB1/β-catenin signaling pathway in cervical cancer cells, as established by co-immunoprecipitation.\",\n      \"method\": \"Co-immunoprecipitation (IP), western blot, cell-based functional assays\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP demonstrating TMED5-WNT7B interaction; pathway activation measured by downstream readouts in a single lab\",\n      \"pmids\": [\"30394198\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TMED5 accumulates in lysosomes in APOE4-expressing neuronal cells, and this lysosomal accumulation contributes to lysosomal alkalinization and impaired lysosomal function. Targeting lysosomal TMED5 levels modulated lysosomal function, validating TMED5 as a functional driver of APOE4-associated lysosomal dysfunction.\",\n      \"method\": \"Quantitative lysosomal proteome profiling (LysoIP + mass spectrometry), siRNA knockdown/overexpression with lysosomal pH and function assays\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — lysosomal proteomics with functional validation via targeted perturbation; two independent publications (preprint and peer-reviewed) reporting the same result\",\n      \"pmids\": [\"41103078\", \"37873080\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Silencing of TMED5 in hepatocellular carcinoma cells (SMMC-7721 and Hep3B) suppressed cell proliferation, migration, and invasion, and enhanced apoptosis, implicating TMED5 in regulation of the cell cycle, mTOR signaling, and TGF-β signaling pathways.\",\n      \"method\": \"siRNA knockdown, cell proliferation assay (CCK-8), flow cytometry (apoptosis/cell cycle), Transwell migration/invasion assay\",\n      \"journal\": \"Advances in clinical and experimental medicine\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, phenotypic readouts without direct mechanistic pathway validation for TMED5 specifically\",\n      \"pmids\": [\"36530030\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TMED5 (p24γ2) is a p24 family cargo receptor in the early secretory pathway whose membrane-adjacent α-helical region mediates selective recognition and COPII-dependent ER-to-Golgi transport of GPI-anchored proteins; its GOLD domain adopts a β-sandwich fold and forms dimers; it is functionally non-redundant with other p24γ subfamily members; in cancer cells it interacts with WNT7B to activate canonical WNT/β-catenin signaling; and it accumulates in lysosomes under APOE4 expression, contributing to lysosomal alkalinization.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TMED5 (p24γ2) is a p24-family cargo receptor of the early secretory pathway that mediates selective ER-to-Golgi transport of secretory and GPI-anchored proteins [#0, #2]. Cargo selectivity for GPI-anchored proteins is conferred by its membrane-adjacent α-helical region rather than its luminal GOLD domain, which is required for incorporation of GPI-APs into COPII-coated vesicles [#0]. The GOLD domain itself adopts a β-sandwich fold and crystallizes as a dimer assisted by a short C-terminal α-helix, consistent with a role in p24 complex assembly [#1]. Within the p24γ subfamily TMED5 is functionally non-redundant, supporting distinct cargo-processing roles such as the transport, glycosylation, sulfation, and cleavage of POMC compared to p24γ3 [#2]. Beyond its core trafficking function, TMED5 interacts with WNT7B to activate canonical WNT/β-catenin signaling in cervical cancer cells [#3], and it accumulates in lysosomes under APOE4 expression where it drives lysosomal alkalinization and impaired lysosomal function [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established that p24 proteins within a single subfamily are functionally distinct, addressing whether p24γ2 simply substitutes for related subunits in cargo handling.\",\n      \"evidence\": \"Melanotrope-specific transgene expression in Xenopus with biochemical analysis of POMC glycosylation, sulfation, and cleavage\",\n      \"pmids\": [\"21118709\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanistic basis for the distinct roles of p24γ2 vs p24γ3 not defined\",\n        \"Direct cargo-binding interface for POMC not mapped\",\n        \"Single physiological model and lab\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identified the membrane-adjacent α-helical region as the determinant of GPI-anchored protein recognition, localizing cargo selectivity to a specific domain rather than the GOLD domain.\",\n      \"evidence\": \"siRNA knockdown plus chimeric p24γ2/p24γ1 domain-swap rescue with a GPI-AP transport reporter\",\n      \"pmids\": [\"24778190\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct physical contact between the α-helical region and GPI-AP cargo not demonstrated\",\n        \"How the α-helix couples cargo to the COPII machinery not resolved\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Provided the first structural model of the TMED5 GOLD domain and proposed dimerization as a basis for p24 complex formation.\",\n      \"evidence\": \"X-ray crystallography of the mouse p24γ2 GOLD domain at 2.8 Å (sulfur SAD)\",\n      \"pmids\": [\"28066915\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Functional consequence of GOLD dimerization not validated in cells\",\n        \"Full-length structure including the cargo-selective α-helical region absent\",\n        \"Partner subunit interfaces not structurally defined\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Connected TMED5 to oncogenic signaling by showing physical interaction with WNT7B and activation of canonical WNT/β-catenin signaling in cancer cells.\",\n      \"evidence\": \"Co-immunoprecipitation, western blot, and cell-based pathway readouts in cervical cancer cells\",\n      \"pmids\": [\"30394198\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single Co-IP without reciprocal validation\",\n        \"Whether the interaction reflects secretory trafficking of WNT7B or a direct signaling role is unclear\",\n        \"Interaction not confirmed in independent systems\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Linked TMED5 to hepatocellular carcinoma cell behavior, implicating it in proliferation, migration, invasion, and apoptosis control.\",\n      \"evidence\": \"siRNA knockdown with CCK-8 proliferation, flow cytometry, and Transwell assays in HCC cell lines\",\n      \"pmids\": [\"36530030\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No direct mechanistic validation that TMED5 acts through cell cycle, mTOR, or TGF-β pathways\",\n        \"Single lab and phenotypic-only readouts\",\n        \"In vivo relevance not tested\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealed a non-secretory disease-relevant role by showing TMED5 accumulates in lysosomes under APOE4 expression and drives lysosomal alkalinization and dysfunction.\",\n      \"evidence\": \"LysoIP-mass spectrometry lysosomal proteomics with siRNA/overexpression and lysosomal pH and function assays in neuronal cells\",\n      \"pmids\": [\"41103078\", \"37873080\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism of TMED5 lysosomal mistargeting under APOE4 not defined\",\n        \"Molecular cause of alkalinization downstream of TMED5 accumulation unknown\",\n        \"Relationship to its secretory-pathway function unresolved\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TMED5's defined ER-to-Golgi cargo receptor activity mechanistically connects to its reported roles in WNT signaling, cancer cell phenotypes, and APOE4-driven lysosomal dysfunction remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No unifying mechanism linking secretory trafficking to signaling and lysosomal roles\",\n        \"Direct cargo and partner interfaces largely unmapped at atomic resolution\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"WNT7B\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}