{"gene":"TMEM259","run_date":"2026-04-28T21:42:59","timeline":{"discoveries":[{"year":2002,"finding":"Membralin (TMEM259/C19orf6) was identified as a novel evolutionary conserved multi-transmembrane protein encoded on human chromosome 19p13.3, with multiple splice variants identified in human, mouse, and rat, and homologues found in Drosophila and C. elegans, establishing it as the sole member of a unique protein family.","method":"cDNA cloning, sequence analysis, in situ hybridization","journal":"Brain research. Gene expression patterns","confidence":"Medium","confidence_rationale":"Tier 3 — original identification by cloning and expression analysis, single lab, no functional assays","pmids":["12638133"],"is_preprint":false},{"year":2020,"finding":"TMEM259/Membralin forms an ER membrane complex with the ubiquitin ligase RNF185 and ubiquitin-like domain proteins TMUB1/2, and this complex cooperates with cytosolic ubiquitin ligase UBE3C and p97 ATPase to degrade a subset of misfolded ER membrane substrates via ERAD.","method":"CRISPR-Cas9 genome-wide screen, biochemical fractionation, mass spectrometry, co-immunoprecipitation","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 — genome-wide CRISPR screen plus reciprocal Co-IP and MS interactome in a single rigorous study with multiple orthogonal methods","pmids":["32738194"],"is_preprint":false},{"year":2023,"finding":"UBE3C facilitates ERAD of misfolded CFTR and ABCB1 downstream of or in parallel with the RNF185/MBRL (Membralin) ERAD branch; loss of both RNF5/185 and UBE3C additively increases functional ΔF508-CFTR at the plasma membrane, placing the RNF185/Membralin complex upstream or parallel to UBE3C in the ERAD pathway for membrane substrates.","method":"siRNA knockdown, CFTR functional assay (Ussing chamber/iodide efflux), flow cytometry for surface expression, epistasis by double KD","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2 — genetic epistasis with functional readout, single lab","pmids":["38067172"],"is_preprint":false},{"year":2025,"finding":"Membralin (TMEM259) functions as a non-canonical ER-phagy receptor: its luminal loop recruits MAN1B1 (an α-mannosidase that trims high-mannose N-glycans), its cytoplasmic loop engages VCP/p97, and its cytoplasmic tail contains a functional LC3-interacting region (LIR). This Membralin-MAN1B1-VCP axis directs viral class I fusion glycoproteins (SARS-CoV-2 spike, Ebola GP, influenza HA, HIV-1 Env) to lysosomes in a ubiquitin-independent manner, while misfolded host glycoproteins are routed through conventional ERAD or FAM134B-dependent ERLAD. Loss of Membralin or MAN1B1 enhances pseudoviral infectivity.","method":"Co-immunoprecipitation, domain mutagenesis (LIR mutants, loop deletion), pseudoviral infectivity assays, lysosomal degradation assays, autophagy flux assays","journal":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods including domain mutagenesis, binding assays, functional infectivity readouts, and pathway dissection in a single study; replicated in companion preprint/commentary","pmids":["41324484"],"is_preprint":false},{"year":2025,"finding":"TMEM259/Membralin selectively recognizes densely glycosylated viral substrates (via MAN1B1 acting as a glycan-density sensor) and directs them to lysosomes via ER-phagy, establishing a ubiquitin-independent ERLAD pathway that discriminates foreign from host glycoproteins for innate antiviral defense.","method":"Co-immunoprecipitation, lysosomal degradation assays, LC3 lipidation assays, LIR motif mutagenesis, pseudoviral infectivity","journal":"Autophagy reports","confidence":"Medium","confidence_rationale":"Tier 2 — mechanistic follow-up/commentary corroborating findings of PMID:41324484, multiple methods but largely overlapping with same group","pmids":["41799849"],"is_preprint":false}],"current_model":"TMEM259/Membralin is a multi-pass ER membrane protein that operates at the intersection of ERAD and ER-phagy: it forms an RNF185/TMUB1/TMUB2/Membralin ubiquitin ligase complex with UBE3C and p97 to ubiquitin-dependently degrade misfolded ER membrane substrates, and separately functions as a non-canonical ER-phagy receptor by assembling a Membralin-MAN1B1-VCP complex that uses a cytoplasmic LIR motif to ubiquitin-independently route densely glycosylated viral class I fusion glycoproteins to lysosomes, thereby coupling ER proteostasis with intrinsic antiviral immunity."},"narrative":{"teleology":[{"year":2002,"claim":"Before any function was known, cloning of TMEM259 (then C19orf6/Membralin) established it as an evolutionarily conserved multi-transmembrane protein with multiple splice variants, defining it as the sole member of a unique protein family and setting the stage for functional characterization.","evidence":"cDNA cloning, sequence analysis, and in situ hybridization in human, mouse, and rat tissues","pmids":["12638133"],"confidence":"Medium","gaps":["No functional data; protein function entirely unknown","Subcellular localization not experimentally determined","No interacting partners identified"]},{"year":2020,"claim":"A genome-wide CRISPR screen revealed that TMEM259 is a core component of an ER membrane ubiquitin ligase complex (with RNF185, TMUB1/2) that cooperates with UBE3C and p97 to degrade misfolded ER membrane substrates, establishing its role as an ERAD factor.","evidence":"CRISPR-Cas9 genome-wide screen, mass spectrometry interactome, reciprocal co-immunoprecipitation, and biochemical fractionation","pmids":["32738194"],"confidence":"High","gaps":["Endogenous substrates of this ERAD branch not fully catalogued","Structural basis of TMEM259 interaction with RNF185 unknown","Whether TMEM259 has functions beyond ERAD not addressed"]},{"year":2023,"claim":"Epistasis experiments placed the RNF185/Membralin complex upstream of or parallel to UBE3C in ERAD of clinically relevant substrates (ΔF508-CFTR, ABCB1), demonstrating that loss of both branches additively rescues functional CFTR at the plasma membrane.","evidence":"siRNA double knockdown with Ussing chamber/iodide efflux functional assays and flow cytometry for surface CFTR expression","pmids":["38067172"],"confidence":"Medium","gaps":["Single-lab study; independent replication of epistasis in other cell types not yet available","Whether TMEM259 directly contacts these substrates or acts indirectly is unresolved","Relative contribution of TMEM259 versus RNF185 within the complex not dissected"]},{"year":2025,"claim":"Discovery of a second, mechanistically distinct function: TMEM259 acts as a non-canonical ER-phagy receptor that uses its luminal loop to recruit MAN1B1 as a glycan-density sensor and its cytoplasmic LIR motif to deliver densely glycosylated viral fusion glycoproteins to lysosomes in a ubiquitin-independent manner, coupling ER proteostasis to innate antiviral defense.","evidence":"Co-immunoprecipitation, domain mutagenesis (LIR mutants, loop deletions), pseudoviral infectivity assays across multiple viral glycoproteins, lysosomal degradation and LC3 lipidation assays","pmids":["41324484","41799849"],"confidence":"High","gaps":["Structural basis for MAN1B1-mediated glycan-density discrimination not resolved","In vivo relevance of TMEM259-dependent antiviral defense not demonstrated in animal models","Whether TMEM259 ER-phagy receptor function extends to non-viral heavily glycosylated substrates is untested"]},{"year":null,"claim":"Key open questions remain: the structural basis of TMEM259 complex assembly with RNF185 and MAN1B1, identification of the full spectrum of endogenous ERAD substrates, the in vivo significance of TMEM259-mediated antiviral ER-phagy, and whether the ERAD and ER-phagy functions are coordinated or mutually exclusive.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of TMEM259 or its complexes","No in vivo animal model phenotype reported for TMEM259 loss","Coordination or switching between ERAD and ER-phagy functions of TMEM259 not characterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,3]},{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[3,4]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[1,3]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[1,2]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[3,4]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[3,4]}],"complexes":["RNF185/TMUB1/TMUB2/Membralin E3 ligase complex","Membralin-MAN1B1-VCP ER-phagy complex"],"partners":["RNF185","TMUB1","TMUB2","UBE3C","VCP","MAN1B1"],"other_free_text":[]},"mechanistic_narrative":"TMEM259 (Membralin) is a multi-pass endoplasmic reticulum membrane protein that functions in both ER-associated degradation (ERAD) and ER-phagy to maintain ER proteostasis and provide intrinsic antiviral defense. In its ERAD role, TMEM259 assembles with the ubiquitin ligase RNF185 and ubiquitin-like domain proteins TMUB1/TMUB2 into an ER membrane complex that cooperates with the cytosolic ubiquitin ligase UBE3C and the p97 ATPase to ubiquitinate and degrade misfolded ER membrane substrates such as CFTR and ABCB1 [PMID:32738194, PMID:38067172]. Independently, TMEM259 acts as a non-canonical ER-phagy receptor: its luminal loop recruits the α-mannosidase MAN1B1, which serves as a glycan-density sensor to selectively recognize densely glycosylated viral class I fusion glycoproteins (SARS-CoV-2 spike, Ebola GP, influenza HA, HIV-1 Env), while its cytoplasmic tail contains a functional LC3-interacting region (LIR) that directs these substrates to lysosomes in a ubiquitin-independent manner via VCP/p97 [PMID:41324484, PMID:41799849]. Loss of TMEM259 or MAN1B1 enhances pseudoviral infectivity, establishing this pathway as a mechanism of innate antiviral immunity that discriminates foreign from host glycoproteins [PMID:41324484]."},"prefetch_data":{"uniprot":{"accession":"Q4ZIN3","full_name":"Membralin","aliases":["Transmembrane protein 259"],"length_aa":620,"mass_kda":67.9,"function":"May have a role in the ERAD pathway required for clearance of misfolded proteins in the endoplasmic reticulum (ER). Promotes survival of motor neurons, probably by protecting against ER stress","subcellular_location":"Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/Q4ZIN3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TMEM259","classification":"Not Classified","n_dependent_lines":4,"n_total_lines":1208,"dependency_fraction":0.0033112582781456954},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TMEM259","total_profiled":1310},"omim":[{"mim_id":"620096","title":"RING FINGER PROTEIN 185; RNF185","url":"https://www.omim.org/entry/620096"},{"mim_id":"613297","title":"MEMBRANE-ASSOCIATED RING-CH FINGER PROTEIN 6; MARCHF6","url":"https://www.omim.org/entry/613297"},{"mim_id":"611011","title":"TRANSMEMBRANE PROTEIN 259; TMEM259","url":"https://www.omim.org/entry/611011"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Endoplasmic reticulum","reliability":"Approved"},{"location":"Nuclear speckles","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TMEM259"},"hgnc":{"alias_symbol":["MGC4022","ASBABP1","MBRL"],"prev_symbol":["C19orf6"]},"alphafold":{"accession":"Q4ZIN3","domains":[{"cath_id":"-","chopping":"64-90_301-464","consensus_level":"high","plddt":84.8043,"start":64,"end":464},{"cath_id":"-","chopping":"96-128_206-297","consensus_level":"medium","plddt":80.1555,"start":96,"end":297}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q4ZIN3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q4ZIN3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q4ZIN3-F1-predicted_aligned_error_v6.png","plddt_mean":63.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TMEM259","jax_strain_url":"https://www.jax.org/strain/search?query=TMEM259"},"sequence":{"accession":"Q4ZIN3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q4ZIN3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q4ZIN3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q4ZIN3"}},"corpus_meta":[{"pmid":"34963663","id":"PMC_34963663","title":"Meta-analysis of human and mouse ALS astrocytes reveals multi-omic signatures of inflammatory reactive states.","date":"2021","source":"Genome research","url":"https://pubmed.ncbi.nlm.nih.gov/34963663","citation_count":72,"is_preprint":false},{"pmid":"30466389","id":"PMC_30466389","title":"Multi-drug resistant Enterobacter bugandensis species isolated from the International Space Station and comparative genomic analyses with human pathogenic strains.","date":"2018","source":"BMC microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/30466389","citation_count":68,"is_preprint":false},{"pmid":"32738194","id":"PMC_32738194","title":"Quality Control of ER Membrane Proteins by the RNF185/Membralin Ubiquitin Ligase Complex.","date":"2020","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/32738194","citation_count":52,"is_preprint":false},{"pmid":"3258791","id":"PMC_3258791","title":"Immunoconjugate generation between the ribosome inactivating protein restrictocin and an anti-human breast carcinoma MAB.","date":"1988","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/3258791","citation_count":38,"is_preprint":false},{"pmid":"18943158","id":"PMC_18943158","title":"Performance and Mapping of Leaf Rust Resistance Transferred to Wheat from Triticum timopheevii subsp. armeniacum.","date":"2003","source":"Phytopathology","url":"https://pubmed.ncbi.nlm.nih.gov/18943158","citation_count":37,"is_preprint":false},{"pmid":"15722182","id":"PMC_15722182","title":"Cloning and expression of the human NMDA receptor subunit NR3B in the adult human hippocampus.","date":"2004","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/15722182","citation_count":29,"is_preprint":false},{"pmid":"29262357","id":"PMC_29262357","title":"Myoglobin and α-Lactalbumin Form Smaller Complexes with the Biosurfactant Rhamnolipid Than with SDS.","date":"2017","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/29262357","citation_count":26,"is_preprint":false},{"pmid":"27247891","id":"PMC_27247891","title":"Keratinolytic activities of alkaliphilic Bacillus sp. 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Gene expression patterns\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — original identification by cloning and expression analysis, single lab, no functional assays\",\n      \"pmids\": [\"12638133\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TMEM259/Membralin forms an ER membrane complex with the ubiquitin ligase RNF185 and ubiquitin-like domain proteins TMUB1/2, and this complex cooperates with cytosolic ubiquitin ligase UBE3C and p97 ATPase to degrade a subset of misfolded ER membrane substrates via ERAD.\",\n      \"method\": \"CRISPR-Cas9 genome-wide screen, biochemical fractionation, mass spectrometry, co-immunoprecipitation\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genome-wide CRISPR screen plus reciprocal Co-IP and MS interactome in a single rigorous study with multiple orthogonal methods\",\n      \"pmids\": [\"32738194\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"UBE3C facilitates ERAD of misfolded CFTR and ABCB1 downstream of or in parallel with the RNF185/MBRL (Membralin) ERAD branch; loss of both RNF5/185 and UBE3C additively increases functional ΔF508-CFTR at the plasma membrane, placing the RNF185/Membralin complex upstream or parallel to UBE3C in the ERAD pathway for membrane substrates.\",\n      \"method\": \"siRNA knockdown, CFTR functional assay (Ussing chamber/iodide efflux), flow cytometry for surface expression, epistasis by double KD\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with functional readout, single lab\",\n      \"pmids\": [\"38067172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Membralin (TMEM259) functions as a non-canonical ER-phagy receptor: its luminal loop recruits MAN1B1 (an α-mannosidase that trims high-mannose N-glycans), its cytoplasmic loop engages VCP/p97, and its cytoplasmic tail contains a functional LC3-interacting region (LIR). This Membralin-MAN1B1-VCP axis directs viral class I fusion glycoproteins (SARS-CoV-2 spike, Ebola GP, influenza HA, HIV-1 Env) to lysosomes in a ubiquitin-independent manner, while misfolded host glycoproteins are routed through conventional ERAD or FAM134B-dependent ERLAD. Loss of Membralin or MAN1B1 enhances pseudoviral infectivity.\",\n      \"method\": \"Co-immunoprecipitation, domain mutagenesis (LIR mutants, loop deletion), pseudoviral infectivity assays, lysosomal degradation assays, autophagy flux assays\",\n      \"journal\": \"Advanced science (Weinheim, Baden-Wurttemberg, Germany)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods including domain mutagenesis, binding assays, functional infectivity readouts, and pathway dissection in a single study; replicated in companion preprint/commentary\",\n      \"pmids\": [\"41324484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TMEM259/Membralin selectively recognizes densely glycosylated viral substrates (via MAN1B1 acting as a glycan-density sensor) and directs them to lysosomes via ER-phagy, establishing a ubiquitin-independent ERLAD pathway that discriminates foreign from host glycoproteins for innate antiviral defense.\",\n      \"method\": \"Co-immunoprecipitation, lysosomal degradation assays, LC3 lipidation assays, LIR motif mutagenesis, pseudoviral infectivity\",\n      \"journal\": \"Autophagy reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic follow-up/commentary corroborating findings of PMID:41324484, multiple methods but largely overlapping with same group\",\n      \"pmids\": [\"41799849\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TMEM259/Membralin is a multi-pass ER membrane protein that operates at the intersection of ERAD and ER-phagy: it forms an RNF185/TMUB1/TMUB2/Membralin ubiquitin ligase complex with UBE3C and p97 to ubiquitin-dependently degrade misfolded ER membrane substrates, and separately functions as a non-canonical ER-phagy receptor by assembling a Membralin-MAN1B1-VCP complex that uses a cytoplasmic LIR motif to ubiquitin-independently route densely glycosylated viral class I fusion glycoproteins to lysosomes, thereby coupling ER proteostasis with intrinsic antiviral immunity.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TMEM259 (Membralin) is a multi-pass endoplasmic reticulum membrane protein that functions in both ER-associated degradation (ERAD) and ER-phagy to maintain ER proteostasis and provide intrinsic antiviral defense. In its ERAD role, TMEM259 assembles with the ubiquitin ligase RNF185 and ubiquitin-like domain proteins TMUB1/TMUB2 into an ER membrane complex that cooperates with the cytosolic ubiquitin ligase UBE3C and the p97 ATPase to ubiquitinate and degrade misfolded ER membrane substrates such as CFTR and ABCB1 [PMID:32738194, PMID:38067172]. Independently, TMEM259 acts as a non-canonical ER-phagy receptor: its luminal loop recruits the α-mannosidase MAN1B1, which serves as a glycan-density sensor to selectively recognize densely glycosylated viral class I fusion glycoproteins (SARS-CoV-2 spike, Ebola GP, influenza HA, HIV-1 Env), while its cytoplasmic tail contains a functional LC3-interacting region (LIR) that directs these substrates to lysosomes in a ubiquitin-independent manner via VCP/p97 [PMID:41324484, PMID:41799849]. Loss of TMEM259 or MAN1B1 enhances pseudoviral infectivity, establishing this pathway as a mechanism of innate antiviral immunity that discriminates foreign from host glycoproteins [PMID:41324484].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Before any function was known, cloning of TMEM259 (then C19orf6/Membralin) established it as an evolutionarily conserved multi-transmembrane protein with multiple splice variants, defining it as the sole member of a unique protein family and setting the stage for functional characterization.\",\n      \"evidence\": \"cDNA cloning, sequence analysis, and in situ hybridization in human, mouse, and rat tissues\",\n      \"pmids\": [\"12638133\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No functional data; protein function entirely unknown\",\n        \"Subcellular localization not experimentally determined\",\n        \"No interacting partners identified\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A genome-wide CRISPR screen revealed that TMEM259 is a core component of an ER membrane ubiquitin ligase complex (with RNF185, TMUB1/2) that cooperates with UBE3C and p97 to degrade misfolded ER membrane substrates, establishing its role as an ERAD factor.\",\n      \"evidence\": \"CRISPR-Cas9 genome-wide screen, mass spectrometry interactome, reciprocal co-immunoprecipitation, and biochemical fractionation\",\n      \"pmids\": [\"32738194\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Endogenous substrates of this ERAD branch not fully catalogued\",\n        \"Structural basis of TMEM259 interaction with RNF185 unknown\",\n        \"Whether TMEM259 has functions beyond ERAD not addressed\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Epistasis experiments placed the RNF185/Membralin complex upstream of or parallel to UBE3C in ERAD of clinically relevant substrates (ΔF508-CFTR, ABCB1), demonstrating that loss of both branches additively rescues functional CFTR at the plasma membrane.\",\n      \"evidence\": \"siRNA double knockdown with Ussing chamber/iodide efflux functional assays and flow cytometry for surface CFTR expression\",\n      \"pmids\": [\"38067172\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single-lab study; independent replication of epistasis in other cell types not yet available\",\n        \"Whether TMEM259 directly contacts these substrates or acts indirectly is unresolved\",\n        \"Relative contribution of TMEM259 versus RNF185 within the complex not dissected\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery of a second, mechanistically distinct function: TMEM259 acts as a non-canonical ER-phagy receptor that uses its luminal loop to recruit MAN1B1 as a glycan-density sensor and its cytoplasmic LIR motif to deliver densely glycosylated viral fusion glycoproteins to lysosomes in a ubiquitin-independent manner, coupling ER proteostasis to innate antiviral defense.\",\n      \"evidence\": \"Co-immunoprecipitation, domain mutagenesis (LIR mutants, loop deletions), pseudoviral infectivity assays across multiple viral glycoproteins, lysosomal degradation and LC3 lipidation assays\",\n      \"pmids\": [\"41324484\", \"41799849\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis for MAN1B1-mediated glycan-density discrimination not resolved\",\n        \"In vivo relevance of TMEM259-dependent antiviral defense not demonstrated in animal models\",\n        \"Whether TMEM259 ER-phagy receptor function extends to non-viral heavily glycosylated substrates is untested\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key open questions remain: the structural basis of TMEM259 complex assembly with RNF185 and MAN1B1, identification of the full spectrum of endogenous ERAD substrates, the in vivo significance of TMEM259-mediated antiviral ER-phagy, and whether the ERAD and ER-phagy functions are coordinated or mutually exclusive.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No high-resolution structure of TMEM259 or its complexes\",\n        \"No in vivo animal model phenotype reported for TMEM259 loss\",\n        \"Coordination or switching between ERAD and ER-phagy functions of TMEM259 not characterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 3]},\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [1, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [3, 4]}\n    ],\n    \"complexes\": [\n      \"RNF185/TMUB1/TMUB2/Membralin E3 ligase complex\",\n      \"Membralin-MAN1B1-VCP ER-phagy complex\"\n    ],\n    \"partners\": [\n      \"RNF185\",\n      \"TMUB1\",\n      \"TMUB2\",\n      \"UBE3C\",\n      \"VCP\",\n      \"MAN1B1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}