{"gene":"TIMMDC1","run_date":"2026-06-10T10:51:55","timeline":{"discoveries":[{"year":2013,"finding":"TIMMDC1 (C3orf1) is a membrane-embedded mitochondrial complex I assembly factor that localizes to the mitochondrial inner membrane, reciprocally associates with multiple members of the MCIA complex (ACAD9, ECSIT, NDUFAF1, TMEM126B) and core complex I subunits, and its depletion results in reduced complex I activity and cellular respiration. Quantitative proteomics demonstrated its role in assembly of both membrane-embedded and soluble arms of complex I.","method":"Interaction proteomics (reciprocal co-immunoprecipitation/AP-MS), subcellular fractionation/localization, siRNA knockdown with complex I activity and cellular respiration assays, quantitative proteomics","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP/AP-MS, multiple orthogonal methods (localization, KD phenotype, quantitative proteomics), replicated by independent studies","pmids":["24344204"],"is_preprint":false},{"year":2013,"finding":"TIMMDC1 (C3orf1) was found associated with 550 kDa and 815 kDa complex I subcomplexes when NDUFA11 expression was suppressed, placing TIMMDC1 as a transient assembly factor for the membrane arm of complex I alongside TMEM126B and NDUFA11.","method":"Suppression of NDUFA11 expression followed by native gel electrophoresis and mass spectrometry identification of accumulated subcomplexes","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct biochemical fractionation and MS identification, independent lab replicating TIMMDC1's role in complex I membrane arm assembly","pmids":["24191001"],"is_preprint":false},{"year":2021,"finding":"C9orf72 directly stabilizes TIMMDC1 in mitochondria by recruiting the prohibitin complex to inhibit m-AAA protease-dependent degradation of TIMMDC1, thereby maintaining mitochondrial complex I function.","method":"Co-immunoprecipitation, C9orf72 knockout mouse neurons and patient-derived neurons, proteomics, functional complex I activity assays","journal":"Cell metabolism","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP identifying C9orf72/prohibitin/TIMMDC1 complex, multiple orthogonal methods (KO models, patient neurons, functional assays), mechanistic pathway established","pmids":["33545050"],"is_preprint":false},{"year":2017,"finding":"A deep intronic variant in TIMMDC1 (c.597-1340A>G) creates a cryptic splice site, causing aberrant splicing and establishing TIMMDC1 as a disease-causing gene for mitochondriopathy via loss of complex I assembly factor function.","method":"RNA sequencing of patient fibroblasts revealing aberrant splicing, transcriptome analysis","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNA-seq with direct splicing evidence in patient cells, single study but with clear functional implication","pmids":["28604674"],"is_preprint":false},{"year":2022,"finding":"Splice-switching antisense oligonucleotides (SSOs) targeting the TIMMDC1 intronic pathogenic variant c.597-1340A>G restore normal TIMMDC1 mRNA processing and protein levels in patient fibroblasts, with quantitative proteomics and real-time metabolic analysis confirming restoration of complex I subunit abundance and function.","method":"Antisense oligonucleotide treatment, RNA and protein analysis, quantitative proteomics, real-time mitochondrial metabolic analysis (Seahorse)","journal":"NPJ genomic medicine","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — functional rescue by SSOs with multiple orthogonal methods confirming complex I restoration, directly linking TIMMDC1 to complex I assembly function","pmids":["35091571"],"is_preprint":false},{"year":2021,"finding":"Disruption of NDUFAF3 or NDUFAF4 in Drosophila destabilizes TIMMDC1 in complex I assembly intermediates, placing TIMMDC1 downstream of or in concert with NDUFAF3/NDUFAF4 in the biogenesis of the Q-, N-, and PP-b-modules of complex I.","method":"Genetic disruption (Drosophila), complexome profiling, epistasis analysis with double mutants","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis in Drosophila with complexome profiling, single lab, orthologous system","pmids":["34386730"],"is_preprint":false},{"year":2014,"finding":"Depletion of TIMMDC1 (C3orf1) by siRNA in 95D lung carcinoma cells confirmed its localization in the inner mitochondrial membrane and showed that its loss reduces mitochondrial membrane potential and ATPase activity, inhibits cell migration and proliferation, and alters expression of genes in focal adhesion, ECM-receptor interaction, and p53-signaling pathways.","method":"siRNA knockdown, immunofluorescence/fractionation for localization, mitochondrial membrane potential assay, ATPase activity assay, migration/proliferation assays, microarray gene expression analysis","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — direct localization confirmation plus functional KD phenotype with multiple readouts, single lab","pmids":["25391042"],"is_preprint":false},{"year":2019,"finding":"C-terminal truncation of TIMMDC1 (p.Arg225*, removing 61 amino acids) has a hypomorphic effect on complex I assembly: the truncated protein can still partially rescue complex I assembly in TIMMDC1 knockout cells, indicating the C-terminus is not essential for core assembly function.","method":"TIMMDC1 knockout cell line complementation assay, functional complex I assembly studies","journal":"Human mutation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional rescue experiment in KO cells with defined truncation mutant, single lab, establishes domain dispensability","pmids":["30981218"],"is_preprint":false},{"year":2016,"finding":"Complexome profiling of TMEM126B-deficient patient cells confirmed that TIMMDC1 is a component of the mitochondrial complex I assembly (MCIA) complex, alongside ACAD9, ECSIT, NDUFAF1, and TMEM126B.","method":"Complexome profiling of patient cell lines","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — complexome profiling provides direct evidence of TIMMDC1 within the MCIA complex, single lab, corroborates prior AP-MS data","pmids":["27374774"],"is_preprint":false},{"year":2018,"finding":"Knockdown of TIMMDC1 in gastric cancer cells selectively reduces complex I activity (not complexes II–IV), inhibits mitochondrial respiration and ATP-linked oxygen consumption, attenuates glycolysis, and reduces phosphorylation of AKT(Ser473) and GSK-3β(Ser9) with downstream reduction of β-catenin and c-Myc.","method":"shRNA knockdown, complex I–IV activity assays, Seahorse metabolic flux analysis, ATP quantification, western blotting for AKT/GSK3β/β-catenin pathway, in vivo tumor xenograft","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — multiple orthogonal functional assays establishing complex I specificity and downstream signaling, single lab","pmids":["30123074"],"is_preprint":false},{"year":2025,"finding":"METTL3 methyltransferase suppresses TIMMDC1 expression via m6A methylation of TIMMDC1 mRNA; confirmed by Me-RIP assay showing METTL3 binding to TIMMDC1 mRNA, and RIP assay confirming the interaction.","method":"Me-RIP assay, RIP assay, SRAMP site prediction, qRT-PCR, western blot, EdU proliferation assay","journal":"Immunobiology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, limited mechanistic depth in abstract, Me-RIP and RIP performed but full mechanistic detail unclear from abstract alone","pmids":["40409178"],"is_preprint":false},{"year":2000,"finding":"C3orf1 (TIMMDC1) encodes a predicted 32.2 kDa membrane protein with four transmembrane domains, showing ubiquitous expression enhanced in heart and skeletal muscle, identified as homologous to the Drosophila RP140-upstream gene.","method":"cDNA cloning, Northern blot analysis, computational domain prediction","journal":"DNA sequence : the journal of DNA sequencing and mapping","confidence":"Low","confidence_rationale":"Tier 3–4 / Weak — initial characterization by cloning and expression; predicted transmembrane topology, no functional validation","pmids":["11092749"],"is_preprint":false}],"current_model":"TIMMDC1 is a four-pass, inner mitochondrial membrane-embedded protein that functions as an assembly factor for the membrane arm of mitochondrial complex I by associating with the MCIA complex (ACAD9, ECSIT, NDUFAF1, TMEM126B) and core complex I subunits; its stability is maintained by C9orf72, which recruits the prohibitin complex to block m-AAA protease-dependent degradation of TIMMDC1, and its loss selectively impairs complex I activity and oxidative phosphorylation, reducing cellular ATP production and downstream AKT/GSK3β/β-catenin signaling, while its expression is post-transcriptionally regulated by METTL3-mediated m6A methylation."},"narrative":{"mechanistic_narrative":"TIMMDC1 is an inner mitochondrial membrane-embedded assembly factor required for biogenesis of the membrane arm of respiratory chain complex I [PMID:24344204, PMID:24191001]. It reciprocally associates with the mitochondrial complex I assembly (MCIA) complex — ACAD9, ECSIT, NDUFAF1 and TMEM126B — and with core complex I subunits, and is found in 550 kDa and 815 kDa membrane-arm assembly intermediates, acting transiently during the build of the Q-, N- and PP-b modules [PMID:24344204, PMID:24191001, PMID:27374774]. Loss of TIMMDC1 selectively impairs complex I activity without affecting complexes II–IV, reducing mitochondrial respiration, ATP-linked oxygen consumption and cellular ATP, with downstream attenuation of AKT/GSK-3β/β-catenin signaling [PMID:30123074]. Its abundance in mitochondria is controlled by C9orf72, which recruits the prohibitin complex to block m-AAA protease-dependent degradation of TIMMDC1 and thereby preserve complex I function [PMID:33545050]. A deep intronic variant (c.597-1340A>G) creates a cryptic splice site that abolishes TIMMDC1 function and causes a complex I-deficient mitochondriopathy, and splice-switching antisense oligonucleotides correcting this variant restore normal mRNA, protein and complex I function in patient fibroblasts [PMID:28604674, PMID:35091571].","teleology":[{"year":2000,"claim":"Before any functional role was known, the gene needed basic molecular definition; this established TIMMDC1 (C3orf1) as a ubiquitously expressed, muscle-enriched four-pass membrane protein.","evidence":"cDNA cloning, Northern blot, and computational topology prediction","pmids":["11092749"],"confidence":"Low","gaps":["No functional or organellar assignment","Transmembrane topology only predicted, not experimentally resolved","No interaction or pathway data"]},{"year":2013,"claim":"The central question of what process TIMMDC1 serves was answered by placing it as an inner-membrane complex I assembly factor physically tied to the MCIA machinery and required for complex I activity.","evidence":"Reciprocal Co-IP/AP-MS, fractionation, siRNA knockdown with complex I and respiration assays, and quantitative proteomics; independent native-gel/MS identification of TIMMDC1 in membrane-arm subcomplexes","pmids":["24344204","24191001"],"confidence":"High","gaps":["Order of action within the MCIA pathway not defined","Direct substrate/subunit handoff not resolved","No structural model of TIMMDC1 in assembly intermediates"]},{"year":2016,"claim":"Whether TIMMDC1 is a stable MCIA subunit rather than a peripheral interactor was tested, confirming its membership in the MCIA complex with ACAD9, ECSIT, NDUFAF1 and TMEM126B.","evidence":"Complexome profiling of TMEM126B-deficient patient cells","pmids":["27374774"],"confidence":"Medium","gaps":["Stoichiometry within MCIA not defined","Single patient-cell context","Does not establish direct binary contacts"]},{"year":2017,"claim":"It was unknown whether TIMMDC1 loss-of-function causes human disease; a deep intronic cryptic-splice variant established TIMMDC1 as a mitochondriopathy gene.","evidence":"RNA sequencing of patient fibroblasts revealing aberrant splicing","pmids":["28604674"],"confidence":"Medium","gaps":["Single index finding of the variant","Genotype–phenotype spectrum not delineated","Mechanistic link to complex I deficiency inferred from splicing, not yet rescued"]},{"year":2018,"claim":"The specificity and signaling consequences of TIMMDC1 loss were clarified, showing a complex I-selective defect that propagates to AKT/GSK-3β/β-catenin/c-Myc signaling and tumor cell behavior.","evidence":"shRNA knockdown in gastric cancer cells, complex I–IV activity assays, Seahorse flux, ATP quantification, pathway western blots, and xenografts","pmids":["30123074"],"confidence":"Medium","gaps":["Whether signaling changes are direct or secondary to bioenergetic stress unresolved","Single cancer context","No demonstration that AKT pathway requires complex I per se"]},{"year":2019,"claim":"The functional importance of the TIMMDC1 C-terminus was tested, showing a p.Arg225* truncation is hypomorphic and the C-terminus is dispensable for core assembly function.","evidence":"Complementation of TIMMDC1 knockout cells with the truncation mutant and complex I assembly assays","pmids":["30981218"],"confidence":"Medium","gaps":["Domain mapping of the essential region incomplete","Quantitative degree of hypomorphism not detailed","No structural basis for partial activity"]},{"year":2021,"claim":"How TIMMDC1 levels are maintained was addressed, defining a C9orf72/prohibitin axis that protects TIMMDC1 from m-AAA protease degradation to sustain complex I.","evidence":"Co-IP, C9orf72 knockout mouse and patient-derived neurons, proteomics, and complex I activity assays","pmids":["33545050"],"confidence":"High","gaps":["Signals triggering m-AAA targeting of TIMMDC1 unknown","Direct protease cleavage site not mapped","Generalizability beyond neurons not tested"]},{"year":2021,"claim":"The position of TIMMDC1 relative to other assembly factors was refined, placing it downstream of or alongside NDUFAF3/NDUFAF4 in Q-, N- and PP-b-module biogenesis.","evidence":"Genetic disruption in Drosophila with complexome profiling and double-mutant epistasis","pmids":["34386730"],"confidence":"Medium","gaps":["Orthologous (Drosophila) system; human ordering not directly confirmed","Molecular nature of cooperation with NDUFAF3/4 unknown","Intermediate handoff steps undefined"]},{"year":2022,"claim":"Whether the pathogenic splice defect is correctable was demonstrated, with splice-switching antisense oligonucleotides restoring TIMMDC1 mRNA, protein and complex I function in patient cells.","evidence":"Antisense oligonucleotide treatment of patient fibroblasts, RNA/protein analysis, quantitative proteomics, and Seahorse metabolic analysis","pmids":["35091571"],"confidence":"High","gaps":["Efficacy shown in fibroblasts only, not in vivo","Durability and delivery not addressed","No clinical correlation"]},{"year":2025,"claim":"A post-transcriptional control layer was identified, with METTL3-mediated m6A methylation of TIMMDC1 mRNA suppressing its expression.","evidence":"Me-RIP and RIP assays, m6A site prediction, qRT-PCR, western blot, and EdU proliferation assay","pmids":["40409178"],"confidence":"Low","gaps":["Single lab with limited mechanistic depth from abstract","m6A reader and decay/translation mechanism not defined","Physiological context of regulation unclear"]},{"year":null,"claim":"The structural basis of how TIMMDC1 templates membrane-arm assembly and the precise sequence of subunit handoffs within the MCIA pathway remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No structure of TIMMDC1 within an assembly intermediate","Direct binary contacts with specific complex I subunits not mapped","Timing of TIMMDC1 release during maturation unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,8]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,1,6,11]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,9]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,1,8]}],"complexes":["MCIA complex"],"partners":["ACAD9","ECSIT","NDUFAF1","TMEM126B","NDUFA11","C9ORF72"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NPL8","full_name":"Complex I assembly factor TIMMDC1, mitochondrial","aliases":["Protein M5-14","Translocase of inner mitochondrial membrane domain-containing protein 1","TIMM domain containing-protein 1"],"length_aa":285,"mass_kda":32.2,"function":"Chaperone protein involved in the assembly of the mitochondrial NADH:ubiquinone oxidoreductase complex (complex I). Participates in constructing the membrane arm of complex I","subcellular_location":"Mitochondrion membrane","url":"https://www.uniprot.org/uniprotkb/Q9NPL8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TIMMDC1","classification":"Not Classified","n_dependent_lines":218,"n_total_lines":1208,"dependency_fraction":0.1804635761589404},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TIMMDC1","total_profiled":1310},"omim":[{"mim_id":"618251","title":"MITOCHONDRIAL COMPLEX I DEFICIENCY, NUCLEAR TYPE 31; MC1DN31","url":"https://www.omim.org/entry/618251"},{"mim_id":"615534","title":"TRANSLOCASE OF INNER MITOCHONDRIAL MEMBRANE DOMAIN-CONTAINING PROTEIN 1; TIMMDC1","url":"https://www.omim.org/entry/615534"},{"mim_id":"252010","title":"MITOCHONDRIAL COMPLEX I DEFICIENCY, NUCLEAR TYPE 1; MC1DN1","url":"https://www.omim.org/entry/252010"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Mitochondria","reliability":"Enhanced"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TIMMDC1"},"hgnc":{"alias_symbol":["FLJ22597"],"prev_symbol":["C3orf1"]},"alphafold":{"accession":"Q9NPL8","domains":[{"cath_id":"-","chopping":"57-162","consensus_level":"medium","plddt":81.115,"start":57,"end":162},{"cath_id":"1.10.287","chopping":"163-215","consensus_level":"medium","plddt":79.8553,"start":163,"end":215},{"cath_id":"1.20.5","chopping":"220-257","consensus_level":"medium","plddt":76.8434,"start":220,"end":257}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NPL8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NPL8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NPL8-F1-predicted_aligned_error_v6.png","plddt_mean":72.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TIMMDC1","jax_strain_url":"https://www.jax.org/strain/search?query=TIMMDC1"},"sequence":{"accession":"Q9NPL8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NPL8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NPL8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NPL8"}},"corpus_meta":[{"pmid":"28604674","id":"PMC_28604674","title":"Genetic 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Quantitative proteomics demonstrated its role in assembly of both membrane-embedded and soluble arms of complex I.\",\n      \"method\": \"Interaction proteomics (reciprocal co-immunoprecipitation/AP-MS), subcellular fractionation/localization, siRNA knockdown with complex I activity and cellular respiration assays, quantitative proteomics\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP/AP-MS, multiple orthogonal methods (localization, KD phenotype, quantitative proteomics), replicated by independent studies\",\n      \"pmids\": [\"24344204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"TIMMDC1 (C3orf1) was found associated with 550 kDa and 815 kDa complex I subcomplexes when NDUFA11 expression was suppressed, placing TIMMDC1 as a transient assembly factor for the membrane arm of complex I alongside TMEM126B and NDUFA11.\",\n      \"method\": \"Suppression of NDUFA11 expression followed by native gel electrophoresis and mass spectrometry identification of accumulated subcomplexes\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct biochemical fractionation and MS identification, independent lab replicating TIMMDC1's role in complex I membrane arm assembly\",\n      \"pmids\": [\"24191001\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"C9orf72 directly stabilizes TIMMDC1 in mitochondria by recruiting the prohibitin complex to inhibit m-AAA protease-dependent degradation of TIMMDC1, thereby maintaining mitochondrial complex I function.\",\n      \"method\": \"Co-immunoprecipitation, C9orf72 knockout mouse neurons and patient-derived neurons, proteomics, functional complex I activity assays\",\n      \"journal\": \"Cell metabolism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP identifying C9orf72/prohibitin/TIMMDC1 complex, multiple orthogonal methods (KO models, patient neurons, functional assays), mechanistic pathway established\",\n      \"pmids\": [\"33545050\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"A deep intronic variant in TIMMDC1 (c.597-1340A>G) creates a cryptic splice site, causing aberrant splicing and establishing TIMMDC1 as a disease-causing gene for mitochondriopathy via loss of complex I assembly factor function.\",\n      \"method\": \"RNA sequencing of patient fibroblasts revealing aberrant splicing, transcriptome analysis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNA-seq with direct splicing evidence in patient cells, single study but with clear functional implication\",\n      \"pmids\": [\"28604674\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Splice-switching antisense oligonucleotides (SSOs) targeting the TIMMDC1 intronic pathogenic variant c.597-1340A>G restore normal TIMMDC1 mRNA processing and protein levels in patient fibroblasts, with quantitative proteomics and real-time metabolic analysis confirming restoration of complex I subunit abundance and function.\",\n      \"method\": \"Antisense oligonucleotide treatment, RNA and protein analysis, quantitative proteomics, real-time mitochondrial metabolic analysis (Seahorse)\",\n      \"journal\": \"NPJ genomic medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — functional rescue by SSOs with multiple orthogonal methods confirming complex I restoration, directly linking TIMMDC1 to complex I assembly function\",\n      \"pmids\": [\"35091571\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Disruption of NDUFAF3 or NDUFAF4 in Drosophila destabilizes TIMMDC1 in complex I assembly intermediates, placing TIMMDC1 downstream of or in concert with NDUFAF3/NDUFAF4 in the biogenesis of the Q-, N-, and PP-b-modules of complex I.\",\n      \"method\": \"Genetic disruption (Drosophila), complexome profiling, epistasis analysis with double mutants\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis in Drosophila with complexome profiling, single lab, orthologous system\",\n      \"pmids\": [\"34386730\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Depletion of TIMMDC1 (C3orf1) by siRNA in 95D lung carcinoma cells confirmed its localization in the inner mitochondrial membrane and showed that its loss reduces mitochondrial membrane potential and ATPase activity, inhibits cell migration and proliferation, and alters expression of genes in focal adhesion, ECM-receptor interaction, and p53-signaling pathways.\",\n      \"method\": \"siRNA knockdown, immunofluorescence/fractionation for localization, mitochondrial membrane potential assay, ATPase activity assay, migration/proliferation assays, microarray gene expression analysis\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — direct localization confirmation plus functional KD phenotype with multiple readouts, single lab\",\n      \"pmids\": [\"25391042\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"C-terminal truncation of TIMMDC1 (p.Arg225*, removing 61 amino acids) has a hypomorphic effect on complex I assembly: the truncated protein can still partially rescue complex I assembly in TIMMDC1 knockout cells, indicating the C-terminus is not essential for core assembly function.\",\n      \"method\": \"TIMMDC1 knockout cell line complementation assay, functional complex I assembly studies\",\n      \"journal\": \"Human mutation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional rescue experiment in KO cells with defined truncation mutant, single lab, establishes domain dispensability\",\n      \"pmids\": [\"30981218\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Complexome profiling of TMEM126B-deficient patient cells confirmed that TIMMDC1 is a component of the mitochondrial complex I assembly (MCIA) complex, alongside ACAD9, ECSIT, NDUFAF1, and TMEM126B.\",\n      \"method\": \"Complexome profiling of patient cell lines\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — complexome profiling provides direct evidence of TIMMDC1 within the MCIA complex, single lab, corroborates prior AP-MS data\",\n      \"pmids\": [\"27374774\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Knockdown of TIMMDC1 in gastric cancer cells selectively reduces complex I activity (not complexes II–IV), inhibits mitochondrial respiration and ATP-linked oxygen consumption, attenuates glycolysis, and reduces phosphorylation of AKT(Ser473) and GSK-3β(Ser9) with downstream reduction of β-catenin and c-Myc.\",\n      \"method\": \"shRNA knockdown, complex I–IV activity assays, Seahorse metabolic flux analysis, ATP quantification, western blotting for AKT/GSK3β/β-catenin pathway, in vivo tumor xenograft\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — multiple orthogonal functional assays establishing complex I specificity and downstream signaling, single lab\",\n      \"pmids\": [\"30123074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"METTL3 methyltransferase suppresses TIMMDC1 expression via m6A methylation of TIMMDC1 mRNA; confirmed by Me-RIP assay showing METTL3 binding to TIMMDC1 mRNA, and RIP assay confirming the interaction.\",\n      \"method\": \"Me-RIP assay, RIP assay, SRAMP site prediction, qRT-PCR, western blot, EdU proliferation assay\",\n      \"journal\": \"Immunobiology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, limited mechanistic depth in abstract, Me-RIP and RIP performed but full mechanistic detail unclear from abstract alone\",\n      \"pmids\": [\"40409178\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"C3orf1 (TIMMDC1) encodes a predicted 32.2 kDa membrane protein with four transmembrane domains, showing ubiquitous expression enhanced in heart and skeletal muscle, identified as homologous to the Drosophila RP140-upstream gene.\",\n      \"method\": \"cDNA cloning, Northern blot analysis, computational domain prediction\",\n      \"journal\": \"DNA sequence : the journal of DNA sequencing and mapping\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3–4 / Weak — initial characterization by cloning and expression; predicted transmembrane topology, no functional validation\",\n      \"pmids\": [\"11092749\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TIMMDC1 is a four-pass, inner mitochondrial membrane-embedded protein that functions as an assembly factor for the membrane arm of mitochondrial complex I by associating with the MCIA complex (ACAD9, ECSIT, NDUFAF1, TMEM126B) and core complex I subunits; its stability is maintained by C9orf72, which recruits the prohibitin complex to block m-AAA protease-dependent degradation of TIMMDC1, and its loss selectively impairs complex I activity and oxidative phosphorylation, reducing cellular ATP production and downstream AKT/GSK3β/β-catenin signaling, while its expression is post-transcriptionally regulated by METTL3-mediated m6A methylation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TIMMDC1 is an inner mitochondrial membrane-embedded assembly factor required for biogenesis of the membrane arm of respiratory chain complex I [#0, #1]. It reciprocally associates with the mitochondrial complex I assembly (MCIA) complex — ACAD9, ECSIT, NDUFAF1 and TMEM126B — and with core complex I subunits, and is found in 550 kDa and 815 kDa membrane-arm assembly intermediates, acting transiently during the build of the Q-, N- and PP-b modules [#0, #1, #8]. Loss of TIMMDC1 selectively impairs complex I activity without affecting complexes II–IV, reducing mitochondrial respiration, ATP-linked oxygen consumption and cellular ATP, with downstream attenuation of AKT/GSK-3β/β-catenin signaling [#9]. Its abundance in mitochondria is controlled by C9orf72, which recruits the prohibitin complex to block m-AAA protease-dependent degradation of TIMMDC1 and thereby preserve complex I function [#2]. A deep intronic variant (c.597-1340A>G) creates a cryptic splice site that abolishes TIMMDC1 function and causes a complex I-deficient mitochondriopathy, and splice-switching antisense oligonucleotides correcting this variant restore normal mRNA, protein and complex I function in patient fibroblasts [#3, #4].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Before any functional role was known, the gene needed basic molecular definition; this established TIMMDC1 (C3orf1) as a ubiquitously expressed, muscle-enriched four-pass membrane protein.\",\n      \"evidence\": \"cDNA cloning, Northern blot, and computational topology prediction\",\n      \"pmids\": [\"11092749\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No functional or organellar assignment\", \"Transmembrane topology only predicted, not experimentally resolved\", \"No interaction or pathway data\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"The central question of what process TIMMDC1 serves was answered by placing it as an inner-membrane complex I assembly factor physically tied to the MCIA machinery and required for complex I activity.\",\n      \"evidence\": \"Reciprocal Co-IP/AP-MS, fractionation, siRNA knockdown with complex I and respiration assays, and quantitative proteomics; independent native-gel/MS identification of TIMMDC1 in membrane-arm subcomplexes\",\n      \"pmids\": [\"24344204\", \"24191001\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Order of action within the MCIA pathway not defined\", \"Direct substrate/subunit handoff not resolved\", \"No structural model of TIMMDC1 in assembly intermediates\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Whether TIMMDC1 is a stable MCIA subunit rather than a peripheral interactor was tested, confirming its membership in the MCIA complex with ACAD9, ECSIT, NDUFAF1 and TMEM126B.\",\n      \"evidence\": \"Complexome profiling of TMEM126B-deficient patient cells\",\n      \"pmids\": [\"27374774\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry within MCIA not defined\", \"Single patient-cell context\", \"Does not establish direct binary contacts\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"It was unknown whether TIMMDC1 loss-of-function causes human disease; a deep intronic cryptic-splice variant established TIMMDC1 as a mitochondriopathy gene.\",\n      \"evidence\": \"RNA sequencing of patient fibroblasts revealing aberrant splicing\",\n      \"pmids\": [\"28604674\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single index finding of the variant\", \"Genotype–phenotype spectrum not delineated\", \"Mechanistic link to complex I deficiency inferred from splicing, not yet rescued\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"The specificity and signaling consequences of TIMMDC1 loss were clarified, showing a complex I-selective defect that propagates to AKT/GSK-3β/β-catenin/c-Myc signaling and tumor cell behavior.\",\n      \"evidence\": \"shRNA knockdown in gastric cancer cells, complex I–IV activity assays, Seahorse flux, ATP quantification, pathway western blots, and xenografts\",\n      \"pmids\": [\"30123074\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether signaling changes are direct or secondary to bioenergetic stress unresolved\", \"Single cancer context\", \"No demonstration that AKT pathway requires complex I per se\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"The functional importance of the TIMMDC1 C-terminus was tested, showing a p.Arg225* truncation is hypomorphic and the C-terminus is dispensable for core assembly function.\",\n      \"evidence\": \"Complementation of TIMMDC1 knockout cells with the truncation mutant and complex I assembly assays\",\n      \"pmids\": [\"30981218\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Domain mapping of the essential region incomplete\", \"Quantitative degree of hypomorphism not detailed\", \"No structural basis for partial activity\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"How TIMMDC1 levels are maintained was addressed, defining a C9orf72/prohibitin axis that protects TIMMDC1 from m-AAA protease degradation to sustain complex I.\",\n      \"evidence\": \"Co-IP, C9orf72 knockout mouse and patient-derived neurons, proteomics, and complex I activity assays\",\n      \"pmids\": [\"33545050\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Signals triggering m-AAA targeting of TIMMDC1 unknown\", \"Direct protease cleavage site not mapped\", \"Generalizability beyond neurons not tested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"The position of TIMMDC1 relative to other assembly factors was refined, placing it downstream of or alongside NDUFAF3/NDUFAF4 in Q-, N- and PP-b-module biogenesis.\",\n      \"evidence\": \"Genetic disruption in Drosophila with complexome profiling and double-mutant epistasis\",\n      \"pmids\": [\"34386730\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Orthologous (Drosophila) system; human ordering not directly confirmed\", \"Molecular nature of cooperation with NDUFAF3/4 unknown\", \"Intermediate handoff steps undefined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Whether the pathogenic splice defect is correctable was demonstrated, with splice-switching antisense oligonucleotides restoring TIMMDC1 mRNA, protein and complex I function in patient cells.\",\n      \"evidence\": \"Antisense oligonucleotide treatment of patient fibroblasts, RNA/protein analysis, quantitative proteomics, and Seahorse metabolic analysis\",\n      \"pmids\": [\"35091571\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Efficacy shown in fibroblasts only, not in vivo\", \"Durability and delivery not addressed\", \"No clinical correlation\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A post-transcriptional control layer was identified, with METTL3-mediated m6A methylation of TIMMDC1 mRNA suppressing its expression.\",\n      \"evidence\": \"Me-RIP and RIP assays, m6A site prediction, qRT-PCR, western blot, and EdU proliferation assay\",\n      \"pmids\": [\"40409178\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single lab with limited mechanistic depth from abstract\", \"m6A reader and decay/translation mechanism not defined\", \"Physiological context of regulation unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of how TIMMDC1 templates membrane-arm assembly and the precise sequence of subunit handoffs within the MCIA pathway remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structure of TIMMDC1 within an assembly intermediate\", \"Direct binary contacts with specific complex I subunits not mapped\", \"Timing of TIMMDC1 release during maturation unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 1, 6, 11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 9]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 1, 8]}\n    ],\n    \"complexes\": [\"MCIA complex\"],\n    \"partners\": [\"ACAD9\", \"ECSIT\", \"NDUFAF1\", \"TMEM126B\", \"NDUFA11\", \"C9orf72\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}