{"gene":"NDUFC2","run_date":"2026-04-29T11:37:56","timeline":{"discoveries":[{"year":2016,"finding":"Ndufc2 disruption alters complex I assembly and activity, reduces mitochondrial membrane potential and ATP levels, and increases reactive oxygen species production and inflammation both in vitro and in vivo in a rat stroke model. Heterozygous Ndufc2 knockout rats showed renal abnormalities and stroke occurrence under a stroke-permissive diet.","method":"Ndufc2 knockout rat model, microarray expression analysis, in vitro and in vivo functional assays (mitochondrial membrane potential, ATP levels, ROS measurement)","journal":"Journal of the American Heart Association","confidence":"High","confidence_rationale":"Tier 2 — clean KO model with multiple orthogonal functional readouts, replicated in vivo and in vitro","pmids":["26888427"],"is_preprint":false},{"year":2017,"finding":"Ndufc2 deficiency causes marked mitochondrial dysfunction including increased ROS generation, reduced ATP, and ultrastructural impairment of mitochondrial morphology with loss of internal cristae, in both fibroblasts from heterozygous knockout rats and PBMCs from human subjects homozygous for a low-expression NDUFC2 variant. Stress stimuli (high-NaCl or LPS) exacerbate mitochondrial damage, and resveratrol counteracts ROS generation.","method":"In vitro study using rat knock-out fibroblasts and human PBMCs; cytofluorimetry, transmission electron microscopy, ROS assays","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (ultrastructure, functional assays) in two independent cellular models","pmids":["28973657"],"is_preprint":false},{"year":2020,"finding":"Bi-allelic loss-of-function variants in NDUFC2 cause severe complex I activity deficiency and stalled biogenesis of the complex I holoenzyme in patients with Leigh syndrome. Complexome profiling revealed aberrant assembly intermediates indicating NDUFC2 is specifically required for assembly of the membrane arm of complex I, particularly the ND2 module. Lentiviral transduction with wild-type NDUFC2 cDNA rescued complex I assembly in patient fibroblasts.","method":"Patient fibroblast biochemical assays, complexome profiling, lentiviral complementation with wild-type cDNA, blue-native PAGE","journal":"EMBO molecular medicine","confidence":"High","confidence_rationale":"Tier 1–2 — complementation rescue, complexome profiling, and biochemical activity assays with multiple orthogonal methods","pmids":["32969598"],"is_preprint":false},{"year":2019,"finding":"NDUFC2 silencing in human endothelial and vascular smooth muscle cells impairs cell viability and angiogenesis and stimulates expression of markers of plaque rupture, indicating a role for NDUFC2-dependent mitochondrial function in vascular cell homeostasis and atherogenesis.","method":"NDUFC2 siRNA silencing in human vascular cells; viability assays, angiogenesis assays, marker expression analysis","journal":"International journal of cardiology","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, KD with defined cellular phenotypes but limited mechanistic pathway placement","pmids":["30808603"],"is_preprint":false},{"year":2023,"finding":"Ndufc2 deficiency in isolated cardiomyocytes causes mitochondrial dysfunction leading to cardiomyocyte hypertrophy through the SIRT3-AMPK-AKT-MnSOD signaling pathway.","method":"Ndufc2 siRNA silencing in H9c2 cells and rat primary cardiomyocytes; signaling pathway analysis (SIRT3, AMPK, AKT, MnSOD)","journal":"Molecular medicine (Cambridge, Mass.)","confidence":"Medium","confidence_rationale":"Tier 2–3 — pathway placement via KD with signaling readouts, single lab","pmids":["37558995"],"is_preprint":false},{"year":2023,"finding":"NDUFC2 overexpression suppresses NLRP3 inflammasome activation and endothelial-to-mesenchymal transition (EndoMT) in human brain microvascular endothelial cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R), and rescues antioxidant gene expression (SOD1, CAT). Conversely, OGD/R-induced NLRP3 activation causes NDUFC2 deficiency. NLRP3 knockout in tMCAO mice inhibits EndoMT in vivo.","method":"NDUFC2 overexpression in HBMECs under OGD/R; tMCAO in NLRP3 KO mice; RT-PCR for SOD1/CAT; α-SMA/CD31 markers for EndoMT","journal":"Neuroreport","confidence":"Medium","confidence_rationale":"Tier 2–3 — overexpression rescue with in vivo epistasis, single lab, moderate mechanistic resolution","pmids":["37506315"],"is_preprint":false}],"current_model":"NDUFC2 encodes a structural subunit of mitochondrial respiratory chain complex I that is specifically required for assembly of the membrane arm (ND2 module) of the complex I holoenzyme; its loss causes stalled complex I biogenesis, severely reduced complex I activity, decreased mitochondrial membrane potential and ATP production, increased ROS, and downstream consequences including cardiomyocyte hypertrophy (via SIRT3-AMPK-AKT-MnSOD), NLRP3-mediated endothelial-mesenchymal transition, and increased stroke and cardiac disease susceptibility."},"narrative":{"teleology":[{"year":2016,"claim":"Establishing that NDUFC2 is functionally required for complex I activity in vivo resolved whether this small subunit is dispensable or essential: Ndufc2 knockout rats showed impaired complex I assembly, reduced membrane potential and ATP, elevated ROS, inflammation, and stroke susceptibility.","evidence":"Ndufc2 heterozygous knockout rat model with in vitro and in vivo functional assays including membrane potential, ATP, and ROS measurements","pmids":["26888427"],"confidence":"High","gaps":["Precise step of complex I assembly at which NDUFC2 acts was not resolved","Mechanism linking NDUFC2 loss to inflammation was not defined","No human genetic disease association yet established"]},{"year":2017,"claim":"Extending findings to human cells and ultrastructural analysis demonstrated that NDUFC2 deficiency causes cristae destruction and that mitochondrial damage is exacerbated by environmental stressors, confirming cross-species conservation of the phenotype.","evidence":"Rat knockout fibroblasts and human PBMCs from subjects homozygous for a low-expression NDUFC2 variant; cytofluorimetry, TEM, ROS assays","pmids":["28973657"],"confidence":"High","gaps":["Human variant was a common low-expression allele, not a clear loss-of-function mutation","Structural basis of cristae disorganization was not determined"]},{"year":2019,"claim":"Demonstrating that NDUFC2 silencing impairs vascular cell viability and angiogenesis connected complex I dysfunction to atherogenic mechanisms, expanding the disease relevance beyond stroke.","evidence":"siRNA knockdown in human endothelial and vascular smooth muscle cells; viability and angiogenesis assays, plaque-rupture marker expression","pmids":["30808603"],"confidence":"Medium","gaps":["Single-lab knockdown without genetic rescue or animal model validation","No direct link to complex I assembly intermediates in vascular cells","Mechanism by which mitochondrial dysfunction triggers plaque-rupture markers not resolved"]},{"year":2020,"claim":"Complexome profiling of patient fibroblasts with bi-allelic NDUFC2 loss-of-function variants pinpointed the assembly defect to the ND2 membrane-arm module and established NDUFC2 mutations as a cause of Leigh syndrome, definitively placing the subunit in the complex I biogenesis pathway.","evidence":"Patient fibroblasts with bi-allelic variants; complexome profiling, blue-native PAGE, lentiviral complementation rescue","pmids":["32969598"],"confidence":"High","gaps":["Structural contacts between NDUFC2 and ND2 module components not mapped","Whether residual subassemblies retain partial electron-transfer activity was not tested"]},{"year":2023,"claim":"Identification of downstream signaling cascades — SIRT3–AMPK–AKT–MnSOD in cardiomyocyte hypertrophy and NLRP3 inflammasome–driven endothelial-to-mesenchymal transition under ischemia — provided mechanistic links between NDUFC2-dependent mitochondrial dysfunction and specific cardiovascular pathologies.","evidence":"siRNA knockdown in H9c2 cells/primary cardiomyocytes and NDUFC2 overexpression in HBMECs under OGD/R; NLRP3 KO mice with tMCAO","pmids":["37558995","37506315"],"confidence":"Medium","gaps":["Signaling pathway studies are single-lab and rely on knockdown/overexpression without genetic models","Whether SIRT3 and NLRP3 pathways interact or represent independent consequences of NDUFC2 loss is unknown","In vivo cardiac phenotypes of NDUFC2 deficiency have not been fully characterized"]},{"year":null,"claim":"The structural basis of NDUFC2's role in ND2 module assembly — including its direct protein contacts within the membrane arm, how its absence stalls the assembly intermediate, and whether pharmacological intervention can bypass or compensate for NDUFC2 loss — remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No high-resolution structural data defining NDUFC2 contacts within the ND2 module","No reconstitution of the assembly defect with purified components","Genotype–phenotype spectrum across different NDUFC2 variants is not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,1,2]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2]}],"complexes":["Mitochondrial complex I (NADH:ubiquinone oxidoreductase)"],"partners":["NLRP3","SIRT3"],"other_free_text":[]},"mechanistic_narrative":"NDUFC2 is a structural subunit of mitochondrial respiratory chain complex I that is specifically required for assembly of the membrane arm (ND2 module) of the holoenzyme; bi-allelic loss-of-function variants cause stalled complex I biogenesis, severely reduced complex I activity, and Leigh syndrome in humans [PMID:32969598]. Loss of NDUFC2 leads to decreased mitochondrial membrane potential, reduced ATP production, increased reactive oxygen species, and ultrastructural disintegration of mitochondrial cristae, phenotypes demonstrated in both rodent knockout models and human cells carrying low-expression variants [PMID:26888427, PMID:28973657]. Downstream of this mitochondrial dysfunction, NDUFC2 deficiency drives cardiomyocyte hypertrophy through the SIRT3–AMPK–AKT–MnSOD pathway and promotes NLRP3 inflammasome–dependent endothelial-to-mesenchymal transition under ischemic conditions [PMID:37558995, PMID:37506315]."},"prefetch_data":{"uniprot":{"accession":"O95298","full_name":"NADH dehydrogenase [ubiquinone] 1 subunit C2","aliases":["Complex I-B14.5b","CI-B14.5b","Human lung cancer oncogene 1 protein","HLC-1","NADH-ubiquinone oxidoreductase subunit B14.5b"],"length_aa":119,"mass_kda":14.2,"function":"Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis but required for the complex assembly. Complex I functions in the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone","subcellular_location":"Mitochondrion inner membrane","url":"https://www.uniprot.org/uniprotkb/O95298/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NDUFC2","classification":"Not Classified","n_dependent_lines":483,"n_total_lines":1208,"dependency_fraction":0.39983443708609273},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/NDUFC2","total_profiled":1310},"omim":[{"mim_id":"619170","title":"MITOCHONDRIAL COMPLEX I DEFICIENCY, NUCLEAR TYPE 36; MC1DN36","url":"https://www.omim.org/entry/619170"},{"mim_id":"603845","title":"NADH-UBIQUINONE OXIDOREDUCTASE SUBUNIT C2; NDUFC2","url":"https://www.omim.org/entry/603845"},{"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":"Approved","locations":[{"location":"Mitochondria","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NDUFC2"},"hgnc":{"alias_symbol":["B14.5b","HLC-1"],"prev_symbol":[]},"alphafold":{"accession":"O95298","domains":[{"cath_id":"1.10.287","chopping":"24-97","consensus_level":"high","plddt":94.2374,"start":24,"end":97}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95298","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95298-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95298-F1-predicted_aligned_error_v6.png","plddt_mean":90.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NDUFC2","jax_strain_url":"https://www.jax.org/strain/search?query=NDUFC2"},"sequence":{"accession":"O95298","fasta_url":"https://rest.uniprot.org/uniprotkb/O95298.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95298/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95298"}},"corpus_meta":[{"pmid":"26888427","id":"PMC_26888427","title":"Ndufc2 Gene Inhibition Is Associated With Mitochondrial Dysfunction and Increased Stroke Susceptibility in an Animal Model of Complex Human Disease.","date":"2016","source":"Journal of the American Heart Association","url":"https://pubmed.ncbi.nlm.nih.gov/26888427","citation_count":45,"is_preprint":false},{"pmid":"31500202","id":"PMC_31500202","title":"High-Throughput RNA Sequencing Reveals NDUFC2-AS lncRNA Promotes Adipogenic Differentiation in Chinese Buffalo (Bubalus bubalis L).","date":"2019","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/31500202","citation_count":25,"is_preprint":false},{"pmid":"32969598","id":"PMC_32969598","title":"Bi-allelic pathogenic variants in NDUFC2 cause early-onset Leigh syndrome and stalled biogenesis of complex I.","date":"2020","source":"EMBO molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/32969598","citation_count":24,"is_preprint":false},{"pmid":"28973657","id":"PMC_28973657","title":"In vitro characterization of mitochondrial function and structure in rat and human cells with a deficiency of the NADH: ubiquinone oxidoreductase Ndufc2 subunit.","date":"2017","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28973657","citation_count":24,"is_preprint":false},{"pmid":"30808603","id":"PMC_30808603","title":"The reduction of NDUFC2 expression is associated with mitochondrial impairment in circulating mononuclear cells of patients with acute coronary syndrome.","date":"2019","source":"International journal of cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/30808603","citation_count":20,"is_preprint":false},{"pmid":"25804238","id":"PMC_25804238","title":"Expression profiling of SCN8A and NDUFC2 genes in colorectal carcinoma.","date":"2015","source":"Experimental oncology","url":"https://pubmed.ncbi.nlm.nih.gov/25804238","citation_count":15,"is_preprint":false},{"pmid":"37558995","id":"PMC_37558995","title":"Polymorphic variants at NDUFC2, encoding a mitochondrial complex I subunit, associate with cardiac hypertrophy in human hypertension.","date":"2023","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/37558995","citation_count":8,"is_preprint":false},{"pmid":"39675531","id":"PMC_39675531","title":"Targeting the HLC-1, LC-2/ad, and PC-14 lung cancer cell lines by the silver nanoparticles green-formulated by Descurainia sophia leaf extract.","date":"2024","source":"Molecular and cellular probes","url":"https://pubmed.ncbi.nlm.nih.gov/39675531","citation_count":6,"is_preprint":false},{"pmid":"35711349","id":"PMC_35711349","title":"Impact of a NDUFC2 Variant on the Occurrence of Acute Coronary Syndromes.","date":"2022","source":"Frontiers in cardiovascular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35711349","citation_count":4,"is_preprint":false},{"pmid":"37506315","id":"PMC_37506315","title":"NDUFC2 deficiency exacerbates endothelial mesenchymal transformation during ischemia-reperfusion via NLRP3.","date":"2023","source":"Neuroreport","url":"https://pubmed.ncbi.nlm.nih.gov/37506315","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7013,"output_tokens":1613,"usd":0.022617},"stage2":{"model":"claude-opus-4-6","input_tokens":4859,"output_tokens":1769,"usd":0.10278},"total_usd":0.125397,"stage1_batch_id":"msgbatch_012ZiiCUBfB62NCTQd4Bk1Jo","stage2_batch_id":"msgbatch_01Xuqq9aUHoQouS7UVGZNStZ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"Ndufc2 disruption alters complex I assembly and activity, reduces mitochondrial membrane potential and ATP levels, and increases reactive oxygen species production and inflammation both in vitro and in vivo in a rat stroke model. Heterozygous Ndufc2 knockout rats showed renal abnormalities and stroke occurrence under a stroke-permissive diet.\",\n      \"method\": \"Ndufc2 knockout rat model, microarray expression analysis, in vitro and in vivo functional assays (mitochondrial membrane potential, ATP levels, ROS measurement)\",\n      \"journal\": \"Journal of the American Heart Association\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO model with multiple orthogonal functional readouts, replicated in vivo and in vitro\",\n      \"pmids\": [\"26888427\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Ndufc2 deficiency causes marked mitochondrial dysfunction including increased ROS generation, reduced ATP, and ultrastructural impairment of mitochondrial morphology with loss of internal cristae, in both fibroblasts from heterozygous knockout rats and PBMCs from human subjects homozygous for a low-expression NDUFC2 variant. Stress stimuli (high-NaCl or LPS) exacerbate mitochondrial damage, and resveratrol counteracts ROS generation.\",\n      \"method\": \"In vitro study using rat knock-out fibroblasts and human PBMCs; cytofluorimetry, transmission electron microscopy, ROS assays\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (ultrastructure, functional assays) in two independent cellular models\",\n      \"pmids\": [\"28973657\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Bi-allelic loss-of-function variants in NDUFC2 cause severe complex I activity deficiency and stalled biogenesis of the complex I holoenzyme in patients with Leigh syndrome. Complexome profiling revealed aberrant assembly intermediates indicating NDUFC2 is specifically required for assembly of the membrane arm of complex I, particularly the ND2 module. Lentiviral transduction with wild-type NDUFC2 cDNA rescued complex I assembly in patient fibroblasts.\",\n      \"method\": \"Patient fibroblast biochemical assays, complexome profiling, lentiviral complementation with wild-type cDNA, blue-native PAGE\",\n      \"journal\": \"EMBO molecular medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — complementation rescue, complexome profiling, and biochemical activity assays with multiple orthogonal methods\",\n      \"pmids\": [\"32969598\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"NDUFC2 silencing in human endothelial and vascular smooth muscle cells impairs cell viability and angiogenesis and stimulates expression of markers of plaque rupture, indicating a role for NDUFC2-dependent mitochondrial function in vascular cell homeostasis and atherogenesis.\",\n      \"method\": \"NDUFC2 siRNA silencing in human vascular cells; viability assays, angiogenesis assays, marker expression analysis\",\n      \"journal\": \"International journal of cardiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, KD with defined cellular phenotypes but limited mechanistic pathway placement\",\n      \"pmids\": [\"30808603\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Ndufc2 deficiency in isolated cardiomyocytes causes mitochondrial dysfunction leading to cardiomyocyte hypertrophy through the SIRT3-AMPK-AKT-MnSOD signaling pathway.\",\n      \"method\": \"Ndufc2 siRNA silencing in H9c2 cells and rat primary cardiomyocytes; signaling pathway analysis (SIRT3, AMPK, AKT, MnSOD)\",\n      \"journal\": \"Molecular medicine (Cambridge, Mass.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — pathway placement via KD with signaling readouts, single lab\",\n      \"pmids\": [\"37558995\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NDUFC2 overexpression suppresses NLRP3 inflammasome activation and endothelial-to-mesenchymal transition (EndoMT) in human brain microvascular endothelial cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R), and rescues antioxidant gene expression (SOD1, CAT). Conversely, OGD/R-induced NLRP3 activation causes NDUFC2 deficiency. NLRP3 knockout in tMCAO mice inhibits EndoMT in vivo.\",\n      \"method\": \"NDUFC2 overexpression in HBMECs under OGD/R; tMCAO in NLRP3 KO mice; RT-PCR for SOD1/CAT; α-SMA/CD31 markers for EndoMT\",\n      \"journal\": \"Neuroreport\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — overexpression rescue with in vivo epistasis, single lab, moderate mechanistic resolution\",\n      \"pmids\": [\"37506315\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NDUFC2 encodes a structural subunit of mitochondrial respiratory chain complex I that is specifically required for assembly of the membrane arm (ND2 module) of the complex I holoenzyme; its loss causes stalled complex I biogenesis, severely reduced complex I activity, decreased mitochondrial membrane potential and ATP production, increased ROS, and downstream consequences including cardiomyocyte hypertrophy (via SIRT3-AMPK-AKT-MnSOD), NLRP3-mediated endothelial-mesenchymal transition, and increased stroke and cardiac disease susceptibility.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"NDUFC2 is a structural subunit of mitochondrial respiratory chain complex I that is specifically required for assembly of the membrane arm (ND2 module) of the holoenzyme; bi-allelic loss-of-function variants cause stalled complex I biogenesis, severely reduced complex I activity, and Leigh syndrome in humans [PMID:32969598]. Loss of NDUFC2 leads to decreased mitochondrial membrane potential, reduced ATP production, increased reactive oxygen species, and ultrastructural disintegration of mitochondrial cristae, phenotypes demonstrated in both rodent knockout models and human cells carrying low-expression variants [PMID:26888427, PMID:28973657]. Downstream of this mitochondrial dysfunction, NDUFC2 deficiency drives cardiomyocyte hypertrophy through the SIRT3–AMPK–AKT–MnSOD pathway and promotes NLRP3 inflammasome–dependent endothelial-to-mesenchymal transition under ischemic conditions [PMID:37558995, PMID:37506315].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Establishing that NDUFC2 is functionally required for complex I activity in vivo resolved whether this small subunit is dispensable or essential: Ndufc2 knockout rats showed impaired complex I assembly, reduced membrane potential and ATP, elevated ROS, inflammation, and stroke susceptibility.\",\n      \"evidence\": \"Ndufc2 heterozygous knockout rat model with in vitro and in vivo functional assays including membrane potential, ATP, and ROS measurements\",\n      \"pmids\": [\"26888427\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Precise step of complex I assembly at which NDUFC2 acts was not resolved\",\n        \"Mechanism linking NDUFC2 loss to inflammation was not defined\",\n        \"No human genetic disease association yet established\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Extending findings to human cells and ultrastructural analysis demonstrated that NDUFC2 deficiency causes cristae destruction and that mitochondrial damage is exacerbated by environmental stressors, confirming cross-species conservation of the phenotype.\",\n      \"evidence\": \"Rat knockout fibroblasts and human PBMCs from subjects homozygous for a low-expression NDUFC2 variant; cytofluorimetry, TEM, ROS assays\",\n      \"pmids\": [\"28973657\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Human variant was a common low-expression allele, not a clear loss-of-function mutation\",\n        \"Structural basis of cristae disorganization was not determined\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrating that NDUFC2 silencing impairs vascular cell viability and angiogenesis connected complex I dysfunction to atherogenic mechanisms, expanding the disease relevance beyond stroke.\",\n      \"evidence\": \"siRNA knockdown in human endothelial and vascular smooth muscle cells; viability and angiogenesis assays, plaque-rupture marker expression\",\n      \"pmids\": [\"30808603\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single-lab knockdown without genetic rescue or animal model validation\",\n        \"No direct link to complex I assembly intermediates in vascular cells\",\n        \"Mechanism by which mitochondrial dysfunction triggers plaque-rupture markers not resolved\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Complexome profiling of patient fibroblasts with bi-allelic NDUFC2 loss-of-function variants pinpointed the assembly defect to the ND2 membrane-arm module and established NDUFC2 mutations as a cause of Leigh syndrome, definitively placing the subunit in the complex I biogenesis pathway.\",\n      \"evidence\": \"Patient fibroblasts with bi-allelic variants; complexome profiling, blue-native PAGE, lentiviral complementation rescue\",\n      \"pmids\": [\"32969598\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural contacts between NDUFC2 and ND2 module components not mapped\",\n        \"Whether residual subassemblies retain partial electron-transfer activity was not tested\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identification of downstream signaling cascades — SIRT3–AMPK–AKT–MnSOD in cardiomyocyte hypertrophy and NLRP3 inflammasome–driven endothelial-to-mesenchymal transition under ischemia — provided mechanistic links between NDUFC2-dependent mitochondrial dysfunction and specific cardiovascular pathologies.\",\n      \"evidence\": \"siRNA knockdown in H9c2 cells/primary cardiomyocytes and NDUFC2 overexpression in HBMECs under OGD/R; NLRP3 KO mice with tMCAO\",\n      \"pmids\": [\"37558995\", \"37506315\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Signaling pathway studies are single-lab and rely on knockdown/overexpression without genetic models\",\n        \"Whether SIRT3 and NLRP3 pathways interact or represent independent consequences of NDUFC2 loss is unknown\",\n        \"In vivo cardiac phenotypes of NDUFC2 deficiency have not been fully characterized\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of NDUFC2's role in ND2 module assembly — including its direct protein contacts within the membrane arm, how its absence stalls the assembly intermediate, and whether pharmacological intervention can bypass or compensate for NDUFC2 loss — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No high-resolution structural data defining NDUFC2 contacts within the ND2 module\",\n        \"No reconstitution of the assembly defect with purified components\",\n        \"Genotype–phenotype spectrum across different NDUFC2 variants is not established\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [\n      \"Mitochondrial complex I (NADH:ubiquinone oxidoreductase)\"\n    ],\n    \"partners\": [\n      \"NLRP3\",\n      \"SIRT3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}