{"gene":"NDUFB3","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2021,"finding":"METTL9 is a methyltransferase that catalyzes 1-methylhistidine (1MH) modification of NDUFB3 at an HxH (His-x-His) motif, where 'x' is preferably a small amino acid. This METTL9-mediated methylation of NDUFB3 enhances respiration via mitochondrial Complex I.","method":"In vitro methyltransferase assay, mass spectrometry identification of 1MH sites, METTL9 knockout mouse proteomics, functional respiration assay","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods including in vitro enzymatic assay, MS-based site identification, KO mouse proteomics, and functional respiration readout in a single rigorous study","pmids":["33563959"],"is_preprint":false},{"year":2012,"finding":"Mutations in NDUFB3 cause mitochondrial Complex I deficiency; expression of wild-type NDUFB3 cDNA in patient-derived mutant cell lines rescued Complex I activity and assembly, establishing NDUFB3 as a structural subunit required for Complex I assembly.","method":"Complementation/rescue experiment — wild-type cDNA transfection into patient mutant cell lines, Complex I activity assay, Blue Native PAGE for complex assembly","journal":"Science translational medicine / Journal of medical genetics","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — functional complementation with activity and assembly rescue, independently reported in two separate studies (PMID:22277967 and PMID:22499348)","pmids":["22277967","22499348"],"is_preprint":false},{"year":2016,"finding":"A recurrent homozygous p.Trp22Arg NDUFB3 variant causes a defect in Complex I assembly, as confirmed by analysis of skeletal muscle from affected patients showing reduced Complex I assembly by Blue Native gel electrophoresis.","method":"Blue Native PAGE on patient skeletal muscle samples; whole-exome/targeted gene sequencing for variant identification","journal":"Journal of medical genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct assembly analysis in patient tissue, single lab, two orthogonal methods (genetic + functional BN-PAGE)","pmids":["27091925"],"is_preprint":false},{"year":2009,"finding":"C20orf7 (a Complex I assembly factor) harbors an S-adenosylmethionine (SAM)-dependent methyltransferase domain possibly involved in methylation of NDUFB3 during Complex I assembly; patients with C20orf7 mutations showed only 30–40% of mature Complex I by Blue Native gel electrophoresis.","method":"Blue Native gel electrophoresis of patient cells; domain analysis of C20orf7; sequencing of patient samples","journal":"Journal of medical genetics","confidence":"Low","confidence_rationale":"Tier 3 / Weak — methylation of NDUFB3 by C20orf7 is proposed based on domain analysis, not directly demonstrated; only the assembly defect is experimentally confirmed","pmids":["19542079"],"is_preprint":false},{"year":2024,"finding":"NDUFB3 knockdown in hepatocellular carcinoma (HCC) cell lines significantly decreased Complex I activity and reduced mitochondrial ROS production, while NDUFB3 overexpression increased Complex I activity, elevated mitochondrial ROS, activated the JNK signaling pathway, and caused G0/G1 cell cycle arrest and apoptosis.","method":"shRNA knockdown and overexpression in HCC cell lines; Complex I activity assay; mitochondrial ROS measurement; JNK pathway western blot; flow cytometry (cell cycle, apoptosis); xenograft mouse model","journal":"Hepatology communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal cellular assays (activity, ROS, signaling, in vivo), single lab","pmids":["38437062"],"is_preprint":false},{"year":2022,"finding":"NDUFB3 overexpression in thyroid cancer cell lines (BCPAP, C643) increased oxygen consumption rate, ATP levels, Complex I activity, and mitochondrial ROS levels; NDUFB3 knockdown had the opposite effect. In vivo, NDUFB3 overexpression suppressed tumor growth in xenograft models concurrent with elevated mitoROS.","method":"Overexpression and knockdown in cancer cell lines; oxygen consumption rate assay; ATP measurement; Complex I activity assay; mitoROS measurement; xenograft mouse model","journal":"Oxidative medicine and cellular longevity","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple functional assays in vitro and in vivo, single lab","pmids":["35087620"],"is_preprint":false},{"year":2021,"finding":"Overexpression of NDUFB3 in decidual cells inhibited cell viability, decreased mitochondrial membrane potential, and increased oxidative stress, suggesting NDUFB3 regulates mitochondrial function in decidual cells.","method":"NDUFB3 overexpression in decidual cells; CCK-8 cell viability assay; Mito-Tracker Red CMXRos mitochondrial membrane potential assay; Western blotting","journal":"Clinical proteomics","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, overexpression-only approach with limited mechanistic pathway placement","pmids":["33618676"],"is_preprint":false}],"current_model":"NDUFB3 is a structural subunit of mitochondrial respiratory Complex I whose integrity is required for proper Complex I assembly and activity; it undergoes METTL9-catalyzed 1-methylhistidine modification at an HxH motif that enhances Complex I-dependent respiration, and loss-of-function mutations (including p.Trp22Arg) cause Complex I assembly defects and clinical mitochondrial disease."},"narrative":{"mechanistic_narrative":"NDUFB3 is a structural subunit of mitochondrial respiratory Complex I whose presence is required for proper assembly and catalytic activity of the complex [PMID:22277967, PMID:22499348]. Complementation of patient-derived mutant cells with wild-type NDUFB3 cDNA restores both Complex I activity and assembly, and a recurrent homozygous p.Trp22Arg variant produces a Complex I assembly defect detectable in patient skeletal muscle, establishing NDUFB3 loss-of-function as a cause of mitochondrial Complex I deficiency [PMID:22277967, PMID:22499348, PMID:27091925]. NDUFB3 is post-translationally modified by the methyltransferase METTL9, which catalyzes 1-methylhistidine modification at an HxH motif; this methylation enhances Complex I-dependent respiration [PMID:33563959]. Modulating NDUFB3 levels in cancer cell lines tunes Complex I activity, oxygen consumption, and mitochondrial ROS output, with overexpression elevating mitochondrial ROS and engaging downstream JNK signaling, cell-cycle arrest, and apoptosis [PMID:38437062, PMID:35087620].","teleology":[{"year":2009,"claim":"An early question was whether NDUFB3 might be a methylation target during Complex I assembly; analysis of the assembly factor C20orf7 raised this possibility while directly confirming only that its loss impairs Complex I maturation.","evidence":"Blue Native gel electrophoresis of patient cells and domain analysis of C20orf7","pmids":["19542079"],"confidence":"Low","gaps":["Methylation of NDUFB3 by C20orf7 was inferred from a SAM-dependent domain, not directly demonstrated","No mapping of any modified residue on NDUFB3","Causal role of NDUFB3 itself not addressed"]},{"year":2012,"claim":"Establishing NDUFB3 as a genuine structural subunit required showing that restoring it rescues the complex; wild-type cDNA complementation of patient mutant cells recovered Complex I activity and assembly, defining NDUFB3 as essential for Complex I biogenesis and a cause of mitochondrial disease.","evidence":"Functional complementation by wild-type cDNA transfection, Complex I activity assay, and Blue Native PAGE in patient cell lines (two independent studies)","pmids":["22277967","22499348"],"confidence":"High","gaps":["Structural position of NDUFB3 within the assembled complex not resolved here","Mechanism by which specific mutations destabilize assembly not defined"]},{"year":2016,"claim":"To consolidate the disease link, a recurrent variant was examined in patient tissue; the homozygous p.Trp22Arg substitution was shown to impair Complex I assembly in skeletal muscle, identifying a specific recurrent pathogenic allele.","evidence":"Blue Native PAGE on patient skeletal muscle plus targeted/whole-exome sequencing","pmids":["27091925"],"confidence":"Medium","gaps":["Single-lab assembly analysis","Molecular basis of how Trp22Arg disrupts subunit incorporation not determined"]},{"year":2021,"claim":"The long-standing question of whether NDUFB3 is methylated was answered by identifying its modifying enzyme: METTL9 installs a 1-methylhistidine mark at an HxH motif, and this modification enhances Complex I-dependent respiration, linking a post-translational mark to respiratory output.","evidence":"In vitro methyltransferase assay, MS site identification, METTL9 knockout mouse proteomics, and respiration assay","pmids":["33563959"],"confidence":"High","gaps":["Effect of losing the methyl mark on Complex I assembly versus activity not separated","Structural consequence of histidine methylation on the subunit unresolved"]},{"year":2022,"claim":"Whether NDUFB3 abundance actively tunes respiratory and redox output, beyond being permissive for assembly, was tested in thyroid cancer cells; gain and loss of NDUFB3 bidirectionally controlled oxygen consumption, ATP, Complex I activity, and mitochondrial ROS, with overexpression suppressing tumor growth in vivo.","evidence":"Overexpression/knockdown in cancer cell lines, OCR/ATP/Complex I/mitoROS assays, and xenograft model","pmids":["35087620"],"confidence":"Medium","gaps":["Single-lab study","Whether effects are cancer-type specific not established"]},{"year":2024,"claim":"A downstream signaling consequence of NDUFB3-driven ROS was placed mechanistically; in hepatocellular carcinoma cells, NDUFB3 overexpression raised Complex I activity and mitochondrial ROS, activated JNK signaling, and triggered G0/G1 arrest and apoptosis.","evidence":"shRNA knockdown/overexpression in HCC lines, Complex I activity and mitoROS assays, JNK western blot, flow cytometry, and xenograft model","pmids":["38437062"],"confidence":"Medium","gaps":["Single-lab study","Direct link between NDUFB3-derived ROS and JNK activation not biochemically dissected"]},{"year":null,"claim":"How NDUFB3 is physically positioned within Complex I, and whether its METTL9-dependent methylation alters assembly versus catalysis, remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of NDUFB3 within the assembled complex in the corpus","Functional separation of methylation effects on assembly vs activity not established","Mechanism connecting the subunit to redox-dependent JNK signaling not fully defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[1,2]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,1,4]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[1,0]}],"complexes":["Mitochondrial respiratory Complex I"],"partners":["METTL9"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O43676","full_name":"NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 3","aliases":["Complex I-B12","CI-B12","NADH-ubiquinone oxidoreductase B12 subunit"],"length_aa":98,"mass_kda":11.4,"function":"Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis. 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/O43676/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/NDUFB3","classification":"Common Essential","n_dependent_lines":757,"n_total_lines":1208,"dependency_fraction":0.6266556291390728},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"HEATR3","stoichiometry":0.2},{"gene":"MYH9","stoichiometry":0.2},{"gene":"PHGDH","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/NDUFB3","total_profiled":1310},"omim":[{"mim_id":"618246","title":"MITOCHONDRIAL COMPLEX I DEFICIENCY, NUCLEAR TYPE 25; MC1DN25","url":"https://www.omim.org/entry/618246"},{"mim_id":"603839","title":"NADH-UBIQUINONE OXIDOREDUCTASE SUBUNIT B3; NDUFB3","url":"https://www.omim.org/entry/603839"},{"mim_id":"252010","title":"MITOCHONDRIAL COMPLEX I DEFICIENCY, NUCLEAR TYPE 1; MC1DN1","url":"https://www.omim.org/entry/252010"},{"mim_id":"191050","title":"TRYPTOPHANYL-tRNA SYNTHETASE 1; WARS1","url":"https://www.omim.org/entry/191050"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":659.2},{"tissue":"tongue","ntpm":676.6}],"url":"https://www.proteinatlas.org/search/NDUFB3"},"hgnc":{"alias_symbol":["B12"],"prev_symbol":[]},"alphafold":{"accession":"O43676","domains":[{"cath_id":"-","chopping":"19-59","consensus_level":"medium","plddt":93.8956,"start":19,"end":59},{"cath_id":"1.20.5","chopping":"61-98","consensus_level":"medium","plddt":90.0292,"start":61,"end":98}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O43676","model_url":"https://alphafold.ebi.ac.uk/files/AF-O43676-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O43676-F1-predicted_aligned_error_v6.png","plddt_mean":86.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NDUFB3","jax_strain_url":"https://www.jax.org/strain/search?query=NDUFB3"},"sequence":{"accession":"O43676","fasta_url":"https://rest.uniprot.org/uniprotkb/O43676.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O43676/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O43676"}},"corpus_meta":[{"pmid":"15983191","id":"PMC_15983191","title":"A high-fat diet coordinately downregulates genes required for mitochondrial oxidative phosphorylation in skeletal muscle.","date":"2005","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/15983191","citation_count":500,"is_preprint":false},{"pmid":"22277967","id":"PMC_22277967","title":"Molecular diagnosis of infantile mitochondrial disease with targeted next-generation sequencing.","date":"2012","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/22277967","citation_count":373,"is_preprint":false},{"pmid":"22499348","id":"PMC_22499348","title":"Molecular diagnosis in mitochondrial complex I deficiency using exome sequencing.","date":"2012","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/22499348","citation_count":147,"is_preprint":false},{"pmid":"33563959","id":"PMC_33563959","title":"The methyltransferase METTL9 mediates pervasive 1-methylhistidine modification in mammalian proteomes.","date":"2021","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/33563959","citation_count":90,"is_preprint":false},{"pmid":"34654366","id":"PMC_34654366","title":"Genome-wide selection signatures detection in Shanghai Holstein cattle population identified genes related to adaption, health and reproduction traits.","date":"2021","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/34654366","citation_count":57,"is_preprint":false},{"pmid":"19542079","id":"PMC_19542079","title":"Defective complex I assembly due to C20orf7 mutations as a new cause of Leigh syndrome.","date":"2009","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19542079","citation_count":57,"is_preprint":false},{"pmid":"28474567","id":"PMC_28474567","title":"Reduced Mitochondrial Activity is Early and Steady in the Entorhinal Cortex but it is Mainly Unmodified in the Frontal Cortex in Alzheimer's Disease.","date":"2017","source":"Current Alzheimer research","url":"https://pubmed.ncbi.nlm.nih.gov/28474567","citation_count":47,"is_preprint":false},{"pmid":"31723016","id":"PMC_31723016","title":"Mitochondrial Oxidative Phosphorylation Complex Regulates NLRP3 Inflammasome Activation and Predicts Patient Survival in Nasopharyngeal Carcinoma.","date":"2019","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/31723016","citation_count":44,"is_preprint":false},{"pmid":"27091925","id":"PMC_27091925","title":"A recurrent mitochondrial p.Trp22Arg NDUFB3 variant causes a distinctive facial appearance, short stature and a mild biochemical and clinical phenotype.","date":"2016","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27091925","citation_count":35,"is_preprint":false},{"pmid":"33618676","id":"PMC_33618676","title":"Proteomic analysis of decidua in patients with recurrent pregnancy loss (RPL) reveals mitochondrial oxidative stress dysfunction.","date":"2021","source":"Clinical proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/33618676","citation_count":26,"is_preprint":false},{"pmid":"39421742","id":"PMC_39421742","title":"The role of lactylation in plasma cells and its impact on rheumatoid arthritis pathogenesis: insights from single-cell RNA sequencing and machine learning.","date":"2024","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/39421742","citation_count":17,"is_preprint":false},{"pmid":"37334608","id":"PMC_37334608","title":"Mitochondria-Related Candidate Genes and Diagnostic Model to Predict Late-Onset Alzheimer's Disease and Mild Cognitive Impairment.","date":"2024","source":"Journal of Alzheimer's disease : JAD","url":"https://pubmed.ncbi.nlm.nih.gov/37334608","citation_count":16,"is_preprint":false},{"pmid":"38437062","id":"PMC_38437062","title":"Hepatocellular carcinoma cells downregulate NADH:Ubiquinone Oxidoreductase Subunit B3 to maintain reactive oxygen species homeostasis.","date":"2024","source":"Hepatology communications","url":"https://pubmed.ncbi.nlm.nih.gov/38437062","citation_count":10,"is_preprint":false},{"pmid":"35034100","id":"PMC_35034100","title":"Expression of actin- and oxidative phosphorylation-related transcripts across the cortical visuospatial working memory network in unaffected comparison and schizophrenia subjects.","date":"2022","source":"Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/35034100","citation_count":10,"is_preprint":false},{"pmid":"39758940","id":"PMC_39758940","title":"New Posttranslational Modification Lactylation Brings New Inspiration for the Treatment of Rheumatoid Arthritis.","date":"2024","source":"Journal of inflammation research","url":"https://pubmed.ncbi.nlm.nih.gov/39758940","citation_count":9,"is_preprint":false},{"pmid":"34664815","id":"PMC_34664815","title":"Evaluation of the Ankylosing Spondylitis Transcriptome for Oxidative Phosphorylation Pathway: The Shared Pathway with Neurodegenerative Diseases.","date":"2021","source":"Iranian journal of allergy, asthma, and immunology","url":"https://pubmed.ncbi.nlm.nih.gov/34664815","citation_count":9,"is_preprint":false},{"pmid":"40069611","id":"PMC_40069611","title":"Identification of key LncRNAs and mRNAs associated with intramuscular fat in pig via WGCNA.","date":"2025","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/40069611","citation_count":8,"is_preprint":false},{"pmid":"35087620","id":"PMC_35087620","title":"Clinical Relevance and Tumor Growth Suppression of Mitochondrial ROS Regulators along NADH:Ubiquinone Oxidoreductase Subunit B3 in Thyroid Cancer.","date":"2022","source":"Oxidative medicine and cellular longevity","url":"https://pubmed.ncbi.nlm.nih.gov/35087620","citation_count":7,"is_preprint":false},{"pmid":"36357826","id":"PMC_36357826","title":"Multiomics analyses reveals Anaplasma phagocytophilum Ats-1 induces anti-apoptosis and energy metabolism by upregulating the respiratory chain-mPTP axis in eukaryotic mitochondria.","date":"2022","source":"BMC microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/36357826","citation_count":7,"is_preprint":false},{"pmid":"35699875","id":"PMC_35699875","title":"Investigation of Mitochondrial Related Variants in a Cerebral Small Vessel Disease Cohort.","date":"2022","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/35699875","citation_count":6,"is_preprint":false},{"pmid":"35490921","id":"PMC_35490921","title":"Curcumin prevents proteins expression changes of oxidative phosphorylation, cellular stress response, and lipid metabolism proteins in liver of mice fed a high-fructose diet.","date":"2022","source":"Journal of proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/35490921","citation_count":6,"is_preprint":false},{"pmid":"39570029","id":"PMC_39570029","title":"Phosphatidylethanolamine exerts anti-inflammatory action by regulating mitochondrial function in macrophages of large yellow croaker (Larimichthys crocea).","date":"2024","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/39570029","citation_count":6,"is_preprint":false},{"pmid":"36450500","id":"PMC_36450500","title":"2,3',4,4',5-Pentachlorobiphenyl induced thyroid dysfunction by increasing mitochondrial oxidative stress.","date":"2022","source":"The Journal of toxicological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36450500","citation_count":5,"is_preprint":false},{"pmid":"39892609","id":"PMC_39892609","title":"Lactational high weight loss impairs follicular development by causing mitochondrial dysfunction of ovarian cells in sows and mitigated by butyrate supplement.","date":"2025","source":"Journal of advanced research","url":"https://pubmed.ncbi.nlm.nih.gov/39892609","citation_count":5,"is_preprint":false},{"pmid":"35257523","id":"PMC_35257523","title":"Surgically Metabolic Resection of Pericardial Fat to Ameliorate Myocardial Mitochondrial Dysfunction in Acute Myocardial Infarction Obese Rats.","date":"2022","source":"Journal of Korean medical science","url":"https://pubmed.ncbi.nlm.nih.gov/35257523","citation_count":5,"is_preprint":false},{"pmid":"39469770","id":"PMC_39469770","title":"Comprehensive Analysis of NADH:Ubiquinone Oxidoreductase Subunit B3 in Gynecological Tumors and Identification of Its Natural Inhibitor Wedelolactone.","date":"2024","source":"Chemical biology & drug design","url":"https://pubmed.ncbi.nlm.nih.gov/39469770","citation_count":3,"is_preprint":false},{"pmid":"39655053","id":"PMC_39655053","title":"Role of COX6C and NDUFB3 in septic shock and stroke.","date":"2024","source":"Open medicine (Warsaw, Poland)","url":"https://pubmed.ncbi.nlm.nih.gov/39655053","citation_count":2,"is_preprint":false},{"pmid":"41438107","id":"PMC_41438107","title":"Identification of hub genes in peripheral blood and construction of a diagnostic nomogram model in ulcerative colitis.","date":"2025","source":"PeerJ","url":"https://pubmed.ncbi.nlm.nih.gov/41438107","citation_count":1,"is_preprint":false},{"pmid":"40009295","id":"PMC_40009295","title":"Clinical manifestations and pathogenesis of mitochondrial dysfunction in short stature.","date":"2025","source":"World journal of pediatrics : WJP","url":"https://pubmed.ncbi.nlm.nih.gov/40009295","citation_count":0,"is_preprint":false},{"pmid":"40141284","id":"PMC_40141284","title":"Single-Cell Analysis of Molecular Mechanisms in Rapid Antler Osteogenesis During Growth and Ossification Stages.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/40141284","citation_count":0,"is_preprint":false},{"pmid":"42179742","id":"PMC_42179742","title":"Shared gene signatures between rheumatoid arthritis and Sjögren's syndrome.","date":"2026","source":"American journal of clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/42179742","citation_count":0,"is_preprint":false},{"pmid":"40551644","id":"PMC_40551644","title":"[Effect of acupuncture on intracerebral mitochondrial function in mice with cerebral hemorrhage].","date":"2025","source":"Zhen ci yan jiu = Acupuncture research","url":"https://pubmed.ncbi.nlm.nih.gov/40551644","citation_count":0,"is_preprint":false},{"pmid":"41610872","id":"PMC_41610872","title":"Single-Cell RNA Sequencing and Network Pharmacology Reveal the Potential Role of Oxidative Phosphorylation Inactivation in Diagnosing and Treating Chronic Tendon Injuries.","date":"2026","source":"The journal of gene medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41610872","citation_count":0,"is_preprint":false},{"pmid":"41517693","id":"PMC_41517693","title":"Identification of mitochondria metabolism-related biomarkers associated with the development of rheumatoid arthritis using bioinformatics: An observational study.","date":"2026","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41517693","citation_count":0,"is_preprint":false},{"pmid":"40962454","id":"PMC_40962454","title":"Identification and Validation of Mitochondria-Related Genes for Diagnosis of Early-Stage Sepsis.","date":"2025","source":"Annals of clinical and laboratory science","url":"https://pubmed.ncbi.nlm.nih.gov/40962454","citation_count":0,"is_preprint":false},{"pmid":"41810912","id":"PMC_41810912","title":"Identification and Verification of Mitochondria-Related Diagnostic Markers of Spinal Cord Injury by WGCNA and Machine Learning.","date":"2026","source":"Behavioural neurology","url":"https://pubmed.ncbi.nlm.nih.gov/41810912","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":22770,"output_tokens":1702,"usd":0.04692,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8611,"output_tokens":2360,"usd":0.051028,"stage2_stop_reason":"end_turn"},"total_usd":0.097948,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"METTL9 is a methyltransferase that catalyzes 1-methylhistidine (1MH) modification of NDUFB3 at an HxH (His-x-His) motif, where 'x' is preferably a small amino acid. This METTL9-mediated methylation of NDUFB3 enhances respiration via mitochondrial Complex I.\",\n      \"method\": \"In vitro methyltransferase assay, mass spectrometry identification of 1MH sites, METTL9 knockout mouse proteomics, functional respiration assay\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods including in vitro enzymatic assay, MS-based site identification, KO mouse proteomics, and functional respiration readout in a single rigorous study\",\n      \"pmids\": [\"33563959\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Mutations in NDUFB3 cause mitochondrial Complex I deficiency; expression of wild-type NDUFB3 cDNA in patient-derived mutant cell lines rescued Complex I activity and assembly, establishing NDUFB3 as a structural subunit required for Complex I assembly.\",\n      \"method\": \"Complementation/rescue experiment — wild-type cDNA transfection into patient mutant cell lines, Complex I activity assay, Blue Native PAGE for complex assembly\",\n      \"journal\": \"Science translational medicine / Journal of medical genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — functional complementation with activity and assembly rescue, independently reported in two separate studies (PMID:22277967 and PMID:22499348)\",\n      \"pmids\": [\"22277967\", \"22499348\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"A recurrent homozygous p.Trp22Arg NDUFB3 variant causes a defect in Complex I assembly, as confirmed by analysis of skeletal muscle from affected patients showing reduced Complex I assembly by Blue Native gel electrophoresis.\",\n      \"method\": \"Blue Native PAGE on patient skeletal muscle samples; whole-exome/targeted gene sequencing for variant identification\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct assembly analysis in patient tissue, single lab, two orthogonal methods (genetic + functional BN-PAGE)\",\n      \"pmids\": [\"27091925\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"C20orf7 (a Complex I assembly factor) harbors an S-adenosylmethionine (SAM)-dependent methyltransferase domain possibly involved in methylation of NDUFB3 during Complex I assembly; patients with C20orf7 mutations showed only 30–40% of mature Complex I by Blue Native gel electrophoresis.\",\n      \"method\": \"Blue Native gel electrophoresis of patient cells; domain analysis of C20orf7; sequencing of patient samples\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — methylation of NDUFB3 by C20orf7 is proposed based on domain analysis, not directly demonstrated; only the assembly defect is experimentally confirmed\",\n      \"pmids\": [\"19542079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NDUFB3 knockdown in hepatocellular carcinoma (HCC) cell lines significantly decreased Complex I activity and reduced mitochondrial ROS production, while NDUFB3 overexpression increased Complex I activity, elevated mitochondrial ROS, activated the JNK signaling pathway, and caused G0/G1 cell cycle arrest and apoptosis.\",\n      \"method\": \"shRNA knockdown and overexpression in HCC cell lines; Complex I activity assay; mitochondrial ROS measurement; JNK pathway western blot; flow cytometry (cell cycle, apoptosis); xenograft mouse model\",\n      \"journal\": \"Hepatology communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal cellular assays (activity, ROS, signaling, in vivo), single lab\",\n      \"pmids\": [\"38437062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"NDUFB3 overexpression in thyroid cancer cell lines (BCPAP, C643) increased oxygen consumption rate, ATP levels, Complex I activity, and mitochondrial ROS levels; NDUFB3 knockdown had the opposite effect. In vivo, NDUFB3 overexpression suppressed tumor growth in xenograft models concurrent with elevated mitoROS.\",\n      \"method\": \"Overexpression and knockdown in cancer cell lines; oxygen consumption rate assay; ATP measurement; Complex I activity assay; mitoROS measurement; xenograft mouse model\",\n      \"journal\": \"Oxidative medicine and cellular longevity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple functional assays in vitro and in vivo, single lab\",\n      \"pmids\": [\"35087620\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Overexpression of NDUFB3 in decidual cells inhibited cell viability, decreased mitochondrial membrane potential, and increased oxidative stress, suggesting NDUFB3 regulates mitochondrial function in decidual cells.\",\n      \"method\": \"NDUFB3 overexpression in decidual cells; CCK-8 cell viability assay; Mito-Tracker Red CMXRos mitochondrial membrane potential assay; Western blotting\",\n      \"journal\": \"Clinical proteomics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, overexpression-only approach with limited mechanistic pathway placement\",\n      \"pmids\": [\"33618676\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NDUFB3 is a structural subunit of mitochondrial respiratory Complex I whose integrity is required for proper Complex I assembly and activity; it undergoes METTL9-catalyzed 1-methylhistidine modification at an HxH motif that enhances Complex I-dependent respiration, and loss-of-function mutations (including p.Trp22Arg) cause Complex I assembly defects and clinical mitochondrial disease.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NDUFB3 is a structural subunit of mitochondrial respiratory Complex I whose presence is required for proper assembly and catalytic activity of the complex [#1]. Complementation of patient-derived mutant cells with wild-type NDUFB3 cDNA restores both Complex I activity and assembly, and a recurrent homozygous p.Trp22Arg variant produces a Complex I assembly defect detectable in patient skeletal muscle, establishing NDUFB3 loss-of-function as a cause of mitochondrial Complex I deficiency [#1, #2]. NDUFB3 is post-translationally modified by the methyltransferase METTL9, which catalyzes 1-methylhistidine modification at an HxH motif; this methylation enhances Complex I-dependent respiration [#0]. Modulating NDUFB3 levels in cancer cell lines tunes Complex I activity, oxygen consumption, and mitochondrial ROS output, with overexpression elevating mitochondrial ROS and engaging downstream JNK signaling, cell-cycle arrest, and apoptosis [#4, #5].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"An early question was whether NDUFB3 might be a methylation target during Complex I assembly; analysis of the assembly factor C20orf7 raised this possibility while directly confirming only that its loss impairs Complex I maturation.\",\n      \"evidence\": \"Blue Native gel electrophoresis of patient cells and domain analysis of C20orf7\",\n      \"pmids\": [\"19542079\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Methylation of NDUFB3 by C20orf7 was inferred from a SAM-dependent domain, not directly demonstrated\", \"No mapping of any modified residue on NDUFB3\", \"Causal role of NDUFB3 itself not addressed\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Establishing NDUFB3 as a genuine structural subunit required showing that restoring it rescues the complex; wild-type cDNA complementation of patient mutant cells recovered Complex I activity and assembly, defining NDUFB3 as essential for Complex I biogenesis and a cause of mitochondrial disease.\",\n      \"evidence\": \"Functional complementation by wild-type cDNA transfection, Complex I activity assay, and Blue Native PAGE in patient cell lines (two independent studies)\",\n      \"pmids\": [\"22277967\", \"22499348\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural position of NDUFB3 within the assembled complex not resolved here\", \"Mechanism by which specific mutations destabilize assembly not defined\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"To consolidate the disease link, a recurrent variant was examined in patient tissue; the homozygous p.Trp22Arg substitution was shown to impair Complex I assembly in skeletal muscle, identifying a specific recurrent pathogenic allele.\",\n      \"evidence\": \"Blue Native PAGE on patient skeletal muscle plus targeted/whole-exome sequencing\",\n      \"pmids\": [\"27091925\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab assembly analysis\", \"Molecular basis of how Trp22Arg disrupts subunit incorporation not determined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"The long-standing question of whether NDUFB3 is methylated was answered by identifying its modifying enzyme: METTL9 installs a 1-methylhistidine mark at an HxH motif, and this modification enhances Complex I-dependent respiration, linking a post-translational mark to respiratory output.\",\n      \"evidence\": \"In vitro methyltransferase assay, MS site identification, METTL9 knockout mouse proteomics, and respiration assay\",\n      \"pmids\": [\"33563959\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Effect of losing the methyl mark on Complex I assembly versus activity not separated\", \"Structural consequence of histidine methylation on the subunit unresolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Whether NDUFB3 abundance actively tunes respiratory and redox output, beyond being permissive for assembly, was tested in thyroid cancer cells; gain and loss of NDUFB3 bidirectionally controlled oxygen consumption, ATP, Complex I activity, and mitochondrial ROS, with overexpression suppressing tumor growth in vivo.\",\n      \"evidence\": \"Overexpression/knockdown in cancer cell lines, OCR/ATP/Complex I/mitoROS assays, and xenograft model\",\n      \"pmids\": [\"35087620\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab study\", \"Whether effects are cancer-type specific not established\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A downstream signaling consequence of NDUFB3-driven ROS was placed mechanistically; in hepatocellular carcinoma cells, NDUFB3 overexpression raised Complex I activity and mitochondrial ROS, activated JNK signaling, and triggered G0/G1 arrest and apoptosis.\",\n      \"evidence\": \"shRNA knockdown/overexpression in HCC lines, Complex I activity and mitoROS assays, JNK western blot, flow cytometry, and xenograft model\",\n      \"pmids\": [\"38437062\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab study\", \"Direct link between NDUFB3-derived ROS and JNK activation not biochemically dissected\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NDUFB3 is physically positioned within Complex I, and whether its METTL9-dependent methylation alters assembly versus catalysis, remains unresolved.\",\n      \"evidence\": null,\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of NDUFB3 within the assembled complex in the corpus\", \"Functional separation of methylation effects on assembly vs activity not established\", \"Mechanism connecting the subunit to redox-dependent JNK signaling not fully defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 1, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [1, 0]}\n    ],\n    \"complexes\": [\"Mitochondrial respiratory Complex I\"],\n    \"partners\": [\"METTL9\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}