{"gene":"OPA3","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2001,"finding":"OPA3 (corresponding to cDNA clone FLJ22187) was identified as the causative gene for type III 3-methylglutaconic aciduria; an intronic G→C mutation abolished mRNA expression in fibroblasts from affected patients, establishing loss-of-function as the disease mechanism.","method":"Sanger sequencing of candidate genes, Northern blot analysis, mRNA expression analysis in patient fibroblasts","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct sequencing and mRNA abolition in patient cells, single lab but multiple methods","pmids":["11668429"],"is_preprint":false},{"year":2010,"finding":"OPA3 protein localizes predominantly to mitochondria (not peroxisomes), as demonstrated by GFP-tagged OPA3 expression studies; OPA3A deficiency causes up-regulation of OPA3B, and two transcripts (OPA3A and OPA3B) are produced from a novel third coding exon.","method":"GFP-tagged protein expression and fluorescence microscopy, RT-PCR, Northern blot","journal":"Molecular genetics and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by tagged protein imaging, single lab, two orthogonal methods","pmids":["20350831"],"is_preprint":false},{"year":2010,"finding":"Mitochondrial localization signals of OPA3 are required for its function: delivery of exogenous Opa3 reduced elevated 3-methylglutaconic acid (MGC) levels in opa3 null zebrafish mutants only when mitochondrial targeting sequences were intact. Elevated MGC in opa3 mutants was shown to derive from extra-mitochondrial HMG-CoA via a non-canonical pathway.","method":"Zebrafish opa3 null mutant rescue experiments with wild-type and mutant (mitochondrial signal-deleted) Opa3 constructs; metabolic profiling of MGC precursor availability","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 1 / Strong — functional rescue with mitochondrial targeting mutant, in vivo genetic model, multiple orthogonal assays","pmids":["20627962"],"is_preprint":false},{"year":2010,"finding":"Loss of OPA3 function (zebrafish null mutant) results in normal mitochondrial oxidative phosphorylation profiles basally, but opa3 mutants are sensitized to electron transport chain inhibitors, indicating a protective role for OPA3 at the mitochondrial ETC.","method":"Zebrafish opa3 null genetic model; mitochondrial oxidative phosphorylation profiling; pharmacological ETC inhibitor treatment","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic null model with functional mitochondrial profiling and pharmacological challenge, replicated across multiple assays in one study","pmids":["20627962"],"is_preprint":false},{"year":2008,"finding":"A missense mutation in murine Opa3 (p.L122P) in homozygous mice causes increased mitochondrial activity in the optic nerve (elevated COX histochemistry), retinal ganglion cell loss, and multi-systemic disease, establishing Opa3 as essential for mitochondrial function in vivo.","method":"ENU-induced mouse model with p.L122P missense mutation; COX histochemistry; retinal ganglion cell quantification; histopathology","journal":"Brain : a journal of neurology","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo mouse genetic model with direct mitochondrial functional readout and multiple tissue assessments","pmids":["18222992"],"is_preprint":false},{"year":2011,"finding":"Mutant Opa3 (L122P) protein retains its mitochondrial localization (does not mislocalize to peroxisomes), yet induces disrupted mitochondrial morphology in the retina of Opa3(-/-) mice; neither wild-type nor mutant Opa3 localizes to peroxisomes.","method":"Immunohistochemistry, mitochondrion-selective probe staining, electron microscopy, RT-PCR, Western blot in Opa3(L122P) mouse model","journal":"Investigative ophthalmology & visual science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by multiple methods in genetic model, single lab","pmids":["21613372"],"is_preprint":false},{"year":2012,"finding":"Opa3 (L122P missense mutation) impairs mitochondrial activity in brown adipose tissue, causing a 90% reduction in UCP1 expression and reduced thermogenesis, and coupling lipid uptake with lipid processing in liver, identifying Opa3 as a novel regulator of thermogenesis and lipid metabolism.","method":"Opa3(L122P) mouse model metabolic phenotyping; UCP1 expression by Western blot/qPCR; surface body temperature measurement; histology; adipose tissue mass quantification","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo genetic model with multiple functional metabolic readouts, single lab","pmids":["22869679"],"is_preprint":false},{"year":2013,"finding":"A novel OPA3 mutation in the mitochondrial presequence (c.10_11insCGCCCG/p.V3_G4insAP) causes decreased steady-state protein levels and a fragmented mitochondrial network in patient fibroblasts, demonstrating that the mitochondrial targeting sequence is required for normal OPA3 stability and mitochondrial network maintenance.","method":"Mitochondrial import analysis, OPA3 protein quantification by Western blot, mitochondrial morphology imaging in patient fibroblasts","journal":"Journal of medical genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional characterization in patient cells with multiple orthogonal methods, single lab","pmids":["24136862"],"is_preprint":false},{"year":2013,"finding":"Knockdown of OPA3 by siRNA/shRNA in retinal pigment epithelial cells increased stress fibers, cell migration, cell elongation, and mitochondrial elongation; forced OPA3 overexpression inhibited F-actin rearrangement and induced mitochondrial fragmentation. TGF-β-induced OPA3 downregulation was mediated via Smad2 signaling.","method":"siRNA/inducible shRNA knockdown; OPA3 overexpression; live cell imaging of mitochondrial morphology; F-actin staining; migration assays; Smad2 siRNA epistasis","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss- and gain-of-function with multiple cellular readouts and epistasis, single lab","pmids":["23658835"],"is_preprint":false},{"year":2019,"finding":"OPA3 expression is consistently upregulated by oncogenic K-ras activation; genetic knockdown of OPA3 suppresses oxygen consumption rate and cellular ATP content, reduces cell proliferation, and decreases EMT marker expression in pancreatic cancer cells, demonstrating OPA3's role in supporting mitochondrial energy metabolism downstream of K-ras.","method":"K-ras inducible cell systems; OPA3 siRNA knockdown; Seahorse oxygen consumption rate measurement; ATP content assay; Western blot for EMT markers","journal":"Cancers","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockdown with multiple orthogonal functional readouts, single lab","pmids":["31881642"],"is_preprint":false},{"year":2023,"finding":"OPA3 physically interacts with NFS1 (iron-sulfur cluster assembly enzyme) and regulates ferroptosis via this interaction; doxorubicin promotes OPA3 ubiquitination and degradation, while exogenous H2S antagonizes OPA3 ubiquitination through promoting OPA3 S-sulfhydration, thereby restoring OPA3-NFS1 axis function and inhibiting ferroptosis in cardiomyocytes.","method":"Co-immunoprecipitation (OPA3-NFS1 interaction); OPA3 overexpression in vivo and in vitro; ubiquitination assay; S-sulfhydration assay; lipid peroxidation measurement; GPX4/NFS1 protein expression analysis","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for binding, functional overexpression rescue, and post-translational modification assays in one study; single lab","pmids":["36924813"],"is_preprint":false},{"year":2024,"finding":"OPA3 knockdown in colorectal cancer cells facilitates mitochondrial dysfunction and mtDNA stress, elevating cGAS and p-STING protein levels and STING target gene expression; OPA3 overexpression inhibits CCCP-induced mitochondrial stress and suppresses the cGAS-STING pathway. Overexpression of cGAS or STING partially reversed OPA3 overexpression-driven cancer cell proliferation/migration/invasion, placing OPA3 upstream of cGAS-STING in maintaining mitochondrial integrity.","method":"OPA3 overexpression and knockdown in HT29 cells; CCCP-induced mitochondrial dysfunction model; Western blot for cGAS, p-STING; RT-PCR for STING target genes; epistasis by cGAS/STING overexpression","journal":"In vitro cellular & developmental biology. Animal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain- and loss-of-function with genetic epistasis and pathway placement, single lab","pmids":["39725842"],"is_preprint":false},{"year":2010,"finding":"A nonsense mutation (c.343C>T) in the bovine OPA3 gene causes dilated cardiomyopathy in Red Holstein cattle with an autosomal recessive pattern, providing genetic and functional evidence that OPA3 loss of function leads to cardiac muscle pathology.","method":"Genetic mapping, PCR-based sequencing of OPA3 in affected and control cattle, segregation analysis","journal":"Genomics","confidence":"Low","confidence_rationale":"Tier 3 / Moderate — genetic evidence with segregation in animal model, no direct cellular mechanism established","pmids":["20923700"],"is_preprint":false},{"year":2005,"finding":"A heterozygous G277A missense mutation in OPA3 (encoding a mitochondrial protein) was identified as the cause of autosomal dominant optic atrophy with cataract and extrapyramidal neurological signs, establishing OPA3 as a nuclear-encoded mitochondrial protein whose dominant mutations cause disease.","method":"Sequencing of OPA3 in a multi-generation family followed over 40 years; segregation analysis","journal":"Revue neurologique","confidence":"Low","confidence_rationale":"Tier 3 / Weak — genetic sequencing and segregation only, no direct cellular mechanism","pmids":["15924081"],"is_preprint":false}],"current_model":"OPA3 is a nuclear-encoded protein that localizes to the inner mitochondrial membrane via its mitochondrial targeting sequence, where it is required to maintain mitochondrial network morphology, protect the electron transport chain from inhibitors, regulate mitochondrial energy metabolism (oxygen consumption and ATP production), couple lipid uptake with thermogenesis in brown adipose tissue, limit extra-mitochondrial HMG-CoA-derived 3-methylglutaconic acid accumulation, interact with the iron-sulfur cluster assembly factor NFS1 to suppress ferroptosis, and suppress mtDNA stress-driven cGAS-STING innate immune signaling; loss-of-function mutations cause the metabolic disorder 3-methylglutaconic aciduria type III (Costeff syndrome) while dominant missense mutations cause optic atrophy with cataracts, and OPA3 protein stability is regulated by ubiquitination and S-sulfhydration post-translational modifications."},"narrative":{"mechanistic_narrative":"OPA3 is a nuclear-encoded mitochondrial protein required to maintain mitochondrial network morphology and regulate mitochondrial energy metabolism [PMID:20627962, PMID:24136862]. It localizes predominantly to mitochondria rather than peroxisomes, and its N-terminal mitochondrial targeting sequence is essential both for protein stability and for function: presequence-disrupting mutations reduce steady-state OPA3 levels and fragment the mitochondrial network, and mitochondrial-signal-deleted constructs fail to rescue metabolic defects in opa3-null models [PMID:20350831, PMID:20627962, PMID:24136862]. Functionally, OPA3 protects the electron transport chain against pharmacological inhibition [PMID:20627962], supports oxygen consumption and ATP production downstream of oncogenic K-ras [PMID:31881642], and limits accumulation of extra-mitochondrial HMG-CoA-derived 3-methylglutaconic acid [PMID:20627962]. In vivo, OPA3 couples lipid uptake with thermogenesis, with mutant Opa3 markedly reducing UCP1 expression in brown adipose tissue [PMID:22869679]. OPA3 additionally interacts physically with the iron-sulfur cluster assembly enzyme NFS1 to suppress ferroptosis, an axis controlled by competing ubiquitination and S-sulfhydration of OPA3 [PMID:36924813], and it acts upstream of the cGAS-STING pathway to restrain mtDNA-stress-driven innate immune signaling [PMID:39725842]. Loss-of-function mutation causes type III 3-methylglutaconic aciduria (Costeff syndrome) [PMID:11668429], and dominant missense mutation causes optic atrophy with cataract [PMID:15924081].","teleology":[{"year":2001,"claim":"Establishing OPA3 as a disease gene defined loss of function as the founding mechanistic entry point, before any molecular role was known.","evidence":"candidate-gene Sanger sequencing and mRNA expression analysis in patient fibroblasts, where an intronic mutation abolished OPA3 mRNA","pmids":["11668429"],"confidence":"Medium","gaps":["No subcellular localization or biochemical activity assigned","Mechanism linking gene loss to 3-methylglutaconic acid accumulation unaddressed"]},{"year":2005,"claim":"Identification of a dominant missense mutation showed that OPA3 dysfunction can act through more than simple haploinsufficiency, broadening the disease spectrum to optic atrophy with cataract.","evidence":"sequencing and 40-year segregation analysis of a multi-generation family","pmids":["15924081"],"confidence":"Low","gaps":["Genetic association only, no cellular mechanism","Molecular consequence of the missense allele not tested"]},{"year":2008,"claim":"An ENU mouse missense model demonstrated in vivo that Opa3 is essential for mitochondrial function, linking the gene to optic-nerve mitochondrial activity and retinal ganglion cell loss.","evidence":"Opa3 p.L122P mouse with COX histochemistry, retinal ganglion cell quantification, and multi-systemic histopathology","pmids":["18222992"],"confidence":"High","gaps":["Molecular function of the protein not defined","Mechanism connecting altered mitochondrial activity to cell loss unresolved"]},{"year":2010,"claim":"Combined imaging, genetic, and rescue studies localized OPA3 to mitochondria (not peroxisomes), showed its mitochondrial targeting sequence is required for function, and revealed a protective role at the electron transport chain.","evidence":"GFP-tagged localization imaging, zebrafish opa3-null rescue with targeting-sequence mutants, and OXPHOS profiling with ETC inhibitor challenge","pmids":["20350831","20627962"],"confidence":"High","gaps":["Direct biochemical activity of OPA3 within the membrane not identified","How OPA3 confers ETC inhibitor protection mechanistically unknown"]},{"year":2010,"claim":"A bovine nonsense mutation extended the loss-of-function phenotype to cardiac muscle pathology, supporting a broad tissue requirement for OPA3.","evidence":"genetic mapping and segregation analysis of dilated cardiomyopathy in Red Holstein cattle","pmids":["20923700"],"confidence":"Low","gaps":["Genetic evidence only, no cellular mechanism","Cardiac-specific OPA3 function untested"]},{"year":2011,"claim":"Showing that mutant Opa3 retains mitochondrial localization while still disrupting mitochondrial morphology dissociated the disease mechanism from mislocalization, pointing to a functional defect within mitochondria.","evidence":"immunohistochemistry, mito-probe staining, and electron microscopy in Opa3(L122P) mice","pmids":["21613372"],"confidence":"Medium","gaps":["Molecular basis of morphology disruption not defined","No interacting machinery identified"]},{"year":2012,"claim":"Metabolic phenotyping connected OPA3 to whole-organism energy handling, identifying it as a regulator of brown adipose thermogenesis and hepatic lipid processing.","evidence":"Opa3(L122P) mouse metabolic phenotyping with UCP1 expression, body temperature, and adipose/liver histology","pmids":["22869679"],"confidence":"Medium","gaps":["Mechanism coupling OPA3 to UCP1 regulation unknown","Direct molecular targets in lipid metabolism unidentified"]},{"year":2013,"claim":"A patient presequence-insertion mutation established that the mitochondrial targeting sequence governs OPA3 stability and network integrity, linking import to function in human cells.","evidence":"mitochondrial import analysis, protein quantification, and morphology imaging in patient fibroblasts","pmids":["24136862"],"confidence":"Medium","gaps":["Degradation pathway for unstable OPA3 not characterized here","Effector of network maintenance unknown"]},{"year":2013,"claim":"Loss- and gain-of-function in epithelial cells tied OPA3 levels to cytoskeletal/migration phenotypes and placed OPA3 downstream of TGF-β/Smad2 signaling.","evidence":"siRNA/shRNA knockdown and overexpression with mitochondrial imaging, F-actin staining, migration assays, and Smad2 epistasis in RPE cells","pmids":["23658835"],"confidence":"Medium","gaps":["Mechanism linking mitochondrial OPA3 to actin dynamics unresolved","Direct transcriptional control of OPA3 by Smad2 not shown structurally"]},{"year":2019,"claim":"Placing OPA3 downstream of oncogenic K-ras showed it actively supports mitochondrial bioenergetics and proliferation in cancer cells.","evidence":"K-ras inducible systems with OPA3 knockdown, Seahorse oxygen consumption, ATP assays, and EMT marker analysis in pancreatic cancer cells","pmids":["31881642"],"confidence":"Medium","gaps":["How K-ras upregulates OPA3 unknown","Direct biochemical contribution to respiration undefined"]},{"year":2023,"claim":"Identification of the OPA3-NFS1 interaction and its redox/ubiquitination control gave OPA3 a defined molecular partnership and a role in suppressing ferroptosis.","evidence":"Co-immunoprecipitation, overexpression rescue, ubiquitination and S-sulfhydration assays, and lipid peroxidation measurement in cardiomyocytes","pmids":["36924813"],"confidence":"Medium","gaps":["Single Co-IP without reciprocal/structural validation of the OPA3-NFS1 interface","Whether OPA3 directly affects NFS1 iron-sulfur cluster assembly activity untested"]},{"year":2024,"claim":"Epistasis experiments positioned OPA3 upstream of cGAS-STING, linking its maintenance of mitochondrial integrity to suppression of mtDNA-stress innate immune signaling and tumor cell behavior.","evidence":"OPA3 overexpression/knockdown with CCCP mitochondrial stress, cGAS/p-STING Western blots, STING target RT-PCR, and cGAS/STING overexpression epistasis in HT29 cells","pmids":["39725842"],"confidence":"Medium","gaps":["Mechanism by which OPA3 limits mtDNA release not defined","Single cell-line context for pathway placement"]},{"year":null,"claim":"The core biochemical activity of OPA3 within the inner mitochondrial membrane remains undefined, leaving open how a single protein integrates network morphology, ETC protection, lipid/thermogenic metabolism, ferroptosis suppression, and innate immune restraint.","evidence":"no enzymatic or structural mechanism reported across the timeline","pmids":[],"confidence":"Low","gaps":["No catalytic or structural activity assigned","Unifying molecular mechanism behind diverse phenotypes unknown","No high-resolution structure or interactome beyond NFS1"]}],"mechanism_profile":{"molecular_activity":[],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[1,2,5,7]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[2,6,9]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[10]}],"complexes":[],"partners":["NFS1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H6K4","full_name":"Optic atrophy 3 protein","aliases":[],"length_aa":179,"mass_kda":20.0,"function":"May play some role in mitochondrial processes","subcellular_location":"Mitochondrion","url":"https://www.uniprot.org/uniprotkb/Q9H6K4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/OPA3","classification":"Not Classified","n_dependent_lines":15,"n_total_lines":1208,"dependency_fraction":0.012417218543046357},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/OPA3","total_profiled":1310},"omim":[{"mim_id":"614296","title":"WOLFRAM-LIKE SYNDROME, AUTOSOMAL DOMINANT; WFSL","url":"https://www.omim.org/entry/614296"},{"mim_id":"606580","title":"OUTER MITOCHONDRIAL MEMBRANE LIPID METABOLISM REGULATOR OPA3; OPA3","url":"https://www.omim.org/entry/606580"},{"mim_id":"535000","title":"LEBER OPTIC ATROPHY","url":"https://www.omim.org/entry/535000"},{"mim_id":"258501","title":"3-@METHYLGLUTACONIC ACIDURIA, TYPE III; MGCA3","url":"https://www.omim.org/entry/258501"},{"mim_id":"250950","title":"3-@METHYLGLUTACONIC ACIDURIA, TYPE I; MGCA1","url":"https://www.omim.org/entry/250950"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/OPA3"},"hgnc":{"alias_symbol":["FLJ22187","MGA3"],"prev_symbol":[]},"alphafold":{"accession":"Q9H6K4","domains":[{"cath_id":"-","chopping":"10-92_108-142","consensus_level":"medium","plddt":86.6506,"start":10,"end":142}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H6K4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H6K4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H6K4-F1-predicted_aligned_error_v6.png","plddt_mean":82.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=OPA3","jax_strain_url":"https://www.jax.org/strain/search?query=OPA3"},"sequence":{"accession":"Q9H6K4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H6K4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H6K4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H6K4"}},"corpus_meta":[{"pmid":"11668429","id":"PMC_11668429","title":"Type III 3-methylglutaconic aciduria (optic atrophy plus syndrome, or Costeff optic atrophy syndrome): identification of the OPA3 gene and its founder mutation in Iraqi Jews.","date":"2001","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11668429","citation_count":134,"is_preprint":false},{"pmid":"24452867","id":"PMC_24452867","title":"Proteomic analysis of the thermophilic methylotroph Bacillus methanolicus MGA3.","date":"2014","source":"Proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/24452867","citation_count":49,"is_preprint":false},{"pmid":"21036400","id":"PMC_21036400","title":"Genetic screening for OPA1 and OPA3 mutations in patients with suspected inherited optic neuropathies.","date":"2010","source":"Ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/21036400","citation_count":43,"is_preprint":false},{"pmid":"26303953","id":"PMC_26303953","title":"Core pathways operating during methylotrophy of Bacillus methanolicus MGA3 and induction of a bacillithiol-dependent detoxification pathway upon formaldehyde stress.","date":"2015","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/26303953","citation_count":42,"is_preprint":false},{"pmid":"25758049","id":"PMC_25758049","title":"Transcriptome analysis of thermophilic methylotrophic Bacillus methanolicus MGA3 using RNA-sequencing provides detailed insights into its previously uncharted transcriptional landscape.","date":"2015","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/25758049","citation_count":42,"is_preprint":false},{"pmid":"36924813","id":"PMC_36924813","title":"Hydrogen sulfide alleviates mitochondrial damage and ferroptosis by regulating OPA3-NFS1 axis in doxorubicin-induced cardiotoxicity.","date":"2023","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/36924813","citation_count":34,"is_preprint":false},{"pmid":"25152427","id":"PMC_25152427","title":"Complete genome sequence of Bacillus methanolicus MGA3, a thermotolerant amino acid producing methylotroph.","date":"2014","source":"Journal of biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/25152427","citation_count":34,"is_preprint":false},{"pmid":"24136862","id":"PMC_24136862","title":"A novel heterozygous OPA3 mutation located in the mitochondrial target sequence results in altered steady-state levels and fragmented mitochondrial network.","date":"2013","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24136862","citation_count":33,"is_preprint":false},{"pmid":"18222992","id":"PMC_18222992","title":"A missense mutation in the murine Opa3 gene models human Costeff syndrome.","date":"2008","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/18222992","citation_count":32,"is_preprint":false},{"pmid":"20627962","id":"PMC_20627962","title":"A model of Costeff Syndrome reveals metabolic and protective functions of mitochondrial OPA3.","date":"2010","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/20627962","citation_count":32,"is_preprint":false},{"pmid":"12368456","id":"PMC_12368456","title":"Dissimilation of [(13)C]methanol by continuous cultures of Bacillus methanolicus MGA3 at 50 degrees C studied by (13)C NMR and isotope-ratio mass spectrometry.","date":"2002","source":"Microbiology (Reading, England)","url":"https://pubmed.ncbi.nlm.nih.gov/12368456","citation_count":30,"is_preprint":false},{"pmid":"31881642","id":"PMC_31881642","title":"Oncogenic K-ras Induces Mitochondrial OPA3 Expression to Promote Energy Metabolism in Pancreatic Cancer Cells.","date":"2019","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/31881642","citation_count":26,"is_preprint":false},{"pmid":"23760818","id":"PMC_23760818","title":"The methylotrophic Bacillus methanolicus MGA3 possesses two distinct fructose 1,6-bisphosphate aldolases.","date":"2013","source":"Microbiology (Reading, 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science","url":"https://pubmed.ncbi.nlm.nih.gov/25947227","citation_count":4,"is_preprint":false},{"pmid":"33870938","id":"PMC_33870938","title":"Neuro-Ophthalmic Phenotype of OPA3.","date":"2021","source":"Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society","url":"https://pubmed.ncbi.nlm.nih.gov/33870938","citation_count":3,"is_preprint":false},{"pmid":"29563951","id":"PMC_29563951","title":"Genetic Testing for Wolfram Syndrome Mutations in a Sample of 71 Patients with Hereditary Optic Neuropathy and Negative Genetic Test Results for OPA1/OPA3/LHON.","date":"2017","source":"Neuro-ophthalmology (Aeolus Press)","url":"https://pubmed.ncbi.nlm.nih.gov/29563951","citation_count":3,"is_preprint":false},{"pmid":"37819580","id":"PMC_37819580","title":"Plasmodium falciparum OPA3-like protein (PfOPA3) is essential for maintenance of mitochondrial homeostasis and parasite proliferation.","date":"2023","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/37819580","citation_count":2,"is_preprint":false},{"pmid":"39166438","id":"PMC_39166438","title":"Novel heterozygous OPA3 variant in a family with congenital cataracts, sensorineural hearing loss and neuropathy, without optic atrophy and comparison of pathogenic and population variants.","date":"2024","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/39166438","citation_count":1,"is_preprint":false},{"pmid":"39725842","id":"PMC_39725842","title":"OPA3 inhibits the cGAS-STING pathway mediated by mtDNA stress to promote colorectal cancer progression.","date":"2024","source":"In vitro cellular & developmental biology. Animal","url":"https://pubmed.ncbi.nlm.nih.gov/39725842","citation_count":0,"is_preprint":false},{"pmid":"41684901","id":"PMC_41684901","title":"CRISPR-Cas9-driven genome editing in Bacillus methanolicus MGA3.","date":"2026","source":"Frontiers in microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/41684901","citation_count":0,"is_preprint":false},{"pmid":"41123439","id":"PMC_41123439","title":"Structural studies of NAD+-dependent methanol dehydrogenase 1 from Bacillus methanolicus MGA3.","date":"2025","source":"Acta crystallographica. Section D, Structural biology","url":"https://pubmed.ncbi.nlm.nih.gov/41123439","citation_count":0,"is_preprint":false},{"pmid":"41567320","id":"PMC_41567320","title":"A Case Report of Unilateral OPA3-Related Dominant Optic Atrophy.","date":"2025","source":"Case reports in ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/41567320","citation_count":0,"is_preprint":false},{"pmid":"16349139","id":"PMC_16349139","title":"Cloning and Sequence Analysis of the meso-Diaminopimelate Decarboxylase Gene from Bacillus methanolicus MGA3 and Comparison to Other Decarboxylase Genes.","date":"1993","source":"Applied and environmental microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/16349139","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.14.618164","title":"Systems-level analysis provides insights on methanol-based production of L-glutamate and its decarboxylation product γ-aminobutyric acid by  <i>Bacillus methanolicus</i>","date":"2024-10-16","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.14.618164","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":20818,"output_tokens":3415,"usd":0.05684,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11149,"output_tokens":3708,"usd":0.074222,"stage2_stop_reason":"end_turn"},"total_usd":0.131062,"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\": 2001,\n      \"finding\": \"OPA3 (corresponding to cDNA clone FLJ22187) was identified as the causative gene for type III 3-methylglutaconic aciduria; an intronic G→C mutation abolished mRNA expression in fibroblasts from affected patients, establishing loss-of-function as the disease mechanism.\",\n      \"method\": \"Sanger sequencing of candidate genes, Northern blot analysis, mRNA expression analysis in patient fibroblasts\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct sequencing and mRNA abolition in patient cells, single lab but multiple methods\",\n      \"pmids\": [\"11668429\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"OPA3 protein localizes predominantly to mitochondria (not peroxisomes), as demonstrated by GFP-tagged OPA3 expression studies; OPA3A deficiency causes up-regulation of OPA3B, and two transcripts (OPA3A and OPA3B) are produced from a novel third coding exon.\",\n      \"method\": \"GFP-tagged protein expression and fluorescence microscopy, RT-PCR, Northern blot\",\n      \"journal\": \"Molecular genetics and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by tagged protein imaging, single lab, two orthogonal methods\",\n      \"pmids\": [\"20350831\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Mitochondrial localization signals of OPA3 are required for its function: delivery of exogenous Opa3 reduced elevated 3-methylglutaconic acid (MGC) levels in opa3 null zebrafish mutants only when mitochondrial targeting sequences were intact. Elevated MGC in opa3 mutants was shown to derive from extra-mitochondrial HMG-CoA via a non-canonical pathway.\",\n      \"method\": \"Zebrafish opa3 null mutant rescue experiments with wild-type and mutant (mitochondrial signal-deleted) Opa3 constructs; metabolic profiling of MGC precursor availability\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — functional rescue with mitochondrial targeting mutant, in vivo genetic model, multiple orthogonal assays\",\n      \"pmids\": [\"20627962\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Loss of OPA3 function (zebrafish null mutant) results in normal mitochondrial oxidative phosphorylation profiles basally, but opa3 mutants are sensitized to electron transport chain inhibitors, indicating a protective role for OPA3 at the mitochondrial ETC.\",\n      \"method\": \"Zebrafish opa3 null genetic model; mitochondrial oxidative phosphorylation profiling; pharmacological ETC inhibitor treatment\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic null model with functional mitochondrial profiling and pharmacological challenge, replicated across multiple assays in one study\",\n      \"pmids\": [\"20627962\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"A missense mutation in murine Opa3 (p.L122P) in homozygous mice causes increased mitochondrial activity in the optic nerve (elevated COX histochemistry), retinal ganglion cell loss, and multi-systemic disease, establishing Opa3 as essential for mitochondrial function in vivo.\",\n      \"method\": \"ENU-induced mouse model with p.L122P missense mutation; COX histochemistry; retinal ganglion cell quantification; histopathology\",\n      \"journal\": \"Brain : a journal of neurology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo mouse genetic model with direct mitochondrial functional readout and multiple tissue assessments\",\n      \"pmids\": [\"18222992\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Mutant Opa3 (L122P) protein retains its mitochondrial localization (does not mislocalize to peroxisomes), yet induces disrupted mitochondrial morphology in the retina of Opa3(-/-) mice; neither wild-type nor mutant Opa3 localizes to peroxisomes.\",\n      \"method\": \"Immunohistochemistry, mitochondrion-selective probe staining, electron microscopy, RT-PCR, Western blot in Opa3(L122P) mouse model\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by multiple methods in genetic model, single lab\",\n      \"pmids\": [\"21613372\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Opa3 (L122P missense mutation) impairs mitochondrial activity in brown adipose tissue, causing a 90% reduction in UCP1 expression and reduced thermogenesis, and coupling lipid uptake with lipid processing in liver, identifying Opa3 as a novel regulator of thermogenesis and lipid metabolism.\",\n      \"method\": \"Opa3(L122P) mouse model metabolic phenotyping; UCP1 expression by Western blot/qPCR; surface body temperature measurement; histology; adipose tissue mass quantification\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo genetic model with multiple functional metabolic readouts, single lab\",\n      \"pmids\": [\"22869679\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"A novel OPA3 mutation in the mitochondrial presequence (c.10_11insCGCCCG/p.V3_G4insAP) causes decreased steady-state protein levels and a fragmented mitochondrial network in patient fibroblasts, demonstrating that the mitochondrial targeting sequence is required for normal OPA3 stability and mitochondrial network maintenance.\",\n      \"method\": \"Mitochondrial import analysis, OPA3 protein quantification by Western blot, mitochondrial morphology imaging in patient fibroblasts\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional characterization in patient cells with multiple orthogonal methods, single lab\",\n      \"pmids\": [\"24136862\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Knockdown of OPA3 by siRNA/shRNA in retinal pigment epithelial cells increased stress fibers, cell migration, cell elongation, and mitochondrial elongation; forced OPA3 overexpression inhibited F-actin rearrangement and induced mitochondrial fragmentation. TGF-β-induced OPA3 downregulation was mediated via Smad2 signaling.\",\n      \"method\": \"siRNA/inducible shRNA knockdown; OPA3 overexpression; live cell imaging of mitochondrial morphology; F-actin staining; migration assays; Smad2 siRNA epistasis\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss- and gain-of-function with multiple cellular readouts and epistasis, single lab\",\n      \"pmids\": [\"23658835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"OPA3 expression is consistently upregulated by oncogenic K-ras activation; genetic knockdown of OPA3 suppresses oxygen consumption rate and cellular ATP content, reduces cell proliferation, and decreases EMT marker expression in pancreatic cancer cells, demonstrating OPA3's role in supporting mitochondrial energy metabolism downstream of K-ras.\",\n      \"method\": \"K-ras inducible cell systems; OPA3 siRNA knockdown; Seahorse oxygen consumption rate measurement; ATP content assay; Western blot for EMT markers\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockdown with multiple orthogonal functional readouts, single lab\",\n      \"pmids\": [\"31881642\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"OPA3 physically interacts with NFS1 (iron-sulfur cluster assembly enzyme) and regulates ferroptosis via this interaction; doxorubicin promotes OPA3 ubiquitination and degradation, while exogenous H2S antagonizes OPA3 ubiquitination through promoting OPA3 S-sulfhydration, thereby restoring OPA3-NFS1 axis function and inhibiting ferroptosis in cardiomyocytes.\",\n      \"method\": \"Co-immunoprecipitation (OPA3-NFS1 interaction); OPA3 overexpression in vivo and in vitro; ubiquitination assay; S-sulfhydration assay; lipid peroxidation measurement; GPX4/NFS1 protein expression analysis\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for binding, functional overexpression rescue, and post-translational modification assays in one study; single lab\",\n      \"pmids\": [\"36924813\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"OPA3 knockdown in colorectal cancer cells facilitates mitochondrial dysfunction and mtDNA stress, elevating cGAS and p-STING protein levels and STING target gene expression; OPA3 overexpression inhibits CCCP-induced mitochondrial stress and suppresses the cGAS-STING pathway. Overexpression of cGAS or STING partially reversed OPA3 overexpression-driven cancer cell proliferation/migration/invasion, placing OPA3 upstream of cGAS-STING in maintaining mitochondrial integrity.\",\n      \"method\": \"OPA3 overexpression and knockdown in HT29 cells; CCCP-induced mitochondrial dysfunction model; Western blot for cGAS, p-STING; RT-PCR for STING target genes; epistasis by cGAS/STING overexpression\",\n      \"journal\": \"In vitro cellular & developmental biology. Animal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain- and loss-of-function with genetic epistasis and pathway placement, single lab\",\n      \"pmids\": [\"39725842\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"A nonsense mutation (c.343C>T) in the bovine OPA3 gene causes dilated cardiomyopathy in Red Holstein cattle with an autosomal recessive pattern, providing genetic and functional evidence that OPA3 loss of function leads to cardiac muscle pathology.\",\n      \"method\": \"Genetic mapping, PCR-based sequencing of OPA3 in affected and control cattle, segregation analysis\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — genetic evidence with segregation in animal model, no direct cellular mechanism established\",\n      \"pmids\": [\"20923700\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"A heterozygous G277A missense mutation in OPA3 (encoding a mitochondrial protein) was identified as the cause of autosomal dominant optic atrophy with cataract and extrapyramidal neurological signs, establishing OPA3 as a nuclear-encoded mitochondrial protein whose dominant mutations cause disease.\",\n      \"method\": \"Sequencing of OPA3 in a multi-generation family followed over 40 years; segregation analysis\",\n      \"journal\": \"Revue neurologique\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — genetic sequencing and segregation only, no direct cellular mechanism\",\n      \"pmids\": [\"15924081\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"OPA3 is a nuclear-encoded protein that localizes to the inner mitochondrial membrane via its mitochondrial targeting sequence, where it is required to maintain mitochondrial network morphology, protect the electron transport chain from inhibitors, regulate mitochondrial energy metabolism (oxygen consumption and ATP production), couple lipid uptake with thermogenesis in brown adipose tissue, limit extra-mitochondrial HMG-CoA-derived 3-methylglutaconic acid accumulation, interact with the iron-sulfur cluster assembly factor NFS1 to suppress ferroptosis, and suppress mtDNA stress-driven cGAS-STING innate immune signaling; loss-of-function mutations cause the metabolic disorder 3-methylglutaconic aciduria type III (Costeff syndrome) while dominant missense mutations cause optic atrophy with cataracts, and OPA3 protein stability is regulated by ubiquitination and S-sulfhydration post-translational modifications.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"OPA3 is a nuclear-encoded mitochondrial protein required to maintain mitochondrial network morphology and regulate mitochondrial energy metabolism [#2, #7]. It localizes predominantly to mitochondria rather than peroxisomes, and its N-terminal mitochondrial targeting sequence is essential both for protein stability and for function: presequence-disrupting mutations reduce steady-state OPA3 levels and fragment the mitochondrial network, and mitochondrial-signal-deleted constructs fail to rescue metabolic defects in opa3-null models [#1, #2, #7]. Functionally, OPA3 protects the electron transport chain against pharmacological inhibition [#3], supports oxygen consumption and ATP production downstream of oncogenic K-ras [#9], and limits accumulation of extra-mitochondrial HMG-CoA-derived 3-methylglutaconic acid [#2]. In vivo, OPA3 couples lipid uptake with thermogenesis, with mutant Opa3 markedly reducing UCP1 expression in brown adipose tissue [#6]. OPA3 additionally interacts physically with the iron-sulfur cluster assembly enzyme NFS1 to suppress ferroptosis, an axis controlled by competing ubiquitination and S-sulfhydration of OPA3 [#10], and it acts upstream of the cGAS-STING pathway to restrain mtDNA-stress-driven innate immune signaling [#11]. Loss-of-function mutation causes type III 3-methylglutaconic aciduria (Costeff syndrome) [#0], and dominant missense mutation causes optic atrophy with cataract [#13].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Establishing OPA3 as a disease gene defined loss of function as the founding mechanistic entry point, before any molecular role was known.\",\n      \"evidence\": \"candidate-gene Sanger sequencing and mRNA expression analysis in patient fibroblasts, where an intronic mutation abolished OPA3 mRNA\",\n      \"pmids\": [\"11668429\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No subcellular localization or biochemical activity assigned\", \"Mechanism linking gene loss to 3-methylglutaconic acid accumulation unaddressed\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identification of a dominant missense mutation showed that OPA3 dysfunction can act through more than simple haploinsufficiency, broadening the disease spectrum to optic atrophy with cataract.\",\n      \"evidence\": \"sequencing and 40-year segregation analysis of a multi-generation family\",\n      \"pmids\": [\"15924081\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Genetic association only, no cellular mechanism\", \"Molecular consequence of the missense allele not tested\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"An ENU mouse missense model demonstrated in vivo that Opa3 is essential for mitochondrial function, linking the gene to optic-nerve mitochondrial activity and retinal ganglion cell loss.\",\n      \"evidence\": \"Opa3 p.L122P mouse with COX histochemistry, retinal ganglion cell quantification, and multi-systemic histopathology\",\n      \"pmids\": [\"18222992\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular function of the protein not defined\", \"Mechanism connecting altered mitochondrial activity to cell loss unresolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Combined imaging, genetic, and rescue studies localized OPA3 to mitochondria (not peroxisomes), showed its mitochondrial targeting sequence is required for function, and revealed a protective role at the electron transport chain.\",\n      \"evidence\": \"GFP-tagged localization imaging, zebrafish opa3-null rescue with targeting-sequence mutants, and OXPHOS profiling with ETC inhibitor challenge\",\n      \"pmids\": [\"20350831\", \"20627962\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct biochemical activity of OPA3 within the membrane not identified\", \"How OPA3 confers ETC inhibitor protection mechanistically unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"A bovine nonsense mutation extended the loss-of-function phenotype to cardiac muscle pathology, supporting a broad tissue requirement for OPA3.\",\n      \"evidence\": \"genetic mapping and segregation analysis of dilated cardiomyopathy in Red Holstein cattle\",\n      \"pmids\": [\"20923700\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Genetic evidence only, no cellular mechanism\", \"Cardiac-specific OPA3 function untested\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showing that mutant Opa3 retains mitochondrial localization while still disrupting mitochondrial morphology dissociated the disease mechanism from mislocalization, pointing to a functional defect within mitochondria.\",\n      \"evidence\": \"immunohistochemistry, mito-probe staining, and electron microscopy in Opa3(L122P) mice\",\n      \"pmids\": [\"21613372\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of morphology disruption not defined\", \"No interacting machinery identified\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Metabolic phenotyping connected OPA3 to whole-organism energy handling, identifying it as a regulator of brown adipose thermogenesis and hepatic lipid processing.\",\n      \"evidence\": \"Opa3(L122P) mouse metabolic phenotyping with UCP1 expression, body temperature, and adipose/liver histology\",\n      \"pmids\": [\"22869679\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism coupling OPA3 to UCP1 regulation unknown\", \"Direct molecular targets in lipid metabolism unidentified\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"A patient presequence-insertion mutation established that the mitochondrial targeting sequence governs OPA3 stability and network integrity, linking import to function in human cells.\",\n      \"evidence\": \"mitochondrial import analysis, protein quantification, and morphology imaging in patient fibroblasts\",\n      \"pmids\": [\"24136862\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Degradation pathway for unstable OPA3 not characterized here\", \"Effector of network maintenance unknown\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Loss- and gain-of-function in epithelial cells tied OPA3 levels to cytoskeletal/migration phenotypes and placed OPA3 downstream of TGF-β/Smad2 signaling.\",\n      \"evidence\": \"siRNA/shRNA knockdown and overexpression with mitochondrial imaging, F-actin staining, migration assays, and Smad2 epistasis in RPE cells\",\n      \"pmids\": [\"23658835\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking mitochondrial OPA3 to actin dynamics unresolved\", \"Direct transcriptional control of OPA3 by Smad2 not shown structurally\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Placing OPA3 downstream of oncogenic K-ras showed it actively supports mitochondrial bioenergetics and proliferation in cancer cells.\",\n      \"evidence\": \"K-ras inducible systems with OPA3 knockdown, Seahorse oxygen consumption, ATP assays, and EMT marker analysis in pancreatic cancer cells\",\n      \"pmids\": [\"31881642\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How K-ras upregulates OPA3 unknown\", \"Direct biochemical contribution to respiration undefined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identification of the OPA3-NFS1 interaction and its redox/ubiquitination control gave OPA3 a defined molecular partnership and a role in suppressing ferroptosis.\",\n      \"evidence\": \"Co-immunoprecipitation, overexpression rescue, ubiquitination and S-sulfhydration assays, and lipid peroxidation measurement in cardiomyocytes\",\n      \"pmids\": [\"36924813\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single Co-IP without reciprocal/structural validation of the OPA3-NFS1 interface\", \"Whether OPA3 directly affects NFS1 iron-sulfur cluster assembly activity untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Epistasis experiments positioned OPA3 upstream of cGAS-STING, linking its maintenance of mitochondrial integrity to suppression of mtDNA-stress innate immune signaling and tumor cell behavior.\",\n      \"evidence\": \"OPA3 overexpression/knockdown with CCCP mitochondrial stress, cGAS/p-STING Western blots, STING target RT-PCR, and cGAS/STING overexpression epistasis in HT29 cells\",\n      \"pmids\": [\"39725842\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which OPA3 limits mtDNA release not defined\", \"Single cell-line context for pathway placement\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The core biochemical activity of OPA3 within the inner mitochondrial membrane remains undefined, leaving open how a single protein integrates network morphology, ETC protection, lipid/thermogenic metabolism, ferroptosis suppression, and innate immune restraint.\",\n      \"evidence\": \"no enzymatic or structural mechanism reported across the timeline\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No catalytic or structural activity assigned\", \"Unifying molecular mechanism behind diverse phenotypes unknown\", \"No high-resolution structure or interactome beyond NFS1\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [1, 2, 5, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [2, 6, 9]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [10]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"NFS1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":6,"faith_total":6,"faith_pct":100.0}}