{"gene":"MIEF2","run_date":"2026-04-28T18:30:28","timeline":{"discoveries":[{"year":2011,"finding":"MiD49 (MIEF2) is anchored in the mitochondrial outer membrane, forms foci and rings around mitochondria similar to Drp1, directly recruits Drp1 to the mitochondrial surface, and its knockdown reduces Drp1 association leading to unopposed fusion.","method":"Immunofluorescence, knockdown, overexpression, subcellular fractionation","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods, foundational discovery paper, highly cited (514 citations)","pmids":["21508961"],"is_preprint":false},{"year":2013,"finding":"MiD49 (MIEF2) can mediate Drp1 recruitment and mitochondrial fission independently of Fis1 and Mff, and its overexpression causes dominant-negative sequestration of Drp1 specifically at mitochondria (not peroxisomes), leading to unopposed fusion requiring mitofusins 1 and 2. When targeted to peroxisomes or lysosomes, MiD49 specifically recruits Drp1 to those organelles.","method":"Fis1/Mff-null cell lines, immunofluorescence, organelle targeting experiments, mitofusin knockout epistasis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple genetic epistasis and targeting experiments, replicated findings across labs","pmids":["23921378"],"is_preprint":false},{"year":2013,"finding":"Either MiD49 or MiD51 can mediate Drp1 recruitment and mitochondrial fission in the absence of both Fis1 and Mff, demonstrating functional redundancy among fission receptors; Fis1 and Mff regulate the number and size of Drp1 puncta on mitochondria.","method":"Fis1-null, Mff-null, Fis1/Mff-null cell lines; immunofluorescence of Drp1 puncta","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — genetic null cell lines with defined phenotypic readouts, highly cited (993 citations)","pmids":["23283981"],"is_preprint":false},{"year":2015,"finding":"Crystal structure of MiD49 (MIEF2) at 2.4 Å resolution revealed a nucleotidyl transferase domain that, unlike MiD51, lacks a small-molecule ligand binding capacity due to structural changes in the putative nucleotide-binding pocket. A surface loop on MiD49 physically interacts with Drp1 and is necessary for Drp1 recruitment to the mitochondrial surface.","method":"X-ray crystallography (2.4 Å), surface entropy reduction mutagenesis, biochemical Drp1 recruitment assay","journal":"Protein science","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with functional mutagenesis validation","pmids":["25581164"],"is_preprint":false},{"year":2015,"finding":"The OMM-associated E3 ubiquitin ligase MARCH5 controls MiD49 ubiquitination and proteasomal degradation; MARCH5 knockout selectively stabilizes MiD49, leading to Drp1-dependent mitochondrial fragmentation and increased sensitivity to stress-induced apoptosis. Re-expression of MARCH5 or MiD49 knockout reverses fragmentation.","method":"MARCH5 knockout cells, co-immunoprecipitation, ubiquitination assay, MiD49 knockout epistasis, proteasome inhibitor experiments","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — reciprocal genetic epistasis with biochemical ubiquitination assay, replicated","pmids":["26564796"],"is_preprint":false},{"year":2016,"finding":"Drp1-dependent mitochondrial fission specifically through MiD49/MiD51 receptors (not Mff) is required for apoptotic cristae remodeling and cytochrome c release during intrinsic apoptosis; MiD49/51-KO cells completely resist cristae remodeling similarly to Drp1-KO cells, and this resistance is abolished by OPA1 depletion.","method":"MiD49/51-KO, Drp1-KO, Mff-KO cell lines; cytochrome c release assay; OPA1 depletion epistasis; electron microscopy of cristae","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — multiple knockout lines with epistasis and defined apoptotic phenotype","pmids":["26903540"],"is_preprint":false},{"year":2016,"finding":"MiD51 can suppress Mff-dependent enhancement of Drp1 GTPase activity; proximity-based biotin labeling (BioID) confirmed close associations between MiD51, Mff and Drp1 but not Fis1; combined loss of MiD51 and Mff caused greater mitochondrial connectivity than individual losses, and MiD49/51 showed more prominent roles in apoptosis resistance than Mff.","method":"CRISPR knockout cell lines, BioID proximity labeling, Drp1 GTPase activity assay, apoptosis assays","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro GTPase assay combined with BioID and genetic epistasis","pmids":["27076521"],"is_preprint":false},{"year":2016,"finding":"Mff and Drp1 negatively regulate MARCH5 E3 ubiquitin ligase activity toward MiD49; knockout of either Drp1 or Mff led to reduced MiD49 expression, shorter half-life, and increased ubiquitination of MiD49, effects eliminated in Drp1-/-/MARCH5-/- and Mff-/-/MARCH5-/- double knockouts. Mff is an integral component of the MARCH5/p97/Npl4 complex.","method":"Double knockout cell lines, co-immunoprecipitation, ubiquitination assay, pulse-chase half-life measurement","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — reciprocal double-knockout epistasis with biochemical complex analysis","pmids":["27932492"],"is_preprint":false},{"year":2017,"finding":"Foxo3a directly targets the MIEF2 promoter and suppresses MIEF2 expression at the transcriptional level; MIEF2 knockdown reduces doxorubicin-induced mitochondrial fission and apoptosis in cardiomyocytes and protects from cardiotoxicity in vivo.","method":"Foxo3a transgenic mice, ChIP/promoter assay, MIEF2 siRNA knockdown, in vivo cardiotoxicity model","journal":"Free radical biology & medicine","confidence":"Medium","confidence_rationale":"Tier 2 — direct transcriptional regulation shown by promoter assay with in vivo validation","pmids":["28137654"],"is_preprint":false},{"year":2018,"finding":"Silencing MiD49 (MIEF2) or MiD51 (but not Fis1 or Mff) promotes mitochondrial fusion and causes G1-phase cell cycle arrest through ERK1/2- and CDK4-dependent mechanisms in pulmonary artery smooth muscle cells; epigenetic upregulation of MiDs via decreased miR-34a-3p drives Drp1-mediated mitotic fission, proliferation, and apoptosis resistance in PAH.","method":"siRNA knockdown, flow cytometry cell cycle analysis, confocal mitochondrial imaging, microRNA microarray, in vivo nebulized siRNA in monocrotaline-PAH rat model","journal":"Circulation","confidence":"High","confidence_rationale":"Tier 2 — multiple cell and in vivo models with pathway placement (ERK1/2-CDK4), highly cited (142 citations)","pmids":["29431643"],"is_preprint":false},{"year":2023,"finding":"X-ray co-crystal structure of DRP1 with a small-molecule inhibitor that disrupts the DRP1/MiD49 protein-protein interaction revealed that the compound locks DRP1 in a closed conformation by inducing dimerization, identifying the DRP1-MiD49 interface as an allosteric regulatory site.","method":"X-ray co-crystallography, in vitro mitochondrial fragmentation assay","journal":"ACS medicinal chemistry letters","confidence":"Medium","confidence_rationale":"Tier 1 — structural determination with functional validation, single study","pmids":["37583827"],"is_preprint":false},{"year":2024,"finding":"Long-chain acyl-CoA (LCACA) activates MiD49 and MiD51 by inducing their oligomerization via binding to the nucleotide-binding pocket, which stimulates DRP1 GTPase activity. A point mutation in MiD51's nucleotide-binding pocket reduces LCACA binding and LCACA-induced oligomerization. This LCACA binding mutant fails to assemble into puncta or rescue mitochondrial length/DRP1 recruitment in cells. MiD49/51 oligomers synergize with Mff but not actin filaments in DRP1 activation. Cellular treatment with oleic acid promotes mitochondrial fission in an MiD49/51-dependent manner.","method":"In vitro oligomerization assay, DRP1 GTPase assay, point mutagenesis, live-cell imaging, oleic acid treatment with MiD49/51 knockdown","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution, mutagenesis, and cellular validation with multiple orthogonal methods","pmids":["38594588"],"is_preprint":false},{"year":2025,"finding":"MARCH5 directly interacts with MIEF2 via co-immunoprecipitation, causing its ubiquitination and proteasomal degradation, thereby regulating mitochondrial dynamics; overexpression of MIEF2 reverses the reduction in lipid accumulation, cell death, mitochondrial fission, and MAM formation caused by MARCH5 overexpression.","method":"Co-immunoprecipitation, ubiquitination assay, gain/loss-of-function experiments, liver-specific MARCH5 knockdown in vivo","journal":"Phytomedicine","confidence":"Medium","confidence_rationale":"Tier 2 — direct interaction shown by Co-IP with ubiquitination assay and epistasis, single lab","pmids":["41353882"],"is_preprint":false},{"year":2025,"finding":"Knockdown of MiD49 impairs PINK1-Parkin-dependent mitophagy and CPT-1A-mediated fatty acid β-oxidation in fibroblast-like synoviocytes; protein-protein interaction analysis revealed potential interactions between MiDs and the PINK1-Parkin pathway.","method":"siRNA knockdown, PPI analysis, mitophagy assay, fatty acid oxidation assay, CIA mouse model with shRNA","journal":"Free radical biology & medicine","confidence":"Medium","confidence_rationale":"Tier 2-3 — functional knockdown with defined pathway readouts but PPI based on computational analysis","pmids":["40846102"],"is_preprint":false}],"current_model":"MIEF2 (MiD49) is a mitochondrial outer membrane protein that recruits cytosolic DRP1 to the mitochondrial surface via a surface loop interaction, where it can oligomerize upon binding long-chain acyl-CoA in its nucleotidyl transferase domain to stimulate DRP1 GTPase activity and drive fission; its abundance is controlled by MARCH5-mediated ubiquitination and proteasomal degradation (regulated by Mff and Drp1), its transcription is suppressed by Foxo3a, and it specifically mediates the DRP1-dependent cristae remodeling required for cytochrome c release during apoptosis, while also coupling mitochondrial fission to cell cycle progression through ERK1/2-CDK4 signaling."},"narrative":{"teleology":[{"year":2011,"claim":"Identification of MIEF2 as a mitochondrial outer membrane protein that directly recruits DRP1 established a new class of fission receptor independent of previously known adaptors.","evidence":"Immunofluorescence, knockdown/overexpression, and subcellular fractionation in mammalian cells","pmids":["21508961"],"confidence":"High","gaps":["Structural basis of DRP1–MiD49 interaction unknown","Relationship to other DRP1 receptors (Mff, Fis1) not yet resolved genetically"]},{"year":2013,"claim":"Genetic epistasis using Fis1/Mff-null cells demonstrated that MIEF2 can recruit DRP1 and drive fission independently of all other known receptors, resolving the question of receptor redundancy.","evidence":"Fis1-null, Mff-null, and Fis1/Mff double-null cell lines with DRP1 puncta quantification and organelle-targeting experiments","pmids":["23921378","23283981"],"confidence":"High","gaps":["Molecular determinants on MIEF2 that contact DRP1 not yet mapped","Functional distinction between MIEF2 and MiD51 unclear"]},{"year":2015,"claim":"The 2.4 Å crystal structure of MIEF2 revealed a nucleotidyl transferase fold and identified a specific surface loop required for DRP1 recruitment, providing the first structural framework for receptor-mediated fission.","evidence":"X-ray crystallography with surface entropy reduction mutagenesis and biochemical DRP1 recruitment assays","pmids":["25581164"],"confidence":"High","gaps":["No co-structure of the MIEF2–DRP1 complex","Ligand binding capacity of the nucleotidyl transferase pocket in MIEF2 unresolved"]},{"year":2015,"claim":"Discovery that MARCH5 E3 ligase ubiquitinates MIEF2 for proteasomal degradation revealed the principal mechanism controlling MIEF2 abundance and explained how excess MIEF2 drives pathological fragmentation and apoptosis sensitization.","evidence":"MARCH5-KO cells, ubiquitination assays, MiD49-KO epistasis, and proteasome inhibitor experiments","pmids":["26564796"],"confidence":"High","gaps":["Specific ubiquitin chain type on MIEF2 not determined","Signals that regulate MARCH5 activity toward MIEF2 unknown"]},{"year":2016,"claim":"Demonstration that DRP1-dependent cristae remodeling and cytochrome c release require MIEF2/MiD51 but not Mff distinguished the apoptotic fission pathway from homeostatic fission and positioned MIEF2 as a specific mediator of intrinsic apoptosis.","evidence":"MiD49/51-KO, Drp1-KO, Mff-KO cell lines with cytochrome c release assays, OPA1 epistasis, and electron microscopy","pmids":["26903540","27076521"],"confidence":"High","gaps":["How MIEF2/MiD51 selectively remodel cristae versus simply fragmenting mitochondria is mechanistically unclear","Whether MIEF2 and MiD51 are individually sufficient for apoptotic remodeling not separated"]},{"year":2016,"claim":"Double-knockout studies showed that Mff and Drp1 negatively regulate MARCH5-mediated ubiquitination of MIEF2, revealing a feedback circuit among fission components that tunes receptor abundance.","evidence":"Drp1−/−/MARCH5−/− and Mff−/−/MARCH5−/− double knockouts, co-immunoprecipitation, pulse-chase half-life measurement","pmids":["27932492"],"confidence":"High","gaps":["Mechanism by which Drp1 and Mff restrain MARCH5 activity toward MIEF2 is unclear","Role of the p97/Npl4 complex in MIEF2 extraction not fully dissected"]},{"year":2017,"claim":"Identification of Foxo3a as a direct transcriptional repressor of the MIEF2 promoter linked stress-responsive transcription factor signaling to mitochondrial fission control, with in vivo relevance to doxorubicin-induced cardiotoxicity.","evidence":"ChIP/promoter assay, Foxo3a transgenic mice, MIEF2 siRNA knockdown, in vivo cardiotoxicity model","pmids":["28137654"],"confidence":"Medium","gaps":["Other transcriptional regulators of MIEF2 not surveyed","Whether Foxo3a regulation is tissue-specific or general is unknown"]},{"year":2018,"claim":"Silencing MIEF2 caused G1-phase arrest through ERK1/2–CDK4 signaling, establishing that MIEF2-mediated mitochondrial fission is coupled to cell cycle progression and proliferative control in vascular smooth muscle cells.","evidence":"siRNA knockdown, flow cytometry, microRNA profiling, in vivo nebulized siRNA in monocrotaline-PAH rat model","pmids":["29431643"],"confidence":"High","gaps":["Direct mechanistic link between mitochondrial morphology and ERK1/2 activation not identified","Whether this cell cycle coupling operates in non-vascular cell types is unknown"]},{"year":2023,"claim":"A co-crystal structure of DRP1 with a small-molecule inhibitor that disrupts the DRP1–MIEF2 interface identified this interaction as an allosteric regulatory site, opening a pharmacological avenue.","evidence":"X-ray co-crystallography of DRP1 with inhibitor compound, in vitro mitochondrial fragmentation assay","pmids":["37583827"],"confidence":"Medium","gaps":["No direct co-crystal of MIEF2 bound to DRP1 is available","In vivo efficacy of the DRP1–MIEF2 interface inhibitor not tested"]},{"year":2024,"claim":"Long-chain acyl-CoAs were identified as activating ligands that bind the nucleotidyl transferase pocket and induce MIEF2 oligomerization, which stimulates DRP1 GTPase activity, directly coupling lipid metabolic status to mitochondrial fission.","evidence":"In vitro oligomerization and DRP1 GTPase assays, point mutagenesis, live-cell imaging with oleic acid treatment and MiD49/51 knockdown","pmids":["38594588"],"confidence":"High","gaps":["Structural basis of LCACA binding to MIEF2 specifically (versus MiD51) not resolved","Physiological range of acyl-CoA concentrations at the OMM in different metabolic states not established"]},{"year":2025,"claim":"MIEF2 knockdown impaired PINK1–Parkin-dependent mitophagy and CPT-1A-mediated fatty acid β-oxidation, extending MIEF2 function beyond fission into mitophagy and metabolic regulation.","evidence":"siRNA knockdown in fibroblast-like synoviocytes, mitophagy and fatty acid oxidation assays, CIA mouse model","pmids":["40846102"],"confidence":"Medium","gaps":["MIEF2–PINK1/Parkin interaction is computationally inferred rather than biochemically validated","Whether the mitophagy role is secondary to fission defects or a direct function is unresolved"]},{"year":null,"claim":"The structural basis of the MIEF2–DRP1 complex at atomic resolution, the mechanism by which MIEF2-dependent fission specifically remodels cristae during apoptosis, and the in vivo physiological functions of MIEF2 in tissue-specific contexts remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No co-crystal structure of the MIEF2–DRP1 complex exists","Mechanism distinguishing apoptotic cristae remodeling from homeostatic fission through MIEF2 is unclear","Tissue-specific in vivo knockout phenotypes of MIEF2 have not been systematically characterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,2,5,11]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,3]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,1,3,4]}],"pathway":[{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,1,2,5,11]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[5,6,8]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[9]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[13]}],"complexes":[],"partners":["DNM1L","MARCH5","MIEF1","MFF","FOXO3"],"other_free_text":[]},"mechanistic_narrative":"MIEF2 (MiD49) is a mitochondrial outer membrane receptor for the dynamin-related GTPase DRP1, serving as a central organizer of mitochondrial fission that couples metabolic and apoptotic signals to organelle dynamics and cell cycle progression. MIEF2 recruits cytosolic DRP1 to the mitochondrial surface through a surface loop within its nucleotidyl transferase domain, functioning independently of the alternative receptors Fis1 and Mff, and its oligomerization upon binding long-chain acyl-CoAs stimulates DRP1 GTPase activity to drive fission [PMID:21508961, PMID:25581164, PMID:38594588]. MIEF2 protein abundance is tightly controlled by MARCH5 E3 ubiquitin ligase–mediated ubiquitination and proteasomal degradation, a process negatively regulated by Mff and Drp1, while its transcription is suppressed by Foxo3a [PMID:26564796, PMID:27932492, PMID:28137654]. DRP1-dependent fission specifically through MIEF2/MiD51 (rather than Mff) is required for apoptotic cristae remodeling and cytochrome c release, and silencing MIEF2 causes G1 cell cycle arrest through ERK1/2–CDK4 signaling, linking mitochondrial fission to proliferative control [PMID:26903540, PMID:29431643]."},"prefetch_data":{"uniprot":{"accession":"Q96C03","full_name":"Mitochondrial dynamics protein MID49","aliases":["Mitochondrial dynamics protein of 49 kDa","Mitochondrial elongation factor 2","Smith-Magenis syndrome chromosomal region candidate gene 7 protein"],"length_aa":454,"mass_kda":49.3,"function":"Mitochondrial outer membrane protein involved in the regulation of mitochondrial organization (PubMed:29361167). It is required for mitochondrial fission and promotes the recruitment and association of the fission mediator dynamin-related protein 1 (DNM1L) to the mitochondrial surface independently of the mitochondrial fission FIS1 and MFF proteins. Regulates DNM1L GTPase activity","subcellular_location":"Mitochondrion outer membrane","url":"https://www.uniprot.org/uniprotkb/Q96C03/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MIEF2","classification":"Not Classified","n_dependent_lines":10,"n_total_lines":1208,"dependency_fraction":0.008278145695364239},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/MIEF2","total_profiled":1310},"omim":[{"mim_id":"619024","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 49; COXPD49","url":"https://www.omim.org/entry/619024"},{"mim_id":"615498","title":"MITOCHONDRIAL ELONGATION FACTOR 2; MIEF2","url":"https://www.omim.org/entry/615498"},{"mim_id":"615497","title":"MITOCHONDRIAL ELONGATION FACTOR 1; MIEF1","url":"https://www.omim.org/entry/615497"},{"mim_id":"609060","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 1; COXPD1","url":"https://www.omim.org/entry/609060"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MIEF2"},"hgnc":{"alias_symbol":["MGC23130","MiD49","D3B"],"prev_symbol":["SMCR7"]},"alphafold":{"accession":"Q96C03","domains":[{"cath_id":"3.30.460.90","chopping":"142-334","consensus_level":"medium","plddt":90.8393,"start":142,"end":334},{"cath_id":"1.10.1410.40","chopping":"351-454","consensus_level":"medium","plddt":90.816,"start":351,"end":454}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96C03","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96C03-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96C03-F1-predicted_aligned_error_v6.png","plddt_mean":76.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MIEF2","jax_strain_url":"https://www.jax.org/strain/search?query=MIEF2"},"sequence":{"accession":"Q96C03","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96C03.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96C03/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96C03"}},"corpus_meta":[{"pmid":"23283981","id":"PMC_23283981","title":"Fis1, Mff, MiD49, and MiD51 mediate Drp1 recruitment in mitochondrial fission.","date":"2013","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/23283981","citation_count":993,"is_preprint":false},{"pmid":"21508961","id":"PMC_21508961","title":"MiD49 and MiD51, new components of the mitochondrial fission machinery.","date":"2011","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/21508961","citation_count":514,"is_preprint":false},{"pmid":"27076521","id":"PMC_27076521","title":"Cooperative and independent roles of the Drp1 adaptors Mff, MiD49 and MiD51 in mitochondrial fission.","date":"2016","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/27076521","citation_count":263,"is_preprint":false},{"pmid":"23921378","id":"PMC_23921378","title":"Adaptor proteins MiD49 and MiD51 can act independently of Mff and Fis1 in Drp1 recruitment and are specific for mitochondrial fission.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23921378","citation_count":247,"is_preprint":false},{"pmid":"26903540","id":"PMC_26903540","title":"Drp1-dependent mitochondrial fission via MiD49/51 is essential for apoptotic cristae remodeling.","date":"2016","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/26903540","citation_count":197,"is_preprint":false},{"pmid":"29431643","id":"PMC_29431643","title":"Epigenetic Dysregulation of the Dynamin-Related Protein 1 Binding Partners MiD49 and MiD51 Increases Mitotic Mitochondrial Fission and Promotes Pulmonary Arterial Hypertension: Mechanistic and Therapeutic Implications.","date":"2018","source":"Circulation","url":"https://pubmed.ncbi.nlm.nih.gov/29431643","citation_count":142,"is_preprint":false},{"pmid":"26564796","id":"PMC_26564796","title":"Mitochondrial E3 ubiquitin ligase MARCH5 controls mitochondrial fission and cell sensitivity to stress-induced apoptosis through regulation of MiD49 protein.","date":"2015","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/26564796","citation_count":126,"is_preprint":false},{"pmid":"27660309","id":"PMC_27660309","title":"The role of Drp1 adaptor proteins MiD49 and MiD51 in mitochondrial fission: implications for human disease.","date":"2016","source":"Clinical science (London, England : 1979)","url":"https://pubmed.ncbi.nlm.nih.gov/27660309","citation_count":98,"is_preprint":false},{"pmid":"33414447","id":"PMC_33414447","title":"MIEF2 reprograms lipid metabolism to drive progression of ovarian cancer through ROS/AKT/mTOR signaling pathway.","date":"2021","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/33414447","citation_count":89,"is_preprint":false},{"pmid":"27932492","id":"PMC_27932492","title":"Novel regulatory roles of Mff and Drp1 in E3 ubiquitin ligase MARCH5-dependent degradation of MiD49 and Mcl1 and control of mitochondrial dynamics.","date":"2016","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/27932492","citation_count":78,"is_preprint":false},{"pmid":"28137654","id":"PMC_28137654","title":"Foxo3a inhibits mitochondrial fission and protects against doxorubicin-induced cardiotoxicity by suppressing MIEF2.","date":"2017","source":"Free radical biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28137654","citation_count":44,"is_preprint":false},{"pmid":"25581164","id":"PMC_25581164","title":"Crystal structure and functional analysis of MiD49, a receptor for the mitochondrial fission protein Drp1.","date":"2015","source":"Protein science : a publication of the Protein Society","url":"https://pubmed.ncbi.nlm.nih.gov/25581164","citation_count":43,"is_preprint":false},{"pmid":"30338314","id":"PMC_30338314","title":"MiD49 and MiD51: New mediators of mitochondrial fission and novel targets for cardioprotection.","date":"2018","source":"Conditioning medicine","url":"https://pubmed.ncbi.nlm.nih.gov/30338314","citation_count":36,"is_preprint":false},{"pmid":"33317572","id":"PMC_33317572","title":"MIEF2 over-expression promotes tumor growth and metastasis through reprogramming of glucose metabolism in ovarian cancer.","date":"2020","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/33317572","citation_count":35,"is_preprint":false},{"pmid":"32068312","id":"PMC_32068312","title":"An epigenetic increase in mitochondrial fission by MiD49 and MiD51 regulates the cell cycle in cancer: Diagnostic and therapeutic implications.","date":"2020","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/32068312","citation_count":24,"is_preprint":false},{"pmid":"38594588","id":"PMC_38594588","title":"Fatty acyl-coenzyme A activates mitochondrial division through oligomerization of MiD49 and MiD51.","date":"2024","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/38594588","citation_count":18,"is_preprint":false},{"pmid":"38203413","id":"PMC_38203413","title":"Dynamin-Related Protein 1 Binding Partners MiD49 and MiD51 Increased Mitochondrial Fission In Vitro and Atherosclerosis in High-Fat-Diet-Fed ApoE-/- Mice.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/38203413","citation_count":12,"is_preprint":false},{"pmid":"32323835","id":"PMC_32323835","title":"Downregulation of MiD49 contributes to tumor growth and metastasis of human pancreatic cancer.","date":"2020","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/32323835","citation_count":11,"is_preprint":false},{"pmid":"36106106","id":"PMC_36106106","title":"CRISPR-based knockout screening identifies the loss of MIEF2 to enhance oxaliplatin resistance in colorectal cancer through inhibiting the mitochondrial apoptosis pathway.","date":"2022","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/36106106","citation_count":8,"is_preprint":false},{"pmid":"37583827","id":"PMC_37583827","title":"Discovery of Potent Allosteric DRP1 Inhibitors by Disrupting Protein-Protein Interaction with MiD49.","date":"2023","source":"ACS medicinal chemistry letters","url":"https://pubmed.ncbi.nlm.nih.gov/37583827","citation_count":7,"is_preprint":false},{"pmid":"38779765","id":"PMC_38779765","title":"PRR34-AS1 promotes mitochondrial division and glycolytic reprogramming in hepatocellular carcinoma cells through upregulation of MIEF2.","date":"2024","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/38779765","citation_count":3,"is_preprint":false},{"pmid":"40846102","id":"PMC_40846102","title":"Knockdown of MiD49 and MiD51 alleviates collagen-induced arthritis and suppresses mitophagy and fatty acid oxidation (FAO) in rheumatoid arthritis fibroblast-like synoviocytes.","date":"2025","source":"Free radical biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/40846102","citation_count":2,"is_preprint":false},{"pmid":"41353882","id":"PMC_41353882","title":"MARCH5-mediated MIEF2 ubiquitination and degradation contribute to gigantol to against hepatic steatosis and mitochondrial fission in alcoholic liver disease.","date":"2025","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41353882","citation_count":0,"is_preprint":false},{"pmid":"39639566","id":"PMC_39639566","title":"The Role of MIEF2 in Cisplatin Sensitivity in KIRP Patients: Insights from Four-gene Mitochondrial Fusion RNA Markers.","date":"2024","source":"Technology in cancer research & treatment","url":"https://pubmed.ncbi.nlm.nih.gov/39639566","citation_count":0,"is_preprint":false},{"pmid":"41892348","id":"PMC_41892348","title":"Mitochondrial Dynamic Proteins MiD49 and MiD51 as Novel Targets of Cardioprotection.","date":"2026","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/41892348","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":14097,"output_tokens":3473,"usd":0.047193},"stage2":{"model":"claude-opus-4-6","input_tokens":6863,"output_tokens":3073,"usd":0.16671},"total_usd":0.213903,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"MiD49 (MIEF2) is anchored in the mitochondrial outer membrane, forms foci and rings around mitochondria similar to Drp1, directly recruits Drp1 to the mitochondrial surface, and its knockdown reduces Drp1 association leading to unopposed fusion.\",\n      \"method\": \"Immunofluorescence, knockdown, overexpression, subcellular fractionation\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, foundational discovery paper, highly cited (514 citations)\",\n      \"pmids\": [\"21508961\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"MiD49 (MIEF2) can mediate Drp1 recruitment and mitochondrial fission independently of Fis1 and Mff, and its overexpression causes dominant-negative sequestration of Drp1 specifically at mitochondria (not peroxisomes), leading to unopposed fusion requiring mitofusins 1 and 2. When targeted to peroxisomes or lysosomes, MiD49 specifically recruits Drp1 to those organelles.\",\n      \"method\": \"Fis1/Mff-null cell lines, immunofluorescence, organelle targeting experiments, mitofusin knockout epistasis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple genetic epistasis and targeting experiments, replicated findings across labs\",\n      \"pmids\": [\"23921378\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Either MiD49 or MiD51 can mediate Drp1 recruitment and mitochondrial fission in the absence of both Fis1 and Mff, demonstrating functional redundancy among fission receptors; Fis1 and Mff regulate the number and size of Drp1 puncta on mitochondria.\",\n      \"method\": \"Fis1-null, Mff-null, Fis1/Mff-null cell lines; immunofluorescence of Drp1 puncta\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic null cell lines with defined phenotypic readouts, highly cited (993 citations)\",\n      \"pmids\": [\"23283981\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Crystal structure of MiD49 (MIEF2) at 2.4 Å resolution revealed a nucleotidyl transferase domain that, unlike MiD51, lacks a small-molecule ligand binding capacity due to structural changes in the putative nucleotide-binding pocket. A surface loop on MiD49 physically interacts with Drp1 and is necessary for Drp1 recruitment to the mitochondrial surface.\",\n      \"method\": \"X-ray crystallography (2.4 Å), surface entropy reduction mutagenesis, biochemical Drp1 recruitment assay\",\n      \"journal\": \"Protein science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with functional mutagenesis validation\",\n      \"pmids\": [\"25581164\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The OMM-associated E3 ubiquitin ligase MARCH5 controls MiD49 ubiquitination and proteasomal degradation; MARCH5 knockout selectively stabilizes MiD49, leading to Drp1-dependent mitochondrial fragmentation and increased sensitivity to stress-induced apoptosis. Re-expression of MARCH5 or MiD49 knockout reverses fragmentation.\",\n      \"method\": \"MARCH5 knockout cells, co-immunoprecipitation, ubiquitination assay, MiD49 knockout epistasis, proteasome inhibitor experiments\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal genetic epistasis with biochemical ubiquitination assay, replicated\",\n      \"pmids\": [\"26564796\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Drp1-dependent mitochondrial fission specifically through MiD49/MiD51 receptors (not Mff) is required for apoptotic cristae remodeling and cytochrome c release during intrinsic apoptosis; MiD49/51-KO cells completely resist cristae remodeling similarly to Drp1-KO cells, and this resistance is abolished by OPA1 depletion.\",\n      \"method\": \"MiD49/51-KO, Drp1-KO, Mff-KO cell lines; cytochrome c release assay; OPA1 depletion epistasis; electron microscopy of cristae\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple knockout lines with epistasis and defined apoptotic phenotype\",\n      \"pmids\": [\"26903540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"MiD51 can suppress Mff-dependent enhancement of Drp1 GTPase activity; proximity-based biotin labeling (BioID) confirmed close associations between MiD51, Mff and Drp1 but not Fis1; combined loss of MiD51 and Mff caused greater mitochondrial connectivity than individual losses, and MiD49/51 showed more prominent roles in apoptosis resistance than Mff.\",\n      \"method\": \"CRISPR knockout cell lines, BioID proximity labeling, Drp1 GTPase activity assay, apoptosis assays\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro GTPase assay combined with BioID and genetic epistasis\",\n      \"pmids\": [\"27076521\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Mff and Drp1 negatively regulate MARCH5 E3 ubiquitin ligase activity toward MiD49; knockout of either Drp1 or Mff led to reduced MiD49 expression, shorter half-life, and increased ubiquitination of MiD49, effects eliminated in Drp1-/-/MARCH5-/- and Mff-/-/MARCH5-/- double knockouts. Mff is an integral component of the MARCH5/p97/Npl4 complex.\",\n      \"method\": \"Double knockout cell lines, co-immunoprecipitation, ubiquitination assay, pulse-chase half-life measurement\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal double-knockout epistasis with biochemical complex analysis\",\n      \"pmids\": [\"27932492\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Foxo3a directly targets the MIEF2 promoter and suppresses MIEF2 expression at the transcriptional level; MIEF2 knockdown reduces doxorubicin-induced mitochondrial fission and apoptosis in cardiomyocytes and protects from cardiotoxicity in vivo.\",\n      \"method\": \"Foxo3a transgenic mice, ChIP/promoter assay, MIEF2 siRNA knockdown, in vivo cardiotoxicity model\",\n      \"journal\": \"Free radical biology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct transcriptional regulation shown by promoter assay with in vivo validation\",\n      \"pmids\": [\"28137654\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Silencing MiD49 (MIEF2) or MiD51 (but not Fis1 or Mff) promotes mitochondrial fusion and causes G1-phase cell cycle arrest through ERK1/2- and CDK4-dependent mechanisms in pulmonary artery smooth muscle cells; epigenetic upregulation of MiDs via decreased miR-34a-3p drives Drp1-mediated mitotic fission, proliferation, and apoptosis resistance in PAH.\",\n      \"method\": \"siRNA knockdown, flow cytometry cell cycle analysis, confocal mitochondrial imaging, microRNA microarray, in vivo nebulized siRNA in monocrotaline-PAH rat model\",\n      \"journal\": \"Circulation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple cell and in vivo models with pathway placement (ERK1/2-CDK4), highly cited (142 citations)\",\n      \"pmids\": [\"29431643\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"X-ray co-crystal structure of DRP1 with a small-molecule inhibitor that disrupts the DRP1/MiD49 protein-protein interaction revealed that the compound locks DRP1 in a closed conformation by inducing dimerization, identifying the DRP1-MiD49 interface as an allosteric regulatory site.\",\n      \"method\": \"X-ray co-crystallography, in vitro mitochondrial fragmentation assay\",\n      \"journal\": \"ACS medicinal chemistry letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — structural determination with functional validation, single study\",\n      \"pmids\": [\"37583827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Long-chain acyl-CoA (LCACA) activates MiD49 and MiD51 by inducing their oligomerization via binding to the nucleotide-binding pocket, which stimulates DRP1 GTPase activity. A point mutation in MiD51's nucleotide-binding pocket reduces LCACA binding and LCACA-induced oligomerization. This LCACA binding mutant fails to assemble into puncta or rescue mitochondrial length/DRP1 recruitment in cells. MiD49/51 oligomers synergize with Mff but not actin filaments in DRP1 activation. Cellular treatment with oleic acid promotes mitochondrial fission in an MiD49/51-dependent manner.\",\n      \"method\": \"In vitro oligomerization assay, DRP1 GTPase assay, point mutagenesis, live-cell imaging, oleic acid treatment with MiD49/51 knockdown\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution, mutagenesis, and cellular validation with multiple orthogonal methods\",\n      \"pmids\": [\"38594588\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MARCH5 directly interacts with MIEF2 via co-immunoprecipitation, causing its ubiquitination and proteasomal degradation, thereby regulating mitochondrial dynamics; overexpression of MIEF2 reverses the reduction in lipid accumulation, cell death, mitochondrial fission, and MAM formation caused by MARCH5 overexpression.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, gain/loss-of-function experiments, liver-specific MARCH5 knockdown in vivo\",\n      \"journal\": \"Phytomedicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct interaction shown by Co-IP with ubiquitination assay and epistasis, single lab\",\n      \"pmids\": [\"41353882\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Knockdown of MiD49 impairs PINK1-Parkin-dependent mitophagy and CPT-1A-mediated fatty acid β-oxidation in fibroblast-like synoviocytes; protein-protein interaction analysis revealed potential interactions between MiDs and the PINK1-Parkin pathway.\",\n      \"method\": \"siRNA knockdown, PPI analysis, mitophagy assay, fatty acid oxidation assay, CIA mouse model with shRNA\",\n      \"journal\": \"Free radical biology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — functional knockdown with defined pathway readouts but PPI based on computational analysis\",\n      \"pmids\": [\"40846102\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MIEF2 (MiD49) is a mitochondrial outer membrane protein that recruits cytosolic DRP1 to the mitochondrial surface via a surface loop interaction, where it can oligomerize upon binding long-chain acyl-CoA in its nucleotidyl transferase domain to stimulate DRP1 GTPase activity and drive fission; its abundance is controlled by MARCH5-mediated ubiquitination and proteasomal degradation (regulated by Mff and Drp1), its transcription is suppressed by Foxo3a, and it specifically mediates the DRP1-dependent cristae remodeling required for cytochrome c release during apoptosis, while also coupling mitochondrial fission to cell cycle progression through ERK1/2-CDK4 signaling.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MIEF2 (MiD49) is a mitochondrial outer membrane receptor for the dynamin-related GTPase DRP1, serving as a central organizer of mitochondrial fission that couples metabolic and apoptotic signals to organelle dynamics and cell cycle progression. MIEF2 recruits cytosolic DRP1 to the mitochondrial surface through a surface loop within its nucleotidyl transferase domain, functioning independently of the alternative receptors Fis1 and Mff, and its oligomerization upon binding long-chain acyl-CoAs stimulates DRP1 GTPase activity to drive fission [PMID:21508961, PMID:25581164, PMID:38594588]. MIEF2 protein abundance is tightly controlled by MARCH5 E3 ubiquitin ligase–mediated ubiquitination and proteasomal degradation, a process negatively regulated by Mff and Drp1, while its transcription is suppressed by Foxo3a [PMID:26564796, PMID:27932492, PMID:28137654]. DRP1-dependent fission specifically through MIEF2/MiD51 (rather than Mff) is required for apoptotic cristae remodeling and cytochrome c release, and silencing MIEF2 causes G1 cell cycle arrest through ERK1/2–CDK4 signaling, linking mitochondrial fission to proliferative control [PMID:26903540, PMID:29431643].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Identification of MIEF2 as a mitochondrial outer membrane protein that directly recruits DRP1 established a new class of fission receptor independent of previously known adaptors.\",\n      \"evidence\": \"Immunofluorescence, knockdown/overexpression, and subcellular fractionation in mammalian cells\",\n      \"pmids\": [\"21508961\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of DRP1–MiD49 interaction unknown\",\n        \"Relationship to other DRP1 receptors (Mff, Fis1) not yet resolved genetically\"\n      ]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Genetic epistasis using Fis1/Mff-null cells demonstrated that MIEF2 can recruit DRP1 and drive fission independently of all other known receptors, resolving the question of receptor redundancy.\",\n      \"evidence\": \"Fis1-null, Mff-null, and Fis1/Mff double-null cell lines with DRP1 puncta quantification and organelle-targeting experiments\",\n      \"pmids\": [\"23921378\", \"23283981\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Molecular determinants on MIEF2 that contact DRP1 not yet mapped\",\n        \"Functional distinction between MIEF2 and MiD51 unclear\"\n      ]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"The 2.4 Å crystal structure of MIEF2 revealed a nucleotidyl transferase fold and identified a specific surface loop required for DRP1 recruitment, providing the first structural framework for receptor-mediated fission.\",\n      \"evidence\": \"X-ray crystallography with surface entropy reduction mutagenesis and biochemical DRP1 recruitment assays\",\n      \"pmids\": [\"25581164\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No co-structure of the MIEF2–DRP1 complex\",\n        \"Ligand binding capacity of the nucleotidyl transferase pocket in MIEF2 unresolved\"\n      ]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Discovery that MARCH5 E3 ligase ubiquitinates MIEF2 for proteasomal degradation revealed the principal mechanism controlling MIEF2 abundance and explained how excess MIEF2 drives pathological fragmentation and apoptosis sensitization.\",\n      \"evidence\": \"MARCH5-KO cells, ubiquitination assays, MiD49-KO epistasis, and proteasome inhibitor experiments\",\n      \"pmids\": [\"26564796\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Specific ubiquitin chain type on MIEF2 not determined\",\n        \"Signals that regulate MARCH5 activity toward MIEF2 unknown\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstration that DRP1-dependent cristae remodeling and cytochrome c release require MIEF2/MiD51 but not Mff distinguished the apoptotic fission pathway from homeostatic fission and positioned MIEF2 as a specific mediator of intrinsic apoptosis.\",\n      \"evidence\": \"MiD49/51-KO, Drp1-KO, Mff-KO cell lines with cytochrome c release assays, OPA1 epistasis, and electron microscopy\",\n      \"pmids\": [\"26903540\", \"27076521\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"How MIEF2/MiD51 selectively remodel cristae versus simply fragmenting mitochondria is mechanistically unclear\",\n        \"Whether MIEF2 and MiD51 are individually sufficient for apoptotic remodeling not separated\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Double-knockout studies showed that Mff and Drp1 negatively regulate MARCH5-mediated ubiquitination of MIEF2, revealing a feedback circuit among fission components that tunes receptor abundance.\",\n      \"evidence\": \"Drp1−/−/MARCH5−/− and Mff−/−/MARCH5−/− double knockouts, co-immunoprecipitation, pulse-chase half-life measurement\",\n      \"pmids\": [\"27932492\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Mechanism by which Drp1 and Mff restrain MARCH5 activity toward MIEF2 is unclear\",\n        \"Role of the p97/Npl4 complex in MIEF2 extraction not fully dissected\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identification of Foxo3a as a direct transcriptional repressor of the MIEF2 promoter linked stress-responsive transcription factor signaling to mitochondrial fission control, with in vivo relevance to doxorubicin-induced cardiotoxicity.\",\n      \"evidence\": \"ChIP/promoter assay, Foxo3a transgenic mice, MIEF2 siRNA knockdown, in vivo cardiotoxicity model\",\n      \"pmids\": [\"28137654\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Other transcriptional regulators of MIEF2 not surveyed\",\n        \"Whether Foxo3a regulation is tissue-specific or general is unknown\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Silencing MIEF2 caused G1-phase arrest through ERK1/2–CDK4 signaling, establishing that MIEF2-mediated mitochondrial fission is coupled to cell cycle progression and proliferative control in vascular smooth muscle cells.\",\n      \"evidence\": \"siRNA knockdown, flow cytometry, microRNA profiling, in vivo nebulized siRNA in monocrotaline-PAH rat model\",\n      \"pmids\": [\"29431643\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct mechanistic link between mitochondrial morphology and ERK1/2 activation not identified\",\n        \"Whether this cell cycle coupling operates in non-vascular cell types is unknown\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"A co-crystal structure of DRP1 with a small-molecule inhibitor that disrupts the DRP1–MIEF2 interface identified this interaction as an allosteric regulatory site, opening a pharmacological avenue.\",\n      \"evidence\": \"X-ray co-crystallography of DRP1 with inhibitor compound, in vitro mitochondrial fragmentation assay\",\n      \"pmids\": [\"37583827\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct co-crystal of MIEF2 bound to DRP1 is available\",\n        \"In vivo efficacy of the DRP1–MIEF2 interface inhibitor not tested\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Long-chain acyl-CoAs were identified as activating ligands that bind the nucleotidyl transferase pocket and induce MIEF2 oligomerization, which stimulates DRP1 GTPase activity, directly coupling lipid metabolic status to mitochondrial fission.\",\n      \"evidence\": \"In vitro oligomerization and DRP1 GTPase assays, point mutagenesis, live-cell imaging with oleic acid treatment and MiD49/51 knockdown\",\n      \"pmids\": [\"38594588\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of LCACA binding to MIEF2 specifically (versus MiD51) not resolved\",\n        \"Physiological range of acyl-CoA concentrations at the OMM in different metabolic states not established\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"MIEF2 knockdown impaired PINK1–Parkin-dependent mitophagy and CPT-1A-mediated fatty acid β-oxidation, extending MIEF2 function beyond fission into mitophagy and metabolic regulation.\",\n      \"evidence\": \"siRNA knockdown in fibroblast-like synoviocytes, mitophagy and fatty acid oxidation assays, CIA mouse model\",\n      \"pmids\": [\"40846102\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"MIEF2–PINK1/Parkin interaction is computationally inferred rather than biochemically validated\",\n        \"Whether the mitophagy role is secondary to fission defects or a direct function is unresolved\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of the MIEF2–DRP1 complex at atomic resolution, the mechanism by which MIEF2-dependent fission specifically remodels cristae during apoptosis, and the in vivo physiological functions of MIEF2 in tissue-specific contexts remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No co-crystal structure of the MIEF2–DRP1 complex exists\",\n        \"Mechanism distinguishing apoptotic cristae remodeling from homeostatic fission through MIEF2 is unclear\",\n        \"Tissue-specific in vivo knockout phenotypes of MIEF2 have not been systematically characterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2, 5, 11]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 1, 3, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 1, 2, 5, 11]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [5, 6, 8]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [13]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"DNM1L\",\n      \"MARCH5\",\n      \"MIEF1\",\n      \"MFF\",\n      \"FOXO3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}