{"gene":"ATAD3B","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2021,"finding":"ATAD3B functions as a mitophagy receptor through a LIR motif that directly binds LC3, promoting oxidative stress-induced mitophagy in a PINK1-independent manner to clear damaged mtDNA.","method":"Co-IP, LIR motif mutagenesis, LC3 binding assays, mitophagy flux assays in cells with oxidative stress","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (Co-IP, mutagenesis, functional mitophagy assays) in a single rigorous study","pmids":["33665835"],"is_preprint":false},{"year":2021,"finding":"Under normal conditions, ATAD3B hetero-oligomerizes with ATAD3A, targeting the ATAD3B C-terminal region to the mitochondrial intermembrane space; oxidative stress or mtDNA damage reduces this hetero-oligomerization and exposes the ATAD3B C-terminus at the mitochondrial outer membrane, enabling LC3 recruitment.","method":"Co-IP, subcellular fractionation, live imaging, oxidative stress perturbations, mtDNA depletion experiments","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP with orthogonal fractionation and functional consequence demonstrated","pmids":["33665835"],"is_preprint":false},{"year":2012,"finding":"ATAD3B associates with ATAD3A and negatively regulates ATAD3A's interaction with mitochondrial matrix nucleoid complexes, contributing to mitochondrial fragmentation.","method":"Co-IP, loss- and gain-of-function experiments, mitochondrial morphology assays","journal":"Mitochondrion","confidence":"Medium","confidence_rationale":"Tier 2/3 — Co-IP plus functional phenotype in single lab study","pmids":["22664726"],"is_preprint":false},{"year":2006,"finding":"ATAD3B (AAA-TOB3) encodes two distinct protein isoforms (AAA-TOB3s and AAA-TOB3l) generated from distinct transcription initiation sites, both localized to mitochondria; knockdown of both isoforms results in polynuclear cells, decreased proliferation, and increased apoptosis, indicating a required role in correct cell division.","method":"siRNA knockdown, RT-PCR, Western blot, confocal immunofluorescence, cell cycle analysis","journal":"Cellular and molecular life sciences : CMLS","confidence":"Medium","confidence_rationale":"Tier 2 — KD with defined cellular phenotype (polynucleation) and mitochondrial localization confirmed","pmids":["16909202"],"is_preprint":false},{"year":2026,"finding":"SEC62 at mitochondria-associated membranes (MAMs) directly interacts with ATAD3B, leading to downregulation of ATAD3B expression, defective mitophagy, increased mitochondrial ROS, and amplified inflammatory responses in the context of MASH.","method":"Co-IP, SEC62 overexpression/knockout in hepatocytes, mitophagy assays, ROS measurement","journal":"Metabolism: clinical and experimental","confidence":"Medium","confidence_rationale":"Tier 2/3 — direct interaction shown by Co-IP with functional downstream phenotypes, single study","pmids":["42001994"],"is_preprint":false},{"year":2017,"finding":"Chimeric ATAD3B/ATAD3A fusion genes generated by deletions in the ATAD3 gene cluster cause mitochondrial DNA abnormalities and altered cholesterol metabolism in patient fibroblasts, demonstrating that the ATAD3 proteins are required for both mtDNA organization and cholesterol homeostasis.","method":"Patient fibroblast studies, SNP array, WES, mtDNA analysis, cholesterol metabolism assays","journal":"Brain : a journal of neurology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple biochemical readouts in patient-derived cells, replicated across four families","pmids":["28549128"],"is_preprint":false},{"year":2020,"finding":"ATAD3B co-precipitates with NEK10 kinase in HEK293T cells, identifying ATAD3B as a potential interactor of NEK10 in a mitochondrial context.","method":"FLAG co-immunoprecipitation followed by LC-MS/MS proteomics","journal":"Proteome science","confidence":"Low","confidence_rationale":"Tier 3 — single Co-IP/MS experiment, no functional follow-up specific to ATAD3B","pmids":["32368190"],"is_preprint":false}],"current_model":"ATAD3B is a primate-specific mitochondrial AAA-ATPase that normally hetero-oligomerizes with ATAD3A to keep its C-terminus in the intermembrane space, negatively regulates ATAD3A's interaction with nucleoid complexes, and—upon oxidative stress-induced mtDNA damage that disrupts the ATAD3A–ATAD3B complex—exposes a LIR motif at the outer mitochondrial membrane to recruit LC3 and drive PINK1-independent mitophagy for selective clearance of damaged mtDNA."},"narrative":{"teleology":[{"year":2006,"claim":"The initial characterization of ATAD3B established it as a mitochondrial AAA-ATPase with two isoforms required for normal cell division, resolving whether this gene encodes a functional protein or a pseudogene.","evidence":"siRNA knockdown in human cells with RT-PCR, Western blot, confocal imaging, and cell-cycle analysis","pmids":["16909202"],"confidence":"Medium","gaps":["Mechanism linking mitochondrial ATAD3B to polynucleation unknown","ATPase activity not directly demonstrated","Relationship to the paralog ATAD3A not defined"]},{"year":2012,"claim":"ATAD3B was shown to hetero-oligomerize with ATAD3A and negatively regulate ATAD3A's association with nucleoid complexes, establishing the first functional relationship between the two paralogs and linking ATAD3B to mtDNA organization and mitochondrial morphology.","evidence":"Co-IP, gain- and loss-of-function experiments, mitochondrial morphology assays in human cells","pmids":["22664726"],"confidence":"Medium","gaps":["Stoichiometry and structural basis of the ATAD3A–ATAD3B oligomer unresolved","Direct contact sites with nucleoid proteins not mapped","Regulatory signals controlling hetero-oligomerization unknown"]},{"year":2017,"claim":"Patient genetics demonstrated that disruption of the ATAD3 gene cluster (generating ATAD3B/ATAD3A chimeric fusions) causes a fatal neurological disorder with mtDNA abnormalities and altered cholesterol metabolism, establishing disease relevance and a dual role in mtDNA maintenance and lipid homeostasis.","evidence":"SNP array, WES, mtDNA analysis, and cholesterol assays in fibroblasts from four unrelated families","pmids":["28549128"],"confidence":"Medium","gaps":["Contribution of ATAD3B loss versus gain of a chimeric protein not disentangled","Mechanism linking ATAD3 proteins to cholesterol metabolism not defined"]},{"year":2021,"claim":"The key mechanistic advance was demonstrating that ATAD3B acts as a mitophagy receptor: oxidative stress disrupts ATAD3A–ATAD3B hetero-oligomerization, exposing a C-terminal LIR motif on the outer mitochondrial membrane that directly binds LC3 to drive PINK1-independent mitophagy and selective clearance of damaged mtDNA.","evidence":"Reciprocal Co-IP, LIR motif mutagenesis, LC3 binding assays, subcellular fractionation, mitophagy flux assays under oxidative stress, mtDNA depletion experiments","pmids":["33665835"],"confidence":"High","gaps":["Structural basis for how ATAD3A masks the ATAD3B LIR motif unresolved","Whether ATAD3B also functions in non-stress mitophagy not tested","In vivo validation in animal models lacking ATAD3B not possible due to primate specificity"]},{"year":2026,"claim":"SEC62 at mitochondria-associated membranes was identified as a direct ATAD3B interactor that downregulates ATAD3B, linking impaired ATAD3B-dependent mitophagy to mitochondrial ROS accumulation and inflammatory responses in metabolic disease (MASH).","evidence":"Co-IP, SEC62 overexpression/knockout in hepatocytes, mitophagy assays, ROS measurement","pmids":["42001994"],"confidence":"Medium","gaps":["Mechanism by which SEC62 reduces ATAD3B expression (transcriptional vs. post-translational) not defined","Whether SEC62 disrupts ATAD3A–ATAD3B hetero-oligomerization specifically not tested","In vivo relevance in human MASH liver tissue not confirmed"]},{"year":null,"claim":"The structural basis of ATAD3A–ATAD3B hetero-oligomerization, the mechanism by which oligomer disassembly exposes the LIR motif, and the ATPase-dependent versus ATPase-independent functions of ATAD3B remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No crystal or cryo-EM structure of the ATAD3A–ATAD3B complex","ATPase activity of ATAD3B not directly measured","Selectivity mechanism for damaged versus healthy mtDNA nucleoids not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[0,3]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,1,2,3]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0,1,4]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[2,5]}],"complexes":["ATAD3A–ATAD3B hetero-oligomer"],"partners":["ATAD3A","LC3","SEC62"],"other_free_text":[]},"mechanistic_narrative":"ATAD3B is a primate-specific mitochondrial AAA-ATPase that hetero-oligomerizes with ATAD3A and negatively regulates ATAD3A's interaction with mitochondrial matrix nucleoid complexes, contributing to mitochondrial fragmentation and mtDNA organization [PMID:22664726]. Under basal conditions, the ATAD3B C-terminus is sequestered in the intermembrane space through ATAD3A binding, but oxidative stress or mtDNA damage disrupts this hetero-oligomer, exposing a LIR motif at the outer mitochondrial membrane that directly recruits LC3 to drive PINK1-independent mitophagy and selective clearance of damaged mtDNA [PMID:33665835]. Knockdown of ATAD3B causes polynucleation, decreased proliferation, and increased apoptosis, indicating a required role in cell division [PMID:16909202]. Deletions generating chimeric ATAD3B/ATAD3A fusion genes cause a fatal neurological disorder with mtDNA abnormalities and altered cholesterol metabolism [PMID:28549128]."},"prefetch_data":{"uniprot":{"accession":"Q5T9A4","full_name":"ATPase family AAA domain-containing protein 3B","aliases":["AAA-TOB3"],"length_aa":648,"mass_kda":72.6,"function":"May play a role in a mitochondrial network organization typical for stem cells, characterized by reduced mitochondrial metabolism, low mtDNA copies and fragmentated mitochondrial network. May act by suppressing ATAD3A function, interfering with ATAD3A interaction with matrix nucleoid complexes","subcellular_location":"Mitochondrion inner membrane","url":"https://www.uniprot.org/uniprotkb/Q5T9A4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ATAD3B","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/ATAD3B","total_profiled":1310},"omim":[{"mim_id":"618815","title":"CHROMOSOME 1p36.33 DUPLICATION SYNDROME, ATAD3 GENE CLUSTER, AUTOSOMAL DOMINANT","url":"https://www.omim.org/entry/618815"},{"mim_id":"618810","title":"PONTOCEREBELLAR HYPOPLASIA, HYPOTONIA, AND RESPIRATORY INSUFFICIENCY SYNDROME, NEONATAL LETHAL; PHRINL","url":"https://www.omim.org/entry/618810"},{"mim_id":"617227","title":"ATPase FAMILY, AAA DOMAIN-CONTAINING, MEMBER 3C; ATAD3C","url":"https://www.omim.org/entry/617227"},{"mim_id":"612317","title":"ATPase FAMILY, AAA DOMAIN-CONTAINING, MEMBER 3B; ATAD3B","url":"https://www.omim.org/entry/612317"},{"mim_id":"612316","title":"ATPase FAMILY, AAA DOMAIN-CONTAINING, MEMBER 3A; ATAD3A","url":"https://www.omim.org/entry/612316"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Mitochondria","reliability":"Supported"},{"location":"Acrosome","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ATAD3B"},"hgnc":{"alias_symbol":["TOB3","KIAA1273"],"prev_symbol":[]},"alphafold":{"accession":"Q5T9A4","domains":[{"cath_id":"-","chopping":"67-239","consensus_level":"medium","plddt":84.9503,"start":67,"end":239},{"cath_id":"3.40.50.300","chopping":"286-475","consensus_level":"high","plddt":85.5526,"start":286,"end":475},{"cath_id":"1.10.8.60","chopping":"480-572","consensus_level":"high","plddt":90.283,"start":480,"end":572},{"cath_id":"1.20.5","chopping":"244-279","consensus_level":"medium","plddt":78.45,"start":244,"end":279}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5T9A4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q5T9A4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q5T9A4-F1-predicted_aligned_error_v6.png","plddt_mean":76.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ATAD3B","jax_strain_url":"https://www.jax.org/strain/search?query=ATAD3B"},"sequence":{"accession":"Q5T9A4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q5T9A4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q5T9A4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5T9A4"}},"corpus_meta":[{"pmid":"27640307","id":"PMC_27640307","title":"Recurrent De Novo and Biallelic Variation of ATAD3A, Encoding a Mitochondrial Membrane Protein, Results in Distinct Neurological Syndromes.","date":"2016","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27640307","citation_count":144,"is_preprint":false},{"pmid":"28549128","id":"PMC_28549128","title":"ATAD3 gene cluster deletions cause cerebellar dysfunction associated with altered mitochondrial DNA and cholesterol metabolism.","date":"2017","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/28549128","citation_count":108,"is_preprint":false},{"pmid":"33665835","id":"PMC_33665835","title":"ATAD3B is a mitophagy receptor mediating clearance of oxidative stress-induced damaged mitochondrial DNA.","date":"2021","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/33665835","citation_count":106,"is_preprint":false},{"pmid":"20332122","id":"PMC_20332122","title":"ATPase family AAA domain-containing 3A is a novel anti-apoptotic factor in lung adenocarcinoma cells.","date":"2010","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/20332122","citation_count":80,"is_preprint":false},{"pmid":"28941010","id":"PMC_28941010","title":"ATAD3 proteins: brokers of a mitochondria-endoplasmic reticulum connection in mammalian cells.","date":"2017","source":"Biological reviews of the Cambridge Philosophical Society","url":"https://pubmed.ncbi.nlm.nih.gov/28941010","citation_count":75,"is_preprint":false},{"pmid":"15141305","id":"PMC_15141305","title":"Profile identification of disease-associated humoral antigens using AMIDA, a novel proteomics-based technology.","date":"2004","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/15141305","citation_count":57,"is_preprint":false},{"pmid":"28556940","id":"PMC_28556940","title":"Three TOB1-related YABBY genes are required to maintain proper function of the spikelet and branch meristems in rice.","date":"2017","source":"The New phytologist","url":"https://pubmed.ncbi.nlm.nih.gov/28556940","citation_count":50,"is_preprint":false},{"pmid":"22318359","id":"PMC_22318359","title":"ATAD3, a vital membrane bound mitochondrial ATPase involved in tumor progression.","date":"2012","source":"Journal of bioenergetics and biomembranes","url":"https://pubmed.ncbi.nlm.nih.gov/22318359","citation_count":48,"is_preprint":false},{"pmid":"28765560","id":"PMC_28765560","title":"Machine Learning-Assisted Network Inference Approach to Identify a New Class of Genes that Coordinate the Functionality of Cancer Networks.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28765560","citation_count":44,"is_preprint":false},{"pmid":"22664726","id":"PMC_22664726","title":"ATAD3B is a human embryonic stem cell specific mitochondrial protein, re-expressed in cancer cells, that functions as dominant negative for the ubiquitous ATAD3A.","date":"2012","source":"Mitochondrion","url":"https://pubmed.ncbi.nlm.nih.gov/22664726","citation_count":32,"is_preprint":false},{"pmid":"31727539","id":"PMC_31727539","title":"Novel ATAD3A recessive mutation associated to fatal cerebellar hypoplasia with multiorgan involvement and mitochondrial structural abnormalities.","date":"2019","source":"Molecular genetics and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/31727539","citation_count":27,"is_preprint":false},{"pmid":"16909202","id":"PMC_16909202","title":"Molecular characterization of the tumor-associated antigen AAA-TOB3.","date":"2006","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/16909202","citation_count":26,"is_preprint":false},{"pmid":"32368190","id":"PMC_32368190","title":"NEK10 interactome and depletion reveal new roles in mitochondria.","date":"2020","source":"Proteome 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assembly and function in the mitochondrial membrane\".","date":"2023","source":"Free radical biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38092275","citation_count":2,"is_preprint":false},{"pmid":"22192748","id":"PMC_22192748","title":"[ATAD3, a vital membrane-bound mitochondrial ATPase involved in tumor progression].","date":"2011","source":"Medecine sciences : M/S","url":"https://pubmed.ncbi.nlm.nih.gov/22192748","citation_count":2,"is_preprint":false},{"pmid":"40688112","id":"PMC_40688112","title":"Exploring potential therapeutic targets for colorectal tumors based on whole genome sequencing of colorectal tumors and paracancerous tissues.","date":"2025","source":"Frontiers in molecular biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/40688112","citation_count":1,"is_preprint":false},{"pmid":"42001994","id":"PMC_42001994","title":"SEC62 at mitochondria-associated membranes drives MASH progression by suppressing ATAD3B-mediated mitochondrial quality 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multiple orthogonal methods (Co-IP, mutagenesis, functional mitophagy assays) in a single rigorous study\",\n      \"pmids\": [\"33665835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Under normal conditions, ATAD3B hetero-oligomerizes with ATAD3A, targeting the ATAD3B C-terminal region to the mitochondrial intermembrane space; oxidative stress or mtDNA damage reduces this hetero-oligomerization and exposes the ATAD3B C-terminus at the mitochondrial outer membrane, enabling LC3 recruitment.\",\n      \"method\": \"Co-IP, subcellular fractionation, live imaging, oxidative stress perturbations, mtDNA depletion experiments\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP with orthogonal fractionation and functional consequence demonstrated\",\n      \"pmids\": [\"33665835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"ATAD3B associates with ATAD3A and negatively regulates ATAD3A's interaction with mitochondrial matrix nucleoid complexes, contributing to mitochondrial fragmentation.\",\n      \"method\": \"Co-IP, loss- and gain-of-function experiments, mitochondrial morphology assays\",\n      \"journal\": \"Mitochondrion\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — Co-IP plus functional phenotype in single lab study\",\n      \"pmids\": [\"22664726\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ATAD3B (AAA-TOB3) encodes two distinct protein isoforms (AAA-TOB3s and AAA-TOB3l) generated from distinct transcription initiation sites, both localized to mitochondria; knockdown of both isoforms results in polynuclear cells, decreased proliferation, and increased apoptosis, indicating a required role in correct cell division.\",\n      \"method\": \"siRNA knockdown, RT-PCR, Western blot, confocal immunofluorescence, cell cycle analysis\",\n      \"journal\": \"Cellular and molecular life sciences : CMLS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KD with defined cellular phenotype (polynucleation) and mitochondrial localization confirmed\",\n      \"pmids\": [\"16909202\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"SEC62 at mitochondria-associated membranes (MAMs) directly interacts with ATAD3B, leading to downregulation of ATAD3B expression, defective mitophagy, increased mitochondrial ROS, and amplified inflammatory responses in the context of MASH.\",\n      \"method\": \"Co-IP, SEC62 overexpression/knockout in hepatocytes, mitophagy assays, ROS measurement\",\n      \"journal\": \"Metabolism: clinical and experimental\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — direct interaction shown by Co-IP with functional downstream phenotypes, single study\",\n      \"pmids\": [\"42001994\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Chimeric ATAD3B/ATAD3A fusion genes generated by deletions in the ATAD3 gene cluster cause mitochondrial DNA abnormalities and altered cholesterol metabolism in patient fibroblasts, demonstrating that the ATAD3 proteins are required for both mtDNA organization and cholesterol homeostasis.\",\n      \"method\": \"Patient fibroblast studies, SNP array, WES, mtDNA analysis, cholesterol metabolism assays\",\n      \"journal\": \"Brain : a journal of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple biochemical readouts in patient-derived cells, replicated across four families\",\n      \"pmids\": [\"28549128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ATAD3B co-precipitates with NEK10 kinase in HEK293T cells, identifying ATAD3B as a potential interactor of NEK10 in a mitochondrial context.\",\n      \"method\": \"FLAG co-immunoprecipitation followed by LC-MS/MS proteomics\",\n      \"journal\": \"Proteome science\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP/MS experiment, no functional follow-up specific to ATAD3B\",\n      \"pmids\": [\"32368190\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ATAD3B is a primate-specific mitochondrial AAA-ATPase that normally hetero-oligomerizes with ATAD3A to keep its C-terminus in the intermembrane space, negatively regulates ATAD3A's interaction with nucleoid complexes, and—upon oxidative stress-induced mtDNA damage that disrupts the ATAD3A–ATAD3B complex—exposes a LIR motif at the outer mitochondrial membrane to recruit LC3 and drive PINK1-independent mitophagy for selective clearance of damaged mtDNA.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ATAD3B is a primate-specific mitochondrial AAA-ATPase that hetero-oligomerizes with ATAD3A and negatively regulates ATAD3A's interaction with mitochondrial matrix nucleoid complexes, contributing to mitochondrial fragmentation and mtDNA organization [PMID:22664726]. Under basal conditions, the ATAD3B C-terminus is sequestered in the intermembrane space through ATAD3A binding, but oxidative stress or mtDNA damage disrupts this hetero-oligomer, exposing a LIR motif at the outer mitochondrial membrane that directly recruits LC3 to drive PINK1-independent mitophagy and selective clearance of damaged mtDNA [PMID:33665835]. Knockdown of ATAD3B causes polynucleation, decreased proliferation, and increased apoptosis, indicating a required role in cell division [PMID:16909202]. Deletions generating chimeric ATAD3B/ATAD3A fusion genes cause a fatal neurological disorder with mtDNA abnormalities and altered cholesterol metabolism [PMID:28549128].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"The initial characterization of ATAD3B established it as a mitochondrial AAA-ATPase with two isoforms required for normal cell division, resolving whether this gene encodes a functional protein or a pseudogene.\",\n      \"evidence\": \"siRNA knockdown in human cells with RT-PCR, Western blot, confocal imaging, and cell-cycle analysis\",\n      \"pmids\": [\"16909202\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking mitochondrial ATAD3B to polynucleation unknown\", \"ATPase activity not directly demonstrated\", \"Relationship to the paralog ATAD3A not defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"ATAD3B was shown to hetero-oligomerize with ATAD3A and negatively regulate ATAD3A's association with nucleoid complexes, establishing the first functional relationship between the two paralogs and linking ATAD3B to mtDNA organization and mitochondrial morphology.\",\n      \"evidence\": \"Co-IP, gain- and loss-of-function experiments, mitochondrial morphology assays in human cells\",\n      \"pmids\": [\"22664726\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry and structural basis of the ATAD3A–ATAD3B oligomer unresolved\", \"Direct contact sites with nucleoid proteins not mapped\", \"Regulatory signals controlling hetero-oligomerization unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Patient genetics demonstrated that disruption of the ATAD3 gene cluster (generating ATAD3B/ATAD3A chimeric fusions) causes a fatal neurological disorder with mtDNA abnormalities and altered cholesterol metabolism, establishing disease relevance and a dual role in mtDNA maintenance and lipid homeostasis.\",\n      \"evidence\": \"SNP array, WES, mtDNA analysis, and cholesterol assays in fibroblasts from four unrelated families\",\n      \"pmids\": [\"28549128\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Contribution of ATAD3B loss versus gain of a chimeric protein not disentangled\", \"Mechanism linking ATAD3 proteins to cholesterol metabolism not defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"The key mechanistic advance was demonstrating that ATAD3B acts as a mitophagy receptor: oxidative stress disrupts ATAD3A–ATAD3B hetero-oligomerization, exposing a C-terminal LIR motif on the outer mitochondrial membrane that directly binds LC3 to drive PINK1-independent mitophagy and selective clearance of damaged mtDNA.\",\n      \"evidence\": \"Reciprocal Co-IP, LIR motif mutagenesis, LC3 binding assays, subcellular fractionation, mitophagy flux assays under oxidative stress, mtDNA depletion experiments\",\n      \"pmids\": [\"33665835\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for how ATAD3A masks the ATAD3B LIR motif unresolved\", \"Whether ATAD3B also functions in non-stress mitophagy not tested\", \"In vivo validation in animal models lacking ATAD3B not possible due to primate specificity\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"SEC62 at mitochondria-associated membranes was identified as a direct ATAD3B interactor that downregulates ATAD3B, linking impaired ATAD3B-dependent mitophagy to mitochondrial ROS accumulation and inflammatory responses in metabolic disease (MASH).\",\n      \"evidence\": \"Co-IP, SEC62 overexpression/knockout in hepatocytes, mitophagy assays, ROS measurement\",\n      \"pmids\": [\"42001994\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which SEC62 reduces ATAD3B expression (transcriptional vs. post-translational) not defined\", \"Whether SEC62 disrupts ATAD3A–ATAD3B hetero-oligomerization specifically not tested\", \"In vivo relevance in human MASH liver tissue not confirmed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of ATAD3A–ATAD3B hetero-oligomerization, the mechanism by which oligomer disassembly exposes the LIR motif, and the ATPase-dependent versus ATPase-independent functions of ATAD3B remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal or cryo-EM structure of the ATAD3A–ATAD3B complex\", \"ATPase activity of ATAD3B not directly measured\", \"Selectivity mechanism for damaged versus healthy mtDNA nucleoids not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 1, 2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [2, 5]}\n    ],\n    \"complexes\": [\n      \"ATAD3A–ATAD3B hetero-oligomer\"\n    ],\n    \"partners\": [\n      \"ATAD3A\",\n      \"LC3\",\n      \"SEC62\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}