{"gene":"BOLA1","run_date":"2026-06-09T22:02:45","timeline":{"discoveries":[{"year":2012,"finding":"BOLA1 is a mitochondrial protein that counterbalances glutathione (GSH) depletion-induced oxidation of the mitochondrial thiol redox potential; knockdown of BOLA1 increases oxidation of mitochondrial thiol groups, and overexpression nullifies the effect of BSO and S-nitrosocysteine on mitochondrial morphology.","method":"Subcellular fractionation/localization, siRNA knockdown, overexpression with BSO/S-nitrosocysteine treatment, mitochondrial thiol redox potential measurement","journal":"Antioxidants & redox signaling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KD/OE with defined cellular phenotype (thiol oxidation, morphology), single lab, two orthogonal functional readouts","pmids":["22746225"],"is_preprint":false},{"year":2012,"finding":"BOLA1 physically interacts with the mitochondrial monothiol glutaredoxin GLRX5, as measured by co-immunoprecipitation.","method":"Co-immunoprecipitation (Co-IP)","journal":"Antioxidants & redox signaling","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single Co-IP result replicated and extended by subsequent structural studies from independent labs","pmids":["22746225"],"is_preprint":false},{"year":2017,"finding":"BOLA1 forms a [2Fe-2S] cluster-bridged heterodimeric complex with GLRX5 in which the cluster is a reduced, Rieske-type [2Fe-2S]1+ species; the BOLA1-GLRX5 complex has higher cluster binding affinity and is preferentially formed over the BOLA3-GLRX5 complex, which instead coordinates an oxidized, ferredoxin-like [2Fe-2S]2+ cluster.","method":"UV/vis, CD, EPR, and NMR spectroscopies combined with computational protein-protein docking (experimentally-driven structural models)","journal":"Biochimica et biophysica acta. General subjects","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal spectroscopic methods (UV/vis, CD, EPR, NMR) plus docking in a single rigorous study, replicated the interaction finding from a prior independent lab","pmids":["28483642"],"is_preprint":false},{"year":2014,"finding":"Structural analysis of Arabidopsis BolA1 (BolA_H group ortholog) in complex with GrxS14 reveals coordination of a Rieske-type [2Fe-2S] cluster via a histidine residue in the variable loop; NMR interaction experiments with apoproteins show a distinct heterodimer interface involving the nucleic acid binding site of BolA and the C-terminal tail of Grx.","method":"X-ray crystallography (three BolA structures solved), 3D modeling, spectroscopic analyses, NMR interaction experiments","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structures plus spectroscopy, but this is the plant ortholog (Arabidopsis), single study","pmids":["25012657"],"is_preprint":false},{"year":2020,"finding":"The [2Fe-2S]-bridged BOLA1-GLRX5 heterodimeric complex can acquire its cluster from donors ISCU or [2Fe-2S](GS)4, but not from ISCA1 or ISCA2; once formed, holo BOLA1-GLRX5 is incapable of donating the cluster to apo protein acceptors, supporting a non-trafficking (likely redox) role. A BOLA1 homodimer can also form and does exhibit facile cluster exchange reactivity, unlike the more thermodynamically stable heterodimer.","method":"CD spectroscopy-based kinetic cluster exchange assays in vitro","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with defined donors/acceptors, single lab, single orthogonal method (CD spectroscopy)","pmids":["32542995"],"is_preprint":false},{"year":2023,"finding":"In Giardia intestinalis mitosomes, a BolA1 homologue was identified that specifically interacts with Grx5 and with other core mitosomal components; CRISPR/Cas9 full knockout of bolA1 did not significantly affect mitosome number or their capacity to form [2Fe-2S] clusters in vitro, indicating BOLA1 is dispensable for core [2Fe-2S] biosynthesis in this anaerobic organism.","method":"Affinity pulldown, CRISPR/Cas9 knockout, in vitro [2Fe-2S] cluster formation assay","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with defined phenotypic readout plus pulldown, but in a divergent protist ortholog","pmids":["37792908"],"is_preprint":false}],"current_model":"BOLA1 is a mitochondrial protein that regulates the mitochondrial thiol redox potential by interacting with the monothiol glutaredoxin GLRX5; together they form a [2Fe-2S] cluster-bridged heterodimer coordinating a reduced Rieske-type [2Fe-2S]1+ cluster with higher affinity than the related BOLA3-GLRX5 complex, and in vitro cluster exchange experiments show this complex receives its cluster from ISCU or glutathione-coordinated [2Fe-2S] but cannot donate it to downstream acceptors, consistent with a redox rather than iron-sulfur trafficking role."},"narrative":{"mechanistic_narrative":"BOLA1 is a mitochondrial protein that buffers the mitochondrial thiol redox potential against glutathione depletion, with knockdown increasing oxidation of mitochondrial thiols and overexpression protecting mitochondrial morphology from oxidative challenge [PMID:22746225]. It executes this function through a direct physical partnership with the monothiol glutaredoxin GLRX5 [PMID:22746225], forming a [2Fe-2S] cluster-bridged heterodimer that uniquely coordinates a reduced, Rieske-type [2Fe-2S]1+ cluster and is preferentially assembled over the related BOLA3-GLRX5 complex, which instead holds an oxidized ferredoxin-like cluster [PMID:28483642]. In vitro, this heterodimer can acquire its cluster from ISCU or glutathione-coordinated [2Fe-2S] but not from ISCA1/ISCA2, and once formed cannot donate the cluster to apo acceptors, marking BOLA1-GLRX5 as a redox-active rather than iron-sulfur trafficking species [PMID:32542995]. Consistent with this non-essential role in cluster biogenesis, knockout of the BolA1 homologue in Giardia mitosomes leaves [2Fe-2S] cluster formation intact [PMID:37792908].","teleology":[{"year":2012,"claim":"Established that BOLA1 is a mitochondrial factor controlling the thiol redox environment, answering whether the uncharacterized protein had any defined cellular function.","evidence":"Subcellular fractionation, siRNA knockdown and overexpression with BSO/S-nitrosocysteine, plus mitochondrial thiol redox potential measurement in cultured cells","pmids":["22746225"],"confidence":"Medium","gaps":["Molecular mechanism linking BOLA1 to thiol potential not defined","Did not identify the cofactor or binding partner mediating the effect"]},{"year":2012,"claim":"Identified GLRX5 as a direct BOLA1 partner, providing the molecular link between BOLA1 and glutaredoxin-based redox chemistry.","evidence":"Co-immunoprecipitation","pmids":["22746225"],"confidence":"Medium","gaps":["Single Co-IP without reciprocal or stoichiometric validation at this stage","Nature of the interaction interface and any shared cofactor unknown"]},{"year":2014,"claim":"Resolved the structural basis of BolA-glutaredoxin assembly and cluster coordination using the Arabidopsis ortholog, revealing a Rieske-type [2Fe-2S] cluster ligated by a variable-loop histidine and a defined heterodimer interface.","evidence":"X-ray crystallography of three BolA structures, 3D modeling, spectroscopy and NMR interaction experiments on the plant ortholog","pmids":["25012657"],"confidence":"Medium","gaps":["Plant ortholog, not human BOLA1","Functional consequence of the Rieske-type coordination not established in this study"]},{"year":2017,"claim":"Defined the human BOLA1-GLRX5 complex as a [2Fe-2S]-bridged heterodimer holding a reduced Rieske-type cluster, distinguishing it from the oxidized cluster of BOLA3-GLRX5 and establishing a redox-distinct identity.","evidence":"UV/vis, CD, EPR and NMR spectroscopy with experimentally-driven protein-protein docking","pmids":["28483642"],"confidence":"High","gaps":["In-cell relevance of the reduced cluster redox state not demonstrated","Physiological electron donor/acceptor of the cluster unidentified"]},{"year":2020,"claim":"Determined the directionality of cluster exchange, showing the heterodimer receives clusters from ISCU or glutathione-coordinated [2Fe-2S] but cannot donate them, ruling against a trafficking role and supporting a redox function.","evidence":"CD spectroscopy-based in vitro kinetic cluster exchange assays with defined donors and acceptors","pmids":["32542995"],"confidence":"Medium","gaps":["Single in vitro method, single lab","Physiological redox substrate not identified","Relevance of the reactive BOLA1 homodimer in cells unknown"]},{"year":2023,"claim":"Tested whether BOLA1 is required for iron-sulfur cluster biogenesis, finding it dispensable for core [2Fe-2S] formation in a divergent anaerobic organism while confirming the conserved Grx5 interaction.","evidence":"Affinity pulldown, CRISPR/Cas9 knockout and in vitro [2Fe-2S] cluster formation assay in Giardia intestinalis mitosomes","pmids":["37792908"],"confidence":"Medium","gaps":["Divergent protist ortholog may not reflect human biology","Redox-buffering role not directly tested by this knockout"]},{"year":null,"claim":"The physiological electron donor/acceptor of the reduced BOLA1-GLRX5 cluster and the in-cell mechanism by which BOLA1 buffers the mitochondrial thiol potential remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No identified physiological redox partner for the cluster","No structural model of the human holo-complex from direct experimental coordinates","Link between cluster redox state and the measured thiol-potential phenotype not mechanistically closed"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140299","term_label":"molecular sensor activity","supporting_discovery_ids":[0,4]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[0]}],"complexes":["BOLA1-GLRX5 [2Fe-2S]-bridged heterodimer"],"partners":["GLRX5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9Y3E2","full_name":"BolA-like protein 1","aliases":["hBolA"],"length_aa":137,"mass_kda":14.3,"function":"Acts as a mitochondrial iron-sulfur (Fe-S) cluster assembly factor that facilitates (Fe-S) cluster insertion into a subset of mitochondrial proteins (By similarity). Probably acts together with the monothiol glutaredoxin GLRX5 (PubMed:27532772). May protect cells against oxidative stress (PubMed:22746225)","subcellular_location":"Mitochondrion","url":"https://www.uniprot.org/uniprotkb/Q9Y3E2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BOLA1","classification":"Not Classified","n_dependent_lines":14,"n_total_lines":1208,"dependency_fraction":0.011589403973509934},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/BOLA1","total_profiled":1310},"omim":[{"mim_id":"613183","title":"BOLA FAMILY MEMBER 3; BOLA3","url":"https://www.omim.org/entry/613183"},{"mim_id":"613182","title":"BOLA FAMILY MEMBER 2; BOLA2","url":"https://www.omim.org/entry/613182"},{"mim_id":"613181","title":"BOLA FAMILY MEMBER 1; BOLA1","url":"https://www.omim.org/entry/613181"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/BOLA1"},"hgnc":{"alias_symbol":["CGI-143"],"prev_symbol":[]},"alphafold":{"accession":"Q9Y3E2","domains":[{"cath_id":"3.30.300.90","chopping":"52-117","consensus_level":"high","plddt":90.397,"start":52,"end":117}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y3E2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y3E2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y3E2-F1-predicted_aligned_error_v6.png","plddt_mean":76.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BOLA1","jax_strain_url":"https://www.jax.org/strain/search?query=BOLA1"},"sequence":{"accession":"Q9Y3E2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y3E2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y3E2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y3E2"}},"corpus_meta":[{"pmid":"22746225","id":"PMC_22746225","title":"BOLA1 is an aerobic protein that prevents mitochondrial morphology changes induced by glutathione depletion.","date":"2012","source":"Antioxidants & redox signaling","url":"https://pubmed.ncbi.nlm.nih.gov/22746225","citation_count":44,"is_preprint":false},{"pmid":"28483642","id":"PMC_28483642","title":"Structural insights into the molecular function of human [2Fe-2S] BOLA1-GRX5 and [2Fe-2S] BOLA3-GRX5 complexes.","date":"2017","source":"Biochimica et biophysica acta. General subjects","url":"https://pubmed.ncbi.nlm.nih.gov/28483642","citation_count":44,"is_preprint":false},{"pmid":"25012657","id":"PMC_25012657","title":"Structural and spectroscopic insights into BolA-glutaredoxin complexes.","date":"2014","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/25012657","citation_count":41,"is_preprint":false},{"pmid":"24775445","id":"PMC_24775445","title":"Use of \"one-pot, mix-and-read\" peptide-MHC class I tetramers and predictive algorithms to improve detection of cytotoxic T lymphocyte responses in cattle.","date":"2014","source":"Veterinary research","url":"https://pubmed.ncbi.nlm.nih.gov/24775445","citation_count":25,"is_preprint":false},{"pmid":"33023155","id":"PMC_33023155","title":"Systematic Surveys of Iron Homeostasis Mechanisms Reveal Ferritin Superfamily and Nucleotide Surveillance Regulation to be Modified by PINK1 Absence.","date":"2020","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/33023155","citation_count":19,"is_preprint":false},{"pmid":"26496773","id":"PMC_26496773","title":"A modern approach for epitope prediction: identification of foot-and-mouth disease virus peptides binding bovine leukocyte antigen (BoLA) class I molecules.","date":"2015","source":"Immunogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/26496773","citation_count":17,"is_preprint":false},{"pmid":"37792908","id":"PMC_37792908","title":"Adaptation of the late ISC pathway in the anaerobic mitochondrial organelles of Giardia intestinalis.","date":"2023","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/37792908","citation_count":8,"is_preprint":false},{"pmid":"32542995","id":"PMC_32542995","title":"Cluster exchange reactivity of [2Fe-2S]-bridged heterodimeric BOLA1-GLRX5.","date":"2020","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/32542995","citation_count":6,"is_preprint":false},{"pmid":"37454394","id":"PMC_37454394","title":"Self-Assembly, In Vitro Gene Transfection, and Antimicrobial Activity of Biodegradable Cationic Bolaamphiphiles.","date":"2023","source":"Langmuir : the ACS journal of surfaces and colloids","url":"https://pubmed.ncbi.nlm.nih.gov/37454394","citation_count":6,"is_preprint":false},{"pmid":"25789713","id":"PMC_25789713","title":"A method to discriminate between closely related bovine major histocompatibility complex class I alleles by combining established PCR-SSP assays with RFLPs.","date":"2015","source":"Tissue antigens","url":"https://pubmed.ncbi.nlm.nih.gov/25789713","citation_count":5,"is_preprint":false},{"pmid":"40697080","id":"PMC_40697080","title":"Multi-omics study of mitochondrial dysfunction in the pathogenesis of hyperuricemia.","date":"2025","source":"Renal failure","url":"https://pubmed.ncbi.nlm.nih.gov/40697080","citation_count":1,"is_preprint":false},{"pmid":"39510574","id":"PMC_39510574","title":"BOLA family genes are the drivers and potential biomarkers of survival in kidney renal clear cell carcinoma patients.","date":"2024","source":"Saudi medical journal","url":"https://pubmed.ncbi.nlm.nih.gov/39510574","citation_count":1,"is_preprint":false},{"pmid":"41154064","id":"PMC_41154064","title":"Selenium Supplementation Mitigates Copper-Induced Systemic Toxicity via Transcriptomic Reprogramming and Redox Homeostasis in Mice.","date":"2025","source":"Foods (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/41154064","citation_count":1,"is_preprint":false},{"pmid":"41107716","id":"PMC_41107716","title":"Causal effects and mediation pathways of circulating plasma proteins on osteoporosis: a two-sample and two-step Mendelian randomization study.","date":"2025","source":"Clinical proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/41107716","citation_count":0,"is_preprint":false},{"pmid":"39893495","id":"PMC_39893495","title":"Mediating Mendelian randomization in the proteome identified potential drug targets for obesity-related allergic asthma.","date":"2025","source":"Hereditas","url":"https://pubmed.ncbi.nlm.nih.gov/39893495","citation_count":0,"is_preprint":false},{"pmid":"41429525","id":"PMC_41429525","title":"[Exploring potential molecular biomarkers of gestational diabetes mellitus through multi-omics data integration].","date":"2025","source":"Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi","url":"https://pubmed.ncbi.nlm.nih.gov/41429525","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11200,"output_tokens":1633,"usd":0.029048,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8409,"output_tokens":2282,"usd":0.049548,"stage2_stop_reason":"end_turn"},"total_usd":0.078596,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2012,\n      \"finding\": \"BOLA1 is a mitochondrial protein that counterbalances glutathione (GSH) depletion-induced oxidation of the mitochondrial thiol redox potential; knockdown of BOLA1 increases oxidation of mitochondrial thiol groups, and overexpression nullifies the effect of BSO and S-nitrosocysteine on mitochondrial morphology.\",\n      \"method\": \"Subcellular fractionation/localization, siRNA knockdown, overexpression with BSO/S-nitrosocysteine treatment, mitochondrial thiol redox potential measurement\",\n      \"journal\": \"Antioxidants & redox signaling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KD/OE with defined cellular phenotype (thiol oxidation, morphology), single lab, two orthogonal functional readouts\",\n      \"pmids\": [\"22746225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"BOLA1 physically interacts with the mitochondrial monothiol glutaredoxin GLRX5, as measured by co-immunoprecipitation.\",\n      \"method\": \"Co-immunoprecipitation (Co-IP)\",\n      \"journal\": \"Antioxidants & redox signaling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single Co-IP result replicated and extended by subsequent structural studies from independent labs\",\n      \"pmids\": [\"22746225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"BOLA1 forms a [2Fe-2S] cluster-bridged heterodimeric complex with GLRX5 in which the cluster is a reduced, Rieske-type [2Fe-2S]1+ species; the BOLA1-GLRX5 complex has higher cluster binding affinity and is preferentially formed over the BOLA3-GLRX5 complex, which instead coordinates an oxidized, ferredoxin-like [2Fe-2S]2+ cluster.\",\n      \"method\": \"UV/vis, CD, EPR, and NMR spectroscopies combined with computational protein-protein docking (experimentally-driven structural models)\",\n      \"journal\": \"Biochimica et biophysica acta. General subjects\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal spectroscopic methods (UV/vis, CD, EPR, NMR) plus docking in a single rigorous study, replicated the interaction finding from a prior independent lab\",\n      \"pmids\": [\"28483642\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Structural analysis of Arabidopsis BolA1 (BolA_H group ortholog) in complex with GrxS14 reveals coordination of a Rieske-type [2Fe-2S] cluster via a histidine residue in the variable loop; NMR interaction experiments with apoproteins show a distinct heterodimer interface involving the nucleic acid binding site of BolA and the C-terminal tail of Grx.\",\n      \"method\": \"X-ray crystallography (three BolA structures solved), 3D modeling, spectroscopic analyses, NMR interaction experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structures plus spectroscopy, but this is the plant ortholog (Arabidopsis), single study\",\n      \"pmids\": [\"25012657\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The [2Fe-2S]-bridged BOLA1-GLRX5 heterodimeric complex can acquire its cluster from donors ISCU or [2Fe-2S](GS)4, but not from ISCA1 or ISCA2; once formed, holo BOLA1-GLRX5 is incapable of donating the cluster to apo protein acceptors, supporting a non-trafficking (likely redox) role. A BOLA1 homodimer can also form and does exhibit facile cluster exchange reactivity, unlike the more thermodynamically stable heterodimer.\",\n      \"method\": \"CD spectroscopy-based kinetic cluster exchange assays in vitro\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with defined donors/acceptors, single lab, single orthogonal method (CD spectroscopy)\",\n      \"pmids\": [\"32542995\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In Giardia intestinalis mitosomes, a BolA1 homologue was identified that specifically interacts with Grx5 and with other core mitosomal components; CRISPR/Cas9 full knockout of bolA1 did not significantly affect mitosome number or their capacity to form [2Fe-2S] clusters in vitro, indicating BOLA1 is dispensable for core [2Fe-2S] biosynthesis in this anaerobic organism.\",\n      \"method\": \"Affinity pulldown, CRISPR/Cas9 knockout, in vitro [2Fe-2S] cluster formation assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with defined phenotypic readout plus pulldown, but in a divergent protist ortholog\",\n      \"pmids\": [\"37792908\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"BOLA1 is a mitochondrial protein that regulates the mitochondrial thiol redox potential by interacting with the monothiol glutaredoxin GLRX5; together they form a [2Fe-2S] cluster-bridged heterodimer coordinating a reduced Rieske-type [2Fe-2S]1+ cluster with higher affinity than the related BOLA3-GLRX5 complex, and in vitro cluster exchange experiments show this complex receives its cluster from ISCU or glutathione-coordinated [2Fe-2S] but cannot donate it to downstream acceptors, consistent with a redox rather than iron-sulfur trafficking role.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"BOLA1 is a mitochondrial protein that buffers the mitochondrial thiol redox potential against glutathione depletion, with knockdown increasing oxidation of mitochondrial thiols and overexpression protecting mitochondrial morphology from oxidative challenge [#0]. It executes this function through a direct physical partnership with the monothiol glutaredoxin GLRX5 [#1], forming a [2Fe-2S] cluster-bridged heterodimer that uniquely coordinates a reduced, Rieske-type [2Fe-2S]1+ cluster and is preferentially assembled over the related BOLA3-GLRX5 complex, which instead holds an oxidized ferredoxin-like cluster [#2]. In vitro, this heterodimer can acquire its cluster from ISCU or glutathione-coordinated [2Fe-2S] but not from ISCA1/ISCA2, and once formed cannot donate the cluster to apo acceptors, marking BOLA1-GLRX5 as a redox-active rather than iron-sulfur trafficking species [#4]. Consistent with this non-essential role in cluster biogenesis, knockout of the BolA1 homologue in Giardia mitosomes leaves [2Fe-2S] cluster formation intact [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2012,\n      \"claim\": \"Established that BOLA1 is a mitochondrial factor controlling the thiol redox environment, answering whether the uncharacterized protein had any defined cellular function.\",\n      \"evidence\": \"Subcellular fractionation, siRNA knockdown and overexpression with BSO/S-nitrosocysteine, plus mitochondrial thiol redox potential measurement in cultured cells\",\n      \"pmids\": [\"22746225\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism linking BOLA1 to thiol potential not defined\", \"Did not identify the cofactor or binding partner mediating the effect\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identified GLRX5 as a direct BOLA1 partner, providing the molecular link between BOLA1 and glutaredoxin-based redox chemistry.\",\n      \"evidence\": \"Co-immunoprecipitation\",\n      \"pmids\": [\"22746225\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single Co-IP without reciprocal or stoichiometric validation at this stage\", \"Nature of the interaction interface and any shared cofactor unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Resolved the structural basis of BolA-glutaredoxin assembly and cluster coordination using the Arabidopsis ortholog, revealing a Rieske-type [2Fe-2S] cluster ligated by a variable-loop histidine and a defined heterodimer interface.\",\n      \"evidence\": \"X-ray crystallography of three BolA structures, 3D modeling, spectroscopy and NMR interaction experiments on the plant ortholog\",\n      \"pmids\": [\"25012657\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Plant ortholog, not human BOLA1\", \"Functional consequence of the Rieske-type coordination not established in this study\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined the human BOLA1-GLRX5 complex as a [2Fe-2S]-bridged heterodimer holding a reduced Rieske-type cluster, distinguishing it from the oxidized cluster of BOLA3-GLRX5 and establishing a redox-distinct identity.\",\n      \"evidence\": \"UV/vis, CD, EPR and NMR spectroscopy with experimentally-driven protein-protein docking\",\n      \"pmids\": [\"28483642\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In-cell relevance of the reduced cluster redox state not demonstrated\", \"Physiological electron donor/acceptor of the cluster unidentified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Determined the directionality of cluster exchange, showing the heterodimer receives clusters from ISCU or glutathione-coordinated [2Fe-2S] but cannot donate them, ruling against a trafficking role and supporting a redox function.\",\n      \"evidence\": \"CD spectroscopy-based in vitro kinetic cluster exchange assays with defined donors and acceptors\",\n      \"pmids\": [\"32542995\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single in vitro method, single lab\", \"Physiological redox substrate not identified\", \"Relevance of the reactive BOLA1 homodimer in cells unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Tested whether BOLA1 is required for iron-sulfur cluster biogenesis, finding it dispensable for core [2Fe-2S] formation in a divergent anaerobic organism while confirming the conserved Grx5 interaction.\",\n      \"evidence\": \"Affinity pulldown, CRISPR/Cas9 knockout and in vitro [2Fe-2S] cluster formation assay in Giardia intestinalis mitosomes\",\n      \"pmids\": [\"37792908\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Divergent protist ortholog may not reflect human biology\", \"Redox-buffering role not directly tested by this knockout\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The physiological electron donor/acceptor of the reduced BOLA1-GLRX5 cluster and the in-cell mechanism by which BOLA1 buffers the mitochondrial thiol potential remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No identified physiological redox partner for the cluster\", \"No structural model of the human holo-complex from direct experimental coordinates\", \"Link between cluster redox state and the measured thiol-potential phenotype not mechanistically closed\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140299\", \"supporting_discovery_ids\": [0, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [\"BOLA1-GLRX5 [2Fe-2S]-bridged heterodimer\"],\n    \"partners\": [\"GLRX5\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}