{"gene":"BAZ2B","run_date":"2026-04-28T17:12:38","timeline":{"discoveries":[{"year":2015,"finding":"GSK2801 binds to BAZ2B bromodomain in an acetyl-lysine competitive manner with a KD of 136 nM; crystal structures demonstrated canonical acetyl-lysine competitive binding mode. Cellular activity confirmed by FRAP showing displacement of GFP-BAZ2A from acetylated chromatin.","method":"Crystal structure, isothermal titration calorimetry/binding assay, FRAP","journal":"Journal of medicinal chemistry","confidence":"High","confidence_rationale":"Tier 1 — crystal structure + in vitro binding assay + cellular FRAP validation","pmids":["25799074"],"is_preprint":false},{"year":2015,"finding":"BAZ2B bromodomain binds acetylated lysine in a shallow pocket; structure-based design of BAZ2-ICR inhibitor confirmed binding mode via crystal structure, with an intramolecular aromatic stacking interaction occupying the bromodomain pocket.","method":"Crystal structure, structure-based drug design, in vitro binding assay","journal":"Journal of medicinal chemistry","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with in vitro validation, replicated across two independent labs","pmids":["25719566"],"is_preprint":false},{"year":2016,"finding":"Fragment docking and X-ray crystallography revealed that the BAZ2B bromodomain acetyl-lysine pocket contains a conserved Tyr1901 residue critical for ligand binding via water-mediated hydrogen bonds; stereoselectivity of the pocket was demonstrated by chiral ligand binding.","method":"X-ray crystallography, fragment soaking, computational docking","journal":"ACS chemical biology","confidence":"High","confidence_rationale":"Tier 1 — multiple crystal structures with orthogonal computational validation","pmids":["26942307"],"is_preprint":false},{"year":2020,"finding":"BAZ2B acts as a reader of H3K14ac modification; it enhances transcription of IRF4 to promote M2 macrophage activation. The lncRNA lnc-BAZ2B stabilizes BAZ2B pre-mRNA in cis to upregulate BAZ2B expression.","method":"Western blot, ChIP assay, RNase protection assay, knockdown experiments in macrophages and mouse model","journal":"The Journal of allergy and clinical immunology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (ChIP, RNase protection, KD with phenotype) but single lab","pmids":["32712329"],"is_preprint":false},{"year":2022,"finding":"The BAZ2B TAM domain adopts a fold nearly identical to BAZ2A TAM domain and binds dsDNA without methyl-cytosine preference, as determined by crystal structure and DNA binding affinity measurements.","method":"X-ray crystallography, DNA binding affinity assay","journal":"Heliyon","confidence":"High","confidence_rationale":"Tier 1 — apo crystal structure combined with biochemical DNA-binding measurement","pmids":["35865993"],"is_preprint":false},{"year":2024,"finding":"Baz2B is a regulatory subunit of ATP-dependent chromatin remodeling complexes BRF1 and BRF5; its TAM domain with AT-hook motifs recognizes histones; cancer-associated point mutations in the bromodomain alter histone code recognition; depletion in Hap1 cells causes altered cell morphology, reduced colony formation, and perturbed transcriptional profiles without global chromatin structural changes.","method":"Biochemical domain characterization, super-resolution microscopy, transcriptomic profiling, cell line knockdown","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (biochemistry, microscopy, transcriptomics) in single lab","pmids":["38000389"],"is_preprint":false},{"year":2025,"finding":"BAZ2B directly binds promoter regions of PPARα pathway genes and reduces chromatin accessibility at these loci, thereby downregulating PPARα-mediated lipid metabolism; hepatocyte-specific Baz2b knockdown in mice attenuates hepatocyte senescence and MASH fibrosis.","method":"Chromatin accessibility assay (ATAC-seq), ChIP/CUT&RUN, hepatocyte-specific genetic knockdown in mouse, transcriptomic profiling","journal":"Nature aging","confidence":"Medium","confidence_rationale":"Tier 2 — direct chromatin binding evidence + in vivo loss-of-function with defined phenotype, single lab","pmids":["40389730"],"is_preprint":false},{"year":2026,"finding":"BAZ2B knockdown reduces H3K4me3 enrichment at promoters of myofibroblast activation-associated genes, leading to downregulation of ECM-related genes; BAZ2B promotes TGFβ1-induced fibroblast-to-myofibroblast differentiation and ECM production in endometrium.","method":"RNA-seq, CUT&Tag-seq, knockdown and overexpression in fibroblasts, mouse intrauterine adhesion model with GSK2801 treatment","journal":"Clinical science","confidence":"Medium","confidence_rationale":"Tier 2 — combined transcriptomic and epigenomic profiling with in vivo validation, single lab","pmids":["41979565"],"is_preprint":false},{"year":2024,"finding":"BAZ2B associates with G-quadruplex (G4) DNA loci and its depletion leads to increased G4 formation, especially at transcriptional regulatory elements; BAZ2B-containing chromatin remodeling complexes act as direct suppressors of G4 DNA structures and G4-related genomic instability.","method":"Chromatin remodeling enzyme screen, G4 immunofluorescence/ChIP, INDUCE-seq DSB profiling, genetic depletion","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — direct G4 loci association by ChIP with functional genomic instability readout, but preprint","pmids":["bio_10.1101_2024.12.10.627505"],"is_preprint":true},{"year":2025,"finding":"HERC2 binds to a DxDKDxD motif in BAZ2B via its RLD2 domain, identifying BAZ2B as a direct interaction partner of HERC2 E3 ubiquitin ligase.","method":"Quantitative binding assays, X-ray crystallography, sequence conservation analysis","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 — direct binding demonstrated but functional consequence for BAZ2B not characterized; preprint","pmids":["bio_10.1101_2025.09.16.670041"],"is_preprint":true}],"current_model":"BAZ2B is a multidomain chromatin remodeling regulatory subunit (of BRF1/BRF5/NoRC-related ISWI complexes) whose bromodomain reads acetylated lysine (notably H3K14ac) in a shallow, canonical pocket, whose TAM domain binds dsDNA without methylation preference, and which acts at gene promoters to reduce chromatin accessibility and regulate transcription of targets including PPARα pathway genes, IRF4, and myofibroblast activation genes, while also suppressing G-quadruplex DNA formation and genomic instability."},"narrative":{"teleology":[{"year":2015,"claim":"Structural characterization of the BAZ2B bromodomain established that it engages acetylated lysine via a shallow, canonical pocket amenable to small-molecule inhibition, providing the first atomic-resolution framework for understanding BAZ2B's histone-reading mechanism.","evidence":"Crystal structures of BAZ2B bromodomain with GSK2801 and BAZ2-ICR inhibitors, ITC binding assays, and FRAP displacement from acetylated chromatin","pmids":["25799074","25719566"],"confidence":"High","gaps":["Endogenous histone mark selectivity not systematically profiled","No information on non-bromodomain regions or full-length protein function","In vivo relevance of bromodomain-acetyl-lysine interaction untested"]},{"year":2016,"claim":"Identification of Tyr1901 as a critical pocket residue mediating water-bridged hydrogen bonds and stereoselectivity refined the molecular basis for acetyl-lysine recognition, explaining bromodomain selectivity.","evidence":"Fragment soaking X-ray crystallography with chiral ligands and computational docking","pmids":["26942307"],"confidence":"High","gaps":["Contribution of Tyr1901 not tested by mutagenesis in cellular context","Relative selectivity for specific acetylated histone peptides undefined"]},{"year":2020,"claim":"BAZ2B was shown to function as an H3K14ac reader that promotes IRF4 transcription in macrophages, establishing its first defined transcriptional target and linking it to immune cell polarization.","evidence":"ChIP, RNase protection, knockdown in macrophages and mouse model","pmids":["32712329"],"confidence":"Medium","gaps":["Whether BAZ2B directly binds H3K14ac at the IRF4 locus versus acting indirectly not fully resolved","Requirement for the bromodomain in IRF4 regulation not tested with domain mutants","Mechanism of lnc-BAZ2B stabilization of BAZ2B pre-mRNA not elucidated"]},{"year":2022,"claim":"Structural and biochemical characterization of the TAM domain revealed it adopts a fold similar to BAZ2A and binds dsDNA without methyl-cytosine preference, defining a second chromatin-reading module in BAZ2B.","evidence":"X-ray crystallography of TAM domain and DNA binding affinity measurements","pmids":["35865993"],"confidence":"High","gaps":["Genomic loci bound by the TAM domain in cells not mapped","Cooperation between TAM and bromodomain in chromatin targeting not tested"]},{"year":2024,"claim":"BAZ2B was identified as a regulatory subunit of BRF1/BRF5 chromatin remodeling complexes; cancer-associated bromodomain mutations alter histone code recognition, and depletion perturbs transcription and cell morphology without global chromatin reorganization, establishing BAZ2B as a gene-specific transcriptional modulator rather than a global chromatin architect.","evidence":"Domain biochemistry, super-resolution microscopy, transcriptomics, and Hap1 cell knockdown","pmids":["38000389"],"confidence":"Medium","gaps":["Stoichiometry and assembly pathway of BRF1/BRF5 complexes with BAZ2B not defined","Direct effects of cancer mutations on remodeling activity in vitro not measured","Mechanism by which BAZ2B selects specific genomic loci unclear"]},{"year":2025,"claim":"Direct binding of BAZ2B to PPARα pathway gene promoters was shown to reduce chromatin accessibility and repress lipid metabolism transcription in hepatocytes, with hepatocyte-specific Baz2b loss attenuating senescence and MASH fibrosis in mice, linking BAZ2B to metabolic disease.","evidence":"ATAC-seq, CUT&RUN, hepatocyte-specific Baz2b knockdown in mouse MASH model","pmids":["40389730"],"confidence":"Medium","gaps":["Whether BAZ2B-mediated repression requires its bromodomain or TAM domain not dissected","Upstream signals recruiting BAZ2B to PPARα loci not identified","Relevance to human MASH not validated"]},{"year":2026,"claim":"BAZ2B was found to maintain H3K4me3 at myofibroblast activation gene promoters, driving TGF-β1-induced fibroblast-to-myofibroblast differentiation and ECM production, broadening its role to fibrotic remodeling beyond hepatic tissue.","evidence":"RNA-seq, CUT&Tag-seq, fibroblast knockdown/overexpression, mouse intrauterine adhesion model treated with GSK2801","pmids":["41979565"],"confidence":"Medium","gaps":["Mechanism by which BAZ2B sustains H3K4me3 (direct reader vs. recruitment of methyltransferase) not resolved","Specificity of GSK2801 effects in vivo not fully controlled for off-target BAZ2A inhibition"]},{"year":null,"claim":"Key unresolved questions include how BAZ2B's bromodomain, TAM, and AT-hook domains cooperate to select specific genomic loci, how BRF1/BRF5 complex assembly is regulated, and whether BAZ2B suppression of G-quadruplex structures is mechanistically coupled to its remodeling activity or represents an independent function.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No reconstituted biochemical system demonstrating BAZ2B-dependent chromatin remodeling in vitro","Cooperative domain usage in full-length protein not characterized structurally","Functional consequence of HERC2 interaction for BAZ2B stability or activity unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[0,1,2,3]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[4,5]}],"localization":[{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[3,5,6]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[3,5,6,7]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[3,5,6,7]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[3,6,7]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[3]}],"complexes":["BRF1","BRF5"],"partners":["SNF2H","SNF2L","HERC2"],"other_free_text":[]},"mechanistic_narrative":"BAZ2B is a chromatin-associated regulatory subunit of ISWI-type ATP-dependent chromatin remodeling complexes (BRF1 and BRF5) that reads histone acetylation marks and modulates transcription at gene promoters [PMID:38000389]. Its bromodomain recognizes acetylated lysine—notably H3K14ac—through a shallow, canonical pocket featuring a conserved Tyr1901 residue critical for ligand coordination, while its TAM domain binds double-stranded DNA without methylation preference [PMID:25799074, PMID:26942307, PMID:35865993]. BAZ2B binds promoter regions to reduce chromatin accessibility and repress PPARα pathway genes in hepatocytes, enhances IRF4 transcription to promote M2 macrophage polarization, and sustains H3K4me3 at myofibroblast activation gene promoters to drive TGF-β1-induced extracellular matrix production [PMID:40389730, PMID:32712329, PMID:41979565]. BAZ2B-containing remodeling complexes also suppress G-quadruplex DNA formation at transcriptional regulatory elements, limiting G4-associated genomic instability [PMID:38000389]."},"prefetch_data":{"uniprot":{"accession":"Q9UIF8","full_name":"Bromodomain adjacent to zinc finger domain protein 2B","aliases":["hWALp4"],"length_aa":2168,"mass_kda":240.5,"function":"Regulatory subunit of the ATP-dependent BRF-1 and BRF-5 ISWI chromatin remodeling complexes, which form ordered nucleosome arrays on chromatin and facilitate access to DNA during DNA-templated processes such as DNA replication, transcription, and repair (PubMed:28801535). Both complexes regulate the spacing of nucleosomes along the chromatin and have the ability to slide mononucleosomes to the center of a DNA template (PubMed:28801535). The BRF-1 ISWI chromatin remodeling complex has a lower ATP hydrolysis rate than the BRF-5 ISWI chromatin remodeling complex (PubMed:28801535). Chromatin reader protein, which may play a role in transcriptional regulation via interaction with ISWI (By similarity) (PubMed:10662543). Involved in positively modulating the rate of age-related behavioral deterioration (By similarity). Represses the expression of mitochondrial function-related genes, perhaps by occupying their promoter regions, working in concert with histone methyltransferase EHMT1 (By similarity)","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9UIF8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BAZ2B","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CSNK2B","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/BAZ2B","total_profiled":1310},"omim":[{"mim_id":"607001","title":"EUCHROMATIC HISTONE METHYLTRANSFERASE 1; EHMT1","url":"https://www.omim.org/entry/607001"},{"mim_id":"605683","title":"BROMODOMAIN ADJACENT TO ZINC FINGER DOMAIN, 2B; BAZ2B","url":"https://www.omim.org/entry/605683"},{"mim_id":"605680","title":"BROMODOMAIN ADJACENT TO ZINC FINGER DOMAIN, 1A; BAZ1A","url":"https://www.omim.org/entry/605680"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/BAZ2B"},"hgnc":{"alias_symbol":["WALp4"],"prev_symbol":[]},"alphafold":{"accession":"Q9UIF8","domains":[{"cath_id":"3.30.890.10","chopping":"747-843","consensus_level":"high","plddt":88.6803,"start":747,"end":843},{"cath_id":"1.20.920.10","chopping":"2063-2167","consensus_level":"high","plddt":93.0915,"start":2063,"end":2167},{"cath_id":"1.20.5","chopping":"883-921","consensus_level":"medium","plddt":75.5826,"start":883,"end":921}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UIF8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UIF8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UIF8-F1-predicted_aligned_error_v6.png","plddt_mean":54.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BAZ2B","jax_strain_url":"https://www.jax.org/strain/search?query=BAZ2B"},"sequence":{"accession":"Q9UIF8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UIF8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UIF8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UIF8"}},"corpus_meta":[{"pmid":"25799074","id":"PMC_25799074","title":"Discovery and Characterization of GSK2801, a Selective Chemical Probe for the Bromodomains BAZ2A and BAZ2B.","date":"2015","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/25799074","citation_count":107,"is_preprint":false},{"pmid":"25719566","id":"PMC_25719566","title":"Structure enabled design of BAZ2-ICR, a chemical probe targeting the bromodomains of BAZ2A and BAZ2B.","date":"2015","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/25719566","citation_count":75,"is_preprint":false},{"pmid":"32712329","id":"PMC_32712329","title":"lnc-BAZ2B promotes M2 macrophage activation and inflammation in children with asthma through stabilizing BAZ2B pre-mRNA.","date":"2020","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/32712329","citation_count":59,"is_preprint":false},{"pmid":"26942307","id":"PMC_26942307","title":"High-Throughput Fragment Docking into the BAZ2B Bromodomain: Efficient in Silico Screening for X-Ray Crystallography.","date":"2016","source":"ACS chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/26942307","citation_count":30,"is_preprint":false},{"pmid":"33296649","id":"PMC_33296649","title":"The Master Regulator Protein BAZ2B Can Reprogram Human Hematopoietic Lineage-Committed Progenitors into a Multipotent State.","date":"2020","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/33296649","citation_count":26,"is_preprint":false},{"pmid":"27731638","id":"PMC_27731638","title":"Derivatives of 3-Amino-2-methylpyridine as BAZ2B Bromodomain Ligands: In Silico Discovery and in Crystallo Validation.","date":"2016","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/27731638","citation_count":21,"is_preprint":false},{"pmid":"31999386","id":"PMC_31999386","title":"BAZ2B haploinsufficiency as a cause of developmental delay, intellectual disability, and autism spectrum disorder.","date":"2020","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/31999386","citation_count":20,"is_preprint":false},{"pmid":"29770599","id":"PMC_29770599","title":"Structural Analysis of Small-Molecule Binding to the BAZ2A and BAZ2B Bromodomains.","date":"2018","source":"ChemMedChem","url":"https://pubmed.ncbi.nlm.nih.gov/29770599","citation_count":14,"is_preprint":false},{"pmid":"37872713","id":"PMC_37872713","title":"Neurodevelopmental and other phenotypes recurrently associated with heterozygous BAZ2B loss-of-function variants.","date":"2023","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/37872713","citation_count":8,"is_preprint":false},{"pmid":"40389730","id":"PMC_40389730","title":"Targeting the chromatin remodeler BAZ2B mitigates hepatic senescence and MASH fibrosis.","date":"2025","source":"Nature aging","url":"https://pubmed.ncbi.nlm.nih.gov/40389730","citation_count":8,"is_preprint":false},{"pmid":"38000389","id":"PMC_38000389","title":"Biochemical and cellular insights into the Baz2B protein, a non-catalytic subunit of the chromatin remodeling complex.","date":"2024","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/38000389","citation_count":5,"is_preprint":false},{"pmid":"35865993","id":"PMC_35865993","title":"Crystal structure of the BAZ2B TAM domain.","date":"2022","source":"Heliyon","url":"https://pubmed.ncbi.nlm.nih.gov/35865993","citation_count":4,"is_preprint":false},{"pmid":"41823793","id":"PMC_41823793","title":"Butachlor-Induced BAZ2B Activation Promotes Cardiomyocyte Senescence through cGAS-STING pathway.","date":"2026","source":"Journal of agricultural and food chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/41823793","citation_count":0,"is_preprint":false},{"pmid":"41979565","id":"PMC_41979565","title":"BAZ2B contributes to endometrial fibrosis by promoting fibroblast-to-myofibroblast differentiation.","date":"2026","source":"Clinical science (London, England : 1979)","url":"https://pubmed.ncbi.nlm.nih.gov/41979565","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.09.16.670041","title":"Structural analysis of HERC2/UBE3A and HERC2/DOCK10 complexes provides new insights into the molecular basis of Angelman, Angelman-like and Dup15q Syndromes","date":"2025-09-16","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.16.670041","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.12.10.627505","title":"The Role of BAZ2-dependent Chromatin Remodeling in Suppressing G4 DNA Structures and Associated Genomic Instability","date":"2024-12-11","source":"bioRxiv","url":"https://doi.org/10.1101/2024.12.10.627505","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8305,"output_tokens":2130,"usd":0.028432},"stage2":{"model":"claude-opus-4-6","input_tokens":5456,"output_tokens":2299,"usd":0.127133},"total_usd":0.155565,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2015,\n      \"finding\": \"GSK2801 binds to BAZ2B bromodomain in an acetyl-lysine competitive manner with a KD of 136 nM; crystal structures demonstrated canonical acetyl-lysine competitive binding mode. Cellular activity confirmed by FRAP showing displacement of GFP-BAZ2A from acetylated chromatin.\",\n      \"method\": \"Crystal structure, isothermal titration calorimetry/binding assay, FRAP\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure + in vitro binding assay + cellular FRAP validation\",\n      \"pmids\": [\"25799074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"BAZ2B bromodomain binds acetylated lysine in a shallow pocket; structure-based design of BAZ2-ICR inhibitor confirmed binding mode via crystal structure, with an intramolecular aromatic stacking interaction occupying the bromodomain pocket.\",\n      \"method\": \"Crystal structure, structure-based drug design, in vitro binding assay\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with in vitro validation, replicated across two independent labs\",\n      \"pmids\": [\"25719566\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Fragment docking and X-ray crystallography revealed that the BAZ2B bromodomain acetyl-lysine pocket contains a conserved Tyr1901 residue critical for ligand binding via water-mediated hydrogen bonds; stereoselectivity of the pocket was demonstrated by chiral ligand binding.\",\n      \"method\": \"X-ray crystallography, fragment soaking, computational docking\",\n      \"journal\": \"ACS chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — multiple crystal structures with orthogonal computational validation\",\n      \"pmids\": [\"26942307\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BAZ2B acts as a reader of H3K14ac modification; it enhances transcription of IRF4 to promote M2 macrophage activation. The lncRNA lnc-BAZ2B stabilizes BAZ2B pre-mRNA in cis to upregulate BAZ2B expression.\",\n      \"method\": \"Western blot, ChIP assay, RNase protection assay, knockdown experiments in macrophages and mouse model\",\n      \"journal\": \"The Journal of allergy and clinical immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (ChIP, RNase protection, KD with phenotype) but single lab\",\n      \"pmids\": [\"32712329\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The BAZ2B TAM domain adopts a fold nearly identical to BAZ2A TAM domain and binds dsDNA without methyl-cytosine preference, as determined by crystal structure and DNA binding affinity measurements.\",\n      \"method\": \"X-ray crystallography, DNA binding affinity assay\",\n      \"journal\": \"Heliyon\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — apo crystal structure combined with biochemical DNA-binding measurement\",\n      \"pmids\": [\"35865993\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Baz2B is a regulatory subunit of ATP-dependent chromatin remodeling complexes BRF1 and BRF5; its TAM domain with AT-hook motifs recognizes histones; cancer-associated point mutations in the bromodomain alter histone code recognition; depletion in Hap1 cells causes altered cell morphology, reduced colony formation, and perturbed transcriptional profiles without global chromatin structural changes.\",\n      \"method\": \"Biochemical domain characterization, super-resolution microscopy, transcriptomic profiling, cell line knockdown\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (biochemistry, microscopy, transcriptomics) in single lab\",\n      \"pmids\": [\"38000389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"BAZ2B directly binds promoter regions of PPARα pathway genes and reduces chromatin accessibility at these loci, thereby downregulating PPARα-mediated lipid metabolism; hepatocyte-specific Baz2b knockdown in mice attenuates hepatocyte senescence and MASH fibrosis.\",\n      \"method\": \"Chromatin accessibility assay (ATAC-seq), ChIP/CUT&RUN, hepatocyte-specific genetic knockdown in mouse, transcriptomic profiling\",\n      \"journal\": \"Nature aging\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct chromatin binding evidence + in vivo loss-of-function with defined phenotype, single lab\",\n      \"pmids\": [\"40389730\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"BAZ2B knockdown reduces H3K4me3 enrichment at promoters of myofibroblast activation-associated genes, leading to downregulation of ECM-related genes; BAZ2B promotes TGFβ1-induced fibroblast-to-myofibroblast differentiation and ECM production in endometrium.\",\n      \"method\": \"RNA-seq, CUT&Tag-seq, knockdown and overexpression in fibroblasts, mouse intrauterine adhesion model with GSK2801 treatment\",\n      \"journal\": \"Clinical science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — combined transcriptomic and epigenomic profiling with in vivo validation, single lab\",\n      \"pmids\": [\"41979565\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"BAZ2B associates with G-quadruplex (G4) DNA loci and its depletion leads to increased G4 formation, especially at transcriptional regulatory elements; BAZ2B-containing chromatin remodeling complexes act as direct suppressors of G4 DNA structures and G4-related genomic instability.\",\n      \"method\": \"Chromatin remodeling enzyme screen, G4 immunofluorescence/ChIP, INDUCE-seq DSB profiling, genetic depletion\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct G4 loci association by ChIP with functional genomic instability readout, but preprint\",\n      \"pmids\": [\"bio_10.1101_2024.12.10.627505\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"HERC2 binds to a DxDKDxD motif in BAZ2B via its RLD2 domain, identifying BAZ2B as a direct interaction partner of HERC2 E3 ubiquitin ligase.\",\n      \"method\": \"Quantitative binding assays, X-ray crystallography, sequence conservation analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — direct binding demonstrated but functional consequence for BAZ2B not characterized; preprint\",\n      \"pmids\": [\"bio_10.1101_2025.09.16.670041\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"BAZ2B is a multidomain chromatin remodeling regulatory subunit (of BRF1/BRF5/NoRC-related ISWI complexes) whose bromodomain reads acetylated lysine (notably H3K14ac) in a shallow, canonical pocket, whose TAM domain binds dsDNA without methylation preference, and which acts at gene promoters to reduce chromatin accessibility and regulate transcription of targets including PPARα pathway genes, IRF4, and myofibroblast activation genes, while also suppressing G-quadruplex DNA formation and genomic instability.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"BAZ2B is a chromatin-associated regulatory subunit of ISWI-type ATP-dependent chromatin remodeling complexes (BRF1 and BRF5) that reads histone acetylation marks and modulates transcription at gene promoters [PMID:38000389]. Its bromodomain recognizes acetylated lysine—notably H3K14ac—through a shallow, canonical pocket featuring a conserved Tyr1901 residue critical for ligand coordination, while its TAM domain binds double-stranded DNA without methylation preference [PMID:25799074, PMID:26942307, PMID:35865993]. BAZ2B binds promoter regions to reduce chromatin accessibility and repress PPARα pathway genes in hepatocytes, enhances IRF4 transcription to promote M2 macrophage polarization, and sustains H3K4me3 at myofibroblast activation gene promoters to drive TGF-β1-induced extracellular matrix production [PMID:40389730, PMID:32712329, PMID:41979565]. BAZ2B-containing remodeling complexes also suppress G-quadruplex DNA formation at transcriptional regulatory elements, limiting G4-associated genomic instability [PMID:38000389].\",\n  \"teleology\": [\n    {\n      \"year\": 2015,\n      \"claim\": \"Structural characterization of the BAZ2B bromodomain established that it engages acetylated lysine via a shallow, canonical pocket amenable to small-molecule inhibition, providing the first atomic-resolution framework for understanding BAZ2B's histone-reading mechanism.\",\n      \"evidence\": \"Crystal structures of BAZ2B bromodomain with GSK2801 and BAZ2-ICR inhibitors, ITC binding assays, and FRAP displacement from acetylated chromatin\",\n      \"pmids\": [\"25799074\", \"25719566\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Endogenous histone mark selectivity not systematically profiled\",\n        \"No information on non-bromodomain regions or full-length protein function\",\n        \"In vivo relevance of bromodomain-acetyl-lysine interaction untested\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identification of Tyr1901 as a critical pocket residue mediating water-bridged hydrogen bonds and stereoselectivity refined the molecular basis for acetyl-lysine recognition, explaining bromodomain selectivity.\",\n      \"evidence\": \"Fragment soaking X-ray crystallography with chiral ligands and computational docking\",\n      \"pmids\": [\"26942307\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Contribution of Tyr1901 not tested by mutagenesis in cellular context\",\n        \"Relative selectivity for specific acetylated histone peptides undefined\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"BAZ2B was shown to function as an H3K14ac reader that promotes IRF4 transcription in macrophages, establishing its first defined transcriptional target and linking it to immune cell polarization.\",\n      \"evidence\": \"ChIP, RNase protection, knockdown in macrophages and mouse model\",\n      \"pmids\": [\"32712329\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether BAZ2B directly binds H3K14ac at the IRF4 locus versus acting indirectly not fully resolved\",\n        \"Requirement for the bromodomain in IRF4 regulation not tested with domain mutants\",\n        \"Mechanism of lnc-BAZ2B stabilization of BAZ2B pre-mRNA not elucidated\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Structural and biochemical characterization of the TAM domain revealed it adopts a fold similar to BAZ2A and binds dsDNA without methyl-cytosine preference, defining a second chromatin-reading module in BAZ2B.\",\n      \"evidence\": \"X-ray crystallography of TAM domain and DNA binding affinity measurements\",\n      \"pmids\": [\"35865993\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Genomic loci bound by the TAM domain in cells not mapped\",\n        \"Cooperation between TAM and bromodomain in chromatin targeting not tested\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"BAZ2B was identified as a regulatory subunit of BRF1/BRF5 chromatin remodeling complexes; cancer-associated bromodomain mutations alter histone code recognition, and depletion perturbs transcription and cell morphology without global chromatin reorganization, establishing BAZ2B as a gene-specific transcriptional modulator rather than a global chromatin architect.\",\n      \"evidence\": \"Domain biochemistry, super-resolution microscopy, transcriptomics, and Hap1 cell knockdown\",\n      \"pmids\": [\"38000389\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Stoichiometry and assembly pathway of BRF1/BRF5 complexes with BAZ2B not defined\",\n        \"Direct effects of cancer mutations on remodeling activity in vitro not measured\",\n        \"Mechanism by which BAZ2B selects specific genomic loci unclear\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Direct binding of BAZ2B to PPARα pathway gene promoters was shown to reduce chromatin accessibility and repress lipid metabolism transcription in hepatocytes, with hepatocyte-specific Baz2b loss attenuating senescence and MASH fibrosis in mice, linking BAZ2B to metabolic disease.\",\n      \"evidence\": \"ATAC-seq, CUT&RUN, hepatocyte-specific Baz2b knockdown in mouse MASH model\",\n      \"pmids\": [\"40389730\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether BAZ2B-mediated repression requires its bromodomain or TAM domain not dissected\",\n        \"Upstream signals recruiting BAZ2B to PPARα loci not identified\",\n        \"Relevance to human MASH not validated\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"BAZ2B was found to maintain H3K4me3 at myofibroblast activation gene promoters, driving TGF-β1-induced fibroblast-to-myofibroblast differentiation and ECM production, broadening its role to fibrotic remodeling beyond hepatic tissue.\",\n      \"evidence\": \"RNA-seq, CUT&Tag-seq, fibroblast knockdown/overexpression, mouse intrauterine adhesion model treated with GSK2801\",\n      \"pmids\": [\"41979565\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism by which BAZ2B sustains H3K4me3 (direct reader vs. recruitment of methyltransferase) not resolved\",\n        \"Specificity of GSK2801 effects in vivo not fully controlled for off-target BAZ2A inhibition\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include how BAZ2B's bromodomain, TAM, and AT-hook domains cooperate to select specific genomic loci, how BRF1/BRF5 complex assembly is regulated, and whether BAZ2B suppression of G-quadruplex structures is mechanistically coupled to its remodeling activity or represents an independent function.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No reconstituted biochemical system demonstrating BAZ2B-dependent chromatin remodeling in vitro\",\n        \"Cooperative domain usage in full-length protein not characterized structurally\",\n        \"Functional consequence of HERC2 interaction for BAZ2B stability or activity unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [0, 1, 2, 3]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [3, 5, 6]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [3, 5, 6, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [3, 5, 6, 7]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [3, 6, 7]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [\n      \"BRF1\",\n      \"BRF5\"\n    ],\n    \"partners\": [\n      \"SNF2H\",\n      \"SNF2L\",\n      \"HERC2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}