{"gene":"PWWP2A","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2017,"finding":"PWWP2A is a novel H2A.Z-nucleosome binding protein identified through H2A.Z interactome analysis. Two internal protein regions mediate H2A.Z-specificity and nucleosome interaction, while the PWWP domain mediates direct DNA binding. PWWP2A binds selectively to H2A.Z-containing nucleosomes with strong preference for promoters of highly transcribed genes. The C-terminal tail of H2A.Z is one important mediator to recruit PWWP2A to chromatin. Depletion of PWWP2A impairs mitotic progression (mitotic delay) and does not influence H2A.Z occupancy.","method":"H2A.Z interactome (co-IP/MS), genome-wide mapping (ChIP-seq), domain mutagenesis, siRNA knockdown with cell proliferation/mitosis readout, Xenopus knockdown","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, genome-wide mapping, domain mutagenesis, and functional knockdown in two model systems; single study but multiple orthogonal methods with rigorous controls","pmids":["28645917"],"is_preprint":false},{"year":2017,"finding":"Knockdown of PWWP2A in Xenopus results in severe craniofacial defects arising from neural crest cell differentiation and migration problems, establishing a functional role in vertebrate development.","method":"Xenopus morpholino knockdown with phenotypic analysis of craniofacial structures and neural crest cell migration","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function in vivo with defined cellular phenotype, replicated in later studies","pmids":["28645917"],"is_preprint":false},{"year":2018,"finding":"PWWP2A binds free linker DNA and H3K36me3-containing nucleosomes via distinct domains (in vitro). In vivo, PWWP2A strongly occupies H2A.Z-containing regulatory regions and weakly binds H3K36me3-containing gene bodies. PWWP2A interacts with an MTA1-specific subcomplex of the NuRD complex (M1HR) consisting of MTA1, HDAC1, and RBBP4/7, excluding CHD, GATAD2, and MBD proteins. Depletion of PWWP2A increases acetylation on H3K27 and H2A.Z, implicating impaired chromatin recruitment of M1HR.","method":"In vitro binding assays, ChIP-seq, co-IP/MS, siRNA knockdown with histone acetylation readout","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vitro assays combined with genome-wide mapping and co-IP with functional acetylation readout, multiple orthogonal methods in single study","pmids":["30327463"],"is_preprint":false},{"year":2020,"finding":"PWWP2A competes with MBD proteins for binding to the MTA-HDAC-RBBP subcomplex of NuRD, establishing a biochemical switching mechanism that regulates NuRD composition. The NuRD complex has an asymmetric architecture built from a 2:2:4 (MTA:HDAC:RBBP) deacetylase module and a 1:1:1 (MBD:GATAD2:CHD) remodeling module.","method":"Quantitative mass spectrometry, cross-linking, protein biochemistry, electron microscopy of native mammalian NuRD complex","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1 / Strong — integrated structural and biochemical analysis with multiple orthogonal methods (native complex, quantitative MS, EM, cross-linking) establishing competitive binding mechanism","pmids":["33264611"],"is_preprint":false},{"year":2020,"finding":"PWWP2A/B function as H3K36me3 readers that form a stable complex with HDAC1/2 and suppress spurious intragenic transcription initiation in mESCs, analogous to the yeast H3K36me3/Rpd3S pathway. Loss of PWWP2A/B enhances spurious intragenic initiation associated with increased initiating Pol-II and histone acetylation.","method":"CAGE-seq in wild-type vs. PWWP2A/B double-knockout (DKO) mESCs; histone acetylation and Pol-II ChIP-seq","journal":"iScience","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic KO with genome-wide transcription initiation profiling and histone modification readout, multiple orthogonal methods in single study","pmids":["33235983"],"is_preprint":false},{"year":2023,"finding":"HMG20A is identified as a component of the H2A.Z/PWWP2A/NuRD axis. Depletion of Hmg20a in Xenopus phenocopies PWWP2A knockdown (craniofacial and heart defects), and loss of HMG20A causes chromatin accessibility changes and deregulation of EMT and differentiation transcription programs, placing HMG20A as part of the PWWP2A-associated chromatin-modifying network.","method":"Co-IP/MS identifying HMG20A in NuRD/PWWP2A complexes; Xenopus morpholino knockdown; mESC differentiation assays; ATAC-seq; RNA-seq","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — complex identification by co-IP/MS, in vivo loss-of-function in two model systems with genome-wide chromatin and transcriptomic readouts","pmids":["36709316"],"is_preprint":false},{"year":2024,"finding":"ZNF512B was identified as a protein associated with H2A.Z, HMG20A, and PWWP2A, placing ZNF512B in the PWWP2A-associated chromatin network at H2A.Z-containing chromatin.","method":"Co-IP/MS identifying ZNF512B in the H2A.Z/PWWP2A/HMG20A complex","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 3 / Weak — single co-IP/MS result implicating PWWP2A as part of a larger complex; primary focus of study is ZNF512B","pmids":["39460621"],"is_preprint":false}],"current_model":"PWWP2A is a vertebrate-specific, multivalent chromatin-binding protein that uses distinct domains to bind H2A.Z-nucleosomes (via two internal regions), free linker DNA, and H3K36me3-nucleosomes (via the PWWP domain), and that recruits an MTA1-specific NuRD deacetylase subcomplex (M1HR) to H2A.Z-containing promoters to regulate histone acetylation, suppress spurious intragenic transcription initiation, ensure proper mitotic progression, and support neural crest cell differentiation and craniofacial development; it also competes with MBD proteins for binding to the MTA-HDAC-RBBP core of NuRD, thereby acting as a molecular switch that controls NuRD composition."},"narrative":{"mechanistic_narrative":"PWWP2A is a multivalent chromatin-binding protein that links the histone variant H2A.Z to histone deacetylase activity to control transcriptional fidelity and vertebrate development [PMID:28645917, PMID:30327463]. It engages chromatin through distinct domains: two internal regions confer selective binding to H2A.Z-containing nucleosomes, with the H2A.Z C-terminal tail acting as a key recruitment determinant, while the PWWP domain mediates direct binding to free linker DNA and to H3K36me3-containing nucleosomes [PMID:28645917, PMID:30327463]. In vivo it concentrates at H2A.Z-marked promoters of highly transcribed genes and more weakly over H3K36me3-marked gene bodies [PMID:28645917, PMID:30327463]. PWWP2A recruits an MTA1-specific NuRD deacetylase subcomplex (M1HR; MTA1–HDAC1–RBBP4/7) that excludes CHD, GATAD2, and MBD subunits, and its loss raises H3K27 and H2A.Z acetylation, reflecting failed M1HR delivery to chromatin [PMID:30327463]. By competing with MBD proteins for the shared MTA–HDAC–RBBP deacetylase module, PWWP2A acts as a switch governing NuRD composition [PMID:33264611]. Functionally, PWWP2A (with PWWP2B) suppresses spurious intragenic transcription initiation in a manner analogous to the yeast H3K36me3/Rpd3S pathway, restraining initiating Pol-II and histone acetylation within gene bodies [PMID:33235983], and it is required for proper mitotic progression [PMID:28645917] and for neural crest cell differentiation and craniofacial development [PMID:28645917]. HMG20A and ZNF512B are additional components of the H2A.Z/PWWP2A chromatin-modifying network, with HMG20A loss phenocopying PWWP2A depletion in vivo [PMID:36709316, PMID:39460621].","teleology":[{"year":2017,"claim":"Established PWWP2A as a dedicated H2A.Z-nucleosome reader, answering how a specific factor distinguishes the H2A.Z variant from canonical H2A in chromatin.","evidence":"H2A.Z interactome co-IP/MS, ChIP-seq, domain mutagenesis, and siRNA knockdown with mitotic readout in cells and Xenopus","pmids":["28645917"],"confidence":"High","gaps":["Structural basis for H2A.Z C-terminal tail recognition not resolved","Downstream effector of mitotic delay not defined at this stage"]},{"year":2017,"claim":"Linked PWWP2A to vertebrate morphogenesis, showing the chromatin reader is required for neural crest differentiation/migration and craniofacial formation.","evidence":"Xenopus morpholino knockdown with craniofacial and neural crest phenotyping","pmids":["28645917"],"confidence":"High","gaps":["Molecular target genes driving the neural crest phenotype not mapped","Connection between developmental defect and biochemical activity not yet established"]},{"year":2018,"claim":"Defined the effector arm: PWWP2A reads multiple chromatin features and recruits a specific NuRD deacetylase subcomplex (M1HR) to control histone acetylation.","evidence":"In vitro binding assays, ChIP-seq, co-IP/MS, and siRNA knockdown with H3K27/H2A.Z acetylation readout","pmids":["30327463"],"confidence":"High","gaps":["Whether M1HR recruitment fully accounts for developmental/mitotic phenotypes not shown","Quantitative contribution of DNA vs H3K36me3 vs H2A.Z binding to in vivo targeting unresolved"]},{"year":2020,"claim":"Provided a mechanistic switch model: PWWP2A competes with MBD proteins for the MTA-HDAC-RBBP module, controlling NuRD complex composition.","evidence":"Quantitative MS, cross-linking, and EM of native mammalian NuRD complex","pmids":["33264611"],"confidence":"High","gaps":["In vivo dynamics and regulation of the competition not characterized","Genome-wide consequences of the compositional switch not directly profiled"]},{"year":2020,"claim":"Assigned a transcriptional-fidelity function, showing PWWP2A/B as H3K36me3 readers that suppress spurious intragenic initiation, analogous to yeast Rpd3S.","evidence":"CAGE-seq with histone acetylation and Pol-II ChIP-seq in WT vs PWWP2A/B DKO mESCs","pmids":["33235983"],"confidence":"High","gaps":["Redundancy and division of labor between PWWP2A and PWWP2B not dissected","Direct demonstration that suppressed cryptic transcripts arise from M1HR loss not shown"]},{"year":2023,"claim":"Expanded the network by identifying HMG20A as a functional partner whose loss phenocopies PWWP2A depletion, linking the axis to EMT and differentiation programs.","evidence":"Co-IP/MS, Xenopus morpholino knockdown, mESC differentiation, ATAC-seq, and RNA-seq","pmids":["36709316"],"confidence":"High","gaps":["Direct physical contacts within the PWWP2A-HMG20A-NuRD assembly not mapped","Whether HMG20A acts within M1HR or a distinct subassembly unresolved"]},{"year":2024,"claim":"Added ZNF512B as a further associated component of the H2A.Z/PWWP2A/HMG20A chromatin network.","evidence":"Co-IP/MS placing ZNF512B in the H2A.Z/PWWP2A/HMG20A complex","pmids":["39460621"],"confidence":"Medium","gaps":["Single co-IP/MS without reciprocal validation or functional follow-up on PWWP2A","Role of ZNF512B in PWWP2A-dependent functions undefined"]},{"year":null,"claim":"How PWWP2A integrates its multivalent chromatin readout to selectively deliver M1HR at specific loci, and how this is coordinated across mitosis, transcriptional fidelity, and development, remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No structure of PWWP2A bound to H2A.Z-nucleosome or to M1HR","Causal chain from chromatin binding to mitotic and developmental phenotypes incomplete"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[0,2]},{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[0,2,4]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,3]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[4]}],"localization":[{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,2,4]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[2,3,4]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[4]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[1,5]}],"complexes":["NuRD (MTA1-specific M1HR subcomplex: MTA1-HDAC1-RBBP4/7)"],"partners":["MTA1","HDAC1","RBBP4","RBBP7","HMG20A","ZNF512B","PWWP2B"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96N64","full_name":"PWWP domain-containing protein 2A","aliases":[],"length_aa":755,"mass_kda":82.0,"function":"Chromatin-binding protein that acts as an adapter between distinct nucleosome components (H3K36me3 or H2A.Z) and chromatin-modifying complexes, contributing to the regulation of the levels of histone acetylation at actively transcribed genes (PubMed:30228260, PubMed:30327463). Competes with CHD4 and MBD3 for interaction with MTA1 to form a NuRD subcomplex, preventing the formation of full NuRD complex (containing CHD4 and MBD3), leading to recruitment of HDACs to gene promoters resulting in turn in the deacetylation of nearby H3K27 and H2A.Z (PubMed:30228260, PubMed:30327463). Plays a role in facilitating transcriptional elongation and repression of spurious transcription initiation through regulation of histone acetylation (By similarity). Essential for proper mitosis progression (PubMed:28645917)","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q96N64/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PWWP2A","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"H1F0","stoichiometry":0.2},{"gene":"H2AFZ","stoichiometry":0.2},{"gene":"HDAC1","stoichiometry":0.2},{"gene":"HDAC2","stoichiometry":0.2},{"gene":"HIST2H2BE","stoichiometry":0.2},{"gene":"HMGA1","stoichiometry":0.2},{"gene":"HMGN5","stoichiometry":0.2},{"gene":"NUMA1","stoichiometry":0.2},{"gene":"TMEM192","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/PWWP2A","total_profiled":1310},"omim":[{"mim_id":"617823","title":"PWWP DOMAIN-CONTAINING PROTEIN 2A; PWWP2A","url":"https://www.omim.org/entry/617823"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Focal adhesion sites","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/PWWP2A"},"hgnc":{"alias_symbol":["KIAA1935"],"prev_symbol":[]},"alphafold":{"accession":"Q96N64","domains":[{"cath_id":"-","chopping":"164-193","consensus_level":"medium","plddt":88.827,"start":164,"end":193},{"cath_id":"2.30.30.140","chopping":"638-753","consensus_level":"high","plddt":93.3912,"start":638,"end":753}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96N64","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96N64-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96N64-F1-predicted_aligned_error_v6.png","plddt_mean":57.72},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PWWP2A","jax_strain_url":"https://www.jax.org/strain/search?query=PWWP2A"},"sequence":{"accession":"Q96N64","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96N64.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96N64/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96N64"}},"corpus_meta":[{"pmid":"36646008","id":"PMC_36646008","title":"Human umbilical cord mesenchymal stem cell-derived extracellular vesicles alleviated silica induced lung inflammation and fibrosis in mice via circPWWP2A/miR-223-3p/NLRP3 axis.","date":"2023","source":"Ecotoxicology and environmental safety","url":"https://pubmed.ncbi.nlm.nih.gov/36646008","citation_count":49,"is_preprint":false},{"pmid":"28645917","id":"PMC_28645917","title":"Multivalent binding of PWWP2A to H2A.Z regulates mitosis and neural crest differentiation.","date":"2017","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/28645917","citation_count":45,"is_preprint":false},{"pmid":"30327463","id":"PMC_30327463","title":"PWWP2A binds distinct chromatin moieties and interacts with an MTA1-specific core NuRD complex.","date":"2018","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30327463","citation_count":45,"is_preprint":false},{"pmid":"31719209","id":"PMC_31719209","title":"TGF-β- and lipopolysaccharide-induced upregulation of circular RNA PWWP2A promotes hepatic fibrosis via sponging miR-203 and miR-223.","date":"2019","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/31719209","citation_count":44,"is_preprint":false},{"pmid":"33264611","id":"PMC_33264611","title":"The Nucleosome Remodeling and Deacetylase Complex Has an Asymmetric, Dynamic, and Modular Architecture.","date":"2020","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/33264611","citation_count":42,"is_preprint":false},{"pmid":"31361613","id":"PMC_31361613","title":"Spitz Tumors With ROS1 Fusions: A Clinicopathological Study of 6 Cases, Including FISH for Chromosomal Copy Number Alterations and Mutation Analysis Using Next-Generation Sequencing.","date":"2020","source":"The American Journal of dermatopathology","url":"https://pubmed.ncbi.nlm.nih.gov/31361613","citation_count":41,"is_preprint":false},{"pmid":"32862201","id":"PMC_32862201","title":"Clinical, morphologic, and genomic findings in ROS1 fusion Spitz neoplasms.","date":"2020","source":"Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc","url":"https://pubmed.ncbi.nlm.nih.gov/32862201","citation_count":34,"is_preprint":false},{"pmid":"38332737","id":"PMC_38332737","title":"Comprehensive clinicopathological, molecular, and methylation analysis of mesenchymal tumors with NTRK and other kinase gene aberrations.","date":"2024","source":"The Journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/38332737","citation_count":28,"is_preprint":false},{"pmid":"36414158","id":"PMC_36414158","title":"Ferroptosis related genes participate in the pathogenesis of spinal cord injury via HIF-1 signaling pathway.","date":"2022","source":"Brain research bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/36414158","citation_count":17,"is_preprint":false},{"pmid":"36709316","id":"PMC_36709316","title":"The H2A.Z and NuRD associated protein HMG20A controls early head and heart developmental transcription programs.","date":"2023","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/36709316","citation_count":16,"is_preprint":false},{"pmid":"33235983","id":"PMC_33235983","title":"The PWWP2A Histone Deacetylase Complex Represses Intragenic Spurious Transcription Initiation in mESCs.","date":"2020","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/33235983","citation_count":9,"is_preprint":false},{"pmid":"34231248","id":"PMC_34231248","title":"ROS1 pattern of immunostaining in 11 cases of spitzoid tumour: comparison with histopathological, fluorescence in-situ hybridisation and next-generation sequencing analysis.","date":"2021","source":"Histopathology","url":"https://pubmed.ncbi.nlm.nih.gov/34231248","citation_count":6,"is_preprint":false},{"pmid":"37672715","id":"PMC_37672715","title":"Circ_PWWP2A promotes lung fibroblast proliferation and fibrosis via the miR-27b-3p/GATA3 axis, thereby aggravating idiopathic pulmonary fibrosis.","date":"2023","source":"Acta biochimica Polonica","url":"https://pubmed.ncbi.nlm.nih.gov/37672715","citation_count":5,"is_preprint":false},{"pmid":"39809369","id":"PMC_39809369","title":"PWWP2A/B: Prominent players in the proteomic landscape.","date":"2025","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/39809369","citation_count":1,"is_preprint":false},{"pmid":"39460621","id":"PMC_39460621","title":"ZNF512B binds RBBP4 via a variant NuRD interaction motif and aggregates chromatin in a NuRD complex-independent manner.","date":"2024","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/39460621","citation_count":1,"is_preprint":false},{"pmid":"38069278","id":"PMC_38069278","title":"Two High-Quality Cygnus Genome Assemblies Reveal Genomic Variations Associated with Plumage Color.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/38069278","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10944,"output_tokens":2080,"usd":0.032016,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8923,"output_tokens":2994,"usd":0.059733,"stage2_stop_reason":"end_turn"},"total_usd":0.091749,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"PWWP2A is a novel H2A.Z-nucleosome binding protein identified through H2A.Z interactome analysis. Two internal protein regions mediate H2A.Z-specificity and nucleosome interaction, while the PWWP domain mediates direct DNA binding. PWWP2A binds selectively to H2A.Z-containing nucleosomes with strong preference for promoters of highly transcribed genes. The C-terminal tail of H2A.Z is one important mediator to recruit PWWP2A to chromatin. Depletion of PWWP2A impairs mitotic progression (mitotic delay) and does not influence H2A.Z occupancy.\",\n      \"method\": \"H2A.Z interactome (co-IP/MS), genome-wide mapping (ChIP-seq), domain mutagenesis, siRNA knockdown with cell proliferation/mitosis readout, Xenopus knockdown\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, genome-wide mapping, domain mutagenesis, and functional knockdown in two model systems; single study but multiple orthogonal methods with rigorous controls\",\n      \"pmids\": [\"28645917\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Knockdown of PWWP2A in Xenopus results in severe craniofacial defects arising from neural crest cell differentiation and migration problems, establishing a functional role in vertebrate development.\",\n      \"method\": \"Xenopus morpholino knockdown with phenotypic analysis of craniofacial structures and neural crest cell migration\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function in vivo with defined cellular phenotype, replicated in later studies\",\n      \"pmids\": [\"28645917\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"PWWP2A binds free linker DNA and H3K36me3-containing nucleosomes via distinct domains (in vitro). In vivo, PWWP2A strongly occupies H2A.Z-containing regulatory regions and weakly binds H3K36me3-containing gene bodies. PWWP2A interacts with an MTA1-specific subcomplex of the NuRD complex (M1HR) consisting of MTA1, HDAC1, and RBBP4/7, excluding CHD, GATAD2, and MBD proteins. Depletion of PWWP2A increases acetylation on H3K27 and H2A.Z, implicating impaired chromatin recruitment of M1HR.\",\n      \"method\": \"In vitro binding assays, ChIP-seq, co-IP/MS, siRNA knockdown with histone acetylation readout\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vitro assays combined with genome-wide mapping and co-IP with functional acetylation readout, multiple orthogonal methods in single study\",\n      \"pmids\": [\"30327463\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PWWP2A competes with MBD proteins for binding to the MTA-HDAC-RBBP subcomplex of NuRD, establishing a biochemical switching mechanism that regulates NuRD composition. The NuRD complex has an asymmetric architecture built from a 2:2:4 (MTA:HDAC:RBBP) deacetylase module and a 1:1:1 (MBD:GATAD2:CHD) remodeling module.\",\n      \"method\": \"Quantitative mass spectrometry, cross-linking, protein biochemistry, electron microscopy of native mammalian NuRD complex\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — integrated structural and biochemical analysis with multiple orthogonal methods (native complex, quantitative MS, EM, cross-linking) establishing competitive binding mechanism\",\n      \"pmids\": [\"33264611\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PWWP2A/B function as H3K36me3 readers that form a stable complex with HDAC1/2 and suppress spurious intragenic transcription initiation in mESCs, analogous to the yeast H3K36me3/Rpd3S pathway. Loss of PWWP2A/B enhances spurious intragenic initiation associated with increased initiating Pol-II and histone acetylation.\",\n      \"method\": \"CAGE-seq in wild-type vs. PWWP2A/B double-knockout (DKO) mESCs; histone acetylation and Pol-II ChIP-seq\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic KO with genome-wide transcription initiation profiling and histone modification readout, multiple orthogonal methods in single study\",\n      \"pmids\": [\"33235983\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"HMG20A is identified as a component of the H2A.Z/PWWP2A/NuRD axis. Depletion of Hmg20a in Xenopus phenocopies PWWP2A knockdown (craniofacial and heart defects), and loss of HMG20A causes chromatin accessibility changes and deregulation of EMT and differentiation transcription programs, placing HMG20A as part of the PWWP2A-associated chromatin-modifying network.\",\n      \"method\": \"Co-IP/MS identifying HMG20A in NuRD/PWWP2A complexes; Xenopus morpholino knockdown; mESC differentiation assays; ATAC-seq; RNA-seq\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — complex identification by co-IP/MS, in vivo loss-of-function in two model systems with genome-wide chromatin and transcriptomic readouts\",\n      \"pmids\": [\"36709316\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ZNF512B was identified as a protein associated with H2A.Z, HMG20A, and PWWP2A, placing ZNF512B in the PWWP2A-associated chromatin network at H2A.Z-containing chromatin.\",\n      \"method\": \"Co-IP/MS identifying ZNF512B in the H2A.Z/PWWP2A/HMG20A complex\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single co-IP/MS result implicating PWWP2A as part of a larger complex; primary focus of study is ZNF512B\",\n      \"pmids\": [\"39460621\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PWWP2A is a vertebrate-specific, multivalent chromatin-binding protein that uses distinct domains to bind H2A.Z-nucleosomes (via two internal regions), free linker DNA, and H3K36me3-nucleosomes (via the PWWP domain), and that recruits an MTA1-specific NuRD deacetylase subcomplex (M1HR) to H2A.Z-containing promoters to regulate histone acetylation, suppress spurious intragenic transcription initiation, ensure proper mitotic progression, and support neural crest cell differentiation and craniofacial development; it also competes with MBD proteins for binding to the MTA-HDAC-RBBP core of NuRD, thereby acting as a molecular switch that controls NuRD composition.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PWWP2A is a multivalent chromatin-binding protein that links the histone variant H2A.Z to histone deacetylase activity to control transcriptional fidelity and vertebrate development [#0, #2]. It engages chromatin through distinct domains: two internal regions confer selective binding to H2A.Z-containing nucleosomes, with the H2A.Z C-terminal tail acting as a key recruitment determinant, while the PWWP domain mediates direct binding to free linker DNA and to H3K36me3-containing nucleosomes [#0, #2]. In vivo it concentrates at H2A.Z-marked promoters of highly transcribed genes and more weakly over H3K36me3-marked gene bodies [#0, #2]. PWWP2A recruits an MTA1-specific NuRD deacetylase subcomplex (M1HR; MTA1–HDAC1–RBBP4/7) that excludes CHD, GATAD2, and MBD subunits, and its loss raises H3K27 and H2A.Z acetylation, reflecting failed M1HR delivery to chromatin [#2]. By competing with MBD proteins for the shared MTA–HDAC–RBBP deacetylase module, PWWP2A acts as a switch governing NuRD composition [#3]. Functionally, PWWP2A (with PWWP2B) suppresses spurious intragenic transcription initiation in a manner analogous to the yeast H3K36me3/Rpd3S pathway, restraining initiating Pol-II and histone acetylation within gene bodies [#4], and it is required for proper mitotic progression [#0] and for neural crest cell differentiation and craniofacial development [#1]. HMG20A and ZNF512B are additional components of the H2A.Z/PWWP2A chromatin-modifying network, with HMG20A loss phenocopying PWWP2A depletion in vivo [#5, #6].\"\n  ,\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established PWWP2A as a dedicated H2A.Z-nucleosome reader, answering how a specific factor distinguishes the H2A.Z variant from canonical H2A in chromatin.\",\n      \"evidence\": \"H2A.Z interactome co-IP/MS, ChIP-seq, domain mutagenesis, and siRNA knockdown with mitotic readout in cells and Xenopus\",\n      \"pmids\": [\"28645917\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis for H2A.Z C-terminal tail recognition not resolved\",\n        \"Downstream effector of mitotic delay not defined at this stage\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Linked PWWP2A to vertebrate morphogenesis, showing the chromatin reader is required for neural crest differentiation/migration and craniofacial formation.\",\n      \"evidence\": \"Xenopus morpholino knockdown with craniofacial and neural crest phenotyping\",\n      \"pmids\": [\"28645917\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Molecular target genes driving the neural crest phenotype not mapped\",\n        \"Connection between developmental defect and biochemical activity not yet established\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined the effector arm: PWWP2A reads multiple chromatin features and recruits a specific NuRD deacetylase subcomplex (M1HR) to control histone acetylation.\",\n      \"evidence\": \"In vitro binding assays, ChIP-seq, co-IP/MS, and siRNA knockdown with H3K27/H2A.Z acetylation readout\",\n      \"pmids\": [\"30327463\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether M1HR recruitment fully accounts for developmental/mitotic phenotypes not shown\",\n        \"Quantitative contribution of DNA vs H3K36me3 vs H2A.Z binding to in vivo targeting unresolved\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Provided a mechanistic switch model: PWWP2A competes with MBD proteins for the MTA-HDAC-RBBP module, controlling NuRD complex composition.\",\n      \"evidence\": \"Quantitative MS, cross-linking, and EM of native mammalian NuRD complex\",\n      \"pmids\": [\"33264611\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"In vivo dynamics and regulation of the competition not characterized\",\n        \"Genome-wide consequences of the compositional switch not directly profiled\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Assigned a transcriptional-fidelity function, showing PWWP2A/B as H3K36me3 readers that suppress spurious intragenic initiation, analogous to yeast Rpd3S.\",\n      \"evidence\": \"CAGE-seq with histone acetylation and Pol-II ChIP-seq in WT vs PWWP2A/B DKO mESCs\",\n      \"pmids\": [\"33235983\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Redundancy and division of labor between PWWP2A and PWWP2B not dissected\",\n        \"Direct demonstration that suppressed cryptic transcripts arise from M1HR loss not shown\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Expanded the network by identifying HMG20A as a functional partner whose loss phenocopies PWWP2A depletion, linking the axis to EMT and differentiation programs.\",\n      \"evidence\": \"Co-IP/MS, Xenopus morpholino knockdown, mESC differentiation, ATAC-seq, and RNA-seq\",\n      \"pmids\": [\"36709316\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct physical contacts within the PWWP2A-HMG20A-NuRD assembly not mapped\",\n        \"Whether HMG20A acts within M1HR or a distinct subassembly unresolved\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Added ZNF512B as a further associated component of the H2A.Z/PWWP2A/HMG20A chromatin network.\",\n      \"evidence\": \"Co-IP/MS placing ZNF512B in the H2A.Z/PWWP2A/HMG20A complex\",\n      \"pmids\": [\"39460621\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single co-IP/MS without reciprocal validation or functional follow-up on PWWP2A\",\n        \"Role of ZNF512B in PWWP2A-dependent functions undefined\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How PWWP2A integrates its multivalent chromatin readout to selectively deliver M1HR at specific loci, and how this is coordinated across mitosis, transcriptional fidelity, and development, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No structure of PWWP2A bound to H2A.Z-nucleosome or to M1HR\",\n        \"Causal chain from chromatin binding to mitotic and developmental phenotypes incomplete\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 2, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [2, 3, 4]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"complexes\": [\"NuRD (MTA1-specific M1HR subcomplex: MTA1-HDAC1-RBBP4/7)\"],\n    \"partners\": [\"MTA1\", \"HDAC1\", \"RBBP4\", \"RBBP7\", \"HMG20A\", \"ZNF512B\", \"PWWP2B\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}