{"gene":"WDR3","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":2010,"finding":"WDR3 is required for 18S rRNA processing and 40S ribosomal subunit synthesis; its depletion causes defects in 18S rRNA processing, transient down-regulation of precursor rRNA levels, and moderate repression of RNA polymerase I activity. In p53-competent cells, WDR3 suppression activates p53 via sequestration of MDM2 by ribosomal protein L11, leading to G1 cell cycle arrest; cells lacking functional p53 do not arrest.","method":"siRNA knockdown, flow cytometry (cell cycle analysis), Western blot, RT-PCR, RNA polymerase I activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (rRNA processing assays, PolI activity, cell cycle, p53/MDM2/L11 pathway dissection) in a single focused mechanistic study with clear epistasis (p53-dependent vs. p53-null cells)","pmids":["20392698"],"is_preprint":false},{"year":2019,"finding":"WDR3 (and WDR6) are substrate receptors for the CRL4 (Cul4-DDB1) E3 ubiquitin ligase complex; this complex binds OSR1 and SPAK kinases in a manner dependent on phosphorylation of their S-motif serine by WNK kinases. Under osmotic stress, S-motif phosphorylation disrupts this binding and abolishes OSR1 ubiquitylation, linking the CRL4-WDR3 complex to ion homeostasis regulation.","method":"Affinity pulldown, mass spectrometry, proteasomal and neddylation inhibitor assays, co-immunoprecipitation","journal":"Chembiochem : a European journal of chemical biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — affinity pulldown + MS identification of complex, functional validation with proteasomal/neddylation inhibitors; single lab","pmids":["31614064"],"is_preprint":false},{"year":2021,"finding":"WDR3 interacts with the transcription factor GATA4 via co-immunoprecipitation, inducing nuclear translocation of GATA4 and thereby transcriptionally upregulating YAP1 expression to activate the Hippo signaling pathway in pancreatic cancer cells.","method":"Co-immunoprecipitation, Western blot, RT-qPCR, nuclear fractionation/immunofluorescence, siRNA knockdown, colony formation and transwell invasion assays","journal":"Journal of experimental & clinical cancer research : CR","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single lab, co-IP for interaction, functional rescue and inhibitor combination experiments; multiple orthogonal cellular assays but no in vitro reconstitution","pmids":["33648545"],"is_preprint":false},{"year":2023,"finding":"WDR3 promotes ubiquitination and proteasomal degradation of the transcription factor USF2, reducing USF2 stability. USF2 normally binds the RASSF1A promoter to transcriptionally activate RASSF1A expression; WDR3-mediated USF2 degradation suppresses RASSF1A transcription and promotes prostate cancer stem cell-like properties and proliferation.","method":"Co-immunoprecipitation, chromatin immunoprecipitation (ChIP), luciferase reporter assay, ubiquitination assay, Western blot, cell proliferation/apoptosis assays, xenograft mouse model","journal":"The journal of gene medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (Co-IP, ChIP, reporter, ubiquitination assay, in vivo xenograft) in a single lab study","pmids":["36905106"],"is_preprint":false},{"year":2025,"finding":"WDR3 interacts with the m6A reader YTHDC1 and facilitates K63-linked ubiquitination of YTHDC1, resulting in increased cytoplasmic localization of YTHDC1. This enhances stability of TGF-α mRNA, upregulates TGF-α expression, and promotes pancreatic cancer cell invasion and metastasis.","method":"Co-immunoprecipitation, ubiquitination assay (K63-linkage-specific), subcellular fractionation, mRNA stability assay, siRNA knockdown, overexpression rescue, invasion/migration assays","journal":"American journal of cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mechanistic pathway (Co-IP, K63-ubiquitination, localization shift, mRNA stability) supported by rescue experiments; single lab","pmids":["41395298"],"is_preprint":false},{"year":2025,"finding":"WDR3 undergoes liquid-liquid phase separation (LLPS) in osteosarcoma cells, forming condensates with liquid-like behavior demonstrated by FRAP. Mutation of the intrinsically disordered region (IDR) impairs phase separation; fusion with hnRNPA1 IDR rescues it. Nilotinib treatment inhibits formation of WDR3 phase-separated condensates and suppresses osteosarcoma progression in vitro and in vivo.","method":"Droplet formation assay, FRAP, IDR mutagenesis, hnRNPA1-IDR fusion rescue, xenograft mouse model, molecular docking","journal":"Journal of experimental & clinical cancer research : CR","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — FRAP and droplet assays with mutagenesis and domain-swap rescue provide direct mechanistic evidence for LLPS; single lab","pmids":["40646517"],"is_preprint":false},{"year":2022,"finding":"Complete homozygous knockout of Wdr3 is lethal during embryogenesis in mice (no homozygous knockouts born), indicating an essential developmental function. Heterozygous knockout reduces brain Wdr3 mRNA to ~60% without significant reduction in 18S rRNA levels, and results in slightly increased spontaneous locomotor activity.","method":"Heterozygous knockout mouse model, immunohistochemistry, X-gal staining, RT-PCR, behavioral assays","journal":"Brain research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — germline knockout with embryonic lethality finding is a defined in vivo genetic result, but 18S rRNA and behavioral outcomes are from a single lab with limited mechanistic follow-up","pmids":["36463953"],"is_preprint":false},{"year":1999,"finding":"WDR3 encodes a 943-amino-acid nuclear protein containing 10 WD repeat modules (characterized by GH-WD repeat units), mapping to chromosome 1p12-p13, and is widely expressed in hematopoietic and non-hematopoietic tissues.","method":"cDNA cloning, sequence analysis, FISH (chromosomal mapping), Northern blot/RT-PCR expression analysis","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — foundational cloning and structural characterization; nuclear localization inferred from sequence; replicated in subsequent work","pmids":["10395803"],"is_preprint":false}],"current_model":"WDR3 is a nuclear WD-repeat protein that functions as a component of the 18S pre-rRNA processing machinery essential for 40S ribosomal subunit biogenesis, acts as a substrate receptor in the CRL4 (Cul4-DDB1) E3 ubiquitin ligase complex to regulate SPAK/OSR1 kinase ubiquitylation, promotes oncogenic signaling by interacting with GATA4 to drive YAP1/Hippo pathway activation, targets USF2 for K63-linked ubiquitination and degradation to repress RASSF1A transcription, facilitates K63-ubiquitination of YTHDC1 to increase cytoplasmic YTHDC1 and stabilize TGF-α mRNA, and undergoes liquid-liquid phase separation via its intrinsically disordered region; complete loss is embryonic lethal in mice, and ribosomal stress from WDR3 depletion activates p53 via RPL11-MDM2 sequestration to arrest the cell cycle."},"narrative":{"mechanistic_narrative":"WDR3 is a nuclear WD-repeat protein with dual roles in ribosome biogenesis and oncogenic signaling [PMID:20392698, PMID:10395803]. As a component of the small-subunit pre-rRNA processing machinery, WDR3 is required for 18S rRNA processing and 40S ribosomal subunit synthesis; its depletion impairs precursor rRNA maturation and dampens RNA polymerase I activity, and in p53-competent cells triggers a ribosomal stress response in which RPL11 sequesters MDM2 to activate p53 and impose G1 arrest [PMID:20392698]. This biogenesis function is developmentally essential, as homozygous Wdr3 knockout is embryonic lethal in mice [PMID:36463953]. In cancer contexts WDR3 operates as a ubiquitin-ligase-associated adaptor and signaling driver: it serves as a substrate receptor for the CRL4 (Cul4-DDB1) E3 complex that binds and ubiquitylates the WNK-regulated kinases OSR1 and SPAK, linking it to ion homeostasis [PMID:31614064], and it directs ubiquitination of multiple transcription factors and readers to reshape gene expression — promoting K63-linked ubiquitination of YTHDC1 to drive its cytoplasmic relocalization and stabilize TGF-α mRNA [PMID:41395298], degrading USF2 to repress RASSF1A transcription [PMID:36905106], and engaging GATA4 to upregulate YAP1 and activate Hippo pathway signaling [PMID:33648545]. WDR3 also undergoes liquid-liquid phase separation through its intrinsically disordered region, forming condensates that support tumor progression [PMID:40646517].","teleology":[{"year":1999,"claim":"Established the molecular identity of WDR3 — that it encodes a nuclear WD-repeat protein, defining a scaffold-type architecture and subcellular compartment for all later functional work.","evidence":"cDNA cloning, sequence/domain analysis, FISH chromosomal mapping, and expression profiling","pmids":["10395803"],"confidence":"Medium","gaps":["Nuclear localization inferred from sequence rather than directly imaged","No functional assay linking the WD repeats to a specific partner or pathway"]},{"year":2010,"claim":"Defined WDR3's core cellular function in 18S rRNA processing and 40S subunit synthesis, and showed its loss triggers a p53-dependent ribosomal stress checkpoint, explaining how WDR3 depletion arrests proliferation.","evidence":"siRNA knockdown with rRNA processing assays, PolI activity measurement, cell-cycle flow cytometry, and p53/MDM2/RPL11 epistasis in p53-competent vs p53-null cells","pmids":["20392698"],"confidence":"High","gaps":["Precise position of WDR3 within the SSU processome not resolved","Direct rRNA or processing-factor binding partners not identified"]},{"year":2019,"claim":"Revealed an unexpected second role beyond ribosome biogenesis — WDR3 acts as a CRL4 substrate receptor coupling WNK-dependent phosphorylation of OSR1/SPAK to their ubiquitylation, placing WDR3 in ion homeostasis signaling.","evidence":"Affinity pulldown with mass spectrometry, co-IP, and proteasomal/neddylation inhibitor assays under osmotic stress","pmids":["31614064"],"confidence":"Medium","gaps":["Single lab without independent confirmation","Physiological consequence of OSR1/SPAK ubiquitylation on ion transport not measured","Whether substrate-receptor role generalizes to other targets unaddressed"]},{"year":2021,"claim":"Connected WDR3 to oncogenic transcriptional programs, showing it drives GATA4 nuclear translocation to upregulate YAP1 and activate Hippo signaling in pancreatic cancer.","evidence":"Co-IP, nuclear fractionation/immunofluorescence, RT-qPCR, and knockdown with colony-formation and invasion assays","pmids":["33648545"],"confidence":"Medium","gaps":["Interaction shown by co-IP only, no in vitro reconstitution","Mechanism by which WDR3 promotes GATA4 translocation unknown","Direct vs indirect effect on YAP1 transcription not separated"]},{"year":2022,"claim":"Demonstrated that WDR3 is developmentally essential, with complete loss being embryonic lethal, while partial loss is tolerated without measurable rRNA deficit.","evidence":"Germline heterozygous/homozygous knockout mouse, X-gal staining, immunohistochemistry, RT-PCR, and behavioral assays","pmids":["36463953"],"confidence":"Medium","gaps":["Developmental stage and cause of lethality not defined","Tissue-specific requirements not dissected","Mechanism linking essentiality to ribosome biogenesis vs other roles not established"]},{"year":2023,"claim":"Extended WDR3's ubiquitin-directed regulation to transcription factor turnover, showing it degrades USF2 to suppress RASSF1A and promote prostate cancer stemness.","evidence":"Co-IP, ChIP, luciferase reporter, ubiquitination assay, and xenograft mouse model","pmids":["36905106"],"confidence":"Medium","gaps":["E3 ligase mediating USF2 ubiquitination not identified","Single lab study","Whether degradation requires the CRL4 association seen for OSR1/SPAK unknown"]},{"year":2025,"claim":"Showed WDR3 controls m6A-reader fate, facilitating K63-linked ubiquitination of YTHDC1 to shift it to the cytoplasm and stabilize TGF-α mRNA, driving pancreatic cancer metastasis.","evidence":"Co-IP, K63-linkage-specific ubiquitination assay, subcellular fractionation, mRNA stability assay, and rescue experiments","pmids":["41395298"],"confidence":"Medium","gaps":["Ubiquitin ligase responsible not identified","Single lab","Link between K63 ubiquitination and cytoplasmic export mechanism unresolved"]},{"year":2025,"claim":"Identified a biophysical mode of action — WDR3 forms liquid-liquid phase-separated condensates via its IDR that support osteosarcoma progression and are druggable by nilotinib.","evidence":"Droplet formation assay, FRAP, IDR mutagenesis, hnRNPA1-IDR domain-swap rescue, molecular docking, and xenograft model","pmids":["40646517"],"confidence":"Medium","gaps":["Functional cargo or clients of the condensates not defined","Relationship of LLPS to ribosome biogenesis or ubiquitin functions unknown","Direct nilotinib-WDR3 binding shown only by docking"]},{"year":null,"claim":"How WDR3's conserved ribosome-biogenesis role mechanistically relates to its multiple cancer-associated ubiquitin and transcription-factor functions, and whether these reflect distinct protein pools or a unified scaffolding activity, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model placing WDR3 in either the SSU processome or a defined ubiquitin complex","Cancer-context functions each rest on single-lab studies","Whether LLPS underlies the diverse interactions is untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1,3,4]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,2]},{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[7,0]},{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[1,3,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2,3,4]}],"complexes":["CRL4 (Cul4-DDB1) E3 ubiquitin ligase"],"partners":["DDB1","CUL4","OSR1","SPAK","GATA4","USF2","YTHDC1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9UNX4","full_name":"WD repeat-containing protein 3","aliases":[],"length_aa":943,"mass_kda":106.1,"function":"Part of the small subunit (SSU) processome, first precursor of the small eukaryotic ribosomal subunit. During the assembly of the SSU processome in the nucleolus, many ribosome biogenesis factors, an RNA chaperone and ribosomal proteins associate with the nascent pre-rRNA and work in concert to generate RNA folding, modifications, rearrangements and cleavage as well as targeted degradation of pre-ribosomal RNA by the RNA exosome","subcellular_location":"Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/Q9UNX4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/WDR3","classification":"Common Essential","n_dependent_lines":1197,"n_total_lines":1208,"dependency_fraction":0.9908940397350994},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000065183","cell_line_id":"CID001006","localizations":[{"compartment":"nucleolus_gc","grade":3},{"compartment":"nucleoplasm","grade":1}],"interactors":[{"gene":"EIF4E","stoichiometry":10.0},{"gene":"PRMT5","stoichiometry":10.0},{"gene":"WDR77","stoichiometry":10.0},{"gene":"TBL3","stoichiometry":10.0},{"gene":"NPM1","stoichiometry":0.2},{"gene":"PSPC1","stoichiometry":0.2},{"gene":"RPS16","stoichiometry":0.2},{"gene":"EPB41","stoichiometry":0.2},{"gene":"CLNS1A","stoichiometry":0.2},{"gene":"ANKRD26","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001006","total_profiled":1310},"omim":[{"mim_id":"606045","title":"INTRAFLAGELLAR TRANSPORT 122; IFT122","url":"https://www.omim.org/entry/606045"},{"mim_id":"606040","title":"WD REPEAT-CONTAINING PROTEIN 8; WDR8","url":"https://www.omim.org/entry/606040"},{"mim_id":"606031","title":"WD REPEAT-CONTAINING PROTEIN 6; WDR6","url":"https://www.omim.org/entry/606031"},{"mim_id":"605924","title":"WD REPEAT-CONTAINING PROTEIN 4; WDR4","url":"https://www.omim.org/entry/605924"},{"mim_id":"604737","title":"WD REPEAT-CONTAINING PROTEIN 3; WDR3","url":"https://www.omim.org/entry/604737"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoli","reliability":"Enhanced"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/WDR3"},"hgnc":{"alias_symbol":["FLJ12796","UTP12","DIP2"],"prev_symbol":[]},"alphafold":{"accession":"Q9UNX4","domains":[{"cath_id":"2.40.10,2.40.128","chopping":"281-312_351-411","consensus_level":"medium","plddt":87.1839,"start":281,"end":411},{"cath_id":"2.130.10.10","chopping":"415-551","consensus_level":"medium","plddt":91.8639,"start":415,"end":551},{"cath_id":"2.130.10.10","chopping":"552-704","consensus_level":"medium","plddt":94.6391,"start":552,"end":704},{"cath_id":"1.20.1050","chopping":"750-892","consensus_level":"medium","plddt":86.1022,"start":750,"end":892}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UNX4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UNX4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UNX4-F1-predicted_aligned_error_v6.png","plddt_mean":84.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=WDR3","jax_strain_url":"https://www.jax.org/strain/search?query=WDR3"},"sequence":{"accession":"Q9UNX4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UNX4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UNX4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UNX4"}},"corpus_meta":[{"pmid":"20392698","id":"PMC_20392698","title":"Ribosomal 18 S RNA processing by the IGF-I-responsive WDR3 protein is integrated with p53 function in cancer cell proliferation.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20392698","citation_count":33,"is_preprint":false},{"pmid":"33648545","id":"PMC_33648545","title":"Overexpressed WDR3 induces the activation of Hippo pathway by interacting with GATA4 in pancreatic cancer.","date":"2021","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/33648545","citation_count":29,"is_preprint":false},{"pmid":"20578902","id":"PMC_20578902","title":"WDR3 gene haplotype is associated with thyroid cancer risk in a Spanish population.","date":"2010","source":"Thyroid : official journal of the American Thyroid Association","url":"https://pubmed.ncbi.nlm.nih.gov/20578902","citation_count":15,"is_preprint":false},{"pmid":"10395803","id":"PMC_10395803","title":"Cloning and expression analysis of a novel WD repeat gene, WDR3, mapping to 1p12-p13.","date":"1999","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/10395803","citation_count":13,"is_preprint":false},{"pmid":"31614064","id":"PMC_31614064","title":"The Cul4-DDB1-WDR3/WDR6 Complex Binds SPAK and OSR1 Kinases in a Phosphorylation-Dependent Manner.","date":"2019","source":"Chembiochem : a European journal of chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/31614064","citation_count":11,"is_preprint":false},{"pmid":"36905106","id":"PMC_36905106","title":"WDR3 promotes stem cell-like properties in prostate cancer by inhibiting USF2-mediated transcription of RASSF1A.","date":"2023","source":"The journal of gene medicine","url":"https://pubmed.ncbi.nlm.nih.gov/36905106","citation_count":10,"is_preprint":false},{"pmid":"23049746","id":"PMC_23049746","title":"Possible role of the WDR3 gene on genome stability in thyroid cancer patients.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23049746","citation_count":6,"is_preprint":false},{"pmid":"40646517","id":"PMC_40646517","title":"WDR3 undergoes phase separation to mediate the therapeutic mechanism of Nilotinib against osteosarcoma.","date":"2025","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/40646517","citation_count":5,"is_preprint":false},{"pmid":"36463953","id":"PMC_36463953","title":"Characterization of a WD-repeat family protein WDR3 in the brain of WDR3 hetero knockout mice.","date":"2022","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/36463953","citation_count":0,"is_preprint":false},{"pmid":"41395298","id":"PMC_41395298","title":"WDR3 drives pancreatic cancer metastasis by enhancing TGF-α mRNA stability through YTHDC1.","date":"2025","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/41395298","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":6819,"output_tokens":2329,"usd":0.027696,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9440,"output_tokens":3298,"usd":0.064825,"stage2_stop_reason":"end_turn"},"total_usd":0.092521,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"WDR3 is required for 18S rRNA processing and 40S ribosomal subunit synthesis; its depletion causes defects in 18S rRNA processing, transient down-regulation of precursor rRNA levels, and moderate repression of RNA polymerase I activity. In p53-competent cells, WDR3 suppression activates p53 via sequestration of MDM2 by ribosomal protein L11, leading to G1 cell cycle arrest; cells lacking functional p53 do not arrest.\",\n      \"method\": \"siRNA knockdown, flow cytometry (cell cycle analysis), Western blot, RT-PCR, RNA polymerase I activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (rRNA processing assays, PolI activity, cell cycle, p53/MDM2/L11 pathway dissection) in a single focused mechanistic study with clear epistasis (p53-dependent vs. p53-null cells)\",\n      \"pmids\": [\"20392698\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"WDR3 (and WDR6) are substrate receptors for the CRL4 (Cul4-DDB1) E3 ubiquitin ligase complex; this complex binds OSR1 and SPAK kinases in a manner dependent on phosphorylation of their S-motif serine by WNK kinases. Under osmotic stress, S-motif phosphorylation disrupts this binding and abolishes OSR1 ubiquitylation, linking the CRL4-WDR3 complex to ion homeostasis regulation.\",\n      \"method\": \"Affinity pulldown, mass spectrometry, proteasomal and neddylation inhibitor assays, co-immunoprecipitation\",\n      \"journal\": \"Chembiochem : a European journal of chemical biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — affinity pulldown + MS identification of complex, functional validation with proteasomal/neddylation inhibitors; single lab\",\n      \"pmids\": [\"31614064\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"WDR3 interacts with the transcription factor GATA4 via co-immunoprecipitation, inducing nuclear translocation of GATA4 and thereby transcriptionally upregulating YAP1 expression to activate the Hippo signaling pathway in pancreatic cancer cells.\",\n      \"method\": \"Co-immunoprecipitation, Western blot, RT-qPCR, nuclear fractionation/immunofluorescence, siRNA knockdown, colony formation and transwell invasion assays\",\n      \"journal\": \"Journal of experimental & clinical cancer research : CR\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single lab, co-IP for interaction, functional rescue and inhibitor combination experiments; multiple orthogonal cellular assays but no in vitro reconstitution\",\n      \"pmids\": [\"33648545\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"WDR3 promotes ubiquitination and proteasomal degradation of the transcription factor USF2, reducing USF2 stability. USF2 normally binds the RASSF1A promoter to transcriptionally activate RASSF1A expression; WDR3-mediated USF2 degradation suppresses RASSF1A transcription and promotes prostate cancer stem cell-like properties and proliferation.\",\n      \"method\": \"Co-immunoprecipitation, chromatin immunoprecipitation (ChIP), luciferase reporter assay, ubiquitination assay, Western blot, cell proliferation/apoptosis assays, xenograft mouse model\",\n      \"journal\": \"The journal of gene medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (Co-IP, ChIP, reporter, ubiquitination assay, in vivo xenograft) in a single lab study\",\n      \"pmids\": [\"36905106\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"WDR3 interacts with the m6A reader YTHDC1 and facilitates K63-linked ubiquitination of YTHDC1, resulting in increased cytoplasmic localization of YTHDC1. This enhances stability of TGF-α mRNA, upregulates TGF-α expression, and promotes pancreatic cancer cell invasion and metastasis.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay (K63-linkage-specific), subcellular fractionation, mRNA stability assay, siRNA knockdown, overexpression rescue, invasion/migration assays\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mechanistic pathway (Co-IP, K63-ubiquitination, localization shift, mRNA stability) supported by rescue experiments; single lab\",\n      \"pmids\": [\"41395298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"WDR3 undergoes liquid-liquid phase separation (LLPS) in osteosarcoma cells, forming condensates with liquid-like behavior demonstrated by FRAP. Mutation of the intrinsically disordered region (IDR) impairs phase separation; fusion with hnRNPA1 IDR rescues it. Nilotinib treatment inhibits formation of WDR3 phase-separated condensates and suppresses osteosarcoma progression in vitro and in vivo.\",\n      \"method\": \"Droplet formation assay, FRAP, IDR mutagenesis, hnRNPA1-IDR fusion rescue, xenograft mouse model, molecular docking\",\n      \"journal\": \"Journal of experimental & clinical cancer research : CR\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — FRAP and droplet assays with mutagenesis and domain-swap rescue provide direct mechanistic evidence for LLPS; single lab\",\n      \"pmids\": [\"40646517\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Complete homozygous knockout of Wdr3 is lethal during embryogenesis in mice (no homozygous knockouts born), indicating an essential developmental function. Heterozygous knockout reduces brain Wdr3 mRNA to ~60% without significant reduction in 18S rRNA levels, and results in slightly increased spontaneous locomotor activity.\",\n      \"method\": \"Heterozygous knockout mouse model, immunohistochemistry, X-gal staining, RT-PCR, behavioral assays\",\n      \"journal\": \"Brain research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — germline knockout with embryonic lethality finding is a defined in vivo genetic result, but 18S rRNA and behavioral outcomes are from a single lab with limited mechanistic follow-up\",\n      \"pmids\": [\"36463953\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"WDR3 encodes a 943-amino-acid nuclear protein containing 10 WD repeat modules (characterized by GH-WD repeat units), mapping to chromosome 1p12-p13, and is widely expressed in hematopoietic and non-hematopoietic tissues.\",\n      \"method\": \"cDNA cloning, sequence analysis, FISH (chromosomal mapping), Northern blot/RT-PCR expression analysis\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — foundational cloning and structural characterization; nuclear localization inferred from sequence; replicated in subsequent work\",\n      \"pmids\": [\"10395803\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"WDR3 is a nuclear WD-repeat protein that functions as a component of the 18S pre-rRNA processing machinery essential for 40S ribosomal subunit biogenesis, acts as a substrate receptor in the CRL4 (Cul4-DDB1) E3 ubiquitin ligase complex to regulate SPAK/OSR1 kinase ubiquitylation, promotes oncogenic signaling by interacting with GATA4 to drive YAP1/Hippo pathway activation, targets USF2 for K63-linked ubiquitination and degradation to repress RASSF1A transcription, facilitates K63-ubiquitination of YTHDC1 to increase cytoplasmic YTHDC1 and stabilize TGF-α mRNA, and undergoes liquid-liquid phase separation via its intrinsically disordered region; complete loss is embryonic lethal in mice, and ribosomal stress from WDR3 depletion activates p53 via RPL11-MDM2 sequestration to arrest the cell cycle.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"WDR3 is a nuclear WD-repeat protein with dual roles in ribosome biogenesis and oncogenic signaling [#0, #7]. As a component of the small-subunit pre-rRNA processing machinery, WDR3 is required for 18S rRNA processing and 40S ribosomal subunit synthesis; its depletion impairs precursor rRNA maturation and dampens RNA polymerase I activity, and in p53-competent cells triggers a ribosomal stress response in which RPL11 sequesters MDM2 to activate p53 and impose G1 arrest [#0]. This biogenesis function is developmentally essential, as homozygous Wdr3 knockout is embryonic lethal in mice [#6]. In cancer contexts WDR3 operates as a ubiquitin-ligase-associated adaptor and signaling driver: it serves as a substrate receptor for the CRL4 (Cul4-DDB1) E3 complex that binds and ubiquitylates the WNK-regulated kinases OSR1 and SPAK, linking it to ion homeostasis [#1], and it directs ubiquitination of multiple transcription factors and readers to reshape gene expression — promoting K63-linked ubiquitination of YTHDC1 to drive its cytoplasmic relocalization and stabilize TGF-α mRNA [#4], degrading USF2 to repress RASSF1A transcription [#3], and engaging GATA4 to upregulate YAP1 and activate Hippo pathway signaling [#2]. WDR3 also undergoes liquid-liquid phase separation through its intrinsically disordered region, forming condensates that support tumor progression [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Established the molecular identity of WDR3 — that it encodes a nuclear WD-repeat protein, defining a scaffold-type architecture and subcellular compartment for all later functional work.\",\n      \"evidence\": \"cDNA cloning, sequence/domain analysis, FISH chromosomal mapping, and expression profiling\",\n      \"pmids\": [\"10395803\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Nuclear localization inferred from sequence rather than directly imaged\", \"No functional assay linking the WD repeats to a specific partner or pathway\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Defined WDR3's core cellular function in 18S rRNA processing and 40S subunit synthesis, and showed its loss triggers a p53-dependent ribosomal stress checkpoint, explaining how WDR3 depletion arrests proliferation.\",\n      \"evidence\": \"siRNA knockdown with rRNA processing assays, PolI activity measurement, cell-cycle flow cytometry, and p53/MDM2/RPL11 epistasis in p53-competent vs p53-null cells\",\n      \"pmids\": [\"20392698\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise position of WDR3 within the SSU processome not resolved\", \"Direct rRNA or processing-factor binding partners not identified\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Revealed an unexpected second role beyond ribosome biogenesis — WDR3 acts as a CRL4 substrate receptor coupling WNK-dependent phosphorylation of OSR1/SPAK to their ubiquitylation, placing WDR3 in ion homeostasis signaling.\",\n      \"evidence\": \"Affinity pulldown with mass spectrometry, co-IP, and proteasomal/neddylation inhibitor assays under osmotic stress\",\n      \"pmids\": [\"31614064\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab without independent confirmation\", \"Physiological consequence of OSR1/SPAK ubiquitylation on ion transport not measured\", \"Whether substrate-receptor role generalizes to other targets unaddressed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected WDR3 to oncogenic transcriptional programs, showing it drives GATA4 nuclear translocation to upregulate YAP1 and activate Hippo signaling in pancreatic cancer.\",\n      \"evidence\": \"Co-IP, nuclear fractionation/immunofluorescence, RT-qPCR, and knockdown with colony-formation and invasion assays\",\n      \"pmids\": [\"33648545\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interaction shown by co-IP only, no in vitro reconstitution\", \"Mechanism by which WDR3 promotes GATA4 translocation unknown\", \"Direct vs indirect effect on YAP1 transcription not separated\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Demonstrated that WDR3 is developmentally essential, with complete loss being embryonic lethal, while partial loss is tolerated without measurable rRNA deficit.\",\n      \"evidence\": \"Germline heterozygous/homozygous knockout mouse, X-gal staining, immunohistochemistry, RT-PCR, and behavioral assays\",\n      \"pmids\": [\"36463953\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Developmental stage and cause of lethality not defined\", \"Tissue-specific requirements not dissected\", \"Mechanism linking essentiality to ribosome biogenesis vs other roles not established\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended WDR3's ubiquitin-directed regulation to transcription factor turnover, showing it degrades USF2 to suppress RASSF1A and promote prostate cancer stemness.\",\n      \"evidence\": \"Co-IP, ChIP, luciferase reporter, ubiquitination assay, and xenograft mouse model\",\n      \"pmids\": [\"36905106\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"E3 ligase mediating USF2 ubiquitination not identified\", \"Single lab study\", \"Whether degradation requires the CRL4 association seen for OSR1/SPAK unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showed WDR3 controls m6A-reader fate, facilitating K63-linked ubiquitination of YTHDC1 to shift it to the cytoplasm and stabilize TGF-α mRNA, driving pancreatic cancer metastasis.\",\n      \"evidence\": \"Co-IP, K63-linkage-specific ubiquitination assay, subcellular fractionation, mRNA stability assay, and rescue experiments\",\n      \"pmids\": [\"41395298\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ubiquitin ligase responsible not identified\", \"Single lab\", \"Link between K63 ubiquitination and cytoplasmic export mechanism unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified a biophysical mode of action — WDR3 forms liquid-liquid phase-separated condensates via its IDR that support osteosarcoma progression and are druggable by nilotinib.\",\n      \"evidence\": \"Droplet formation assay, FRAP, IDR mutagenesis, hnRNPA1-IDR domain-swap rescue, molecular docking, and xenograft model\",\n      \"pmids\": [\"40646517\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional cargo or clients of the condensates not defined\", \"Relationship of LLPS to ribosome biogenesis or ubiquitin functions unknown\", \"Direct nilotinib-WDR3 binding shown only by docking\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How WDR3's conserved ribosome-biogenesis role mechanistically relates to its multiple cancer-associated ubiquitin and transcription-factor functions, and whether these reflect distinct protein pools or a unified scaffolding activity, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model placing WDR3 in either the SSU processome or a defined ubiquitin complex\", \"Cancer-context functions each rest on single-lab studies\", \"Whether LLPS underlies the diverse interactions is untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1, 3, 4]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [7, 0]},\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [1, 3, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2, 3, 4]}\n    ],\n    \"complexes\": [\"CRL4 (Cul4-DDB1) E3 ubiquitin ligase\"],\n    \"partners\": [\"DDB1\", \"CUL4\", \"OSR1\", \"SPAK\", \"GATA4\", \"USF2\", \"YTHDC1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":5,"faith_total":5,"faith_pct":100.0}}