{"gene":"JOSD2","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":2020,"finding":"JOSD2 directly interacts with and deubiquitinates a metabolic enzyme complex comprising Aldolase A, Phosphofructokinase-1, and Phosphoglycerate dehydrogenase, stabilizing these enzymes and enhancing their activities and the glycolytic rate; a catalytically inactive JOSD2 mutant fails to deubiquitinate or stabilize this complex, demonstrating activity dependence.","method":"In vitro and in vivo deubiquitination assays, catalytically inactive mutant analysis, enzyme activity assays, co-immunoprecipitation","journal":"Cell death and differentiation","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro and in vivo assays with catalytically inactive mutant control and functional enzyme activity readouts, single lab but multiple orthogonal methods","pmids":["33082514"],"is_preprint":false},{"year":2021,"finding":"JOSD2 deubiquitinates YAP and TAZ, cleaving their polyubiquitin chains in a deubiquitinase activity-dependent manner, thereby preventing their proteasomal degradation and sustaining their protein levels in cholangiocarcinoma cells.","method":"Deubiquitination assays, proteasome inhibitor rescue, JOSD2 knockdown/depletion with YAP/TAZ protein level measurement, in vitro and in vivo proliferation assays","journal":"Acta pharmaceutica Sinica. B","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — deubiquitination assays with activity-dependence shown, knockdown with defined substrate readout, single lab","pmids":["35024322"],"is_preprint":false},{"year":2022,"finding":"JOSD2 interacts with PKM2 (identified by mass spectrometry and co-immunoprecipitation) and inhibits PKM2 nuclear localization by reducing its K433 acetylation modification, without affecting PKM2 protein stability.","method":"Mass spectrometry, co-immunoprecipitation, co-immunofluorescence, acetylation assays, nuclear/cytoplasmic fractionation","journal":"Experimental hematology & oncology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — reciprocal co-IP and MS identification with acetylation readout, single lab, mechanism of nuclear exclusion via acetylation change established","pmids":["35836282"],"is_preprint":false},{"year":2022,"finding":"JOSD2 binds to CTNNB1 (beta-catenin) and reduces its ubiquitination level, thereby stabilizing CTNNB1 and augmenting Wnt signaling pathway transduction in hepatocellular carcinoma cells.","method":"Co-immunoprecipitation, ubiquitination assays, Wnt pathway reporter assays, rescue experiments","journal":"Cell biology international","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP with ubiquitination assay and pathway-level rescue experiments, single lab","pmids":["35568970"],"is_preprint":false},{"year":2023,"finding":"JOSD2 interacts with SERCA2a (sarco/endoplasmic reticulum calcium ATPase 2a) and mediates its deubiquitination, enhancing SERCA2a stability; JOSD2 deficiency impairs calcium handling and promotes hypertrophy in primary cardiomyocytes.","method":"Proteome-wide quantitative analysis (mass spectrometry), co-immunoprecipitation, deubiquitination assays, JOSD2 knockout mice, AAV9-mediated cardiac overexpression, calcium handling assays","journal":"Nature cardiovascular research","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo KO and OE with AAV9, proteome-wide substrate identification, deubiquitination assays, and functional calcium handling readout, multiple orthogonal methods","pmids":["39195964"],"is_preprint":false},{"year":2023,"finding":"DNA damaging agents increase nuclear localization of JOSD2, and JOSD2 overexpression promotes DNA damage repair (DDR) pathway activation in NSCLC cells; JOSD2 depletion enhances sensitivity to DNA damaging agents.","method":"Immunofluorescence (nuclear localization), Western blotting (DDR pathway proteins), sulforhodamine B cytotoxicity assay, gene set enrichment analysis","journal":"Journal of Zhejiang University. Medical sciences","confidence":"Low","confidence_rationale":"Tier 3 / Weak — localization by immunofluorescence and phenotypic drug sensitivity assay, no direct substrate identified for DDR role, single lab single method per endpoint","pmids":["37899394"],"is_preprint":false},{"year":2024,"finding":"JOSD2 restricts the kinase activity of LKB1 by removing K6-linked polyubiquitination from LKB1, an action vital for maintaining integrity of the LKB1-STRAD-MO25 complex, thereby suppressing LKB1 tumor suppressor function in NSCLC.","method":"Co-immunoprecipitation, ubiquitination assays (K6-linked chain specificity), kinase activity assays, in vivo xenograft models","journal":"Signal transduction and targeted therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — specific ubiquitin-chain-type (K6) identified, kinase activity assay, in vivo validation, single lab","pmids":["38177135"],"is_preprint":false},{"year":2024,"finding":"JOSD2 interacts with CaMKIIδ and directly hydrolyzes K63-linked polyubiquitin chains on CaMKIIδ, thereby increasing CaMKIIδ phosphorylation and resulting in calcium mishandling, hypertrophy, and fibrosis in cardiomyocytes; these effects are reversed by the CaMKIIδ inhibitor KN-93.","method":"Mass spectrometry, co-immunoprecipitation, deubiquitination assays (K63-chain specific), phosphorylation assays, in vivo cardiac remodeling models, pharmacological inhibition rescue","journal":"Cellular and molecular life sciences : CMLS","confidence":"High","confidence_rationale":"Tier 2 / Strong — mass spectrometry substrate identification, specific K63 chain hydrolysis shown, phosphorylation readout, in vivo rescue with inhibitor, multiple orthogonal methods single lab","pmids":["38195959"],"is_preprint":false},{"year":2024,"finding":"JOSD2 binds to the C-terminal of IMPDH2 and preferentially cleaves K63-linked polyubiquitin chains at the K134 site of IMPDH2, suppressing IMPDH2 activity and preventing NF-κB activation and inflammation in macrophages.","method":"Co-immunoprecipitation, ubiquitination assays (K63-linked, K134 site-specific), IMPDH2 enzyme activity assays, NF-κB reporter assays, myeloid-specific JOSD2 knockout mice, bone marrow transplantation, AAV6-mediated overexpression","journal":"Acta pharmaceutica Sinica. B","confidence":"High","confidence_rationale":"Tier 2 / Strong — specific ubiquitin linkage and lysine site identified, enzyme activity assay, tissue-specific KO and OE with in vivo models, multiple orthogonal methods","pmids":["40177575"],"is_preprint":false},{"year":2024,"finding":"JOSD2 interacts with SMAD7 at its MH1 domain and removes K48-linked ubiquitin chains from SMAD7 at lysine 220, sustaining SMAD7 stability and inhibiting TGFβ-SMAD pathway-driven vascular remodeling.","method":"LC-MS/MS, co-immunoprecipitation, ubiquitination assays (K48-chain and K220 site-specific), domain mapping, JOSD2 KO mice, VSMC-specific JOSD2 overexpression","journal":"Acta pharmacologica Sinica","confidence":"High","confidence_rationale":"Tier 2 / Strong — specific ubiquitin linkage (K48) and modification site (K220) identified by LC-MS/MS, domain interaction mapped, in vivo KO and cell-specific OE, multiple orthogonal methods","pmids":["39833306"],"is_preprint":false},{"year":2025,"finding":"JOSD2 directly interacts with and stabilizes KRAS mutant variants by removing their proteolytic ubiquitination; reciprocally, KRAS mutants inhibit CHIP (E3 ubiquitin ligase for JOSD2), forming a JOSD2/KRAS positive feedback circuit. Inhibition of JOSD2 promotes polyubiquitination and proteasomal degradation of KRAS mutants.","method":"DUB siRNA library screen, co-immunoprecipitation, ubiquitination assays, CHIP kinase activity assays, RNA interference, pharmacological JOSD2 inhibitor, patient-derived cells/xenografts/organoids","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic siRNA library screen, reciprocal regulation (JOSD2 stabilizes KRAS; KRAS inhibits CHIP), validated in PDCs/PDXs/PDOs across multiple KRAS mutants, multiple orthogonal methods","pmids":["40240366"],"is_preprint":false},{"year":2025,"finding":"JOSD2 removes K63-linked ubiquitination from SIRT7 via its active site C24 and promotes P62-mediated autophagic degradation of SIRT7, which prevents phosphorylation and nuclear translocation of P65 (NF-κB) and reduces inflammatory responses in renal tubular epithelial cells.","method":"Mass spectrometry, co-immunoprecipitation, ubiquitination assays (K63-linked), active site mutagenesis (C24), autophagy flux assays, P65 nuclear translocation assays, JOSD2 KO mice, renal tubular-specific JOSD2 overexpression","journal":"Acta pharmacologica Sinica","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — active site mutagenesis (C24), specific K63 chain identified, autophagic degradation mechanism established, in vivo KO and cell-specific OE, multiple orthogonal methods","pmids":["40217118"],"is_preprint":false},{"year":2025,"finding":"JOSD2 interacts with and stabilizes SMAD4 by removing polyubiquitin chains, promoting TGF-β signaling and breast cancer metastasis; RNA interference-mediated JOSD2 inhibition reduces breast cancer cell metastasis in vitro and in vivo.","method":"Co-immunoprecipitation, ubiquitination assays, in vitro migration/invasion assays, in vivo metastasis models","journal":"Biochemical pharmacology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP and ubiquitination assay with in vivo validation, single lab, ubiquitin chain type not specified in abstract","pmids":["39793716"],"is_preprint":false},{"year":2025,"finding":"JOSD2 suppresses cGAS enzymatic activity by removing K27-linked ubiquitination from cGAS, thereby inhibiting the cGAS-STING signaling pathway and promoting M2 macrophage polarization; pharmacological inhibition of JOSD2 reactivates cGAS-STING signaling.","method":"Co-immunoprecipitation, ubiquitination assays (K27-linked chain specific), cGAS enzymatic activity assays, macrophage polarization assays, pharmacological JOSD2 inhibitor in vitro and in vivo","journal":"Oncoimmunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — specific K27 ubiquitin linkage identified, cGAS activity assay, macrophage polarization readout, in vivo pharmacological validation, single lab","pmids":["41351298"],"is_preprint":false},{"year":2025,"finding":"JOSD2 deubiquitinates K63-linked ubiquitin chains on AKT via its active site H125, promoting P62-mediated autophagic degradation of AKT in renal tubular epithelial cells, thereby reducing AKT levels, renal EMT, and fibrosis.","method":"Mass spectrometry, co-immunoprecipitation, ubiquitination assays (K63-linked), active site mutagenesis (H125), autophagic degradation assays, JOSD2 KO mice, renal tubular-specific JOSD2 overexpression","journal":"Cellular signalling","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — active site mutagenesis (H125), specific K63 chain identified, autophagic degradation mechanism, in vivo KO and cell-specific OE, multiple orthogonal methods","pmids":["41412561"],"is_preprint":false},{"year":2025,"finding":"A small-molecule JOSD2 inhibitor (compound 31) bearing a cyanamide warhead covalently engages the catalytic cysteine residue of JOSD2, confirming cysteine-dependent catalytic mechanism; compound 31 induces downregulation of KRAS protein in HCT116 cells.","method":"High-throughput screening, structure-activity relationship analysis, covalent binding mode characterization, Western blotting for KRAS protein levels","journal":"Bioorganic chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — covalent warhead targeting catalytic cysteine with functional substrate (KRAS) downregulation, single lab, abstract-level description of covalent binding","pmids":["41092805"],"is_preprint":false}],"current_model":"JOSD2 is a Machado-Joseph disease (MJD) family cysteine deubiquitinase whose active site (C24 or H125 depending on substrate context) cleaves K6-, K27-, K48-, and K63-linked polyubiquitin chains from a broad range of substrates—including YAP/TAZ, SERCA2a, CaMKIIδ, LKB1, KRAS mutants, CTNNB1, SMAD4, SMAD7, IMPDH2, SIRT7, AKT, and Aldolase A/PFK1/PHGDH complexes—to regulate their stability, activity, or localization, with context-dependent outcomes in cancer metabolism, cardiac physiology, renal and vascular biology, and immune signaling."},"narrative":{"mechanistic_narrative":"JOSD2 is a cysteine deubiquitinase that controls the stability, activity, and localization of diverse substrates across cancer metabolism, cardiac and renal physiology, vascular remodeling, and immune signaling by cleaving specific polyubiquitin linkages, with catalysis depending on its active-site cysteine (C24) or, in some substrate contexts, H125 [PMID:40217118, PMID:41412561, PMID:41092805]. It acts on multiple chain types: removing K48-linked chains to stabilize substrates such as SMAD7 [PMID:39833306], K6-linked chains to restrict LKB1 kinase activity and the LKB1-STRAD-MO25 complex [PMID:38177135], and K63-linked chains on CaMKIIδ, IMPDH2, SIRT7, and AKT to modulate their activity or routing to autophagic degradation [PMID:38195959, PMID:40177575, PMID:40217118, PMID:41412561], as well as K27-linked chains on cGAS to suppress its enzymatic activity [PMID:41351298]. Through these activities JOSD2 stabilizes oncogenic and proliferative effectors—deubiquitinating and stabilizing YAP/TAZ, CTNNB1/Wnt signaling, SMAD4-driven TGF-β signaling, mutant KRAS, and a glycolytic enzyme complex of Aldolase A, PFK1, and PHGDH to enhance glycolysis [PMID:33082514, PMID:35024322, PMID:35568970, PMID:40240366, PMID:39793716]. In the cardiovascular and renal systems it has context-dependent roles, stabilizing SERCA2a to support calcium handling while deubiquitinating CaMKIIδ to drive hypertrophy and fibrosis, and promoting autophagic turnover of SIRT7 and AKT to limit NF-κB-driven inflammation and EMT-associated fibrosis [PMID:39195964, PMID:38195959, PMID:40217118, PMID:41412561]. A covalent cyanamide-warhead small molecule engages the catalytic cysteine and downregulates KRAS, establishing JOSD2 as a druggable target and confirming its cysteine-dependent mechanism [PMID:40240366, PMID:41092805].","teleology":[{"year":2020,"claim":"Established that JOSD2 acts catalytically on a metabolic enzyme complex, linking its deubiquitinase activity to glycolytic flux rather than to a single substrate.","evidence":"In vitro/in vivo deubiquitination assays with catalytically inactive mutant control and enzyme activity readouts on the Aldolase A/PFK1/PHGDH complex","pmids":["33082514"],"confidence":"High","gaps":["Ubiquitin chain linkage type not defined","Direct vs. indirect deubiquitination of each enzyme not fully resolved"]},{"year":2021,"claim":"Extended JOSD2 function to oncogenic transcriptional coactivators by showing it deubiquitinates and stabilizes YAP/TAZ to sustain proliferation.","evidence":"Activity-dependent deubiquitination assays, proteasome inhibitor rescue, and knockdown with YAP/TAZ readouts in cholangiocarcinoma cells","pmids":["35024322"],"confidence":"Medium","gaps":["Chain linkage not specified","Single lab, no structural detail"]},{"year":2022,"claim":"Showed JOSD2 can regulate substrates non-degradatively, controlling PKM2 nuclear localization via acetylation and stabilizing CTNNB1 to amplify Wnt signaling.","evidence":"MS/co-IP, acetylation assays, nuclear/cytoplasmic fractionation for PKM2; co-IP, ubiquitination and Wnt reporter assays for CTNNB1","pmids":["35836282","35568970"],"confidence":"Medium","gaps":["Mechanism linking JOSD2 to PKM2 acetylation unclear","CTNNB1 chain linkage not defined"]},{"year":2023,"claim":"Defined an in vivo cardiac role by demonstrating JOSD2 stabilizes SERCA2a to maintain calcium handling, with loss promoting hypertrophy.","evidence":"Proteome-wide MS, co-IP, deubiquitination assays, JOSD2 KO mice and AAV9 overexpression with calcium handling assays","pmids":["39195964"],"confidence":"High","gaps":["Chain linkage on SERCA2a not specified","Reconciliation with pro-hypertrophic CaMKIIδ role not addressed"]},{"year":2023,"claim":"Linked JOSD2 to genotoxic stress responses, showing DNA damage drives its nuclear accumulation and that it promotes DDR pathway activation.","evidence":"Immunofluorescence, Western blotting of DDR proteins, and drug sensitivity assays in NSCLC cells","pmids":["37899394"],"confidence":"Low","gaps":["No direct DDR substrate identified","Single method per endpoint; correlative phenotype only"]},{"year":2024,"claim":"Resolved linkage-specific catalysis by showing JOSD2 cleaves K6 chains on LKB1 to restrict its tumor-suppressor kinase activity and K63 chains on CaMKIIδ to drive cardiac hypertrophy and fibrosis.","evidence":"Chain-specific ubiquitination assays, kinase/phosphorylation assays, xenograft and cardiac remodeling models with KN-93 rescue","pmids":["38177135","38195959"],"confidence":"High","gaps":["Structural basis of chain-type selectivity unknown","How substrate context selects degradative vs. non-degradative outcome unclear"]},{"year":2024,"claim":"Established site- and linkage-specific control of immune and vascular signaling, with JOSD2 cleaving K63 chains at IMPDH2 K134 to limit NF-κB inflammation and K48 chains at SMAD7 K220 to dampen TGF-β-driven vascular remodeling.","evidence":"LC-MS/MS, site-specific ubiquitination assays, domain mapping, enzyme/reporter assays, tissue-specific KO and OE mouse models","pmids":["40177575","39833306"],"confidence":"High","gaps":["Determinants of K134/K220 site selection not defined","Tissue-specificity of effects not mechanistically explained"]},{"year":2025,"claim":"Identified JOSD2 as a stabilizer of mutant KRAS through a positive feedback circuit and validated it as a covalently druggable cysteine deubiquitinase.","evidence":"DUB siRNA library screen, co-IP, ubiquitination and CHIP activity assays in PDCs/PDXs/PDOs; covalent cyanamide-warhead inhibitor engaging the catalytic cysteine with KRAS downregulation","pmids":["40240366","41092805"],"confidence":"High","gaps":["Co-crystal structure of inhibitor-enzyme not reported","Selectivity over other DUBs not fully established"]},{"year":2025,"claim":"Defined active-site residues and an autophagic degradation mode, with C24 (SIRT7) and H125 (AKT) mediating K63 chain removal that routes substrates to P62-dependent autophagy, plus K27 cleavage on cGAS suppressing cGAS-STING signaling.","evidence":"Active-site mutagenesis (C24, H125), chain-specific ubiquitination assays, autophagy flux assays, KO/cell-specific OE mice; cGAS activity and macrophage polarization assays with pharmacological inhibition","pmids":["40217118","41412561","41351298"],"confidence":"High","gaps":["How K63 deubiquitination promotes autophagic rather than proteasomal routing unresolved","Whether C24 and H125 act on distinct substrate sets or cooperatively unclear"]},{"year":null,"claim":"How JOSD2 selects among substrates, chain types (K6/K27/K48/K63), and degradative versus non-degradative or autophagic outcomes in a tissue-specific manner remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No structural basis for linkage or substrate selectivity","No unifying model for context-dependent stabilizing vs. destabilizing outcomes","Endogenous regulation of JOSD2 activity and localization largely uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,4,6,7,8,9,11,14]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,8,11,14]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[2,5]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[2]}],"pathway":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[7,8,9]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,1,4,9,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[3,6,9,12,13]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[8,13]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[11,14]}],"complexes":[],"partners":["YAP1","WWTR1","CTNNB1","SERCA2A","CAMK2D","STK11","IMPDH2","KRAS"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8TAC2","full_name":"Josephin-2","aliases":["Josephin domain-containing protein 2"],"length_aa":188,"mass_kda":20.8,"function":"Cleaves 'Lys-63'-linked poly-ubiquitin chains, and with lesser efficiency 'Lys-48'-linked poly-ubiquitin chains (in vitro). May act as a deubiquitinating enzyme","subcellular_location":"Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/Q8TAC2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/JOSD2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/JOSD2","total_profiled":1310},"omim":[{"mim_id":"615324","title":"JOSEPHIN DOMAIN-CONTAINING PROTEIN 2; JOSD2","url":"https://www.omim.org/entry/615324"},{"mim_id":"615323","title":"JOSEPHIN DOMAIN-CONTAINING PROTEIN 1; JOSD1","url":"https://www.omim.org/entry/615323"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/JOSD2"},"hgnc":{"alias_symbol":["SBBI54"],"prev_symbol":[]},"alphafold":{"accession":"Q8TAC2","domains":[{"cath_id":"3.90.70.40","chopping":"22-180","consensus_level":"medium","plddt":92.309,"start":22,"end":180}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TAC2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TAC2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TAC2-F1-predicted_aligned_error_v6.png","plddt_mean":89.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=JOSD2","jax_strain_url":"https://www.jax.org/strain/search?query=JOSD2"},"sequence":{"accession":"Q8TAC2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8TAC2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8TAC2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TAC2"}},"corpus_meta":[{"pmid":"35024322","id":"PMC_35024322","title":"Deubiquitinase JOSD2 stabilizes YAP/TAZ to promote cholangiocarcinoma progression.","date":"2021","source":"Acta pharmaceutica Sinica. B","url":"https://pubmed.ncbi.nlm.nih.gov/35024322","citation_count":39,"is_preprint":false},{"pmid":"33082514","id":"PMC_33082514","title":"The deubiquitinase JOSD2 is a positive regulator of glucose metabolism.","date":"2020","source":"Cell death and differentiation","url":"https://pubmed.ncbi.nlm.nih.gov/33082514","citation_count":36,"is_preprint":false},{"pmid":"39195964","id":"PMC_39195964","title":"Deubiquitinase JOSD2 improves calcium handling and attenuates cardiac hypertrophy and dysfunction by stabilizing SERCA2a in cardiomyocytes.","date":"2023","source":"Nature cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/39195964","citation_count":27,"is_preprint":false},{"pmid":"35836282","id":"PMC_35836282","title":"JOSD2 regulates PKM2 nuclear translocation and reduces acute myeloid leukemia progression.","date":"2022","source":"Experimental hematology & oncology","url":"https://pubmed.ncbi.nlm.nih.gov/35836282","citation_count":20,"is_preprint":false},{"pmid":"38177135","id":"PMC_38177135","title":"Josephin domain containing 2 (JOSD2) promotes lung cancer by inhibiting LKB1 (Liver kinase B1) activity.","date":"2024","source":"Signal transduction and targeted therapy","url":"https://pubmed.ncbi.nlm.nih.gov/38177135","citation_count":18,"is_preprint":false},{"pmid":"35568970","id":"PMC_35568970","title":"Deubiquitinating enzyme JOSD2 promotes hepatocellular carcinoma progression through interacting with and inhibiting CTNNB1 degradation.","date":"2022","source":"Cell biology international","url":"https://pubmed.ncbi.nlm.nih.gov/35568970","citation_count":13,"is_preprint":false},{"pmid":"38195959","id":"PMC_38195959","title":"JOSD2 mediates isoprenaline-induced heart failure by deubiquitinating CaMKIIδ in cardiomyocytes.","date":"2024","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/38195959","citation_count":12,"is_preprint":false},{"pmid":"40240366","id":"PMC_40240366","title":"Josephin Domain Containing 2 (JOSD2) inhibition as Pan-KRAS-mutation-targeting strategy for colorectal cancer.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/40240366","citation_count":9,"is_preprint":false},{"pmid":"40217118","id":"PMC_40217118","title":"JOSD2 alleviates acute kidney injury through deubiquitinating SIRT7 and negativity regulating SIRT7-NF-κB inflammatory pathway in renal tubular epithelial cells.","date":"2025","source":"Acta pharmacologica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/40217118","citation_count":8,"is_preprint":false},{"pmid":"40177575","id":"PMC_40177575","title":"Deubiquitinase JOSD2 alleviates colitis by inhibiting inflammation via deubiquitination of IMPDH2 in macrophages.","date":"2024","source":"Acta pharmaceutica Sinica. 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Yi xue ban = Journal of Zhejiang University. Medical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37899394","citation_count":3,"is_preprint":false},{"pmid":"39793716","id":"PMC_39793716","title":"JOSD2 promotes breast cancer metastasis by deubiquitinating and stabilizing SMAD4.","date":"2025","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/39793716","citation_count":2,"is_preprint":false},{"pmid":"41092805","id":"PMC_41092805","title":"Rational DESIGN and Structure-activity relationship study of novel JOSD2 inhibitor against colorectal cancer.","date":"2025","source":"Bioorganic chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/41092805","citation_count":1,"is_preprint":false},{"pmid":"41412561","id":"PMC_41412561","title":"JOSD2 alleviates hypertensive renal disease through deubiquitinating AKT in renal tubular epithelial cells.","date":"2025","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/41412561","citation_count":1,"is_preprint":false},{"pmid":"42069099","id":"PMC_42069099","title":"JOSD2 deubiquitinating enzyme: Structure, function, and potential as a therapeutic target.","date":"2026","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/42069099","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11100,"output_tokens":4178,"usd":0.047985,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12068,"output_tokens":3671,"usd":0.076058,"stage2_stop_reason":"end_turn"},"total_usd":0.124043,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2020,\n      \"finding\": \"JOSD2 directly interacts with and deubiquitinates a metabolic enzyme complex comprising Aldolase A, Phosphofructokinase-1, and Phosphoglycerate dehydrogenase, stabilizing these enzymes and enhancing their activities and the glycolytic rate; a catalytically inactive JOSD2 mutant fails to deubiquitinate or stabilize this complex, demonstrating activity dependence.\",\n      \"method\": \"In vitro and in vivo deubiquitination assays, catalytically inactive mutant analysis, enzyme activity assays, co-immunoprecipitation\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro and in vivo assays with catalytically inactive mutant control and functional enzyme activity readouts, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"33082514\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"JOSD2 deubiquitinates YAP and TAZ, cleaving their polyubiquitin chains in a deubiquitinase activity-dependent manner, thereby preventing their proteasomal degradation and sustaining their protein levels in cholangiocarcinoma cells.\",\n      \"method\": \"Deubiquitination assays, proteasome inhibitor rescue, JOSD2 knockdown/depletion with YAP/TAZ protein level measurement, in vitro and in vivo proliferation assays\",\n      \"journal\": \"Acta pharmaceutica Sinica. B\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — deubiquitination assays with activity-dependence shown, knockdown with defined substrate readout, single lab\",\n      \"pmids\": [\"35024322\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"JOSD2 interacts with PKM2 (identified by mass spectrometry and co-immunoprecipitation) and inhibits PKM2 nuclear localization by reducing its K433 acetylation modification, without affecting PKM2 protein stability.\",\n      \"method\": \"Mass spectrometry, co-immunoprecipitation, co-immunofluorescence, acetylation assays, nuclear/cytoplasmic fractionation\",\n      \"journal\": \"Experimental hematology & oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — reciprocal co-IP and MS identification with acetylation readout, single lab, mechanism of nuclear exclusion via acetylation change established\",\n      \"pmids\": [\"35836282\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"JOSD2 binds to CTNNB1 (beta-catenin) and reduces its ubiquitination level, thereby stabilizing CTNNB1 and augmenting Wnt signaling pathway transduction in hepatocellular carcinoma cells.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, Wnt pathway reporter assays, rescue experiments\",\n      \"journal\": \"Cell biology international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP with ubiquitination assay and pathway-level rescue experiments, single lab\",\n      \"pmids\": [\"35568970\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"JOSD2 interacts with SERCA2a (sarco/endoplasmic reticulum calcium ATPase 2a) and mediates its deubiquitination, enhancing SERCA2a stability; JOSD2 deficiency impairs calcium handling and promotes hypertrophy in primary cardiomyocytes.\",\n      \"method\": \"Proteome-wide quantitative analysis (mass spectrometry), co-immunoprecipitation, deubiquitination assays, JOSD2 knockout mice, AAV9-mediated cardiac overexpression, calcium handling assays\",\n      \"journal\": \"Nature cardiovascular research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo KO and OE with AAV9, proteome-wide substrate identification, deubiquitination assays, and functional calcium handling readout, multiple orthogonal methods\",\n      \"pmids\": [\"39195964\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"DNA damaging agents increase nuclear localization of JOSD2, and JOSD2 overexpression promotes DNA damage repair (DDR) pathway activation in NSCLC cells; JOSD2 depletion enhances sensitivity to DNA damaging agents.\",\n      \"method\": \"Immunofluorescence (nuclear localization), Western blotting (DDR pathway proteins), sulforhodamine B cytotoxicity assay, gene set enrichment analysis\",\n      \"journal\": \"Journal of Zhejiang University. Medical sciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — localization by immunofluorescence and phenotypic drug sensitivity assay, no direct substrate identified for DDR role, single lab single method per endpoint\",\n      \"pmids\": [\"37899394\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"JOSD2 restricts the kinase activity of LKB1 by removing K6-linked polyubiquitination from LKB1, an action vital for maintaining integrity of the LKB1-STRAD-MO25 complex, thereby suppressing LKB1 tumor suppressor function in NSCLC.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays (K6-linked chain specificity), kinase activity assays, in vivo xenograft models\",\n      \"journal\": \"Signal transduction and targeted therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — specific ubiquitin-chain-type (K6) identified, kinase activity assay, in vivo validation, single lab\",\n      \"pmids\": [\"38177135\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"JOSD2 interacts with CaMKIIδ and directly hydrolyzes K63-linked polyubiquitin chains on CaMKIIδ, thereby increasing CaMKIIδ phosphorylation and resulting in calcium mishandling, hypertrophy, and fibrosis in cardiomyocytes; these effects are reversed by the CaMKIIδ inhibitor KN-93.\",\n      \"method\": \"Mass spectrometry, co-immunoprecipitation, deubiquitination assays (K63-chain specific), phosphorylation assays, in vivo cardiac remodeling models, pharmacological inhibition rescue\",\n      \"journal\": \"Cellular and molecular life sciences : CMLS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — mass spectrometry substrate identification, specific K63 chain hydrolysis shown, phosphorylation readout, in vivo rescue with inhibitor, multiple orthogonal methods single lab\",\n      \"pmids\": [\"38195959\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"JOSD2 binds to the C-terminal of IMPDH2 and preferentially cleaves K63-linked polyubiquitin chains at the K134 site of IMPDH2, suppressing IMPDH2 activity and preventing NF-κB activation and inflammation in macrophages.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays (K63-linked, K134 site-specific), IMPDH2 enzyme activity assays, NF-κB reporter assays, myeloid-specific JOSD2 knockout mice, bone marrow transplantation, AAV6-mediated overexpression\",\n      \"journal\": \"Acta pharmaceutica Sinica. B\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — specific ubiquitin linkage and lysine site identified, enzyme activity assay, tissue-specific KO and OE with in vivo models, multiple orthogonal methods\",\n      \"pmids\": [\"40177575\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"JOSD2 interacts with SMAD7 at its MH1 domain and removes K48-linked ubiquitin chains from SMAD7 at lysine 220, sustaining SMAD7 stability and inhibiting TGFβ-SMAD pathway-driven vascular remodeling.\",\n      \"method\": \"LC-MS/MS, co-immunoprecipitation, ubiquitination assays (K48-chain and K220 site-specific), domain mapping, JOSD2 KO mice, VSMC-specific JOSD2 overexpression\",\n      \"journal\": \"Acta pharmacologica Sinica\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — specific ubiquitin linkage (K48) and modification site (K220) identified by LC-MS/MS, domain interaction mapped, in vivo KO and cell-specific OE, multiple orthogonal methods\",\n      \"pmids\": [\"39833306\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"JOSD2 directly interacts with and stabilizes KRAS mutant variants by removing their proteolytic ubiquitination; reciprocally, KRAS mutants inhibit CHIP (E3 ubiquitin ligase for JOSD2), forming a JOSD2/KRAS positive feedback circuit. Inhibition of JOSD2 promotes polyubiquitination and proteasomal degradation of KRAS mutants.\",\n      \"method\": \"DUB siRNA library screen, co-immunoprecipitation, ubiquitination assays, CHIP kinase activity assays, RNA interference, pharmacological JOSD2 inhibitor, patient-derived cells/xenografts/organoids\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic siRNA library screen, reciprocal regulation (JOSD2 stabilizes KRAS; KRAS inhibits CHIP), validated in PDCs/PDXs/PDOs across multiple KRAS mutants, multiple orthogonal methods\",\n      \"pmids\": [\"40240366\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"JOSD2 removes K63-linked ubiquitination from SIRT7 via its active site C24 and promotes P62-mediated autophagic degradation of SIRT7, which prevents phosphorylation and nuclear translocation of P65 (NF-κB) and reduces inflammatory responses in renal tubular epithelial cells.\",\n      \"method\": \"Mass spectrometry, co-immunoprecipitation, ubiquitination assays (K63-linked), active site mutagenesis (C24), autophagy flux assays, P65 nuclear translocation assays, JOSD2 KO mice, renal tubular-specific JOSD2 overexpression\",\n      \"journal\": \"Acta pharmacologica Sinica\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — active site mutagenesis (C24), specific K63 chain identified, autophagic degradation mechanism established, in vivo KO and cell-specific OE, multiple orthogonal methods\",\n      \"pmids\": [\"40217118\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"JOSD2 interacts with and stabilizes SMAD4 by removing polyubiquitin chains, promoting TGF-β signaling and breast cancer metastasis; RNA interference-mediated JOSD2 inhibition reduces breast cancer cell metastasis in vitro and in vivo.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, in vitro migration/invasion assays, in vivo metastasis models\",\n      \"journal\": \"Biochemical pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP and ubiquitination assay with in vivo validation, single lab, ubiquitin chain type not specified in abstract\",\n      \"pmids\": [\"39793716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"JOSD2 suppresses cGAS enzymatic activity by removing K27-linked ubiquitination from cGAS, thereby inhibiting the cGAS-STING signaling pathway and promoting M2 macrophage polarization; pharmacological inhibition of JOSD2 reactivates cGAS-STING signaling.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays (K27-linked chain specific), cGAS enzymatic activity assays, macrophage polarization assays, pharmacological JOSD2 inhibitor in vitro and in vivo\",\n      \"journal\": \"Oncoimmunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — specific K27 ubiquitin linkage identified, cGAS activity assay, macrophage polarization readout, in vivo pharmacological validation, single lab\",\n      \"pmids\": [\"41351298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"JOSD2 deubiquitinates K63-linked ubiquitin chains on AKT via its active site H125, promoting P62-mediated autophagic degradation of AKT in renal tubular epithelial cells, thereby reducing AKT levels, renal EMT, and fibrosis.\",\n      \"method\": \"Mass spectrometry, co-immunoprecipitation, ubiquitination assays (K63-linked), active site mutagenesis (H125), autophagic degradation assays, JOSD2 KO mice, renal tubular-specific JOSD2 overexpression\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — active site mutagenesis (H125), specific K63 chain identified, autophagic degradation mechanism, in vivo KO and cell-specific OE, multiple orthogonal methods\",\n      \"pmids\": [\"41412561\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A small-molecule JOSD2 inhibitor (compound 31) bearing a cyanamide warhead covalently engages the catalytic cysteine residue of JOSD2, confirming cysteine-dependent catalytic mechanism; compound 31 induces downregulation of KRAS protein in HCT116 cells.\",\n      \"method\": \"High-throughput screening, structure-activity relationship analysis, covalent binding mode characterization, Western blotting for KRAS protein levels\",\n      \"journal\": \"Bioorganic chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — covalent warhead targeting catalytic cysteine with functional substrate (KRAS) downregulation, single lab, abstract-level description of covalent binding\",\n      \"pmids\": [\"41092805\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"JOSD2 is a Machado-Joseph disease (MJD) family cysteine deubiquitinase whose active site (C24 or H125 depending on substrate context) cleaves K6-, K27-, K48-, and K63-linked polyubiquitin chains from a broad range of substrates—including YAP/TAZ, SERCA2a, CaMKIIδ, LKB1, KRAS mutants, CTNNB1, SMAD4, SMAD7, IMPDH2, SIRT7, AKT, and Aldolase A/PFK1/PHGDH complexes—to regulate their stability, activity, or localization, with context-dependent outcomes in cancer metabolism, cardiac physiology, renal and vascular biology, and immune signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"JOSD2 is a cysteine deubiquitinase that controls the stability, activity, and localization of diverse substrates across cancer metabolism, cardiac and renal physiology, vascular remodeling, and immune signaling by cleaving specific polyubiquitin linkages, with catalysis depending on its active-site cysteine (C24) or, in some substrate contexts, H125 [#11, #14, #15]. It acts on multiple chain types: removing K48-linked chains to stabilize substrates such as SMAD7 [#9], K6-linked chains to restrict LKB1 kinase activity and the LKB1-STRAD-MO25 complex [#6], and K63-linked chains on CaMKIIδ, IMPDH2, SIRT7, and AKT to modulate their activity or routing to autophagic degradation [#7, #8, #11, #14], as well as K27-linked chains on cGAS to suppress its enzymatic activity [#13]. Through these activities JOSD2 stabilizes oncogenic and proliferative effectors\\u2014deubiquitinating and stabilizing YAP/TAZ, CTNNB1/Wnt signaling, SMAD4-driven TGF-\\u03b2 signaling, mutant KRAS, and a glycolytic enzyme complex of Aldolase A, PFK1, and PHGDH to enhance glycolysis [#0, #1, #3, #10, #12]. In the cardiovascular and renal systems it has context-dependent roles, stabilizing SERCA2a to support calcium handling while deubiquitinating CaMKIIδ to drive hypertrophy and fibrosis, and promoting autophagic turnover of SIRT7 and AKT to limit NF-\\u03baB-driven inflammation and EMT-associated fibrosis [#4, #7, #11, #14]. A covalent cyanamide-warhead small molecule engages the catalytic cysteine and downregulates KRAS, establishing JOSD2 as a druggable target and confirming its cysteine-dependent mechanism [#10, #15].\",\n  \"teleology\": [\n    {\n      \"year\": 2020,\n      \"claim\": \"Established that JOSD2 acts catalytically on a metabolic enzyme complex, linking its deubiquitinase activity to glycolytic flux rather than to a single substrate.\",\n      \"evidence\": \"In vitro/in vivo deubiquitination assays with catalytically inactive mutant control and enzyme activity readouts on the Aldolase A/PFK1/PHGDH complex\",\n      \"pmids\": [\"33082514\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Ubiquitin chain linkage type not defined\", \"Direct vs. indirect deubiquitination of each enzyme not fully resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extended JOSD2 function to oncogenic transcriptional coactivators by showing it deubiquitinates and stabilizes YAP/TAZ to sustain proliferation.\",\n      \"evidence\": \"Activity-dependent deubiquitination assays, proteasome inhibitor rescue, and knockdown with YAP/TAZ readouts in cholangiocarcinoma cells\",\n      \"pmids\": [\"35024322\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Chain linkage not specified\", \"Single lab, no structural detail\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Showed JOSD2 can regulate substrates non-degradatively, controlling PKM2 nuclear localization via acetylation and stabilizing CTNNB1 to amplify Wnt signaling.\",\n      \"evidence\": \"MS/co-IP, acetylation assays, nuclear/cytoplasmic fractionation for PKM2; co-IP, ubiquitination and Wnt reporter assays for CTNNB1\",\n      \"pmids\": [\"35836282\", \"35568970\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking JOSD2 to PKM2 acetylation unclear\", \"CTNNB1 chain linkage not defined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined an in vivo cardiac role by demonstrating JOSD2 stabilizes SERCA2a to maintain calcium handling, with loss promoting hypertrophy.\",\n      \"evidence\": \"Proteome-wide MS, co-IP, deubiquitination assays, JOSD2 KO mice and AAV9 overexpression with calcium handling assays\",\n      \"pmids\": [\"39195964\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Chain linkage on SERCA2a not specified\", \"Reconciliation with pro-hypertrophic CaMKII\\u03b4 role not addressed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Linked JOSD2 to genotoxic stress responses, showing DNA damage drives its nuclear accumulation and that it promotes DDR pathway activation.\",\n      \"evidence\": \"Immunofluorescence, Western blotting of DDR proteins, and drug sensitivity assays in NSCLC cells\",\n      \"pmids\": [\"37899394\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct DDR substrate identified\", \"Single method per endpoint; correlative phenotype only\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Resolved linkage-specific catalysis by showing JOSD2 cleaves K6 chains on LKB1 to restrict its tumor-suppressor kinase activity and K63 chains on CaMKII\\u03b4 to drive cardiac hypertrophy and fibrosis.\",\n      \"evidence\": \"Chain-specific ubiquitination assays, kinase/phosphorylation assays, xenograft and cardiac remodeling models with KN-93 rescue\",\n      \"pmids\": [\"38177135\", \"38195959\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of chain-type selectivity unknown\", \"How substrate context selects degradative vs. non-degradative outcome unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Established site- and linkage-specific control of immune and vascular signaling, with JOSD2 cleaving K63 chains at IMPDH2 K134 to limit NF-\\u03baB inflammation and K48 chains at SMAD7 K220 to dampen TGF-\\u03b2-driven vascular remodeling.\",\n      \"evidence\": \"LC-MS/MS, site-specific ubiquitination assays, domain mapping, enzyme/reporter assays, tissue-specific KO and OE mouse models\",\n      \"pmids\": [\"40177575\", \"39833306\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Determinants of K134/K220 site selection not defined\", \"Tissue-specificity of effects not mechanistically explained\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified JOSD2 as a stabilizer of mutant KRAS through a positive feedback circuit and validated it as a covalently druggable cysteine deubiquitinase.\",\n      \"evidence\": \"DUB siRNA library screen, co-IP, ubiquitination and CHIP activity assays in PDCs/PDXs/PDOs; covalent cyanamide-warhead inhibitor engaging the catalytic cysteine with KRAS downregulation\",\n      \"pmids\": [\"40240366\", \"41092805\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Co-crystal structure of inhibitor-enzyme not reported\", \"Selectivity over other DUBs not fully established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined active-site residues and an autophagic degradation mode, with C24 (SIRT7) and H125 (AKT) mediating K63 chain removal that routes substrates to P62-dependent autophagy, plus K27 cleavage on cGAS suppressing cGAS-STING signaling.\",\n      \"evidence\": \"Active-site mutagenesis (C24, H125), chain-specific ubiquitination assays, autophagy flux assays, KO/cell-specific OE mice; cGAS activity and macrophage polarization assays with pharmacological inhibition\",\n      \"pmids\": [\"40217118\", \"41412561\", \"41351298\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How K63 deubiquitination promotes autophagic rather than proteasomal routing unresolved\", \"Whether C24 and H125 act on distinct substrate sets or cooperatively unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How JOSD2 selects among substrates, chain types (K6/K27/K48/K63), and degradative versus non-degradative or autophagic outcomes in a tissue-specific manner remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural basis for linkage or substrate selectivity\", \"No unifying model for context-dependent stabilizing vs. destabilizing outcomes\", \"Endogenous regulation of JOSD2 activity and localization largely uncharacterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 4, 6, 7, 8, 9, 11, 14]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 8, 11, 14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [2, 5]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [7, 8, 9]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 1, 4, 9, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [3, 6, 9, 12, 13]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [8, 13]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [11, 14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"YAP1\", \"WWTR1\", \"CTNNB1\", \"SERCA2a\", \"CAMK2D\", \"STK11\", \"IMPDH2\", \"KRAS\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}