{"gene":"USP53","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":2015,"finding":"USP53 contains a catalytically inactive ubiquitin-specific protease domain (as annotated at the time) and colocalizes and physically interacts with tight junction scaffolding proteins TJP1 and TJP2 in polarized epithelial cells, indicating it is part of the tight junction complex. Loss of USP53 in mambo mice causes outer hair cell degeneration and reduced endocochlear potential; hair cell loss is rescued in low-potassium cochlear organotypic cultures, indicating it is triggered by extracellular factors.","method":"ENU mutagenesis mouse model, co-immunoprecipitation, colocalization imaging, biotin tracer assay for tight junction barrier, cochlear organotypic culture rescue experiment","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP plus functional rescue experiment in a defined genetic model, multiple orthogonal methods in one study","pmids":["26609154"],"is_preprint":false},{"year":2018,"finding":"USP53 interacts with tight junction constituent TJP2, and loss-of-function (homozygous truncating variants) causes low-GGT cholestasis and hearing loss in humans, placing USP53 functionally in the TJP2-containing tight junction pathway in bile homeostasis.","method":"Exome sequencing with segregation analysis; prior interaction evidence cited from mouse data","journal":"Genetics in medicine","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — human genetics plus cited interaction data; interaction itself established in earlier mouse paper (PMID 26609154)","pmids":["30250217"],"is_preprint":false},{"year":2020,"finding":"USP53 deubiquitinates FKBP51 (identified by co-immunoprecipitation and ubiquitination assay), stabilizing it; stabilized FKBP51 then dephosphorylates AKT1, thereby inhibiting tumor growth in lung adenocarcinoma cells.","method":"Co-immunoprecipitation, ubiquitination assay, stable overexpression/shRNA cell lines, AKT pathway inhibitor (LY294002), in vivo xenograft","journal":"Molecular carcinogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP plus ubiquitination assay plus in vivo tumor model, but single lab and single study","pmids":["32511815"],"is_preprint":false},{"year":2020,"finding":"USP53 interacts with TJP2; in USP53-deficient human liver biopsies, hepatocyte–hepatocyte tight junctions are elongated by ultrastructural analysis, recapitulating TJP2 disease morphology.","method":"Whole-exome sequencing, transmission electron microscopy of liver biopsies, clinical phenotype correlation","journal":"Liver international","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — ultrastructural phenotype in human biopsies with genetic confirmation; interaction based on prior published data","pmids":["32124521"],"is_preprint":false},{"year":2021,"finding":"USP53 is a transcriptional target of PTH-activated NACA in osteoblasts; a NACA binding site in the Usp53 promoter was confirmed by EMSA. Usp53 knockdown in ST2 stromal cells increases osteoblastic markers and decreases adipogenic markers, and in vivo implantation of Usp53-knockdown bone marrow stromal cells increases osteoblast number and decreases adipocyte counts, indicating USP53 modulates mesenchymal lineage commitment.","method":"ChIP-Seq, RNA-seq, EMSA, promoter-activity luciferase assay, shRNA knockdown, in vivo implantation in immunocompromised mice","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (ChIP, EMSA, in vivo) in single lab study","pmids":["33875709"],"is_preprint":false},{"year":2022,"finding":"USP53 physically interacts with cytochrome c (CYCS), identified by co-immunoprecipitation and mass spectrometry, and overexpression of USP53 increases CYCS protein stability following cycloheximide treatment. Overexpression of CYCS compensates for decreased apoptosis in USP53-knockdown HCC cells, demonstrating that USP53 promotes apoptosis through deubiquitination of CYCS.","method":"Co-immunoprecipitation, mass spectrometry, cycloheximide chase, shRNA knockdown, overexpression rescue assay","journal":"Oncogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP/MS plus functional rescue, single lab","pmids":["35654790"],"is_preprint":false},{"year":2022,"finding":"H3K27 acetylation activates USP53 transcription by binding to the USP53 promoter region, as shown by ChIP assay. USP53 suppresses glycolysis, oxidative metabolism, and mitochondrial dynamics, and its knockdown is reversed by AMPK inhibitor, placing USP53 upstream of the AMPK signaling pathway in esophageal carcinoma.","method":"ChIP assay, AMPK inhibitor treatment, shRNA knockdown, in vitro and in vivo growth assays, metabolic assays","journal":"Carcinogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — ChIP plus pharmacological epistasis plus in vivo, but single lab","pmids":["34919659"],"is_preprint":false},{"year":2023,"finding":"USP53 regulates RANKL (Rankl) expression by enhancing the interaction between VDR and SMAD3 in osteoblasts and bone marrow adipocytes. Usp53 null mice show low bone mass, increased osteoclast numbers, and elevated serum RANKL.","method":"Usp53 knockout mice, microCT, histomorphometry, ELISA for RANKL, co-immunoprecipitation of VDR-SMAD3 complex","journal":"Journal of bone and mineral research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo KO phenotype plus Co-IP mechanistic support, single lab with multiple orthogonal methods","pmids":["36726200"],"is_preprint":false},{"year":2023,"finding":"USP53 directly binds CRKL and deubiquitinates it, preventing proteasomal degradation and stabilizing CRKL protein, thereby promoting tumor growth, metastasis, and chemoresistance in triple-negative breast cancer.","method":"Co-immunoprecipitation, ubiquitination assay, overexpression and knockdown functional assays","journal":"Cancers","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP and ubiquitination assay, single lab","pmids":["37894400"],"is_preprint":false},{"year":2023,"finding":"USP53 colocalizes in hippocampal CA1-3 and granular dentate neurons with GRIA2/GluA2 and GRIP2, and all three proteins co-immunoprecipitate, placing USP53 within the AMPA receptor interactome in brain tissue.","method":"Immunofluorescence colocalization, co-immunoprecipitation","journal":"Genes","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP in murine brain tissue, single lab, no functional follow-up","pmids":["37895270"],"is_preprint":false},{"year":2024,"finding":"USP53 binds SR-A via its USP domain and cysteine at position 41, removes K48-linked ubiquitin chains from SR-A, and prevents its proteasomal degradation, thereby mediating foam cell formation in smooth muscle cells downstream of endothelial DKK1 signaling. DKK1 regulates USP53 transcription by facilitating CREB binding to the USP53 promoter.","method":"Co-immunoprecipitation, ChIP, RNA-seq, endothelium-specific DKK1 KO and overexpression mice, AAV-mediated SMC-specific USP53 overexpression, parallel-plate co-culture flow system","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ChIP, and in vivo genetic rescue with multiple mouse models, single lab","pmids":["38904030"],"is_preprint":false},{"year":2024,"finding":"USP53 interacts with ZMYND11, catalyzes its deubiquitination and stabilization. The Cys-box domain (aa 33–50) is key for USP53 enzymatic activity but not required for binding to ZMYND11. Rescue experiments show USP53's anti-tumor effect in breast cancer is at least partially mediated through ZMYND11.","method":"Co-immunoprecipitation, ubiquitination assay, domain deletion/mutation analysis, rescue overexpression experiments, xenograft","journal":"Biological procedures online","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP plus ubiquitination assay plus domain mutagenesis plus rescue, single lab","pmids":["39044157"],"is_preprint":false},{"year":2024,"finding":"USP53 interacts with and deubiquitinates MYO5B via its IQ domain. Loss of USP53 causes increased ubiquitination of MYO5B and impairs endosomal recruitment of MYO5B, resulting in BSEP accumulation in MYO5B/RAB11A-positive recycling endosomes and failure of BSEP trafficking to the plasma membrane. The recurrent PFIC-associated MYO5B p.(Arg824Cys) variant (in the IQ domain) fails to interact with USP53.","method":"Co-immunoprecipitation, CRISPR-KO, surface protein biotinylation, confocal immunofluorescence, live cell imaging, FRAP, site-directed mutagenesis, immunohistochemistry of patient tissue","journal":"Hepatology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (Co-IP, CRISPR-KO, biotinylation, live imaging/FRAP, mutagenesis, patient tissue) in single study with clear molecular mechanism","pmids":["40828662"],"is_preprint":false},{"year":2024,"finding":"USP53 interacts with and deubiquitinates USP53 interacts with TJP2 in hepatocytes, demonstrated by co-immunoprecipitation and immunofluorescence. Usp53 liver-specific KO mice show upregulation of Tjp2 and longer hepatocellular tight junctions, and are protected from DDC-induced liver injury, suggesting USP53 and TJP2 share mechanistic pathways in bile homeostasis.","method":"Liver-specific Cre-lox knockout mice, immunofluorescence, co-immunoprecipitation, dietary challenge models, RT-qPCR, histopathology, electron microscopy","journal":"Biochimica et biophysica acta. Molecular basis of disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus conditional KO plus ultrastructural and molecular analysis, single lab","pmids":["39705897"],"is_preprint":false},{"year":2025,"finding":"USP53 is active against K63-linked polyubiquitin chains (not catalytically inactive as previously annotated). USP53 patient mutations abrogate catalytic activity. USP53 deubiquitinates substrates in a K63-linkage-dependent manner, and depletion of USP53 increases K63-linked ubiquitination of tricellular junction components. Structural analysis reveals K63-specific S2-ubiquitin-binding sites within the catalytic domain.","method":"Biochemical DUB activity assays with defined ubiquitin chain linkages, structural analysis, patient mutation functional testing, substrate-bound polyubiquitin assays, depletion experiments with K63-ubiquitination readout","journal":"bioRxiv (preprint)","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution of catalytic activity, structural analysis, mutagenesis of patient variants, and linkage-specific biochemical assays, multiple orthogonal methods in one study","pmids":["bio_10.1101_2024.07.07.602376"],"is_preprint":true},{"year":2025,"finding":"USP53 interacts with RIPK1 (via its intermediate domain) and removes K63-linked ubiquitination at lysine-377 (K377) of RIPK1, facilitating RIPK1 autophosphorylation and triggering apoptotic and necroptotic pathways in cardiomyocytes. Ethanol induces USP53 expression via transcription factor EGR1. Cardiomyocyte-specific USP53 knockout mice show improved survival and less cardiomyocyte death in an alcoholic cardiomyopathy model.","method":"Co-immunoprecipitation combined with LC-MS/MS, site-specific ubiquitination mapping (K377), cardiomyocyte-specific KO mouse model, in vivo/in vitro ethanol exposure models","journal":"Research (Washington, D.C.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP/MS plus site-specific ubiquitination mapping plus conditional KO in vivo, single lab","pmids":["40822127"],"is_preprint":false},{"year":2025,"finding":"USP53 interacts with NOTCH2 and its knockdown prevents Aβ-induced deubiquitination of NOTCH2 in microglia. USP53 knockdown reduces Aβ-induced neuroinflammatory mediators (IL-1β, TNF-α) and represses IKKβ/NFκB signaling pathway activation. USP53 knockout in 5XFAD mice improves learning and memory and reduces Tau accumulation.","method":"Co-immunoprecipitation, USP53 knockout in 5XFAD AD mouse model, Morris Water Maze, Western blot, immunofluorescence, qRT-PCR, primary human microglia knockdown","journal":"Neurochemistry international","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP plus in vivo KO phenotype plus in vitro pathway analysis, single lab","pmids":["41482165"],"is_preprint":false},{"year":2025,"finding":"USP53 binds MORF4L1 and deubiquitinates it, with K249 and K227 of MORF4L1 identified as key ubiquitination sites. USP53 overexpression prevents MORF4L1 ubiquitination and degradation, and suppresses colorectal cancer cell growth; this effect is abrogated by MORF4L1 silencing.","method":"Co-immunoprecipitation combined with LC-MS/MS (IP-LC/MS), ubiquitylome analysis, site-directed mutagenesis of MORF4L1 ubiquitination sites, in vitro and in vivo gain/loss-of-function, rescue experiments","journal":"Biochimica et biophysica acta. Molecular basis of disease","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP/MS plus ubiquitylome and mutagenesis plus rescue, single lab","pmids":["41061828"],"is_preprint":false},{"year":2025,"finding":"ATF3 transcriptionally represses USP53 by binding the USP53 promoter (validated by ChIP and luciferase reporter assay). USP53 upregulation promotes adipogenesis and activates the RhoA/ROCK pathway; USP53 overexpression partially rescues the inhibitory effect of ATF3 overexpression on adipogenesis.","method":"ChIP assay, luciferase reporter assay, Oil Red O staining, triglyceride measurement, Western blot, RT-qPCR, 3T3-L1 adipocyte differentiation model","journal":"Journal of molecular endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — ChIP plus luciferase reporter plus rescue experiments, single lab","pmids":["39641389"],"is_preprint":false},{"year":2025,"finding":"USP53 deubiquitinates SMAD5, stabilizing its protein expression; the EIF4A3 RNA-binding protein stabilizes USP53 mRNA. Knockdown of USP53 inhibits BMSC viability, invasion, and osteogenic differentiation, effects rescued by SMAD5 overexpression, establishing the EIF4A3–USP53–SMAD5 axis in BMSC osteogenic differentiation.","method":"Co-immunoprecipitation, ubiquitination assay, shRNA knockdown, overexpression rescue, ALP activity assay, Alizarin Red S staining, RT-qPCR, Western blot","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 3 / Weak — Co-IP and ubiquitination assay plus rescue, single lab, no orthogonal structural or in vitro reconstitution","pmids":["40481141"],"is_preprint":false},{"year":2025,"finding":"USP53 deubiquitinates MLKL and GSDMD, promoting their stability; FOS transcriptionally activates USP53 expression by directly binding the USP53 promoter (validated by ChIP-qPCR). Reduced FOS (by juglone treatment) lowers USP53, promoting ubiquitination and degradation of MLKL and GSDMD, thereby inhibiting necroptosis and pyroptosis in injured neurons.","method":"ChIP-qPCR, immunoprecipitation, Western blot, RNA-seq, qRT-PCR, in vitro OGD/R and in vivo SCI models","journal":"Phytomedicine","confidence":"Low","confidence_rationale":"Tier 3 / Weak — ChIP-qPCR plus immunoprecipitation, mechanistic pathway partially inferred, single lab","pmids":["41045624"],"is_preprint":false}],"current_model":"USP53 is an active K63-linkage-directed deubiquitinase (revising earlier annotation as a pseudo-enzyme) that associates with tight junction scaffolding proteins TJP1/TJP2 and MYO5B, where it deubiquitinates MYO5B to regulate BSEP trafficking to the plasma membrane; loss of USP53 causes mislocalization of BSEP to recycling endosomes, producing low-GGT intrahepatic cholestasis, while in other cellular contexts USP53 deubiquitinates diverse substrates—including FKBP51, cytochrome c, CRKL, ZMYND11, MORF4L1, SR-A, RIPK1, NOTCH2, and SMAD5—to regulate apoptosis, glycolysis, bone homeostasis, and tumor suppression."},"narrative":{"mechanistic_narrative":"USP53 is a K63-linkage-directed deubiquitinase that integrates epithelial tight-junction architecture, intracellular trafficking, and protein-stability control across multiple tissues [PMID:bio_10.1101_2024.07.07.602376, PMID:40828662]. Originally annotated as a catalytically inactive USP-domain protein, it was reclassified as an active enzyme: biochemical and structural analysis demonstrated K63-specific cleavage through S2-ubiquitin-binding sites in its catalytic domain, and disease-associated patient mutations abolish this activity [PMID:bio_10.1101_2024.07.07.602376]. In polarized epithelia and hepatocytes USP53 colocalizes and physically associates with the tight-junction scaffolds TJP1 and TJP2, and its loss elongates hepatocyte–hepatocyte tight junctions, recapitulating TJP2 disease morphology [PMID:26609154, PMID:32124521, PMID:39705897]. Its best-defined biliary mechanism is the deubiquitination of MYO5B through the MYO5B IQ domain: USP53 loss raises MYO5B ubiquitination, impairs endosomal MYO5B recruitment, and traps the bile-salt export pump BSEP in RAB11A-positive recycling endosomes, blocking its delivery to the plasma membrane [PMID:40828662]. Consistent with this, human truncating USP53 variants cause low-GGT intrahepatic cholestasis with hearing loss [PMID:30250217]. Beyond the liver, USP53 acts as a substrate-stabilizing DUB in diverse contexts—removing degradative ubiquitin from FKBP51, CYCS, CRKL, ZMYND11, MORF4L1, SR-A, RIPK1, NOTCH2 and SMAD5—to modulate apoptosis, glycolysis, foam-cell formation, bone and adipocyte lineage commitment, and tumor growth [PMID:32511815, PMID:35654790, PMID:37894400, PMID:38904030, PMID:39044157, PMID:40828662, PMID:41061828, PMID:40481141]. Its expression is tightly controlled transcriptionally by inputs including PTH/NACA, H3K27ac, DKK1/CREB, EGR1, ATF3, FOS and EIF4A3 [PMID:33875709, PMID:34919659, PMID:38904030, PMID:40822127, PMID:39641389, PMID:41045624].","teleology":[{"year":2015,"claim":"Established USP53 as a tight-junction-associated protein by showing it interacts with the scaffolds TJP1/TJP2 and is required for cochlear hair-cell integrity, framing it as a junctional component rather than a free enzyme.","evidence":"ENU mutant (mambo) mice, reciprocal Co-IP, colocalization, barrier tracer and organotypic rescue assays","pmids":["26609154"],"confidence":"High","gaps":["USP domain annotated as catalytically inactive—no enzymatic activity tested","no biliary phenotype examined","direct substrate of any junction-associated activity unknown"]},{"year":2018,"claim":"Linked USP53 loss-of-function to a human Mendelian disease, defining low-GGT cholestasis with hearing loss and placing USP53 in the TJP2 bile-homeostasis pathway.","evidence":"Exome sequencing with segregation in human families; interaction cited from prior mouse work","pmids":["30250217"],"confidence":"Medium","gaps":["molecular mechanism of cholestasis not resolved","no demonstration of how junctional disruption causes bile defect"]},{"year":2020,"claim":"Provided ultrastructural evidence that USP53 deficiency phenocopies TJP2 disease at the tight junction, supporting a shared mechanistic pathway in hepatocytes.","evidence":"Whole-exome sequencing and transmission electron microscopy of patient liver biopsies","pmids":["32124521"],"confidence":"Medium","gaps":["correlative human morphology, no manipulation","no enzymatic mechanism"]},{"year":2020,"claim":"First implicated USP53 as a deubiquitinase acting on a specific substrate (FKBP51) with downstream signaling consequences, opening the catalytic-substrate question.","evidence":"Co-IP, ubiquitination assay, AKT inhibitor epistasis, xenograft in lung adenocarcinoma cells","pmids":["32511815"],"confidence":"Medium","gaps":["catalytic activity not directly demonstrated at the time given inactive annotation","single lab","linkage specificity not defined"]},{"year":2021,"claim":"Identified USP53 as a transcriptionally regulated (PTH/NACA) modulator of mesenchymal lineage commitment, extending its role to bone and fat.","evidence":"ChIP-seq, EMSA, luciferase, shRNA, in vivo stromal cell implantation","pmids":["33875709"],"confidence":"Medium","gaps":["substrate mediating lineage effect not identified","enzymatic dependence untested"]},{"year":2022,"claim":"Expanded USP53 substrate range to apoptotic and metabolic regulation, deubiquitinating CYCS to promote apoptosis and suppressing glycolysis upstream of AMPK in cancer.","evidence":"Co-IP/MS, cycloheximide chase, rescue assays (CYCS); ChIP and AMPK inhibitor epistasis (esophageal carcinoma)","pmids":["35654790","34919659"],"confidence":"Medium","gaps":["linkage specificity of CYCS deubiquitination undefined","AMPK connection lacks direct substrate","single lab per study"]},{"year":2023,"claim":"Accumulated multiple context-specific substrates (CRKL, AMPA-receptor interactome) and a bone mechanism via VDR–SMAD3, broadening USP53 to tumor progression, synaptic, and skeletal roles.","evidence":"Co-IP and ubiquitination assays (CRKL); colocalization/Co-IP in brain (GRIA2/GRIP2); Usp53 KO mice with microCT and VDR-SMAD3 Co-IP","pmids":["37894400","37895270","36726200"],"confidence":"Medium","gaps":["AMPA-receptor association lacks functional follow-up","CRKL study single Co-IP/single lab","how USP53 enhances VDR-SMAD3 binding mechanistically unclear"]},{"year":2024,"claim":"Defined the central biliary mechanism: USP53 deubiquitinates MYO5B via its IQ domain to enable endosomal recruitment and BSEP plasma-membrane trafficking, mechanistically uniting the cholestasis phenotype with a substrate.","evidence":"Co-IP, CRISPR-KO, surface biotinylation, live imaging/FRAP, site-directed mutagenesis, patient tissue","pmids":["40828662"],"confidence":"High","gaps":["link between MYO5B deubiquitination and tight-junction morphology not fully integrated","ubiquitin-linkage type on MYO5B not specified in this study"]},{"year":2024,"claim":"Added further substrates and transcriptional regulators—SR-A (K48 chains, foam-cell formation downstream of DKK1/CREB), ZMYND11 (anti-tumor), and TJP2 in liver-specific KO mice—broadening USP53's reach in atherosclerosis, cancer, and bile homeostasis.","evidence":"Co-IP, ChIP, domain mapping, conditional/AAV mouse models","pmids":["38904030","39044157","39705897"],"confidence":"Medium","gaps":["mixed linkage specificity across substrates (K48 vs K63) not reconciled","single lab per finding"]},{"year":2025,"claim":"Resolved the long-standing catalytic question by reconstituting USP53 as an active K63-linkage-specific DUB with K63-specific S2-ubiquitin-binding sites, and showed patient mutations abrogate this activity.","evidence":"Linkage-specific biochemical DUB assays, structural analysis, patient-variant functional testing (preprint)","pmids":["bio_10.1101_2024.07.07.602376"],"confidence":"High","gaps":["preprint, not peer-reviewed","reconciliation with reported K48 activity on SR-A unresolved","physiological tricellular-junction substrates incompletely mapped"]},{"year":2025,"claim":"Extended K63-directed activity to cell-death control via site-specific deubiquitination of RIPK1 (K377) and stabilization of MLKL/GSDMD, plus NOTCH2, SMAD5 and MORF4L1, with multiple transcription factors (EGR1, FOS, EIF4A3, ATF3) controlling USP53 levels.","evidence":"Co-IP/MS, site-specific ubiquitination mapping, conditional KO mice, ChIP/luciferase, rescue experiments","pmids":["40822127","41045624","41482165","40481141","41061828","39641389"],"confidence":"Medium","gaps":["substrate set is large and largely single-lab","tissue selectivity of substrate choice unexplained","RIPK1/MLKL/GSDMD studies lack structural validation"]},{"year":null,"claim":"How a single K63-directed DUB selects such divergent substrates across liver, bone, brain, heart, and tumor tissues—and how this reconciles with reported K48 cleavage—remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["no unified model of substrate-recruitment specificity","linkage-specificity conflict (K63 vs K48) unreconciled","most non-hepatic substrates rest on single Co-IP/ubiquitination studies"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[2,5,10,11,12,14,15,17]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[12,14]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,12]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[12]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[12]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[5,15,20]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[4,7,19]}],"complexes":["tight junction"],"partners":["TJP1","TJP2","MYO5B","RIPK1","CRKL","ZMYND11","MORF4L1","FKBP51"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q70EK8","full_name":"Ubiquitin carboxyl-terminal hydrolase 53","aliases":["Ubiquitin-specific peptidase 53"],"length_aa":1073,"mass_kda":120.8,"function":"Deubiquitinase that mediates 'Lys-63'-linked deubiquitination of tight junction proteins, such as MARVELD2 and LSR, and which is involved in the survival of auditory hair cells and hearing (PubMed:32124521, PubMed:39587316). Specifically cleaves 'Lys-63'-linked polyubiquitin chains composed of at least 3 ubiquitin molecules, while it is not able to deubiquitinate substrates with shorter ubiquitin chains: recognizes ubiquitin chain in position S2 and catalyzes en bloc cleavage of polyubiquitin chains from substrate proteins (PubMed:39587316). Probably acts by modulating the barrier properties and mechanical stability of tight junctions via deubiquitination of MARVELD2 and LSR (PubMed:32124521, PubMed:39587316)","subcellular_location":"Cell junction, tight junction","url":"https://www.uniprot.org/uniprotkb/Q70EK8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/USP53","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/USP53","total_profiled":1310},"omim":[{"mim_id":"621016","title":"NEURODEVELOPMENTAL DISORDER WITH VARIABLE FAMILIAL HYPERCHOLANEMIA; NEDFHCA","url":"https://www.omim.org/entry/621016"},{"mim_id":"619662","title":"CHOLESTASIS, PROGRESSIVE FAMILIAL INTRAHEPATIC, 8; PFIC8","url":"https://www.omim.org/entry/619662"},{"mim_id":"619658","title":"CHOLESTASIS, PROGRESSIVE FAMILIAL INTRAHEPATIC, 7, WITH OR WITHOUT HEARING LOSS; PFIC7","url":"https://www.omim.org/entry/619658"},{"mim_id":"619309","title":"PROTEIN PHOSPHATASE, MAGNESIUM/MANGANESE-DEPENDENT, 1F; PPM1F","url":"https://www.omim.org/entry/619309"},{"mim_id":"618474","title":"WDR83 OPPOSITE STRAND; WDR83OS","url":"https://www.omim.org/entry/618474"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/USP53"},"hgnc":{"alias_symbol":["KIAA1350"],"prev_symbol":[]},"alphafold":{"accession":"Q70EK8","domains":[{"cath_id":"3.90.70.10","chopping":"32-373","consensus_level":"medium","plddt":93.6438,"start":32,"end":373}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q70EK8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q70EK8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q70EK8-F1-predicted_aligned_error_v6.png","plddt_mean":55.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=USP53","jax_strain_url":"https://www.jax.org/strain/search?query=USP53"},"sequence":{"accession":"Q70EK8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q70EK8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q70EK8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q70EK8"}},"corpus_meta":[{"pmid":"30250217","id":"PMC_30250217","title":"Identification of novel loci for pediatric cholestatic liver disease defined by KIF12, PPM1F, USP53, LSR, and WDR83OS pathogenic variants.","date":"2018","source":"Genetics in medicine : official journal of the American College of Medical Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30250217","citation_count":88,"is_preprint":false},{"pmid":"26609154","id":"PMC_26609154","title":"Progressive Hearing Loss in Mice Carrying a Mutation in Usp53.","date":"2015","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/26609154","citation_count":56,"is_preprint":false},{"pmid":"32124521","id":"PMC_32124521","title":"Low-GGT intrahepatic cholestasis associated with biallelic USP53 variants: Clinical, histological and ultrastructural characterization.","date":"2020","source":"Liver international : official journal of the International Association for the Study of the Liver","url":"https://pubmed.ncbi.nlm.nih.gov/32124521","citation_count":42,"is_preprint":false},{"pmid":"32511815","id":"PMC_32511815","title":"USP53 promotes apoptosis and inhibits glycolysis in lung adenocarcinoma through FKBP51-AKT1 signaling.","date":"2020","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/32511815","citation_count":31,"is_preprint":false},{"pmid":"33075013","id":"PMC_33075013","title":"Cholestasis Due to USP53 Deficiency.","date":"2021","source":"Journal of pediatric gastroenterology and nutrition","url":"https://pubmed.ncbi.nlm.nih.gov/33075013","citation_count":30,"is_preprint":false},{"pmid":"32759993","id":"PMC_32759993","title":"New paradigms of USP53 disease: normal GGT cholestasis, BRIC, cholangiopathy, and responsiveness to rifampicin.","date":"2020","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32759993","citation_count":29,"is_preprint":false},{"pmid":"36726200","id":"PMC_36726200","title":"USP53 Regulates Bone Homeostasis by Controlling Rankl Expression in Osteoblasts and Bone Marrow Adipocytes.","date":"2023","source":"Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research","url":"https://pubmed.ncbi.nlm.nih.gov/36726200","citation_count":21,"is_preprint":false},{"pmid":"35654790","id":"PMC_35654790","title":"USP53 plays an antitumor role in hepatocellular carcinoma through deubiquitination of cytochrome c.","date":"2022","source":"Oncogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/35654790","citation_count":20,"is_preprint":false},{"pmid":"33875709","id":"PMC_33875709","title":"Ubiquitin specific peptidase Usp53 regulates osteoblast versus adipocyte lineage commitment.","date":"2021","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/33875709","citation_count":16,"is_preprint":false},{"pmid":"34919659","id":"PMC_34919659","title":"USP53 activated by H3K27 acetylation regulates cell viability, apoptosis and metabolism in esophageal carcinoma via the AMPK signaling pathway.","date":"2022","source":"Carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/34919659","citation_count":14,"is_preprint":false},{"pmid":"33661244","id":"PMC_33661244","title":"Progressive Familial Intrahepatic Cholestasis Associated With USP53 Gene Mutation in a Brazilian Child.","date":"2021","source":"Journal of pediatric gastroenterology and nutrition","url":"https://pubmed.ncbi.nlm.nih.gov/33661244","citation_count":11,"is_preprint":false},{"pmid":"34809518","id":"PMC_34809518","title":"Biallelic Mutations in Ubiquitin-Specific Peptidase 53 (USP53) Causing Progressive Intrahepatic Cholestasis. Report of a Case With Review of Literature.","date":"2021","source":"Pediatric and developmental pathology : the official journal of the Society for Pediatric Pathology and the Paediatric Pathology Society","url":"https://pubmed.ncbi.nlm.nih.gov/34809518","citation_count":11,"is_preprint":false},{"pmid":"36660033","id":"PMC_36660033","title":"Biallelic Novel USP53 Splicing Variant Disrupting the Gene Function that Causes Cholestasis Phenotype and Review of the Literature.","date":"2022","source":"Molecular syndromology","url":"https://pubmed.ncbi.nlm.nih.gov/36660033","citation_count":10,"is_preprint":false},{"pmid":"34681012","id":"PMC_34681012","title":"A Two-Year Clinical Description of a Patient with a Rare Type of Low-GGT Cholestasis Caused by a Novel Variant of USP53.","date":"2021","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/34681012","citation_count":9,"is_preprint":false},{"pmid":"38904030","id":"PMC_38904030","title":"Endothelial Dickkopf-1 Promotes Smooth Muscle Cell-derived Foam Cell Formation via USP53-mediated Deubiquitination of SR-A During Atherosclerosis.","date":"2024","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/38904030","citation_count":8,"is_preprint":false},{"pmid":"39300775","id":"PMC_39300775","title":"An Overview of the Deubiquitinase USP53: A Promising Diagnostic Marker and Therapeutic Target.","date":"2024","source":"Current protein & peptide science","url":"https://pubmed.ncbi.nlm.nih.gov/39300775","citation_count":8,"is_preprint":false},{"pmid":"39044157","id":"PMC_39044157","title":"USP53 Affects the Proliferation and Apoptosis of Breast Cancer Cells by Regulating the Ubiquitination Level of ZMYND11.","date":"2024","source":"Biological procedures online","url":"https://pubmed.ncbi.nlm.nih.gov/39044157","citation_count":8,"is_preprint":false},{"pmid":"37894400","id":"PMC_37894400","title":"USP53 Exerts Tumor-Promoting Effects in Triple-Negative Breast Cancer by Deubiquitinating CRKL.","date":"2023","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/37894400","citation_count":4,"is_preprint":false},{"pmid":"37895270","id":"PMC_37895270","title":"Genome Sequencing of Consanguineous Family Implicates Ubiquitin-Specific Protease 53 (USP53) Variant in Psychosis/Schizophrenia: Wild-Type Expression in Murine Hippocampal CA 1-3 and Granular Dentate with AMPA Synapse Interactions.","date":"2023","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/37895270","citation_count":4,"is_preprint":false},{"pmid":"39705897","id":"PMC_39705897","title":"Loss of hepatocyte Usp53 protects mice from a form of xenobiotic-induced liver injury.","date":"2024","source":"Biochimica et biophysica acta. Molecular basis of disease","url":"https://pubmed.ncbi.nlm.nih.gov/39705897","citation_count":3,"is_preprint":false},{"pmid":"39440620","id":"PMC_39440620","title":"Natural course and outcomes of children with ubiquitin-specific protease 53 (USP53)-related genetic chronic cholestasis.","date":"2024","source":"Journal of pediatric gastroenterology and nutrition","url":"https://pubmed.ncbi.nlm.nih.gov/39440620","citation_count":3,"is_preprint":false},{"pmid":"40822127","id":"PMC_40822127","title":"USP53 Drives Ethanol-Induced Myocardial Injury by Promoting K63 Deubiquitination-Dependent RIPK1 Activation at K377.","date":"2025","source":"Research (Washington, D.C.)","url":"https://pubmed.ncbi.nlm.nih.gov/40822127","citation_count":2,"is_preprint":false},{"pmid":"41045624","id":"PMC_41045624","title":"Juglone promotes spinal cord injury recovery by suppressing pyroptosis and necroptosis through FOS/USP53/ubiquitination.","date":"2025","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41045624","citation_count":2,"is_preprint":false},{"pmid":"40481141","id":"PMC_40481141","title":"EIF4A3 enhances the viability, invasion and osteogenic differentiation of BMSCs via the USP53/SMAD5 pathway.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/40481141","citation_count":2,"is_preprint":false},{"pmid":"38204320","id":"PMC_38204320","title":"A novel homozygous mutation in the USP53 gene as the cause of benign recurrent intrahepatic cholestasis in children: a case report.","date":"2023","source":"The Turkish journal of pediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/38204320","citation_count":2,"is_preprint":false},{"pmid":"38544763","id":"PMC_38544763","title":"Cholestatic Liver Disease due to Novel USP53 Mutations: A Case Series of Three Indian Children.","date":"2023","source":"Journal of clinical and experimental hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/38544763","citation_count":2,"is_preprint":false},{"pmid":"37992747","id":"PMC_37992747","title":"The First Korean Adult Case of Progressive Familial Intrahepatic Cholestasis Type 7 with Novel USP53 Splicing Variants by Next Generation Sequencing.","date":"2023","source":"Yonsei medical journal","url":"https://pubmed.ncbi.nlm.nih.gov/37992747","citation_count":1,"is_preprint":false},{"pmid":"40828662","id":"PMC_40828662","title":"A novel mechanism involving USP53-regulated BSEP trafficking underlies low-GGT intrahepatic cholestasis.","date":"2025","source":"Hepatology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/40828662","citation_count":0,"is_preprint":false},{"pmid":"41482165","id":"PMC_41482165","title":"USP53 promotes NOTCH2-induced neuroinflammation in Alzheimer's disease.","date":"2025","source":"Neurochemistry international","url":"https://pubmed.ncbi.nlm.nih.gov/41482165","citation_count":0,"is_preprint":false},{"pmid":"41061828","id":"PMC_41061828","title":"Deubiquitinase USP53 suppressed tumorigenesis of colorectal cancer cells by mediating deubiquitination of MORF4L1.","date":"2025","source":"Biochimica et biophysica acta. Molecular basis of disease","url":"https://pubmed.ncbi.nlm.nih.gov/41061828","citation_count":0,"is_preprint":false},{"pmid":"39641389","id":"PMC_39641389","title":"ATF3 suppresses 3T3-L1 adipocyte adipogenesis by transcriptionally repressing USP53.","date":"2025","source":"Journal of molecular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/39641389","citation_count":0,"is_preprint":false},{"pmid":"41356217","id":"PMC_41356217","title":"Case Report: Mild BRIC-like cholestasis despite a gross USP53 deletion-novel findings and literature review.","date":"2025","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41356217","citation_count":0,"is_preprint":false},{"pmid":"39071191","id":"PMC_39071191","title":"A novel case report of benign recurrent intrahepatic cholestasis-associated USP53 genetic mutation in a Pakistani girl.","date":"2024","source":"SAGE open medical case reports","url":"https://pubmed.ncbi.nlm.nih.gov/39071191","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.07.07.602376","title":"Discovery and mechanism of K63-linkage-directed deubiquitinase activity in USP53","date":"2024-07-07","source":"bioRxiv","url":"https://doi.org/10.1101/2024.07.07.602376","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":19412,"output_tokens":5448,"usd":0.069978,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":13818,"output_tokens":4014,"usd":0.08472,"stage2_stop_reason":"end_turn"},"total_usd":0.154698,"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\": 2015,\n      \"finding\": \"USP53 contains a catalytically inactive ubiquitin-specific protease domain (as annotated at the time) and colocalizes and physically interacts with tight junction scaffolding proteins TJP1 and TJP2 in polarized epithelial cells, indicating it is part of the tight junction complex. Loss of USP53 in mambo mice causes outer hair cell degeneration and reduced endocochlear potential; hair cell loss is rescued in low-potassium cochlear organotypic cultures, indicating it is triggered by extracellular factors.\",\n      \"method\": \"ENU mutagenesis mouse model, co-immunoprecipitation, colocalization imaging, biotin tracer assay for tight junction barrier, cochlear organotypic culture rescue experiment\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP plus functional rescue experiment in a defined genetic model, multiple orthogonal methods in one study\",\n      \"pmids\": [\"26609154\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"USP53 interacts with tight junction constituent TJP2, and loss-of-function (homozygous truncating variants) causes low-GGT cholestasis and hearing loss in humans, placing USP53 functionally in the TJP2-containing tight junction pathway in bile homeostasis.\",\n      \"method\": \"Exome sequencing with segregation analysis; prior interaction evidence cited from mouse data\",\n      \"journal\": \"Genetics in medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — human genetics plus cited interaction data; interaction itself established in earlier mouse paper (PMID 26609154)\",\n      \"pmids\": [\"30250217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"USP53 deubiquitinates FKBP51 (identified by co-immunoprecipitation and ubiquitination assay), stabilizing it; stabilized FKBP51 then dephosphorylates AKT1, thereby inhibiting tumor growth in lung adenocarcinoma cells.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, stable overexpression/shRNA cell lines, AKT pathway inhibitor (LY294002), in vivo xenograft\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP plus ubiquitination assay plus in vivo tumor model, but single lab and single study\",\n      \"pmids\": [\"32511815\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"USP53 interacts with TJP2; in USP53-deficient human liver biopsies, hepatocyte–hepatocyte tight junctions are elongated by ultrastructural analysis, recapitulating TJP2 disease morphology.\",\n      \"method\": \"Whole-exome sequencing, transmission electron microscopy of liver biopsies, clinical phenotype correlation\",\n      \"journal\": \"Liver international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — ultrastructural phenotype in human biopsies with genetic confirmation; interaction based on prior published data\",\n      \"pmids\": [\"32124521\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"USP53 is a transcriptional target of PTH-activated NACA in osteoblasts; a NACA binding site in the Usp53 promoter was confirmed by EMSA. Usp53 knockdown in ST2 stromal cells increases osteoblastic markers and decreases adipogenic markers, and in vivo implantation of Usp53-knockdown bone marrow stromal cells increases osteoblast number and decreases adipocyte counts, indicating USP53 modulates mesenchymal lineage commitment.\",\n      \"method\": \"ChIP-Seq, RNA-seq, EMSA, promoter-activity luciferase assay, shRNA knockdown, in vivo implantation in immunocompromised mice\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (ChIP, EMSA, in vivo) in single lab study\",\n      \"pmids\": [\"33875709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"USP53 physically interacts with cytochrome c (CYCS), identified by co-immunoprecipitation and mass spectrometry, and overexpression of USP53 increases CYCS protein stability following cycloheximide treatment. Overexpression of CYCS compensates for decreased apoptosis in USP53-knockdown HCC cells, demonstrating that USP53 promotes apoptosis through deubiquitination of CYCS.\",\n      \"method\": \"Co-immunoprecipitation, mass spectrometry, cycloheximide chase, shRNA knockdown, overexpression rescue assay\",\n      \"journal\": \"Oncogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP/MS plus functional rescue, single lab\",\n      \"pmids\": [\"35654790\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"H3K27 acetylation activates USP53 transcription by binding to the USP53 promoter region, as shown by ChIP assay. USP53 suppresses glycolysis, oxidative metabolism, and mitochondrial dynamics, and its knockdown is reversed by AMPK inhibitor, placing USP53 upstream of the AMPK signaling pathway in esophageal carcinoma.\",\n      \"method\": \"ChIP assay, AMPK inhibitor treatment, shRNA knockdown, in vitro and in vivo growth assays, metabolic assays\",\n      \"journal\": \"Carcinogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — ChIP plus pharmacological epistasis plus in vivo, but single lab\",\n      \"pmids\": [\"34919659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"USP53 regulates RANKL (Rankl) expression by enhancing the interaction between VDR and SMAD3 in osteoblasts and bone marrow adipocytes. Usp53 null mice show low bone mass, increased osteoclast numbers, and elevated serum RANKL.\",\n      \"method\": \"Usp53 knockout mice, microCT, histomorphometry, ELISA for RANKL, co-immunoprecipitation of VDR-SMAD3 complex\",\n      \"journal\": \"Journal of bone and mineral research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO phenotype plus Co-IP mechanistic support, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"36726200\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"USP53 directly binds CRKL and deubiquitinates it, preventing proteasomal degradation and stabilizing CRKL protein, thereby promoting tumor growth, metastasis, and chemoresistance in triple-negative breast cancer.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, overexpression and knockdown functional assays\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP and ubiquitination assay, single lab\",\n      \"pmids\": [\"37894400\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"USP53 colocalizes in hippocampal CA1-3 and granular dentate neurons with GRIA2/GluA2 and GRIP2, and all three proteins co-immunoprecipitate, placing USP53 within the AMPA receptor interactome in brain tissue.\",\n      \"method\": \"Immunofluorescence colocalization, co-immunoprecipitation\",\n      \"journal\": \"Genes\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP in murine brain tissue, single lab, no functional follow-up\",\n      \"pmids\": [\"37895270\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP53 binds SR-A via its USP domain and cysteine at position 41, removes K48-linked ubiquitin chains from SR-A, and prevents its proteasomal degradation, thereby mediating foam cell formation in smooth muscle cells downstream of endothelial DKK1 signaling. DKK1 regulates USP53 transcription by facilitating CREB binding to the USP53 promoter.\",\n      \"method\": \"Co-immunoprecipitation, ChIP, RNA-seq, endothelium-specific DKK1 KO and overexpression mice, AAV-mediated SMC-specific USP53 overexpression, parallel-plate co-culture flow system\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ChIP, and in vivo genetic rescue with multiple mouse models, single lab\",\n      \"pmids\": [\"38904030\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP53 interacts with ZMYND11, catalyzes its deubiquitination and stabilization. The Cys-box domain (aa 33–50) is key for USP53 enzymatic activity but not required for binding to ZMYND11. Rescue experiments show USP53's anti-tumor effect in breast cancer is at least partially mediated through ZMYND11.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, domain deletion/mutation analysis, rescue overexpression experiments, xenograft\",\n      \"journal\": \"Biological procedures online\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP plus ubiquitination assay plus domain mutagenesis plus rescue, single lab\",\n      \"pmids\": [\"39044157\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP53 interacts with and deubiquitinates MYO5B via its IQ domain. Loss of USP53 causes increased ubiquitination of MYO5B and impairs endosomal recruitment of MYO5B, resulting in BSEP accumulation in MYO5B/RAB11A-positive recycling endosomes and failure of BSEP trafficking to the plasma membrane. The recurrent PFIC-associated MYO5B p.(Arg824Cys) variant (in the IQ domain) fails to interact with USP53.\",\n      \"method\": \"Co-immunoprecipitation, CRISPR-KO, surface protein biotinylation, confocal immunofluorescence, live cell imaging, FRAP, site-directed mutagenesis, immunohistochemistry of patient tissue\",\n      \"journal\": \"Hepatology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (Co-IP, CRISPR-KO, biotinylation, live imaging/FRAP, mutagenesis, patient tissue) in single study with clear molecular mechanism\",\n      \"pmids\": [\"40828662\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP53 interacts with and deubiquitinates USP53 interacts with TJP2 in hepatocytes, demonstrated by co-immunoprecipitation and immunofluorescence. Usp53 liver-specific KO mice show upregulation of Tjp2 and longer hepatocellular tight junctions, and are protected from DDC-induced liver injury, suggesting USP53 and TJP2 share mechanistic pathways in bile homeostasis.\",\n      \"method\": \"Liver-specific Cre-lox knockout mice, immunofluorescence, co-immunoprecipitation, dietary challenge models, RT-qPCR, histopathology, electron microscopy\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular basis of disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus conditional KO plus ultrastructural and molecular analysis, single lab\",\n      \"pmids\": [\"39705897\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 is active against K63-linked polyubiquitin chains (not catalytically inactive as previously annotated). USP53 patient mutations abrogate catalytic activity. USP53 deubiquitinates substrates in a K63-linkage-dependent manner, and depletion of USP53 increases K63-linked ubiquitination of tricellular junction components. Structural analysis reveals K63-specific S2-ubiquitin-binding sites within the catalytic domain.\",\n      \"method\": \"Biochemical DUB activity assays with defined ubiquitin chain linkages, structural analysis, patient mutation functional testing, substrate-bound polyubiquitin assays, depletion experiments with K63-ubiquitination readout\",\n      \"journal\": \"bioRxiv (preprint)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution of catalytic activity, structural analysis, mutagenesis of patient variants, and linkage-specific biochemical assays, multiple orthogonal methods in one study\",\n      \"pmids\": [\"bio_10.1101_2024.07.07.602376\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 interacts with RIPK1 (via its intermediate domain) and removes K63-linked ubiquitination at lysine-377 (K377) of RIPK1, facilitating RIPK1 autophosphorylation and triggering apoptotic and necroptotic pathways in cardiomyocytes. Ethanol induces USP53 expression via transcription factor EGR1. Cardiomyocyte-specific USP53 knockout mice show improved survival and less cardiomyocyte death in an alcoholic cardiomyopathy model.\",\n      \"method\": \"Co-immunoprecipitation combined with LC-MS/MS, site-specific ubiquitination mapping (K377), cardiomyocyte-specific KO mouse model, in vivo/in vitro ethanol exposure models\",\n      \"journal\": \"Research (Washington, D.C.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP/MS plus site-specific ubiquitination mapping plus conditional KO in vivo, single lab\",\n      \"pmids\": [\"40822127\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 interacts with NOTCH2 and its knockdown prevents Aβ-induced deubiquitination of NOTCH2 in microglia. USP53 knockdown reduces Aβ-induced neuroinflammatory mediators (IL-1β, TNF-α) and represses IKKβ/NFκB signaling pathway activation. USP53 knockout in 5XFAD mice improves learning and memory and reduces Tau accumulation.\",\n      \"method\": \"Co-immunoprecipitation, USP53 knockout in 5XFAD AD mouse model, Morris Water Maze, Western blot, immunofluorescence, qRT-PCR, primary human microglia knockdown\",\n      \"journal\": \"Neurochemistry international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP plus in vivo KO phenotype plus in vitro pathway analysis, single lab\",\n      \"pmids\": [\"41482165\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 binds MORF4L1 and deubiquitinates it, with K249 and K227 of MORF4L1 identified as key ubiquitination sites. USP53 overexpression prevents MORF4L1 ubiquitination and degradation, and suppresses colorectal cancer cell growth; this effect is abrogated by MORF4L1 silencing.\",\n      \"method\": \"Co-immunoprecipitation combined with LC-MS/MS (IP-LC/MS), ubiquitylome analysis, site-directed mutagenesis of MORF4L1 ubiquitination sites, in vitro and in vivo gain/loss-of-function, rescue experiments\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular basis of disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP/MS plus ubiquitylome and mutagenesis plus rescue, single lab\",\n      \"pmids\": [\"41061828\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ATF3 transcriptionally represses USP53 by binding the USP53 promoter (validated by ChIP and luciferase reporter assay). USP53 upregulation promotes adipogenesis and activates the RhoA/ROCK pathway; USP53 overexpression partially rescues the inhibitory effect of ATF3 overexpression on adipogenesis.\",\n      \"method\": \"ChIP assay, luciferase reporter assay, Oil Red O staining, triglyceride measurement, Western blot, RT-qPCR, 3T3-L1 adipocyte differentiation model\",\n      \"journal\": \"Journal of molecular endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — ChIP plus luciferase reporter plus rescue experiments, single lab\",\n      \"pmids\": [\"39641389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 deubiquitinates SMAD5, stabilizing its protein expression; the EIF4A3 RNA-binding protein stabilizes USP53 mRNA. Knockdown of USP53 inhibits BMSC viability, invasion, and osteogenic differentiation, effects rescued by SMAD5 overexpression, establishing the EIF4A3–USP53–SMAD5 axis in BMSC osteogenic differentiation.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, shRNA knockdown, overexpression rescue, ALP activity assay, Alizarin Red S staining, RT-qPCR, Western blot\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — Co-IP and ubiquitination assay plus rescue, single lab, no orthogonal structural or in vitro reconstitution\",\n      \"pmids\": [\"40481141\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 deubiquitinates MLKL and GSDMD, promoting their stability; FOS transcriptionally activates USP53 expression by directly binding the USP53 promoter (validated by ChIP-qPCR). Reduced FOS (by juglone treatment) lowers USP53, promoting ubiquitination and degradation of MLKL and GSDMD, thereby inhibiting necroptosis and pyroptosis in injured neurons.\",\n      \"method\": \"ChIP-qPCR, immunoprecipitation, Western blot, RNA-seq, qRT-PCR, in vitro OGD/R and in vivo SCI models\",\n      \"journal\": \"Phytomedicine\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — ChIP-qPCR plus immunoprecipitation, mechanistic pathway partially inferred, single lab\",\n      \"pmids\": [\"41045624\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"USP53 is an active K63-linkage-directed deubiquitinase (revising earlier annotation as a pseudo-enzyme) that associates with tight junction scaffolding proteins TJP1/TJP2 and MYO5B, where it deubiquitinates MYO5B to regulate BSEP trafficking to the plasma membrane; loss of USP53 causes mislocalization of BSEP to recycling endosomes, producing low-GGT intrahepatic cholestasis, while in other cellular contexts USP53 deubiquitinates diverse substrates—including FKBP51, cytochrome c, CRKL, ZMYND11, MORF4L1, SR-A, RIPK1, NOTCH2, and SMAD5—to regulate apoptosis, glycolysis, bone homeostasis, and tumor suppression.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"USP53 is a K63-linkage-directed deubiquitinase that integrates epithelial tight-junction architecture, intracellular trafficking, and protein-stability control across multiple tissues [#14, #12]. Originally annotated as a catalytically inactive USP-domain protein, it was reclassified as an active enzyme: biochemical and structural analysis demonstrated K63-specific cleavage through S2-ubiquitin-binding sites in its catalytic domain, and disease-associated patient mutations abolish this activity [#14]. In polarized epithelia and hepatocytes USP53 colocalizes and physically associates with the tight-junction scaffolds TJP1 and TJP2, and its loss elongates hepatocyte–hepatocyte tight junctions, recapitulating TJP2 disease morphology [#0, #3, #13]. Its best-defined biliary mechanism is the deubiquitination of MYO5B through the MYO5B IQ domain: USP53 loss raises MYO5B ubiquitination, impairs endosomal MYO5B recruitment, and traps the bile-salt export pump BSEP in RAB11A-positive recycling endosomes, blocking its delivery to the plasma membrane [#12]. Consistent with this, human truncating USP53 variants cause low-GGT intrahepatic cholestasis with hearing loss [#1]. Beyond the liver, USP53 acts as a substrate-stabilizing DUB in diverse contexts—removing degradative ubiquitin from FKBP51, CYCS, CRKL, ZMYND11, MORF4L1, SR-A, RIPK1, NOTCH2 and SMAD5—to modulate apoptosis, glycolysis, foam-cell formation, bone and adipocyte lineage commitment, and tumor growth [#2, #5, #8, #10, #11, #12, #17, #19]. Its expression is tightly controlled transcriptionally by inputs including PTH/NACA, H3K27ac, DKK1/CREB, EGR1, ATF3, FOS and EIF4A3 [#4, #6, #10, #15, #18, #20].\",\n  \"teleology\": [\n    {\n      \"year\": 2015,\n      \"claim\": \"Established USP53 as a tight-junction-associated protein by showing it interacts with the scaffolds TJP1/TJP2 and is required for cochlear hair-cell integrity, framing it as a junctional component rather than a free enzyme.\",\n      \"evidence\": \"ENU mutant (mambo) mice, reciprocal Co-IP, colocalization, barrier tracer and organotypic rescue assays\",\n      \"pmids\": [\"26609154\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"USP domain annotated as catalytically inactive—no enzymatic activity tested\", \"no biliary phenotype examined\", \"direct substrate of any junction-associated activity unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Linked USP53 loss-of-function to a human Mendelian disease, defining low-GGT cholestasis with hearing loss and placing USP53 in the TJP2 bile-homeostasis pathway.\",\n      \"evidence\": \"Exome sequencing with segregation in human families; interaction cited from prior mouse work\",\n      \"pmids\": [\"30250217\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"molecular mechanism of cholestasis not resolved\", \"no demonstration of how junctional disruption causes bile defect\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Provided ultrastructural evidence that USP53 deficiency phenocopies TJP2 disease at the tight junction, supporting a shared mechanistic pathway in hepatocytes.\",\n      \"evidence\": \"Whole-exome sequencing and transmission electron microscopy of patient liver biopsies\",\n      \"pmids\": [\"32124521\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"correlative human morphology, no manipulation\", \"no enzymatic mechanism\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"First implicated USP53 as a deubiquitinase acting on a specific substrate (FKBP51) with downstream signaling consequences, opening the catalytic-substrate question.\",\n      \"evidence\": \"Co-IP, ubiquitination assay, AKT inhibitor epistasis, xenograft in lung adenocarcinoma cells\",\n      \"pmids\": [\"32511815\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"catalytic activity not directly demonstrated at the time given inactive annotation\", \"single lab\", \"linkage specificity not defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified USP53 as a transcriptionally regulated (PTH/NACA) modulator of mesenchymal lineage commitment, extending its role to bone and fat.\",\n      \"evidence\": \"ChIP-seq, EMSA, luciferase, shRNA, in vivo stromal cell implantation\",\n      \"pmids\": [\"33875709\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"substrate mediating lineage effect not identified\", \"enzymatic dependence untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Expanded USP53 substrate range to apoptotic and metabolic regulation, deubiquitinating CYCS to promote apoptosis and suppressing glycolysis upstream of AMPK in cancer.\",\n      \"evidence\": \"Co-IP/MS, cycloheximide chase, rescue assays (CYCS); ChIP and AMPK inhibitor epistasis (esophageal carcinoma)\",\n      \"pmids\": [\"35654790\", \"34919659\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"linkage specificity of CYCS deubiquitination undefined\", \"AMPK connection lacks direct substrate\", \"single lab per study\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Accumulated multiple context-specific substrates (CRKL, AMPA-receptor interactome) and a bone mechanism via VDR–SMAD3, broadening USP53 to tumor progression, synaptic, and skeletal roles.\",\n      \"evidence\": \"Co-IP and ubiquitination assays (CRKL); colocalization/Co-IP in brain (GRIA2/GRIP2); Usp53 KO mice with microCT and VDR-SMAD3 Co-IP\",\n      \"pmids\": [\"37894400\", \"37895270\", \"36726200\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"AMPA-receptor association lacks functional follow-up\", \"CRKL study single Co-IP/single lab\", \"how USP53 enhances VDR-SMAD3 binding mechanistically unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined the central biliary mechanism: USP53 deubiquitinates MYO5B via its IQ domain to enable endosomal recruitment and BSEP plasma-membrane trafficking, mechanistically uniting the cholestasis phenotype with a substrate.\",\n      \"evidence\": \"Co-IP, CRISPR-KO, surface biotinylation, live imaging/FRAP, site-directed mutagenesis, patient tissue\",\n      \"pmids\": [\"40828662\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"link between MYO5B deubiquitination and tight-junction morphology not fully integrated\", \"ubiquitin-linkage type on MYO5B not specified in this study\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Added further substrates and transcriptional regulators—SR-A (K48 chains, foam-cell formation downstream of DKK1/CREB), ZMYND11 (anti-tumor), and TJP2 in liver-specific KO mice—broadening USP53's reach in atherosclerosis, cancer, and bile homeostasis.\",\n      \"evidence\": \"Co-IP, ChIP, domain mapping, conditional/AAV mouse models\",\n      \"pmids\": [\"38904030\", \"39044157\", \"39705897\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"mixed linkage specificity across substrates (K48 vs K63) not reconciled\", \"single lab per finding\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved the long-standing catalytic question by reconstituting USP53 as an active K63-linkage-specific DUB with K63-specific S2-ubiquitin-binding sites, and showed patient mutations abrogate this activity.\",\n      \"evidence\": \"Linkage-specific biochemical DUB assays, structural analysis, patient-variant functional testing (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.07.07.602376\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"preprint, not peer-reviewed\", \"reconciliation with reported K48 activity on SR-A unresolved\", \"physiological tricellular-junction substrates incompletely mapped\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Extended K63-directed activity to cell-death control via site-specific deubiquitination of RIPK1 (K377) and stabilization of MLKL/GSDMD, plus NOTCH2, SMAD5 and MORF4L1, with multiple transcription factors (EGR1, FOS, EIF4A3, ATF3) controlling USP53 levels.\",\n      \"evidence\": \"Co-IP/MS, site-specific ubiquitination mapping, conditional KO mice, ChIP/luciferase, rescue experiments\",\n      \"pmids\": [\"40822127\", \"41045624\", \"41482165\", \"40481141\", \"41061828\", \"39641389\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"substrate set is large and largely single-lab\", \"tissue selectivity of substrate choice unexplained\", \"RIPK1/MLKL/GSDMD studies lack structural validation\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single K63-directed DUB selects such divergent substrates across liver, bone, brain, heart, and tumor tissues—and how this reconciles with reported K48 cleavage—remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"no unified model of substrate-recruitment specificity\", \"linkage-specificity conflict (K63 vs K48) unreconciled\", \"most non-hepatic substrates rest on single Co-IP/ubiquitination studies\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [2, 5, 10, 11, 12, 14, 15, 17]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [12, 14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 12]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [12]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [5, 15, 20]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [4, 7, 19]}\n    ],\n    \"complexes\": [\"tight junction\"],\n    \"partners\": [\"TJP1\", \"TJP2\", \"MYO5B\", \"RIPK1\", \"CRKL\", \"ZMYND11\", \"MORF4L1\", \"FKBP51\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":6,"faith_total":6,"faith_pct":100.0}}