{"gene":"USP8","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":1998,"finding":"USP8/UBPY is a ubiquitin isopeptidase that cleaves linear and isopeptide-linked ubiquitin chains both as a recombinant protein and upon immunoprecipitation from cell extracts; its levels accumulate upon growth stimulation and its inhibition by antisense prevents S-phase entry, indicating a role in regulating the ubiquitin-proteasome pathway during cell proliferation.","method":"In vitro ubiquitin cleavage assay with recombinant protein, immunoprecipitation followed by activity assay, antisense microinjection with S-phase readout","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic reconstitution plus functional loss-of-function with specific proliferative phenotype, single lab but multiple orthogonal methods","pmids":["9628861"],"is_preprint":false},{"year":2000,"finding":"USP8/UBPY interacts with the SH3 domain of Hrs-binding protein (STAM) via a novel non-canonical SH3-binding motif PX(V/I)(D/N)RXXKP, linking it to endocytic trafficking of growth factor receptor complexes through early endosomes.","method":"Far Western screening, mutagenic analysis of SH3 binding motif, in vitro binding assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro binding reconstitution with mutagenesis identifying consensus motif, single lab but multiple orthogonal methods","pmids":["10982817"],"is_preprint":false},{"year":2001,"finding":"Mouse UBPy (USP8 ortholog) interacts with the Ras GEF CDC25(Mm)/Ras-GRF1 via the N-terminal domain of CDC25(Mm), deubiquitinates CDC25(Mm) in vivo, and increases its protein half-life.","method":"Yeast two-hybrid screen, GST pulldown in vitro, co-immunoprecipitation in mammalian cells, ubiquitination assay by co-transfection","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus in vitro pulldown plus ubiquitination assay, single lab","pmids":["11500497"],"is_preprint":false},{"year":2004,"finding":"USP8 physically interacts with the E3 ubiquitin ligase Nrdp1 via its rhodanese and catalytic domains, deubiquitinates Nrdp1, and markedly enhances Nrdp1 stability; a catalytically inactive USP8 point mutant destabilizes endogenous Nrdp1.","method":"Affinity chromatography, co-immunoprecipitation, domain-mapping with deletion constructs, catalytic mutant overexpression, protein stability assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — affinity chromatography identification plus Co-IP plus catalytic mutant functional validation, single lab with multiple orthogonal methods","pmids":["15314180"],"is_preprint":false},{"year":2005,"finding":"USP8/UBPY deubiquitinates EGFR on endosomes in vitro and in vivo; overexpression reduces EGFR ubiquitination and delays EGF-stimulated EGFR degradation, while RNAi depletion of UBPY leads to elevated EGFR ubiquitination and accelerated degradation; catalytically inactive UBPY localizes to endosomes overlapping with EGFR.","method":"Immunopurification followed by in vitro deubiquitination assay, overexpression, RNAi knockdown, immunofluorescence co-localization on endosomes","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro deubiquitination assay plus gain- and loss-of-function with mechanistic readout, replicated by multiple labs","pmids":["16120644"],"is_preprint":false},{"year":2006,"finding":"USP8/UBPY processes Lys-48- and Lys-63-linked polyubiquitin chains in vitro; its knockdown causes global increase in ubiquitinated proteins, accumulation of ubiquitin on enlarged multivesicular endosomes, and strongly inhibits degradation of EGFR and Met receptor tyrosine kinases; depletion also dramatically destabilizes its binding partner STAM.","method":"siRNA knockdown, in vitro ubiquitin chain cleavage assay, electron microscopy of endosomes, receptor degradation assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro biochemistry plus siRNA loss-of-function with multiple mechanistic readouts, replicated across labs","pmids":["16520378"],"is_preprint":false},{"year":2006,"finding":"USP8/UBPY deubiquitinates EGFR to promote (not inhibit) its lysosomal degradation; dominant-negative UBPY mutants cause EGFR hyperubiquitination, alter EGFR expression levels and degradation intermediates, and affect downstream MAPK signaling; UBPY is a substrate for Src-family tyrosine kinases activated by EGFR and constitutively co-precipitates with EGFR.","method":"Dominant-negative mutant overexpression (C748A, truncation constructs), co-immunoprecipitation, ubiquitination assay, MAPK signaling readout","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple dominant-negative constructs plus Co-IP, single lab; contradicts Mizuno 2005 on directionality of degradation effect","pmids":["17121848"],"is_preprint":false},{"year":2006,"finding":"USP8/UBPY deubiquitinates Eps15 in vitro; inactivation of UBPY causes elevated Eps15 monoubiquitination and its accumulation on aberrant multivesicular endosomes, indicating UBPY regulates endosomal ubiquitin levels and endosome morphology.","method":"Catalytic-inactive mutant overexpression, RNAi knockdown, in vitro deubiquitination assay, immunofluorescence and electron microscopy","journal":"Traffic","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro deubiquitination plus loss-of-function, single lab","pmids":["16771824"],"is_preprint":false},{"year":2006,"finding":"Crystal structures of three USP8 domains were determined: (1) the N-terminal domain forms a homodimer with a novel fold via helix-swapping; (2) the rhodanese domain interacts with Nrdp1 via a conserved peptide loop, revealing the structural basis for USP8-Nrdp1 binding; (3) the catalytic domain adopts an inhibited closed conformation with the ubiquitin-binding pocket inaccessible, suggesting substrate-induced conformational activation.","method":"X-ray crystallography of three domain structures, structural analysis of NRDP1-rhodanese complex","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple high-resolution crystal structures with mechanistic interpretation, single study with multiple domains","pmids":["17035239"],"is_preprint":false},{"year":2007,"finding":"USP8/UBPY contains an N-terminal MIT domain that binds CHMP proteins (CHMP1A, CHMP1B, CHMP7) of the ESCRT-III complex; the MIT domain is required for endosomal localization of USP8 but is dispensable for catalytic activity; MIT-deleted USP8 cannot rescue STAM from proteasomal degradation or reverse the block to EGFR degradation caused by USP8 depletion; STAM stimulates USP8 deubiquitinase activity.","method":"MIT domain identification and deletion mutagenesis, CHMP binding assays, siRNA rescue experiments, STAM activity stimulation assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — domain mutagenesis with functional rescue assays plus binding characterization, single lab with multiple orthogonal methods","pmids":["17711858"],"is_preprint":false},{"year":2007,"finding":"14-3-3 proteins (ε, γ, ζ) bind USP8 in a phosphorylation-dependent manner at Ser680 within the consensus motif RSYS(680)SP; 14-3-3 binding inhibits USP8 deubiquitinating activity toward polyubiquitin chains and EGFR in vitro; during M phase, USP8 is dephosphorylated at Ser680, dissociates from 14-3-3, and displays enhanced activity.","method":"Co-immunoprecipitation followed by mass spectrometry, phosphatase treatment, metabolic 32P labeling, phospho-specific antibody, peptide competition, in vitro deubiquitination assay with 14-3-3","journal":"Experimental cell research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro inhibition assay plus multiple biochemical methods establishing phosphorylation-dependent regulation, single lab","pmids":["17720156"],"is_preprint":false},{"year":2010,"finding":"USP8 depletion accelerates EGFR degradation via an Hrs-dependent pathway; catalytically inactive USP8 causes EGFR hyperubiquitination and endosomal accumulation; USP8 interacts with STAM1/2 SH3 domains via three RXXK motifs in its central region; the USP8·STAM complex regulates EGFR ubiquitination dynamics at early endosomes, with USP8-mediated deubiquitination slowing EGFR progression past the early-to-recycling endosome circuit.","method":"USP8 depletion, catalytic mutant overexpression, domain mutagenesis of RXXK motifs, co-immunoprecipitation, endosomal localization assays, receptor degradation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple domain mutants plus epistasis with Hrs plus endosomal localization with functional consequence, single lab","pmids":["20736164"],"is_preprint":false},{"year":2010,"finding":"USP8 depletion stabilizes CXCR4 on the cell surface and attenuates receptor degradation without affecting CXCR4 ubiquitination status; USP8 functionally opposes the E3 ligase AIP4 at the ESCRT-0 checkpoint to regulate ESCRT-0 ubiquitination and promote CXCR4 trafficking.","method":"siRNA knockdown, surface receptor degradation assay, ubiquitination analysis, endosomal colocalization, epistasis with AIP4","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function with multiple mechanistic readouts including ESCRT-0 epistasis, single lab","pmids":["20876529"],"is_preprint":false},{"year":2010,"finding":"USP8 interacts with ERBB2 (HER-2) indirectly through a chimeric EGFR-ErbB2 construct; catalytically inactive USP8 (C748A) enhances EGFR-ErbB2 ubiquitination both with and without EGF stimulation; USP8 is tyrosine phosphorylated upon EGFR-ErbB2 activation in a Src- and EGFR-kinase-dependent, MIT domain-dependent manner.","method":"Chimeric receptor co-expression, catalytic mutant overexpression, ubiquitination assay, kinase inhibitor treatment, MIT domain mutant analysis","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple mutant constructs plus kinase dependency characterization, single lab","pmids":["21044682"],"is_preprint":false},{"year":2011,"finding":"USP8 associates with KCa3.1 channel following endocytosis (detected by DUB Chip protein microarray and confirmed by co-immunoprecipitation); overexpression of wild-type USP8 accelerates channel deubiquitination, while catalytically inactive USP8 or siRNA knockdown enhances accumulation of ubiquitylated KCa3.1 and inhibits channel lysosomal degradation.","method":"DUB Chip protein microarray, co-immunoprecipitation, BLAP-tagged receptor with TUBE pulldown, overexpression of WT and catalytic mutant, siRNA knockdown, degradation assay","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — protein microarray identification confirmed by Co-IP plus gain/loss-of-function, single lab","pmids":["21828287"],"is_preprint":false},{"year":2012,"finding":"USP8 is identified by in vivo RNAi screen as a deubiquitinase that removes ubiquitin from multi-monoubiquitinated Smoothened (Smo) in the Hedgehog pathway; USP8 inactivation increases Smo ubiquitination and attenuates Hh-induced Smo cell-surface accumulation; Hh signaling promotes USP8-Smo interaction via Smo aa625-753 covering PKA/CK1 phosphorylation clusters; USP8 overexpression elevates Smo cell-surface accumulation and promotes Smo away from early endosomes.","method":"In vivo RNAi screen in Drosophila, ubiquitination assay, co-immunoprecipitation, immunofluorescence localization, Hh pathway activity assay","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vivo screen validated by multiple approaches including Co-IP, localization and pathway activity assays, single lab with multiple orthogonal methods","pmids":["22253573"],"is_preprint":false},{"year":2012,"finding":"USP8 deubiquitylates the CLOCK transcription factor in Drosophila circadian neurons; loss of USP8 function or dominant-negative USP8 enhances CLK/CYC transcriptional activity and disrupts circadian molecular oscillations; CLK ubiquitylation cycles robustly peaking at maximal CLK/CYC transcription; USP8 interacts with CLK and its expression is directly activated by CLK/CYC.","method":"Loss-of-function RNAi, dominant-negative USP8 expression, CLK ubiquitylation cycling assay, co-immunoprecipitation, circadian locomotor activity assay","journal":"Genes & development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic approaches plus Co-IP plus cycling ubiquitylation assay, single lab","pmids":["23154984"],"is_preprint":false},{"year":2013,"finding":"HD-PTP/PTPN23 recruits UBPY/USP8 to EGFR at ESCRT-0; USP8 associates with HD-PTP-bound CHMP4B and with HD-PTP directly; UBPY/HD-PTP cooperation transfers EGFR from ESCRT-0 to ESCRT-III and drives EGFR sorting to intralumenal vesicles; USP8 RXXK motifs compete with HD-PTP for STAM2 SH3 binding to facilitate EGFR deubiquitination.","method":"Co-immunoprecipitation, siRNA knockdown, sorting to intralumenal vesicle assay, domain-interaction mapping","journal":"Current biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — Co-IP plus functional sorting assay plus domain competition experiments, single lab with multiple orthogonal methods","pmids":["23477725"],"is_preprint":false},{"year":2013,"finding":"RNF41 ubiquitylates and reduces levels of USP8 (i.e., USP8 is a substrate of RNF41); USP8 in turn stabilizes RNF41; loss of USP8 mimics RNF41 overexpression effects on leptin receptor and LIF receptor trafficking (stabilization and enhanced ectodomain shedding); USP8 depletion also indirectly destabilizes the ESCRT-0 complex.","method":"Co-immunoprecipitation, ubiquitylation assay, siRNA knockdown, receptor trafficking assay, epistasis experiments","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal regulation demonstrated by Co-IP plus functional receptor trafficking epistasis, single lab","pmids":["23750007"],"is_preprint":false},{"year":2013,"finding":"USP8 depletion reduced levels of endogenous BACE1, increased BACE1 ubiquitination at K501, caused BACE1 accumulation in early and late endosomes/lysosomes, decreased BACE1 in recycling endosomes, and reduced BACE1-mediated APP cleavage and amyloid-β production, establishing USP8 as a deubiquitinase that deubiquitinates BACE1 at K501 to regulate its endosomal trafficking and stability.","method":"siRNA knockdown, ubiquitination assay, subcellular fractionation/endosomal localization, APP cleavage assay, Aβ measurement","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function with multiple mechanistic readouts, site-specific ubiquitination identified, single lab","pmids":["27302062"],"is_preprint":false},{"year":2013,"finding":"USP8 regulates epithelial Na+ channel (ENaC) by deubiquitinating ENaC; USP8 increases ENaC current in Xenopus oocytes and surface abundance in HEK293 cells by preventing ENaC lysosomal degradation in the endocytic pathway without affecting endocytosis; co-immunoprecipitation confirmed USP8-ENaC interaction; ENaC cytoplasmic lysine mutants reduce USP8 effects.","method":"Xenopus oocyte electrophysiology, HEK293 surface biotinylation, co-immunoprecipitation, ENaC lysine mutant analysis, endocytic sorting assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — electrophysiology plus Co-IP plus lysine mutant, single lab with multiple orthogonal methods","pmids":["23297398"],"is_preprint":false},{"year":2014,"finding":"USP8 mutations in Cushing's disease cluster in the 14-3-3 binding motif, enhance proteolytic cleavage and catalytic activity of USP8, lead to increased deubiquitination of EGFR impairing its downregulation, sustain EGF signaling, and enhance POMC promoter activity in corticotroph adenomas.","method":"Exome sequencing, in vitro catalytic activity assay, EGFR ubiquitination assay, POMC promoter-reporter assay, USP8 cleavage analysis","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal mechanistic experiments (catalytic activity, EGFR ubiquitination, promoter assay) establishing mechanism of gain-of-function mutations","pmids":["25485838"],"is_preprint":false},{"year":2014,"finding":"USP8 preferentially removes K6-linked ubiquitin chains from parkin; this deubiquitination is required for efficient recruitment of parkin to depolarized mitochondria and subsequent mitophagy; USP8 knockdown causes persistence of K6-linked ubiquitin conjugates on parkin and delays mitophagy.","method":"Co-immunoprecipitation, in vitro deubiquitination assay with K6-linkage specificity, siRNA knockdown, mitophagy assay (parkin translocation, mitochondrial clearance)","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro deubiquitination with linkage specificity plus loss-of-function mitophagy assay, replicated in subsequent commentary paper","pmids":["25216678"],"is_preprint":false},{"year":2014,"finding":"BRUCE acts as a scaffold bridging USP8 and BRIT1 in a complex; USP8 catalyzes deubiquitination of K63-linked ubiquitin on BRIT1, which is required for BRIT1 recruitment to DNA double-strand break sites via γ-H2AX; loss of BRUCE or USP8 impairs BRIT1 deubiquitination, BRIT1 foci formation, chromatin relaxation, and homologous recombination repair.","method":"Co-immunoprecipitation, in vivo ubiquitination assay, DNA damage foci assay (immunofluorescence), HR repair assay, BRUCE-mutant mouse analysis","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 2 / Moderate — Co-IP establishing tripartite complex plus functional ubiquitination and DNA damage assays plus mouse model, single lab with multiple methods","pmids":["25733871"],"is_preprint":false},{"year":2014,"finding":"USP8 interacts with and deubiquitinates LRIG1; SAIT301 anti-Met antibody triggers Met degradation by inducing LRIG1 ubiquitination through inhibition of USP8-LRIG1 interaction, demonstrating USP8 as a LRIG1-specific deubiquitinase that controls Met degradation efficiency.","method":"Co-immunoprecipitation, ubiquitination assay, siRNA knockdown, receptor degradation assay","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination assay, single lab","pmids":["24828152"],"is_preprint":false},{"year":2014,"finding":"USP8 depletion in somatic cells causes redistribution of cation-independent mannose-6-phosphate receptor (ci-M6PR) from TGN to endosomes, leading to defective retromer-dependent trafficking and secretion of unprocessed Cathepsin D; this requires USP8 catalytic activity and MIT domain for endosomal localization.","method":"siRNA knockdown, siRNA-resistant rescue with WT and mutant USP8, subcellular fractionation, Cathepsin D processing/secretion assay","journal":"Traffic","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA with domain mutant rescue, single lab","pmids":["24894536"],"is_preprint":false},{"year":2015,"finding":"USP8 is a regulatory component of the TCR signalosome that interacts with adaptor Gads and 14-3-3β; caspase-dependent processing of USP8 occurs upon TCR stimulation; T cell-specific USP8 deletion in mice causes defective thymocyte maturation, failure to upregulate IL-7Rα via Foxo1, and development of colitis with impaired regulatory T cell function.","method":"Co-immunoprecipitation, T cell-specific conditional knockout mouse, flow cytometry for thymocyte maturation, gene expression analysis, colitis phenotyping","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional KO mouse with defined cellular phenotypes plus Co-IP establishing signalosome interaction, multiple mechanistic readouts","pmids":["26214742"],"is_preprint":false},{"year":2015,"finding":"Somatic USP8 gain-of-function mutations in Cushing's disease disrupt 14-3-3 protein interaction, elevate USP8 capacity to protect EGFR from lysosomal degradation, result in higher EGFR and POMC/ACTH expression; USP8 knockdown or EGFR blockade attenuates ACTH secretion in primary USP8-mutated tumor cells.","method":"Whole-exome and Sanger sequencing, 14-3-3 interaction disruption assay, EGFR protein levels, POMC mRNA levels, siRNA knockdown in primary cultures","journal":"Cell research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods confirming mechanism, large cohort, replicated across multiple labs","pmids":["25675982"],"is_preprint":false},{"year":2015,"finding":"In Drosophila, USP8 deubiquitylates and stabilizes Hrs (ESCRT-0); in Ubpy-null cells Hrs becomes ubiquitylated and degraded in lysosomes, disrupting ESCRT-0 sorting machinery and causing accumulation of signaling proteins in enlarged aberrant endosomes.","method":"Drosophila Ubpy null genetics, co-immunoprecipitation, ubiquitination assay, endosomal morphology analysis","journal":"Development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic null model plus Co-IP plus ubiquitination assay, single lab","pmids":["24574010"],"is_preprint":false},{"year":2015,"finding":"USP8 deubiquitinates and stabilizes the long isoform of FLIP (FLIPL) but not the short isoform; USP8 depletion induces FLIPL destabilization and promotes death receptor-mediated extrinsic apoptosis via enhanced DISC and TNFR1 complex II formation and caspase-8/3 activation.","method":"Co-immunoprecipitation, in vitro deubiquitination assay, siRNA knockdown, apoptosis assays (Annexin V, caspase activity), DISC complex immunoprecipitation","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro deubiquitination plus Co-IP plus functional apoptosis assay, single lab","pmids":["27321185"],"is_preprint":false},{"year":2015,"finding":"USP8 promotes VEGFR2 deubiquitination; USP8 depletion in endothelial cells alters VEGFR2 ubiquitination and causes VEGFR2 accumulation in endosome-lysosome system with production of a unique extracellular domain proteolytic fragment, and impairs VEGF-A-stimulated signal transduction.","method":"siRNA knockdown, VEGFR2 ubiquitination assay, endosomal localization, VEGFR2 proteolytic fragment analysis, VEGF-A signaling readout","journal":"Traffic","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function with multiple mechanistic readouts, single lab","pmids":["26459808"],"is_preprint":false},{"year":2016,"finding":"USP8 interacts and co-localizes with α-synuclein in endosomal membranes and deubiquitinates K63-linked chains from α-synuclein both in cells and after purification; Usp8 knockdown in Drosophila and human cells increases lysosomal degradation of α-synuclein; in dopaminergic neurons, Usp8 protects against α-synuclein-induced locomotor deficits and cell loss.","method":"Co-immunoprecipitation, in vitro/in-cell deubiquitination assay with K63 specificity, siRNA knockdown with lysosomal degradation assay, Drosophila genetics (locomotor, neuronal loss)","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro deubiquitination plus Co-IP plus Drosophila in vivo genetics plus human cell loss-of-function, single lab with multiple orthogonal methods","pmids":["27444016"],"is_preprint":false},{"year":2016,"finding":"EGFR kinase directly phosphorylates USP8 on Tyr-717 and Tyr-810; these phosphorylations elevate USP8 deubiquitinase activity, which stabilizes the trichoplein-Aurora A pathway to suppress ciliogenesis; EGFR knockdown and serum starvation induce ciliogenesis through downregulation of this USP8-trichoplein-Aurora A signal.","method":"In vitro kinase assay with EGFR and USP8, phospho-specific mutant analysis, trichoplein/Aurora A stability assay, ciliogenesis assay, zebrafish usp8 KO","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro kinase assay establishing direct phosphorylation plus functional pathway cascade plus in vivo zebrafish validation, single lab with multiple orthogonal methods","pmids":["29472535"],"is_preprint":false},{"year":2013,"finding":"USP8 deubiquitinates HIF1α, counteracting pVHL-mediated HIF1α ubiquitination; USP8 maintains basal HIF1α expression in normoxia, and this HIF1α deubiquitination is required for ciliogenesis through repression of Rabaptin5, which controls endosome trafficking.","method":"siRNA screen for ciliogenesis genes, HIF1α ubiquitination assay, epistasis with pVHL, ciliogenesis assay, Rabaptin5 expression assay","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA screen with mechanistic follow-up (ubiquitination and epistasis assays), single lab","pmids":["24378640"],"is_preprint":false},{"year":2014,"finding":"NMDAR activation causes dephosphorylation and activation of USP8 in neurons; activated USP8 deubiquitinates AMPARs; surface AMPAR levels and synaptic strength are inversely regulated by Nedd4-1 and USP8; USP8 levels decrease during homeostatic downscaling, while Nedd4-1 increases.","method":"NMDAR activation, phosphorylation assay, co-immunoprecipitation, surface AMPAR biotinylation, electrophysiology (synaptic strength), USP8/Nedd4-1 protein level analysis","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus phosphorylation assay plus electrophysiology, single lab","pmids":["25505317"],"is_preprint":false},{"year":2017,"finding":"USP8 forms a ubiquitin-dependent tripartite complex with Nrdp1 (E3 ligase) and Clec16a (which encodes an E3 ligase promoting non-degradative ubiquitin conjugates to direct mitophagy effectors); this complex is essential for β-cell mitophagy; lenalidomide inhibits Clec16a and destabilizes the complex, impairing β-cell mitophagy and insulin secretion.","method":"Co-immunoprecipitation, ubiquitination assay, mitophagy assay, β-cell oxygen consumption and insulin secretion assay, pharmacological inhibition","journal":"Diabetes","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP establishing tripartite complex plus functional mitophagy and metabolic assays, single lab","pmids":["29180353"],"is_preprint":false},{"year":2018,"finding":"Crystal structure of the 14-3-3ζ protein in complex with the USP8 Ser718-phosphorylated motif was determined; fluorescence polarization and isothermal titration calorimetry quantified the interaction affinity; Cushing's disease mutations in USP8 impair 14-3-3 binding.","method":"X-ray crystallography, fluorescence polarization, isothermal titration calorimetry","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 / Moderate — high-resolution crystal structure with biophysical quantification, single lab but multiple orthogonal methods","pmids":["29473952"],"is_preprint":false},{"year":2018,"finding":"USP8 deubiquitinates and stabilizes SHANK3 (and SHANK1) in neurons; USP8 overexpression enhances SHANK3/SHANK1 protein levels via deubiquitination and increases dendritic spine density; USP8 is essential for activity-dependent changes in SHANK3 protein levels.","method":"Co-immunoprecipitation, in vitro deubiquitination assay, USP8 overexpression, USP8 knockdown, dendritic spine counting, synaptic activity modulation","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus deubiquitination assay plus neuronal gain/loss-of-function, single lab","pmids":["29735556"],"is_preprint":false},{"year":2018,"finding":"CHMP1B is ubiquitinated within its flexible loop and is deubiquitinated by USP8; CHMP1B ubiquitination is induced by EGF stimulation; CHMP1B ubiquitination is necessary for EGFR trafficking and wing development in Drosophila; USP8 deubiquitination of CHMP1B may favor its assembly into ESCRT-III polymers.","method":"Co-immunoprecipitation, ubiquitination assay, Drosophila genetics (wing phenotype), EGF-stimulated CHMP1B ubiquitination assay","journal":"PLoS genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus in vivo Drosophila genetics plus stimulated ubiquitination assay, single lab","pmids":["29933386"],"is_preprint":false},{"year":2019,"finding":"USP8 interacts with and deubiquitinates SQSTM1/p62 preferentially removing K11-linked ubiquitin chains at K420 within the UBA domain; this deubiquitination inhibits p62 degradation and suppresses autophagic flux; the K420R mutant abolishes USP8 effects.","method":"Co-immunoprecipitation, in vitro deubiquitination assay with linkage specificity, K420R mutant analysis, autophagic flux assay","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro deubiquitination with site and linkage specificity plus functional autophagy assay plus mutagenesis, single lab","pmids":["31241013"],"is_preprint":false},{"year":2019,"finding":"USP8 deubiquitinates EPG5 by removing K63-linked ubiquitin chains at K252, leading to enhanced EPG5-LC3 interaction and autophagic flux maintenance in embryonic stem cells; USP8-EPG5 interaction is through the Coiled-coil domain of EPG5.","method":"Co-immunoprecipitation (Coiled-coil domain mapping), in vitro deubiquitination assay with K63 specificity, K252 site identification, EPG5-LC3 interaction assay, autophagic flux assay in ESCs","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro deubiquitination with site and linkage specificity plus Co-IP domain mapping plus functional autophagy assay, single lab with multiple orthogonal methods","pmids":["30931944"],"is_preprint":false},{"year":2019,"finding":"USP8 interacts with and deubiquitinates TRAF6, TAB2, TAK1, p62, and BECN1; USP8 deubiquitinates K63-linked ubiquitination of TAK1; USP8 knockout in liver cancer cells increases NF-κB activation and autophagy in response to TLR4/LPS stimulation, enhancing cancer progression and metastasis.","method":"Co-immunoprecipitation, K63-linked ubiquitination assay of TAK1, USP8 knockout (CRISPR), NF-κB reporter, invasion/metastasis assay, xenograft","journal":"Translational oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus K63 ubiquitination assay plus KO functional assay, single lab","pmids":["34688043"],"is_preprint":false},{"year":2020,"finding":"H2S promotes S-sulfhydration of USP8 at specific cysteine residues; S-sulfhydration of USP8 is decreased under hyperglycemia/hyperlipidemia; H2S-mediated USP8 sulfhydration enhances USP8 deubiquitinase activity toward parkin and promotes USP8-parkin interaction, facilitating parkin translocation to mitochondria and mitophagy formation in diabetic cardiomyopathy.","method":"S-sulfhydration detection assay, dithiothreitol reversal of sulfhydration, co-immunoprecipitation (USP8-parkin), ubiquitination assay of parkin, mitophagy assay, db/db mouse model","journal":"Aging and disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — post-translational modification assay with functional reversal plus Co-IP plus mitophagy readout, single lab","pmids":["32257541"],"is_preprint":false},{"year":2020,"finding":"USP8 inhibition in macrophages increases expression of Nrdp1 (E3 ligase for TLR4), which downregulates TLR4 and MyD88 protein levels and inhibits IKKβ/IκBα phosphorylation, thereby reducing NF-κB p65 nuclear translocation and pro-inflammatory cytokine production; USP8 opposes TLR4/MyD88/NF-κB signaling.","method":"In vivo LPS mouse model, intracerebroventricular USP8 administration, TLR4 knockout mice, TLR4 inhibitor, Western blot for NF-κB pathway components, cytokine measurement","journal":"Brain, behavior, and immunity","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo mouse model with pathway epistasis (TLR4 KO), single lab","pmids":["32335193"],"is_preprint":false},{"year":2021,"finding":"USP8 interacts with and deubiquitinates TAK1 via K63-linked ubiquitination in liver cells; USP8 promotes mRNA stability of USP8 through PTBP1/MALAT1 axis; USP8 stabilizes TAK1 and its depletion promotes TAK1 degradation, pyroptosis, and M1 macrophage polarization contributing to liver fibrosis.","method":"Co-immunoprecipitation, protein degradation assay, ubiquitination assay, RNA pulldown, RIP assay, methylated RNA immunoprecipitation, gain/loss-of-function","journal":"Cell death discovery","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination assay plus RNA stability assay, single lab","pmids":["34839365"],"is_preprint":false},{"year":2019,"finding":"USP8 deubiquitinates the leptin receptor (LepRb), inhibiting its lysosomal degradation and enhancing surface localization; USP8 is in complex with LepRb; leptin stimulation increases USP8 activity and induces USP8 gene expression via CREB-dependent transcription; increased USP8 expression enhances MAPK/ERK pathway activation and glutamatergic synapse formation in hippocampal neurons in a LepRb-dependent manner.","method":"Co-immunoprecipitation, surface receptor assay, USP8 activity assay, dominant-negative CREB, shRNA knockdown, synapse formation assay","journal":"Endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus activity assay plus transcriptional regulation assay plus functional synaptogenesis, single lab","pmids":["31199479"],"is_preprint":false},{"year":2018,"finding":"USP8 interacts with and deubiquitinates Cx43 (connexin-43), reducing both monoubiquitination and polyubiquitination of Cx43 to prevent autophagy-mediated degradation; USP8 knockdown decreases Cx43 protein levels and suppresses intercellular dye transfer (gap junction communication).","method":"Co-immunoprecipitation, ubiquitination assay, siRNA knockdown, dye transfer assay for gap junction function","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination assay plus functional gap junction assay, single lab","pmids":["29626091"],"is_preprint":false},{"year":2019,"finding":"Inhibition of USP8 in Drosophila PINK1 KO model normalizes elevated Mitofusin (MFN) protein levels; a targeted DUB RNAi screen identified USP8 as prominently influencing MFN levels; USP8 inhibition in PINK1-deficient models improves mitochondrial function, locomotor performance, lifespan, and prevents dopaminergic neuron loss.","method":"RNAi DUB screen for MFN levels, genetic USP8 inhibition, pharmacological USP8 inhibition, PINK1 KO Drosophila, mitochondrial function assay, dopaminergic neuron counting","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi screen validated in vivo with multiple functional readouts, single lab","pmids":["30988163"],"is_preprint":false},{"year":2022,"finding":"USP8 directly deubiquitinates and stabilizes the type II TGF-β receptor TβRII, leading to increased TβRII expression at the plasma membrane and in tumor-derived extracellular vesicles; USP8 promotes TGF-β/SMAD-induced EMT, invasion, and metastasis; elevated TβRII+ extracellular vesicles mediate T cell exhaustion; pharmacological USP8 inhibition reduces TβRII stability and TβRII+ circulating EVs.","method":"Co-immunoprecipitation, ubiquitination assay, TβRII surface expression assay, extracellular vesicle isolation and characterization, EMT/invasion assay, T cell exhaustion assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination assay plus multiple functional mechanistic assays (EMT, EV, T cell), single lab with multiple orthogonal methods","pmids":["35811497"],"is_preprint":false},{"year":2022,"finding":"USP8 inhibition increases PD-L1 protein abundance by elevating TRAF6-mediated K63-linked ubiquitination of PD-L1 to antagonize its K48-linked ubiquitination and degradation; USP8 inhibition also activates NF-κB signaling to trigger innate immune response and MHC-I expression.","method":"K63/K48 ubiquitination assays of PD-L1, TRAF6 pathway analysis, NF-κB activation assay, MHC-I expression assay, tumor immunotherapy mouse models","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — linkage-specific ubiquitination assays plus NF-κB pathway analysis plus in vivo tumor models, single lab with multiple orthogonal methods","pmids":["35361799"],"is_preprint":false},{"year":2022,"finding":"USP8 deubiquitinates ESCRT-III proteins CHMP2B and Shrub/CHMP4 in Drosophila germline; loss of USP8 causes ectopic ESCRT-III recruitment at intercellular bridges converting incomplete cell divisions to complete cytokinesis; a Shrub/CHMP4 variant that cannot be ubiquitinated fails to localize at abscission bridges; overexpression of USP8 in germline stem cells converts complete to incomplete cytokinesis.","method":"Drosophila genetics (usp8 mutant, overexpression), ubiquitination-resistant CHMP4 mutant analysis, ESCRT localization at intercellular bridges, cytokinesis assay","journal":"Science","confidence":"High","confidence_rationale":"Tier 2 / Strong — Drosophila genetics with gain/loss-of-function plus ubiquitination-resistant mutant establishing ESCRT-III as direct target, rigorous mechanistic study","pmids":["35587967"],"is_preprint":false},{"year":2024,"finding":"USP8 interacts with and deubiquitinates GPX4, leading to GPX4 stabilization; USP8 inhibition destabilizes GPX4 and sensitizes cancer cells to ferroptosis; homozygous USP8 deletion in intestinal epithelial cells causes lipid peroxidation and cell death.","method":"Co-immunoprecipitation, ubiquitination/stability assay, USP8 conditional knockout mouse, ferroptosis assay (lipid peroxidation), in vitro cancer cell ferroptosis, in vivo tumor model","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination/stability assay plus conditional KO mouse plus multiple functional assays, single lab with multiple orthogonal methods","pmids":["38598341"],"is_preprint":false},{"year":2024,"finding":"USP8 is recruited to stress granules (SGs) upon dsDNA stimulation and cleaves K27-linked ubiquitin chains from the intrinsically disordered region (IDR) of DDX3X, enhancing DDX3X condensation and liquid-liquid phase separation; enhanced DDX3X LLPS promotes cGAS phase separation and activation, potentiating cGAS-STING signaling and type I interferonopathy.","method":"Co-immunoprecipitation, K27-linkage-specific ubiquitination assay of DDX3X, stress granule localization assay, LLPS assay, cGAS activation assay, USP8 inhibitor in Trex1-/- mice","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — linkage-specific deubiquitination assay plus LLPS assay plus in vivo Trex1 KO model plus stress granule localization, single lab with multiple orthogonal methods","pmids":["38795350"],"is_preprint":false},{"year":2024,"finding":"USP8 depletion causes aberrant accumulation of K63-linked ubiquitin chains on endosomes; TAB2/3 (decoder for K63-Ub) is recruited to endosomes, activating TAK1-NF-κB signaling; p62 is also recruited to endosomes activating Keap1-Nrf2; oxidative stress suppresses USP8 activity, causing K63-Ub accumulation on endosomes and TAB2 recruitment triggering inflammatory cytokine expression.","method":"USP8 depletion, K63-linked ubiquitin chain accumulation assay on endosomes, TAB2/p62 endosomal recruitment assay, NF-κB and Nrf2 reporter assays, oxidative stress treatment","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — mechanistic epistasis establishing K63-Ub/TAB2/TAK1-NF-κB and K63-Ub/p62/Nrf2 pathways downstream of USP8 on endosomes, multiple readouts, single lab","pmids":["38180476"],"is_preprint":false},{"year":2023,"finding":"USP8 stabilizes O-GlcNAc transferase (OGT) by inhibiting K48-specific poly-ubiquitination of OGT at K117; SLK-mediated phosphorylation of USP8 at S716 is required for USP8-OGT interaction; OGT O-GlcNAcylates SLC7A11 at Ser26, enabling cystine import; USP8 inhibition reduces OGT stability, decreases SLC7A11 O-GlcNAcylation, and induces ferroptosis in HCC.","method":"Co-immunoprecipitation, K48-specific ubiquitination assay at OGT K117, phosphorylation site mutagenesis (S716), O-GlcNAcylation assay of SLC7A11 at Ser26, cystine import assay, ferroptosis assay","journal":"Advanced science","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — site-specific ubiquitination and phosphorylation assays plus O-GlcNAcylation site identified plus functional ferroptosis assay, single lab with multiple orthogonal methods","pmids":["37867237"],"is_preprint":false},{"year":2023,"finding":"USP8 directly deubiquitinates β-catenin, inhibiting K48-specific poly-ubiquitination, and stabilizes β-catenin protein; the USP domain of USP8 interacts with the ARM domain of β-catenin; USP8 depletion decreases β-catenin protein levels, β-catenin target gene expression, and promotes ferroptosis resistance.","method":"Co-immunoprecipitation (domain mapping of USP8 USP domain and β-catenin ARM domain), K48-specific ubiquitination assay, TOP-luciferase reporter, siRNA knockdown, ferroptosis assay","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP domain mapping plus ubiquitination assay plus reporter assay, single lab","pmids":["37311739"],"is_preprint":false},{"year":2023,"finding":"USP8 directly interacts with and deubiquitinates Nrf2 by removing K48-linked polyubiquitin chains, stabilizing Nrf2 expression; this enhances Nrf2 signaling activation and promotes gemcitabine resistance in pancreatic cancer.","method":"Co-immunoprecipitation, K48-specific ubiquitination assay of Nrf2, siRNA/overexpression, in vivo xenograft","journal":"Biomedicine & pharmacotherapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus linkage-specific ubiquitination assay, single lab","pmids":["37639742"],"is_preprint":false}],"current_model":"USP8 (also known as UBPY) is a multidomain deubiquitinating enzyme whose catalytic activity is regulated by 14-3-3 binding to a phospho-Ser680/Ser718 motif (inhibitory during interphase, relieved in M phase and by Cushing's disease gain-of-function mutations) and by EGFR/Src-mediated tyrosine phosphorylation; it localizes to endosomes via its N-terminal MIT domain that interacts with CHMP/ESCRT-III proteins, where it deubiquitinates cargo receptors (EGFR, CXCR4, VEGFR2, LepRb, TβRII, ENaC, KCa3.1, BACE1, ERBB2) and endosomal machinery components (STAM, Hrs, CHMP1B, ESCRT-III subunits) to regulate receptor trafficking, recycling, and lysosomal degradation; beyond endosomes, USP8 deubiquitinates diverse substrates including parkin (K6-linked chains, required for mitophagy), α-synuclein (K63-linked, reducing lysosomal degradation), GPX4 (stabilizing ferroptosis defense), p62/SQSTM1 (K11 at K420, suppressing autophagy), FLIPL (suppressing apoptosis), BRIT1 (K63-linked, enabling DNA damage repair), SHANK3 (stabilizing synaptic scaffolds), Smoothened (promoting Hedgehog signaling), CLOCK (suppressing circadian transcription), HIF1α (maintaining normoxic levels for ciliogenesis), TβRII (promoting TGF-β/SMAD signaling), OGT (stabilizing cystine import machinery), Nrf2, β-catenin, DDX3X (facilitating cGAS condensation), and TAK1; accumulation of K63-linked ubiquitin chains on endosomes upon USP8 depletion aberrantly activates TAK1-NF-κB and Keap1-Nrf2 inflammatory/stress pathways through TAB2/3 and p62 recruitment, identifying USP8 as a gatekeeper preventing misdirected ubiquitin signaling from endosomes."},"narrative":{"mechanistic_narrative":"USP8 (UBPY) is a multidomain deubiquitinating isopeptidase that cleaves both K48- and K63-linked polyubiquitin chains and governs the ubiquitin economy of the endosomal system, where it controls receptor trafficking, recycling, and lysosomal degradation [PMID:9628861, PMID:16520378]. It is recruited to endosomes through an N-terminal MIT domain that binds ESCRT-III CHMP proteins (CHMP1A/1B/7); this localization is required for its function but dispensable for catalysis, and the enzyme engages the ESCRT-0 machinery by binding STAM1/2 SH3 domains through central RXXK motifs, with STAM in turn stimulating its activity [PMID:17711858, PMID:20736164]. At endosomes USP8 deubiquitinates the cargo receptor EGFR and stabilizes ESCRT components such as STAM and Hrs to set receptor sorting dynamics, and it cooperates with HD-PTP/PTPN23 to hand EGFR from ESCRT-0 to ESCRT-III for delivery into intralumenal vesicles [PMID:16120644, PMID:16520378, PMID:20736164, PMID:23477725, PMID:24574010]. Beyond EGFR, USP8 deubiquitinates a broad panel of membrane proteins and channels—CXCR4, VEGFR2, BACE1, ENaC, KCa3.1, the leptin receptor, and TβRII—to oppose their lysosomal degradation and tune their surface abundance and downstream signaling [PMID:20876529, PMID:27302062, PMID:23297398, PMID:26459808, PMID:31199479, PMID:35811497]. Its catalytic output is gated by phosphorylation-dependent 14-3-3 binding at a Ser680/Ser718 motif that inhibits activity during interphase and is relieved in M phase, while EGFR/Src-mediated tyrosine phosphorylation at Tyr717/Tyr810 elevates activity [PMID:17720156, PMID:29472535, PMID:29473952]. Gain-of-function USP8 mutations clustered in the 14-3-3 motif cause Cushing's disease by disrupting 14-3-3 inhibition, enhancing EGFR deubiquitination and sustaining EGF signaling and POMC/ACTH expression in corticotroph adenomas [PMID:25485838, PMID:25675982]. USP8 also extends to non-endosomal substrates: it removes K6-linked chains from parkin to enable mitophagy [PMID:25216678], deubiquitinates SHANK3 and AMPARs at synapses [PMID:25505317, PMID:29735556], processes K63 chains on α-synuclein and BRIT1 [PMID:25733871, PMID:27444016], and stabilizes effectors such as GPX4, OGT/SLC7A11, β-catenin, and Nrf2 [PMID:38598341, PMID:37867237, PMID:37311739, PMID:37639742]. By restraining endosomal K63-ubiquitin accumulation, USP8 acts as a gatekeeper preventing TAB2/3–TAK1–NF-κB and p62–Keap1–Nrf2 signaling from being aberrantly triggered from endosomes [PMID:38180476].","teleology":[{"year":1998,"claim":"Established that USP8 is a catalytically active ubiquitin isopeptidase whose abundance and activity are coupled to cell proliferation, framing it as a regulator of the ubiquitin-proteasome system rather than a passive enzyme.","evidence":"in vitro ubiquitin cleavage with recombinant protein plus antisense microinjection with S-phase readout","pmids":["9628861"],"confidence":"High","gaps":["No substrate identified at this stage","Mechanism linking activity to S-phase entry undefined"]},{"year":2000,"claim":"Connected USP8 to endocytic trafficking by identifying its non-canonical SH3-binding motif interaction with the ESCRT-0 adaptor STAM, anchoring it to growth factor receptor complexes at early endosomes.","evidence":"Far Western screening and mutagenic mapping of the SH3-binding motif with in vitro binding assays","pmids":["10982817"],"confidence":"High","gaps":["Functional consequence of the STAM interaction not yet demonstrated","Endosomal recruitment determinant not yet mapped"]},{"year":2001,"claim":"Showed USP8 can act as a stabilizing deubiquitinase for a binding partner (CDC25Mm/Ras-GRF1), extending its role beyond chain disassembly to controlling substrate half-life.","evidence":"yeast two-hybrid, GST pulldown, Co-IP and co-transfection ubiquitination assay","pmids":["11500497"],"confidence":"Medium","gaps":["Single lab, ortholog-based","Physiological context of CDC25 stabilization unclear"]},{"year":2004,"claim":"Demonstrated reciprocal regulation between USP8 and an E3 ligase (Nrdp1), with catalytic activity required to stabilize the partner, defining a DUB–E3 stabilization module.","evidence":"affinity chromatography, Co-IP, domain mapping, and catalytic-mutant stability assays","pmids":["15314180"],"confidence":"High","gaps":["Linkage type of Nrdp1 ubiquitin not defined","Downstream consequence of Nrdp1 stabilization not addressed"]},{"year":2005,"claim":"Identified EGFR as a direct endosomal substrate, establishing USP8 as a regulator of receptor tyrosine kinase ubiquitination and trafficking.","evidence":"in vitro deubiquitination assay, gain/loss-of-function, and endosomal co-localization of catalytic-dead USP8 with EGFR","pmids":["16120644"],"confidence":"High","gaps":["Directionality of effect on degradation became contested (see #6)","Ubiquitin linkage on EGFR not resolved here"]},{"year":2006,"claim":"Resolved the biochemical scope and broad endosomal role of USP8: it processes both K48- and K63-linked chains, and its loss destabilizes its partner STAM while disrupting MVE morphology and RTK degradation.","evidence":"siRNA knockdown, in vitro chain-cleavage assays, electron microscopy, and EGFR/Met degradation assays (plus parallel work on Eps15 and Src-dependent tyrosine phosphorylation)","pmids":["16520378","17121848","16771824"],"confidence":"High","gaps":["Whether USP8 net promotes or restrains EGFR degradation remained discrepant between studies","Mechanism of endosome enlargement upon depletion not fully defined"]},{"year":2006,"claim":"Provided the structural framework for USP8 regulation: a helix-swapped N-terminal dimer, a rhodanese–Nrdp1 interface, and a catalytic domain in an autoinhibited closed conformation requiring substrate-induced activation.","evidence":"X-ray crystallography of three USP8 domains and the Nrdp1-rhodanese complex","pmids":["17035239"],"confidence":"High","gaps":["No full-length structure","Conformational activation not captured in an active state"]},{"year":2007,"claim":"Defined the two pillars of spatial and activity control: the MIT domain mediates ESCRT-III/CHMP-dependent endosomal targeting, while phospho-Ser680-dependent 14-3-3 binding inhibits catalysis and is relieved in M phase.","evidence":"MIT deletion with CHMP binding and siRNA rescue assays; Co-IP/MS, phosphatase and phospho-antibody analyses with in vitro deubiquitination in the presence of 14-3-3","pmids":["17711858","17720156"],"confidence":"High","gaps":["How cell-cycle phosphatases target Ser680 not defined","Relationship between MIT targeting and 14-3-3 gating not integrated"]},{"year":2010,"claim":"Mapped USP8 into the ESCRT-0 checkpoint mechanism, showing it sets EGFR and CXCR4 ubiquitination dynamics via multiple STAM-binding RXXK motifs and opposes specific E3 ligases (AIP4) at endosomes.","evidence":"domain mutagenesis of RXXK motifs, Hrs/AIP4 epistasis, endosomal localization, and surface receptor degradation assays; plus ERBB2 chimera and MIT/Src-dependent tyrosine phosphorylation work","pmids":["20736164","20876529","21044682"],"confidence":"High","gaps":["Receptor-specific differences in ubiquitin-status dependence unexplained","Precise step of the early-to-recycling transition controlled by USP8 not defined"]},{"year":2012,"claim":"Generalized USP8 to developmental and circadian signaling, deubiquitinating Smoothened to promote Hedgehog surface accumulation and deubiquitinating CLOCK to restrain CLK/CYC circadian transcription.","evidence":"in vivo Drosophila RNAi screen, ubiquitination assays, Co-IP, localization, and circadian/Hh pathway activity readouts","pmids":["22253573","23154984"],"confidence":"High","gaps":["Whether Smo/CLOCK effects are endosome-dependent unclear","Conservation of CLOCK regulation in mammals not tested"]},{"year":2013,"claim":"Expanded the trafficking interactome and substrate range: USP8 is recruited by HD-PTP to transfer EGFR between ESCRT complexes, is itself an RNF41 substrate, and deubiquitinates BACE1, ENaC, and HIF1α to control trafficking, channel surface levels, and ciliogenesis.","evidence":"Co-IP, ILV sorting assays, reciprocal ubiquitination/epistasis, site-specific ubiquitination (BACE1 K501), oocyte electrophysiology, and HIF1α/pVHL epistasis","pmids":["23477725","23750007","27302062","23297398","24378640"],"confidence":"High","gaps":["How substrate selectivity is achieved among many endosomal cargos unresolved","Direct vs indirect effects on HIF1α not fully separated"]},{"year":2014,"claim":"Linked USP8 to organelle quality control, DNA repair, immune development, and disease genetics: K6-chain removal from parkin enables mitophagy, K63-chain removal from BRIT1 enables HR repair, T-cell USP8 controls thymocyte maturation, and Cushing's disease mutations cause 14-3-3-resistant gain of function.","evidence":"linkage-specific in vitro deubiquitination, mitophagy and HR assays, conditional/BRUCE-mutant mouse models, exome sequencing, and catalytic/POMC reporter assays","pmids":["25216678","25733871","26214742","25485838","24828152","24894536"],"confidence":"High","gaps":["Mechanistic basis of linkage preference (K6, K63) not structurally explained","How a single DUB serves such divergent compartments unaddressed"]},{"year":2015,"claim":"Established the mechanism of Cushing's disease gain-of-function and broadened substrates: mutations disrupt 14-3-3 to protect EGFR and drive ACTH; USP8 also stabilizes Hrs, FLIPL, and VEGFR2, controlling endosomal sorting, apoptosis, and angiogenic signaling.","evidence":"sequencing cohorts with 14-3-3 disruption and EGFR/POMC assays; Drosophila Ubpy-null genetics; in vitro deubiquitination and apoptosis/DISC assays; VEGFR2 ubiquitination and signaling assays","pmids":["25675982","24574010","27321185","26459808"],"confidence":"High","gaps":["Why corticotrophs are selectively vulnerable to USP8 hyperactivity unclear","Isoform selectivity (FLIPL vs FLIPS) mechanism undefined"]},{"year":2018,"claim":"Refined activity control and neuronal/structural roles: EGFR directly phosphorylates USP8 at Tyr717/Tyr810 to raise activity in a ciliogenesis-suppressing trichoplein-Aurora A axis, a 14-3-3ζ:phospho-Ser718 structure was solved, and USP8 stabilizes SHANK3 and deubiquitinates ESCRT-III CHMP1B.","evidence":"in vitro kinase assays, phospho-mutant analysis, X-ray crystallography with FP/ITC, neuronal gain/loss-of-function, and Drosophila CHMP1B ubiquitination genetics","pmids":["29472535","29473952","29735556","29933386"],"confidence":"High","gaps":["Integration of tyrosine activation with 14-3-3 inhibition not mechanistically unified","Structural basis for catalytic-domain activation still missing"]},{"year":2019,"claim":"Positioned USP8 as a regulator of autophagy and metabolic/neuronal signaling: linkage- and site-specific deubiquitination of p62 (K11 at K420) and EPG5 (K63 at K252) tunes autophagic flux, while LepRb deubiquitination links it to leptin/CREB signaling and synaptogenesis.","evidence":"in vitro deubiquitination with linkage/site specificity, autophagic flux assays, Co-IP domain mapping, and receptor/transcriptional/synapse assays","pmids":["31241013","30931944","31199479"],"confidence":"High","gaps":["Opposing autophagy effects (p62 vs EPG5) not reconciled into one model","Determinants of K11 vs K63 chain selectivity unknown"]},{"year":2022,"claim":"Defined USP8 as a node in cancer immune evasion and ESCRT-dependent cytokinesis: it stabilizes TβRII to drive TGF-β-mediated EMT and T-cell exhaustion, its inhibition rewires PD-L1/NF-κB/MHC-I immunity, and germline ESCRT-III deubiquitination controls abscission.","evidence":"Co-IP/ubiquitination assays, EV characterization, EMT and T-cell exhaustion assays, K63/K48 PD-L1 ubiquitination with tumor models, and Drosophila ESCRT-III cytokinesis genetics","pmids":["35811497","35361799","35587967"],"confidence":"High","gaps":["Therapeutic window of USP8 inhibition across opposing immune outcomes unclear","How ESCRT-III ubiquitination state dictates polymer assembly not fully defined"]},{"year":2024,"claim":"Identified USP8 as a guardian of ferroptosis defense and against misdirected endosomal ubiquitin signaling: it stabilizes GPX4, OGT/SLC7A11, β-catenin and Nrf2 to resist ferroptosis, deubiquitinates DDX3X to potentiate cGAS-STING, and prevents endosomal K63-Ub from triggering TAK1-NF-κB and Keap1-Nrf2 inflammation.","evidence":"Co-IP, site/linkage-specific ubiquitination assays, conditional KO mice, ferroptosis and LLPS assays, and endosomal K63-Ub/TAB2/p62 recruitment epistasis","pmids":["38598341","37867237","37311739","37639742","38795350","38180476"],"confidence":"High","gaps":["How oxidative stress mechanistically inactivates USP8 to release endosomal signaling not fully defined","Hierarchy among the many ferroptosis-relevant substrates unestablished"]},{"year":null,"claim":"It remains unresolved how a single deubiquitinase achieves substrate- and linkage-selectivity across endosomes, mitochondria, the nucleus, synapses, and stress granules, and how its competing phospho/tyrosine/sulfhydration inputs are integrated into a unified activation logic.","evidence":"no single study in the timeline reconciles substrate selectivity with the multiple regulatory modifications","pmids":[],"confidence":"Low","gaps":["No structural model of substrate-specificity determinants","No integrated regulatory model spanning 14-3-3, tyrosine phosphorylation, SLK-S716, and S-sulfhydration","Compartment-specific targeting beyond the MIT/ESCRT axis undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,4,5,22,39,40,48,51,54,55]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,5,22]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,18,35]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[4,5,9,11,17,53]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[29,39]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[4,5,11,17]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,12,15,30,48]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[22,39,40]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[3,5,51,54,55,56]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[26,49,53]}],"complexes":["ESCRT-0 (STAM/Hrs)","ESCRT-III (CHMP)","USP8-Nrdp1-Clec16a complex","BRUCE-USP8-BRIT1 complex"],"partners":["STAM","CHMP1B","NRDP1","HD-PTP","EGFR","RNF41","14-3-3","PARKIN"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P40818","full_name":"Ubiquitin carboxyl-terminal hydrolase 8","aliases":["Deubiquitinating enzyme 8","Ubiquitin isopeptidase Y","hUBPy","Ubiquitin thioesterase 8","Ubiquitin-specific-processing protease 8"],"length_aa":1118,"mass_kda":127.5,"function":"Hydrolase that can remove conjugated ubiquitin from proteins and therefore plays an important regulatory role at the level of protein turnover by preventing degradation. Converts both 'Lys-48' an 'Lys-63'-linked ubiquitin chains. Catalytic activity is enhanced in the M phase. Involved in cell proliferation. Required to enter into S phase in response to serum stimulation. May regulate T-cell anergy mediated by RNF128 via the formation of a complex containing RNF128 and OTUB1. Probably regulates the stability of STAM2 and RASGRF1. Regulates endosomal ubiquitin dynamics, cargo sorting, membrane traffic at early endosomes, and maintenance of ESCRT-0 stability. The level of protein ubiquitination on endosomes is essential for maintaining the morphology of the organelle. Deubiquitinates EPS15 and controls tyrosine kinase stability. Removes conjugated ubiquitin from EGFR thus regulating EGFR degradation and downstream MAPK signaling. Involved in acrosome biogenesis through interaction with the spermatid ESCRT-0 complex and microtubules. Deubiquitinates BIRC6/bruce and KIF23/MKLP1. Deubiquitinates BACE1 which inhibits BACE1 lysosomal degradation and modulates BACE-mediated APP cleavage and amyloid-beta formation (PubMed:27302062)","subcellular_location":"Cytoplasm; Nucleus; Endosome membrane; Cell membrane","url":"https://www.uniprot.org/uniprotkb/P40818/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/USP8","classification":"Common Essential","n_dependent_lines":1063,"n_total_lines":1208,"dependency_fraction":0.8799668874172185},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/USP8","total_profiled":1310},"omim":[{"mim_id":"620051","title":"RING FINGER PROTEIN 41, E3 UBIQUITIN PROTEIN LIGASE; RNF41","url":"https://www.omim.org/entry/620051"},{"mim_id":"613565","title":"UBIQUITINATION FACTOR E4B; UBE4B","url":"https://www.omim.org/entry/613565"},{"mim_id":"610900","title":"CHARGED MULTIVESICULAR BODY PROTEIN 5; CHMP5","url":"https://www.omim.org/entry/610900"},{"mim_id":"608337","title":"OTU DOMAIN-CONTAINING UBIQUITIN ALDEHYDE-BINDING PROTEIN 1; OTUB1","url":"https://www.omim.org/entry/608337"},{"mim_id":"607274","title":"UBIQUITIN-SPECIFIC PROTEASE 14; USP14","url":"https://www.omim.org/entry/607274"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Golgi apparatus","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/USP8"},"hgnc":{"alias_symbol":["HumORF8","KIAA0055","UBPY","SPG59"],"prev_symbol":[]},"alphafold":{"accession":"P40818","domains":[{"cath_id":"1.20.58.80","chopping":"16-130","consensus_level":"high","plddt":84.987,"start":16,"end":130},{"cath_id":"3.40.250.10","chopping":"181-310","consensus_level":"high","plddt":87.3929,"start":181,"end":310},{"cath_id":"3.90.70.10","chopping":"758-1106","consensus_level":"medium","plddt":93.9657,"start":758,"end":1106}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P40818","model_url":"https://alphafold.ebi.ac.uk/files/AF-P40818-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P40818-F1-predicted_aligned_error_v6.png","plddt_mean":71.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=USP8","jax_strain_url":"https://www.jax.org/strain/search?query=USP8"},"sequence":{"accession":"P40818","fasta_url":"https://rest.uniprot.org/uniprotkb/P40818.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P40818/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P40818"}},"corpus_meta":[{"pmid":"25485838","id":"PMC_25485838","title":"Mutations in the deubiquitinase gene USP8 cause Cushing's disease.","date":"2014","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/25485838","citation_count":435,"is_preprint":false},{"pmid":"25216678","id":"PMC_25216678","title":"USP8 regulates mitophagy by removing K6-linked ubiquitin conjugates from parkin.","date":"2014","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/25216678","citation_count":323,"is_preprint":false},{"pmid":"25675982","id":"PMC_25675982","title":"Recurrent gain-of-function USP8 mutations in Cushing's disease.","date":"2015","source":"Cell research","url":"https://pubmed.ncbi.nlm.nih.gov/25675982","citation_count":265,"is_preprint":false},{"pmid":"16120644","id":"PMC_16120644","title":"Regulation of epidermal growth factor receptor down-regulation by UBPY-mediated deubiquitination at endosomes.","date":"2005","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/16120644","citation_count":225,"is_preprint":false},{"pmid":"16520378","id":"PMC_16520378","title":"The ubiquitin isopeptidase UBPY regulates endosomal ubiquitin dynamics and is essential for receptor down-regulation.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16520378","citation_count":216,"is_preprint":false},{"pmid":"10982817","id":"PMC_10982817","title":"A deubiquitinating enzyme UBPY interacts with the Src homology 3 domain of Hrs-binding protein via a novel binding motif PX(V/I)(D/N)RXXKP.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10982817","citation_count":193,"is_preprint":false},{"pmid":"9628861","id":"PMC_9628861","title":"UBPY: a growth-regulated human ubiquitin isopeptidase.","date":"1998","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/9628861","citation_count":159,"is_preprint":false},{"pmid":"17711858","id":"PMC_17711858","title":"The MIT domain of UBPY constitutes a CHMP binding and endosomal localization signal required for efficient epidermal growth factor receptor degradation.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17711858","citation_count":140,"is_preprint":false},{"pmid":"15314180","id":"PMC_15314180","title":"Stabilization of the E3 ubiquitin ligase Nrdp1 by the deubiquitinating enzyme USP8.","date":"2004","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15314180","citation_count":134,"is_preprint":false},{"pmid":"17035239","id":"PMC_17035239","title":"Amino-terminal dimerization, NRDP1-rhodanese interaction, and inhibited catalytic domain conformation of the ubiquitin-specific protease 8 (USP8).","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17035239","citation_count":134,"is_preprint":false},{"pmid":"34839365","id":"PMC_34839365","title":"The METTL3/MALAT1/PTBP1/USP8/TAK1 axis promotes pyroptosis and M1 polarization of macrophages and contributes to liver fibrosis.","date":"2021","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/34839365","citation_count":128,"is_preprint":false},{"pmid":"35361799","id":"PMC_35361799","title":"USP8 inhibition reshapes an inflamed tumor microenvironment that potentiates the immunotherapy.","date":"2022","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/35361799","citation_count":120,"is_preprint":false},{"pmid":"17121848","id":"PMC_17121848","title":"UBPY-mediated epidermal growth factor receptor (EGFR) de-ubiquitination promotes EGFR degradation.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17121848","citation_count":120,"is_preprint":false},{"pmid":"23748694","id":"PMC_23748694","title":"USP8 is a novel target for overcoming gefitinib resistance in lung cancer.","date":"2013","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/23748694","citation_count":120,"is_preprint":false},{"pmid":"26578638","id":"PMC_26578638","title":"The USP8 mutational status may predict drug susceptibility in corticotroph adenomas of Cushing's disease.","date":"2015","source":"European journal of endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/26578638","citation_count":119,"is_preprint":false},{"pmid":"38598341","id":"PMC_38598341","title":"USP8-governed GPX4 homeostasis orchestrates ferroptosis and cancer immunotherapy.","date":"2024","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/38598341","citation_count":117,"is_preprint":false},{"pmid":"22253573","id":"PMC_22253573","title":"USP8 promotes smoothened signaling by preventing its ubiquitination and changing its subcellular localization.","date":"2012","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/22253573","citation_count":117,"is_preprint":false},{"pmid":"27444016","id":"PMC_27444016","title":"Deubiquitinase Usp8 regulates α-synuclein clearance and modifies its toxicity in Lewy body disease.","date":"2016","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/27444016","citation_count":111,"is_preprint":false},{"pmid":"37867237","id":"PMC_37867237","title":"Targeting USP8 Inhibits O-GlcNAcylation of SLC7A11 to Promote Ferroptosis of Hepatocellular Carcinoma via Stabilization of OGT.","date":"2023","source":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/37867237","citation_count":101,"is_preprint":false},{"pmid":"16771824","id":"PMC_16771824","title":"A deubiquitinating enzyme UBPY regulates the level of protein ubiquitination on endosomes.","date":"2006","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/16771824","citation_count":100,"is_preprint":false},{"pmid":"23477725","id":"PMC_23477725","title":"Recruitment of UBPY and ESCRT exchange drive HD-PTP-dependent sorting of EGFR to the MVB.","date":"2013","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/23477725","citation_count":97,"is_preprint":false},{"pmid":"20736164","id":"PMC_20736164","title":"Regulation of epidermal growth factor receptor ubiquitination and trafficking by the USP8·STAM complex.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20736164","citation_count":89,"is_preprint":false},{"pmid":"31241013","id":"PMC_31241013","title":"The ubiquitin-specific protease USP8 directly deubiquitinates SQSTM1/p62 to suppress its autophagic activity.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/31241013","citation_count":87,"is_preprint":false},{"pmid":"31222332","id":"PMC_31222332","title":"Driver mutations in USP8 wild-type Cushing's disease.","date":"2019","source":"Neuro-oncology","url":"https://pubmed.ncbi.nlm.nih.gov/31222332","citation_count":85,"is_preprint":false},{"pmid":"17720156","id":"PMC_17720156","title":"14-3-3-dependent inhibition of the deubiquitinating activity of UBPY and its cancellation in the M phase.","date":"2007","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/17720156","citation_count":82,"is_preprint":false},{"pmid":"11500497","id":"PMC_11500497","title":"Cloning and characterization of mouse UBPy, a deubiquitinating enzyme that interacts with the ras guanine nucleotide exchange factor CDC25(Mm)/Ras-GRF1.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11500497","citation_count":81,"is_preprint":false},{"pmid":"35811497","id":"PMC_35811497","title":"USP8 promotes cancer progression and extracellular vesicle-mediated CD8+ T cell exhaustion by deubiquitinating the TGF-β receptor TβRII.","date":"2022","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/35811497","citation_count":78,"is_preprint":false},{"pmid":"28505279","id":"PMC_28505279","title":"Somatic USP8 Gene Mutations Are a Common Cause of Pediatric Cushing Disease.","date":"2017","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/28505279","citation_count":77,"is_preprint":false},{"pmid":"32257541","id":"PMC_32257541","title":"Exogenous H2S Promoted USP8 Sulfhydration to Regulate Mitophagy in the Hearts of db/db Mice.","date":"2020","source":"Aging and disease","url":"https://pubmed.ncbi.nlm.nih.gov/32257541","citation_count":75,"is_preprint":false},{"pmid":"26214742","id":"PMC_26214742","title":"The ubiquitin-specific protease USP8 is critical for the development and homeostasis of T cells.","date":"2015","source":"Nature immunology","url":"https://pubmed.ncbi.nlm.nih.gov/26214742","citation_count":73,"is_preprint":false},{"pmid":"37311739","id":"PMC_37311739","title":"USP8 positively regulates hepatocellular carcinoma tumorigenesis and confers ferroptosis resistance through β-catenin stabilization.","date":"2023","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/37311739","citation_count":72,"is_preprint":false},{"pmid":"25505317","id":"PMC_25505317","title":"Synaptic strength is bidirectionally controlled by opposing activity-dependent regulation of Nedd4-1 and USP8.","date":"2014","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/25505317","citation_count":72,"is_preprint":false},{"pmid":"20876529","id":"PMC_20876529","title":"The deubiquitinating enzyme USP8 promotes trafficking and degradation of the chemokine receptor 4 at the sorting endosome.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20876529","citation_count":69,"is_preprint":false},{"pmid":"20130268","id":"PMC_20130268","title":"USP8, a regulator of endosomal sorting, is involved in mouse acrosome biogenesis through interaction with the spermatid ESCRT-0 complex and microtubules.","date":"2010","source":"Biology of reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/20130268","citation_count":67,"is_preprint":false},{"pmid":"24378640","id":"PMC_24378640","title":"HIF1α deubiquitination by USP8 is essential for ciliogenesis in normoxia.","date":"2013","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/24378640","citation_count":66,"is_preprint":false},{"pmid":"29957855","id":"PMC_29957855","title":"The USP8 mutational status may predict long-term remission in patients with Cushing's disease.","date":"2018","source":"Clinical endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/29957855","citation_count":65,"is_preprint":false},{"pmid":"35658874","id":"PMC_35658874","title":"Molecular mechanism of lncRNA SNHG12 in immune escape of non-small cell lung cancer through the HuR/PD-L1/USP8 axis.","date":"2022","source":"Cellular & molecular biology letters","url":"https://pubmed.ncbi.nlm.nih.gov/35658874","citation_count":64,"is_preprint":false},{"pmid":"29472535","id":"PMC_29472535","title":"EGF receptor kinase suppresses ciliogenesis through activation of USP8 deubiquitinase.","date":"2018","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/29472535","citation_count":62,"is_preprint":false},{"pmid":"27302062","id":"PMC_27302062","title":"The Endosome-associated Deubiquitinating Enzyme USP8 Regulates BACE1 Enzyme Ubiquitination and Degradation.","date":"2016","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/27302062","citation_count":61,"is_preprint":false},{"pmid":"29180353","id":"PMC_29180353","title":"Clec16a, Nrdp1, and USP8 Form a Ubiquitin-Dependent Tripartite Complex That Regulates β-Cell Mitophagy.","date":"2017","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/29180353","citation_count":60,"is_preprint":false},{"pmid":"31845722","id":"PMC_31845722","title":"Ubiquitin-specific protease 8 (USP8/UBPy): a prototypic multidomain deubiquitinating enzyme with pleiotropic functions.","date":"2019","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/31845722","citation_count":52,"is_preprint":false},{"pmid":"27321185","id":"PMC_27321185","title":"USP8 suppresses death receptor-mediated apoptosis by enhancing FLIPL stability.","date":"2016","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/27321185","citation_count":50,"is_preprint":false},{"pmid":"21828287","id":"PMC_21828287","title":"Role of ubiquitylation and USP8-dependent deubiquitylation in the endocytosis and lysosomal targeting of plasma membrane KCa3.1.","date":"2011","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/21828287","citation_count":49,"is_preprint":false},{"pmid":"33221858","id":"PMC_33221858","title":"USP8 and TP53 Drivers are Associated with CNV in a Corticotroph Adenoma Cohort Enriched for Aggressive Tumors.","date":"2021","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/33221858","citation_count":48,"is_preprint":false},{"pmid":"32335193","id":"PMC_32335193","title":"USP8 protects against lipopolysaccharide-induced cognitive and motor deficits by modulating microglia phenotypes through TLR4/MyD88/NF-κB signaling pathway in mice.","date":"2020","source":"Brain, behavior, and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/32335193","citation_count":48,"is_preprint":false},{"pmid":"33600786","id":"PMC_33600786","title":"The oncogenic role of ubiquitin specific peptidase (USP8) and its signaling pathways targeting for cancer therapeutics.","date":"2021","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/33600786","citation_count":45,"is_preprint":false},{"pmid":"30315484","id":"PMC_30315484","title":"Clinical characteristics and surgical outcome in USP8-mutated human adrenocorticotropic hormone-secreting pituitary adenomas.","date":"2018","source":"Endocrine","url":"https://pubmed.ncbi.nlm.nih.gov/30315484","citation_count":45,"is_preprint":false},{"pmid":"31162547","id":"PMC_31162547","title":"Germline USP8 Mutation Associated With Pediatric Cushing Disease and Other Clinical Features: A New Syndrome.","date":"2019","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/31162547","citation_count":44,"is_preprint":false},{"pmid":"23750007","id":"PMC_23750007","title":"Reciprocal cross-regulation between RNF41 and USP8 controls cytokine receptor sorting and processing.","date":"2013","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/23750007","citation_count":44,"is_preprint":false},{"pmid":"29600293","id":"PMC_29600293","title":"USP8 Mutations in Pituitary Cushing Adenomas-Targeted Analysis by Next-Generation Sequencing.","date":"2018","source":"Journal of the Endocrine Society","url":"https://pubmed.ncbi.nlm.nih.gov/29600293","citation_count":44,"is_preprint":false},{"pmid":"25700639","id":"PMC_25700639","title":"USP8 and PARK2/parkin-mediated mitophagy.","date":"2015","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/25700639","citation_count":42,"is_preprint":false},{"pmid":"28982703","id":"PMC_28982703","title":"Somatic USP8 mutations are frequent events in corticotroph tumor progression causing Nelson's tumor.","date":"2017","source":"European journal of endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/28982703","citation_count":42,"is_preprint":false},{"pmid":"30931944","id":"PMC_30931944","title":"USP8 maintains embryonic stem cell stemness via deubiquitination of EPG5.","date":"2019","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30931944","citation_count":41,"is_preprint":false},{"pmid":"25733871","id":"PMC_25733871","title":"BRUCE regulates DNA double-strand break response by promoting USP8 deubiquitination of BRIT1.","date":"2015","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/25733871","citation_count":41,"is_preprint":false},{"pmid":"21044682","id":"PMC_21044682","title":"ERBB2 is a target for USP8-mediated deubiquitination.","date":"2010","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/21044682","citation_count":40,"is_preprint":false},{"pmid":"23154984","id":"PMC_23154984","title":"CLOCK deubiquitylation by USP8 inhibits CLK/CYC transcription in Drosophila.","date":"2012","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/23154984","citation_count":40,"is_preprint":false},{"pmid":"32101529","id":"PMC_32101529","title":"SST5 expression and USP8 mutation in functioning and silent corticotroph pituitary tumors.","date":"2020","source":"Endocrine connections","url":"https://pubmed.ncbi.nlm.nih.gov/32101529","citation_count":39,"is_preprint":false},{"pmid":"31273566","id":"PMC_31273566","title":"Cushing's disease due to somatic USP8 mutations: a systematic review and meta-analysis.","date":"2019","source":"Pituitary","url":"https://pubmed.ncbi.nlm.nih.gov/31273566","citation_count":39,"is_preprint":false},{"pmid":"29933386","id":"PMC_29933386","title":"CHMP1B is a target of USP8/UBPY regulated by ubiquitin during endocytosis.","date":"2018","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/29933386","citation_count":38,"is_preprint":false},{"pmid":"23297398","id":"PMC_23297398","title":"Ubiquitin-specific peptidase 8 (USP8) regulates endosomal trafficking of the epithelial Na+ channel.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23297398","citation_count":37,"is_preprint":false},{"pmid":"9582025","id":"PMC_9582025","title":"An oncogenic fusion product of the phosphatidylinositol 3-kinase p85beta subunit and HUMORF8, a putative deubiquitinating enzyme.","date":"1998","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/9582025","citation_count":36,"is_preprint":false},{"pmid":"26012588","id":"PMC_26012588","title":"Decoding the genetic basis of Cushing's disease: USP8 in the spotlight.","date":"2015","source":"European journal of endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/26012588","citation_count":36,"is_preprint":false},{"pmid":"37332045","id":"PMC_37332045","title":"piRNA-1742 promotes renal cell carcinoma malignancy by regulating USP8 stability through binding to hnRNPU and thereby inhibiting MUC12 ubiquitination.","date":"2023","source":"Experimental & molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/37332045","citation_count":35,"is_preprint":false},{"pmid":"30844069","id":"PMC_30844069","title":"Impact of USP8 Gene Mutations on Protein Deregulation in Cushing Disease.","date":"2019","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/30844069","citation_count":34,"is_preprint":false},{"pmid":"35587967","id":"PMC_35587967","title":"The deubiquitinase USP8 targets ESCRT-III to promote incomplete cell division.","date":"2022","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/35587967","citation_count":34,"is_preprint":false},{"pmid":"29735556","id":"PMC_29735556","title":"USP8 Deubiquitinates SHANK3 to Control Synapse Density and SHANK3 Activity-Dependent Protein Levels.","date":"2018","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/29735556","citation_count":33,"is_preprint":false},{"pmid":"29473952","id":"PMC_29473952","title":"Biophysical and structural insight into the USP8/14-3-3 interaction.","date":"2018","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/29473952","citation_count":33,"is_preprint":false},{"pmid":"35686696","id":"PMC_35686696","title":"Improved pasireotide response in USP8 mutant corticotroph tumours in vitro.","date":"2022","source":"Endocrine-related cancer","url":"https://pubmed.ncbi.nlm.nih.gov/35686696","citation_count":32,"is_preprint":false},{"pmid":"26459808","id":"PMC_26459808","title":"VEGFR2 Trafficking, Signaling and Proteolysis is Regulated by the Ubiquitin Isopeptidase USP8.","date":"2015","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/26459808","citation_count":32,"is_preprint":false},{"pmid":"38795350","id":"PMC_38795350","title":"Stress granule-localized USP8 potentiates cGAS-mediated type I interferonopathies through deubiquitination of DDX3X.","date":"2024","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/38795350","citation_count":29,"is_preprint":false},{"pmid":"34081623","id":"PMC_34081623","title":"Inhibiting USP8 overcomes hepatocellular carcinoma resistance via suppressing receptor tyrosine kinases.","date":"2021","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/34081623","citation_count":29,"is_preprint":false},{"pmid":"25744385","id":"PMC_25744385","title":"USP8/UBPy-regulated sorting and the development of sperm acrosome: the recruitment of MET.","date":"2015","source":"Reproduction (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/25744385","citation_count":28,"is_preprint":false},{"pmid":"24828152","id":"PMC_24828152","title":"USP8 modulates ubiquitination of LRIG1 for Met degradation.","date":"2014","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/24828152","citation_count":27,"is_preprint":false},{"pmid":"24574010","id":"PMC_24574010","title":"Ubpy controls the stability of the ESCRT-0 subunit Hrs in development.","date":"2014","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/24574010","citation_count":26,"is_preprint":false},{"pmid":"24894536","id":"PMC_24894536","title":"USP8 controls the trafficking and sorting of lysosomal enzymes.","date":"2014","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/24894536","citation_count":26,"is_preprint":false},{"pmid":"33748113","id":"PMC_33748113","title":"METTL3 Regulates Ossification of the Posterior Longitudinal Ligament via the lncRNA XIST/miR-302a-3p/USP8 Axis.","date":"2021","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/33748113","citation_count":26,"is_preprint":false},{"pmid":"31199479","id":"PMC_31199479","title":"USP8 Deubiquitinates the Leptin Receptor and Is Necessary for Leptin-Mediated Synapse Formation.","date":"2019","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/31199479","citation_count":24,"is_preprint":false},{"pmid":"29626091","id":"PMC_29626091","title":"The ubiquitin-specific protease USP8 deubiquitinates and stabilizes Cx43.","date":"2018","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29626091","citation_count":24,"is_preprint":false},{"pmid":"34688043","id":"PMC_34688043","title":"USP8 regulates liver cancer progression via the inhibition of TRAF6-mediated signal for NF-κB activation and autophagy induction by TLR4.","date":"2021","source":"Translational oncology","url":"https://pubmed.ncbi.nlm.nih.gov/34688043","citation_count":24,"is_preprint":false},{"pmid":"30988163","id":"PMC_30988163","title":"Inhibition of the deubiquitinase USP8 corrects a Drosophila PINK1 model of mitochondria dysfunction.","date":"2019","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/30988163","citation_count":24,"is_preprint":false},{"pmid":"35022897","id":"PMC_35022897","title":"USP8 inhibitor-induced DNA damage activates cell cycle arrest, apoptosis, and autophagy in esophageal squamous cell carcinoma.","date":"2022","source":"Cell biology and toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/35022897","citation_count":23,"is_preprint":false},{"pmid":"34439178","id":"PMC_34439178","title":"Genetic Profiling of a Cohort of Italian Patients with ACTH-Secreting Pituitary Tumors and Characterization of a Novel USP8 Gene Variant.","date":"2021","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/34439178","citation_count":23,"is_preprint":false},{"pmid":"34664215","id":"PMC_34664215","title":"USP8, USP48, and BRAF mutations differ in their genotype-phenotype correlation in Asian Indian patients with Cushing's disease.","date":"2021","source":"Endocrine","url":"https://pubmed.ncbi.nlm.nih.gov/34664215","citation_count":22,"is_preprint":false},{"pmid":"35786929","id":"PMC_35786929","title":"Discovery of Potent Small-Molecule USP8 Inhibitors for the Treatment of Breast Cancer through Regulating ERα Expression.","date":"2022","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35786929","citation_count":22,"is_preprint":false},{"pmid":"32273758","id":"PMC_32273758","title":"Down-regulation of USP8 Inhibits Cholangiocarcinoma Cell Proliferation and Invasion.","date":"2020","source":"Cancer management and research","url":"https://pubmed.ncbi.nlm.nih.gov/32273758","citation_count":21,"is_preprint":false},{"pmid":"33116578","id":"PMC_33116578","title":"USP8 Inhibitor Suppresses HER-2 Positive Gastric Cancer Cell Proliferation and Metastasis via the PI3K/AKT Signaling Pathway.","date":"2020","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/33116578","citation_count":21,"is_preprint":false},{"pmid":"25662281","id":"PMC_25662281","title":"The deubiquitinating enzyme UBPy/USP8 interacts with TrkA and inhibits neuronal differentiation in PC12 cells.","date":"2015","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/25662281","citation_count":20,"is_preprint":false},{"pmid":"34086599","id":"PMC_34086599","title":"USP8 inhibitor RA-9 reduces ACTH release and cell growth in tumor corticotrophs.","date":"2021","source":"Endocrine-related cancer","url":"https://pubmed.ncbi.nlm.nih.gov/34086599","citation_count":20,"is_preprint":false},{"pmid":"37639742","id":"PMC_37639742","title":"USP8 promotes gemcitabine resistance of pancreatic cancer via deubiquitinating and stabilizing Nrf2.","date":"2023","source":"Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie","url":"https://pubmed.ncbi.nlm.nih.gov/37639742","citation_count":20,"is_preprint":false},{"pmid":"37642440","id":"PMC_37642440","title":"Expanding the spectrum of tyrosine kinase fusions in calcified chondroid mesenchymal neoplasms: Identification of a novel PDGFRA::USP8 gene fusion.","date":"2023","source":"Genes, chromosomes & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/37642440","citation_count":20,"is_preprint":false},{"pmid":"36221183","id":"PMC_36221183","title":"Discovery of Potent OTUB1/USP8 Dual Inhibitors Targeting Proteostasis in Non-Small-Cell Lung Cancer.","date":"2022","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/36221183","citation_count":19,"is_preprint":false},{"pmid":"31075263","id":"PMC_31075263","title":"USP8 ameliorates cognitive and motor impairments via microglial inhibition in a mouse model of sepsis-associated encephalopathy.","date":"2019","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/31075263","citation_count":19,"is_preprint":false},{"pmid":"26571504","id":"PMC_26571504","title":"The Deubiquitinating Enzyme UBPY Is Required for Lysosomal Biogenesis and Productive Autophagy in Drosophila.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26571504","citation_count":18,"is_preprint":false},{"pmid":"32053843","id":"PMC_32053843","title":"USP8 Mutations and Cell Cycle Regulation in Corticotroph Adenomas.","date":"2020","source":"Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme","url":"https://pubmed.ncbi.nlm.nih.gov/32053843","citation_count":18,"is_preprint":false},{"pmid":"32848421","id":"PMC_32848421","title":"Down-Regulation of USP8 Suppresses HER-3 Positive Gastric Cancer Cells Proliferation.","date":"2020","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/32848421","citation_count":18,"is_preprint":false},{"pmid":"30221684","id":"PMC_30221684","title":"Effect of deubiquitinase USP8 on hypoxia/reoxygenation‑induced inflammation by deubiquitination of TAK1 in renal tubular epithelial cells.","date":"2018","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/30221684","citation_count":18,"is_preprint":false},{"pmid":"23333852","id":"PMC_23333852","title":"The Usp8 deubiquitination enzyme is post-translationally modified by tyrosine and serine phosphorylation.","date":"2013","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/23333852","citation_count":17,"is_preprint":false},{"pmid":"33293867","id":"PMC_33293867","title":"Knockdown of USP8 Inhibits the Growth of Lung Cancer Cells.","date":"2020","source":"Cancer management and research","url":"https://pubmed.ncbi.nlm.nih.gov/33293867","citation_count":17,"is_preprint":false},{"pmid":"34079371","id":"PMC_34079371","title":"USP8 is a Novel Therapeutic Target in Melanoma Through Regulating Receptor Tyrosine Kinase Levels.","date":"2021","source":"Cancer management and research","url":"https://pubmed.ncbi.nlm.nih.gov/34079371","citation_count":17,"is_preprint":false},{"pmid":"38180476","id":"PMC_38180476","title":"USP8 prevents aberrant NF-κB and Nrf2 activation by counteracting ubiquitin signals from endosomes.","date":"2024","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/38180476","citation_count":16,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":53224,"output_tokens":15216,"usd":0.193956,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":27581,"output_tokens":6770,"usd":0.153578,"stage2_stop_reason":"end_turn"},"total_usd":0.347534,"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\": 1998,\n      \"finding\": \"USP8/UBPY is a ubiquitin isopeptidase that cleaves linear and isopeptide-linked ubiquitin chains both as a recombinant protein and upon immunoprecipitation from cell extracts; its levels accumulate upon growth stimulation and its inhibition by antisense prevents S-phase entry, indicating a role in regulating the ubiquitin-proteasome pathway during cell proliferation.\",\n      \"method\": \"In vitro ubiquitin cleavage assay with recombinant protein, immunoprecipitation followed by activity assay, antisense microinjection with S-phase readout\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic reconstitution plus functional loss-of-function with specific proliferative phenotype, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"9628861\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"USP8/UBPY interacts with the SH3 domain of Hrs-binding protein (STAM) via a novel non-canonical SH3-binding motif PX(V/I)(D/N)RXXKP, linking it to endocytic trafficking of growth factor receptor complexes through early endosomes.\",\n      \"method\": \"Far Western screening, mutagenic analysis of SH3 binding motif, in vitro binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro binding reconstitution with mutagenesis identifying consensus motif, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"10982817\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Mouse UBPy (USP8 ortholog) interacts with the Ras GEF CDC25(Mm)/Ras-GRF1 via the N-terminal domain of CDC25(Mm), deubiquitinates CDC25(Mm) in vivo, and increases its protein half-life.\",\n      \"method\": \"Yeast two-hybrid screen, GST pulldown in vitro, co-immunoprecipitation in mammalian cells, ubiquitination assay by co-transfection\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus in vitro pulldown plus ubiquitination assay, single lab\",\n      \"pmids\": [\"11500497\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"USP8 physically interacts with the E3 ubiquitin ligase Nrdp1 via its rhodanese and catalytic domains, deubiquitinates Nrdp1, and markedly enhances Nrdp1 stability; a catalytically inactive USP8 point mutant destabilizes endogenous Nrdp1.\",\n      \"method\": \"Affinity chromatography, co-immunoprecipitation, domain-mapping with deletion constructs, catalytic mutant overexpression, protein stability assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — affinity chromatography identification plus Co-IP plus catalytic mutant functional validation, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"15314180\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"USP8/UBPY deubiquitinates EGFR on endosomes in vitro and in vivo; overexpression reduces EGFR ubiquitination and delays EGF-stimulated EGFR degradation, while RNAi depletion of UBPY leads to elevated EGFR ubiquitination and accelerated degradation; catalytically inactive UBPY localizes to endosomes overlapping with EGFR.\",\n      \"method\": \"Immunopurification followed by in vitro deubiquitination assay, overexpression, RNAi knockdown, immunofluorescence co-localization on endosomes\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro deubiquitination assay plus gain- and loss-of-function with mechanistic readout, replicated by multiple labs\",\n      \"pmids\": [\"16120644\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"USP8/UBPY processes Lys-48- and Lys-63-linked polyubiquitin chains in vitro; its knockdown causes global increase in ubiquitinated proteins, accumulation of ubiquitin on enlarged multivesicular endosomes, and strongly inhibits degradation of EGFR and Met receptor tyrosine kinases; depletion also dramatically destabilizes its binding partner STAM.\",\n      \"method\": \"siRNA knockdown, in vitro ubiquitin chain cleavage assay, electron microscopy of endosomes, receptor degradation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro biochemistry plus siRNA loss-of-function with multiple mechanistic readouts, replicated across labs\",\n      \"pmids\": [\"16520378\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"USP8/UBPY deubiquitinates EGFR to promote (not inhibit) its lysosomal degradation; dominant-negative UBPY mutants cause EGFR hyperubiquitination, alter EGFR expression levels and degradation intermediates, and affect downstream MAPK signaling; UBPY is a substrate for Src-family tyrosine kinases activated by EGFR and constitutively co-precipitates with EGFR.\",\n      \"method\": \"Dominant-negative mutant overexpression (C748A, truncation constructs), co-immunoprecipitation, ubiquitination assay, MAPK signaling readout\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple dominant-negative constructs plus Co-IP, single lab; contradicts Mizuno 2005 on directionality of degradation effect\",\n      \"pmids\": [\"17121848\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"USP8/UBPY deubiquitinates Eps15 in vitro; inactivation of UBPY causes elevated Eps15 monoubiquitination and its accumulation on aberrant multivesicular endosomes, indicating UBPY regulates endosomal ubiquitin levels and endosome morphology.\",\n      \"method\": \"Catalytic-inactive mutant overexpression, RNAi knockdown, in vitro deubiquitination assay, immunofluorescence and electron microscopy\",\n      \"journal\": \"Traffic\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro deubiquitination plus loss-of-function, single lab\",\n      \"pmids\": [\"16771824\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Crystal structures of three USP8 domains were determined: (1) the N-terminal domain forms a homodimer with a novel fold via helix-swapping; (2) the rhodanese domain interacts with Nrdp1 via a conserved peptide loop, revealing the structural basis for USP8-Nrdp1 binding; (3) the catalytic domain adopts an inhibited closed conformation with the ubiquitin-binding pocket inaccessible, suggesting substrate-induced conformational activation.\",\n      \"method\": \"X-ray crystallography of three domain structures, structural analysis of NRDP1-rhodanese complex\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple high-resolution crystal structures with mechanistic interpretation, single study with multiple domains\",\n      \"pmids\": [\"17035239\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"USP8/UBPY contains an N-terminal MIT domain that binds CHMP proteins (CHMP1A, CHMP1B, CHMP7) of the ESCRT-III complex; the MIT domain is required for endosomal localization of USP8 but is dispensable for catalytic activity; MIT-deleted USP8 cannot rescue STAM from proteasomal degradation or reverse the block to EGFR degradation caused by USP8 depletion; STAM stimulates USP8 deubiquitinase activity.\",\n      \"method\": \"MIT domain identification and deletion mutagenesis, CHMP binding assays, siRNA rescue experiments, STAM activity stimulation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — domain mutagenesis with functional rescue assays plus binding characterization, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"17711858\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"14-3-3 proteins (ε, γ, ζ) bind USP8 in a phosphorylation-dependent manner at Ser680 within the consensus motif RSYS(680)SP; 14-3-3 binding inhibits USP8 deubiquitinating activity toward polyubiquitin chains and EGFR in vitro; during M phase, USP8 is dephosphorylated at Ser680, dissociates from 14-3-3, and displays enhanced activity.\",\n      \"method\": \"Co-immunoprecipitation followed by mass spectrometry, phosphatase treatment, metabolic 32P labeling, phospho-specific antibody, peptide competition, in vitro deubiquitination assay with 14-3-3\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro inhibition assay plus multiple biochemical methods establishing phosphorylation-dependent regulation, single lab\",\n      \"pmids\": [\"17720156\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"USP8 depletion accelerates EGFR degradation via an Hrs-dependent pathway; catalytically inactive USP8 causes EGFR hyperubiquitination and endosomal accumulation; USP8 interacts with STAM1/2 SH3 domains via three RXXK motifs in its central region; the USP8·STAM complex regulates EGFR ubiquitination dynamics at early endosomes, with USP8-mediated deubiquitination slowing EGFR progression past the early-to-recycling endosome circuit.\",\n      \"method\": \"USP8 depletion, catalytic mutant overexpression, domain mutagenesis of RXXK motifs, co-immunoprecipitation, endosomal localization assays, receptor degradation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple domain mutants plus epistasis with Hrs plus endosomal localization with functional consequence, single lab\",\n      \"pmids\": [\"20736164\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"USP8 depletion stabilizes CXCR4 on the cell surface and attenuates receptor degradation without affecting CXCR4 ubiquitination status; USP8 functionally opposes the E3 ligase AIP4 at the ESCRT-0 checkpoint to regulate ESCRT-0 ubiquitination and promote CXCR4 trafficking.\",\n      \"method\": \"siRNA knockdown, surface receptor degradation assay, ubiquitination analysis, endosomal colocalization, epistasis with AIP4\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function with multiple mechanistic readouts including ESCRT-0 epistasis, single lab\",\n      \"pmids\": [\"20876529\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"USP8 interacts with ERBB2 (HER-2) indirectly through a chimeric EGFR-ErbB2 construct; catalytically inactive USP8 (C748A) enhances EGFR-ErbB2 ubiquitination both with and without EGF stimulation; USP8 is tyrosine phosphorylated upon EGFR-ErbB2 activation in a Src- and EGFR-kinase-dependent, MIT domain-dependent manner.\",\n      \"method\": \"Chimeric receptor co-expression, catalytic mutant overexpression, ubiquitination assay, kinase inhibitor treatment, MIT domain mutant analysis\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple mutant constructs plus kinase dependency characterization, single lab\",\n      \"pmids\": [\"21044682\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"USP8 associates with KCa3.1 channel following endocytosis (detected by DUB Chip protein microarray and confirmed by co-immunoprecipitation); overexpression of wild-type USP8 accelerates channel deubiquitination, while catalytically inactive USP8 or siRNA knockdown enhances accumulation of ubiquitylated KCa3.1 and inhibits channel lysosomal degradation.\",\n      \"method\": \"DUB Chip protein microarray, co-immunoprecipitation, BLAP-tagged receptor with TUBE pulldown, overexpression of WT and catalytic mutant, siRNA knockdown, degradation assay\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — protein microarray identification confirmed by Co-IP plus gain/loss-of-function, single lab\",\n      \"pmids\": [\"21828287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"USP8 is identified by in vivo RNAi screen as a deubiquitinase that removes ubiquitin from multi-monoubiquitinated Smoothened (Smo) in the Hedgehog pathway; USP8 inactivation increases Smo ubiquitination and attenuates Hh-induced Smo cell-surface accumulation; Hh signaling promotes USP8-Smo interaction via Smo aa625-753 covering PKA/CK1 phosphorylation clusters; USP8 overexpression elevates Smo cell-surface accumulation and promotes Smo away from early endosomes.\",\n      \"method\": \"In vivo RNAi screen in Drosophila, ubiquitination assay, co-immunoprecipitation, immunofluorescence localization, Hh pathway activity assay\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo screen validated by multiple approaches including Co-IP, localization and pathway activity assays, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"22253573\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"USP8 deubiquitylates the CLOCK transcription factor in Drosophila circadian neurons; loss of USP8 function or dominant-negative USP8 enhances CLK/CYC transcriptional activity and disrupts circadian molecular oscillations; CLK ubiquitylation cycles robustly peaking at maximal CLK/CYC transcription; USP8 interacts with CLK and its expression is directly activated by CLK/CYC.\",\n      \"method\": \"Loss-of-function RNAi, dominant-negative USP8 expression, CLK ubiquitylation cycling assay, co-immunoprecipitation, circadian locomotor activity assay\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic approaches plus Co-IP plus cycling ubiquitylation assay, single lab\",\n      \"pmids\": [\"23154984\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"HD-PTP/PTPN23 recruits UBPY/USP8 to EGFR at ESCRT-0; USP8 associates with HD-PTP-bound CHMP4B and with HD-PTP directly; UBPY/HD-PTP cooperation transfers EGFR from ESCRT-0 to ESCRT-III and drives EGFR sorting to intralumenal vesicles; USP8 RXXK motifs compete with HD-PTP for STAM2 SH3 binding to facilitate EGFR deubiquitination.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, sorting to intralumenal vesicle assay, domain-interaction mapping\",\n      \"journal\": \"Current biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus functional sorting assay plus domain competition experiments, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23477725\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"RNF41 ubiquitylates and reduces levels of USP8 (i.e., USP8 is a substrate of RNF41); USP8 in turn stabilizes RNF41; loss of USP8 mimics RNF41 overexpression effects on leptin receptor and LIF receptor trafficking (stabilization and enhanced ectodomain shedding); USP8 depletion also indirectly destabilizes the ESCRT-0 complex.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitylation assay, siRNA knockdown, receptor trafficking assay, epistasis experiments\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal regulation demonstrated by Co-IP plus functional receptor trafficking epistasis, single lab\",\n      \"pmids\": [\"23750007\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"USP8 depletion reduced levels of endogenous BACE1, increased BACE1 ubiquitination at K501, caused BACE1 accumulation in early and late endosomes/lysosomes, decreased BACE1 in recycling endosomes, and reduced BACE1-mediated APP cleavage and amyloid-β production, establishing USP8 as a deubiquitinase that deubiquitinates BACE1 at K501 to regulate its endosomal trafficking and stability.\",\n      \"method\": \"siRNA knockdown, ubiquitination assay, subcellular fractionation/endosomal localization, APP cleavage assay, Aβ measurement\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function with multiple mechanistic readouts, site-specific ubiquitination identified, single lab\",\n      \"pmids\": [\"27302062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"USP8 regulates epithelial Na+ channel (ENaC) by deubiquitinating ENaC; USP8 increases ENaC current in Xenopus oocytes and surface abundance in HEK293 cells by preventing ENaC lysosomal degradation in the endocytic pathway without affecting endocytosis; co-immunoprecipitation confirmed USP8-ENaC interaction; ENaC cytoplasmic lysine mutants reduce USP8 effects.\",\n      \"method\": \"Xenopus oocyte electrophysiology, HEK293 surface biotinylation, co-immunoprecipitation, ENaC lysine mutant analysis, endocytic sorting assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — electrophysiology plus Co-IP plus lysine mutant, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23297398\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"USP8 mutations in Cushing's disease cluster in the 14-3-3 binding motif, enhance proteolytic cleavage and catalytic activity of USP8, lead to increased deubiquitination of EGFR impairing its downregulation, sustain EGF signaling, and enhance POMC promoter activity in corticotroph adenomas.\",\n      \"method\": \"Exome sequencing, in vitro catalytic activity assay, EGFR ubiquitination assay, POMC promoter-reporter assay, USP8 cleavage analysis\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal mechanistic experiments (catalytic activity, EGFR ubiquitination, promoter assay) establishing mechanism of gain-of-function mutations\",\n      \"pmids\": [\"25485838\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"USP8 preferentially removes K6-linked ubiquitin chains from parkin; this deubiquitination is required for efficient recruitment of parkin to depolarized mitochondria and subsequent mitophagy; USP8 knockdown causes persistence of K6-linked ubiquitin conjugates on parkin and delays mitophagy.\",\n      \"method\": \"Co-immunoprecipitation, in vitro deubiquitination assay with K6-linkage specificity, siRNA knockdown, mitophagy assay (parkin translocation, mitochondrial clearance)\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro deubiquitination with linkage specificity plus loss-of-function mitophagy assay, replicated in subsequent commentary paper\",\n      \"pmids\": [\"25216678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"BRUCE acts as a scaffold bridging USP8 and BRIT1 in a complex; USP8 catalyzes deubiquitination of K63-linked ubiquitin on BRIT1, which is required for BRIT1 recruitment to DNA double-strand break sites via γ-H2AX; loss of BRUCE or USP8 impairs BRIT1 deubiquitination, BRIT1 foci formation, chromatin relaxation, and homologous recombination repair.\",\n      \"method\": \"Co-immunoprecipitation, in vivo ubiquitination assay, DNA damage foci assay (immunofluorescence), HR repair assay, BRUCE-mutant mouse analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP establishing tripartite complex plus functional ubiquitination and DNA damage assays plus mouse model, single lab with multiple methods\",\n      \"pmids\": [\"25733871\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"USP8 interacts with and deubiquitinates LRIG1; SAIT301 anti-Met antibody triggers Met degradation by inducing LRIG1 ubiquitination through inhibition of USP8-LRIG1 interaction, demonstrating USP8 as a LRIG1-specific deubiquitinase that controls Met degradation efficiency.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, siRNA knockdown, receptor degradation assay\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination assay, single lab\",\n      \"pmids\": [\"24828152\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"USP8 depletion in somatic cells causes redistribution of cation-independent mannose-6-phosphate receptor (ci-M6PR) from TGN to endosomes, leading to defective retromer-dependent trafficking and secretion of unprocessed Cathepsin D; this requires USP8 catalytic activity and MIT domain for endosomal localization.\",\n      \"method\": \"siRNA knockdown, siRNA-resistant rescue with WT and mutant USP8, subcellular fractionation, Cathepsin D processing/secretion assay\",\n      \"journal\": \"Traffic\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA with domain mutant rescue, single lab\",\n      \"pmids\": [\"24894536\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"USP8 is a regulatory component of the TCR signalosome that interacts with adaptor Gads and 14-3-3β; caspase-dependent processing of USP8 occurs upon TCR stimulation; T cell-specific USP8 deletion in mice causes defective thymocyte maturation, failure to upregulate IL-7Rα via Foxo1, and development of colitis with impaired regulatory T cell function.\",\n      \"method\": \"Co-immunoprecipitation, T cell-specific conditional knockout mouse, flow cytometry for thymocyte maturation, gene expression analysis, colitis phenotyping\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional KO mouse with defined cellular phenotypes plus Co-IP establishing signalosome interaction, multiple mechanistic readouts\",\n      \"pmids\": [\"26214742\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Somatic USP8 gain-of-function mutations in Cushing's disease disrupt 14-3-3 protein interaction, elevate USP8 capacity to protect EGFR from lysosomal degradation, result in higher EGFR and POMC/ACTH expression; USP8 knockdown or EGFR blockade attenuates ACTH secretion in primary USP8-mutated tumor cells.\",\n      \"method\": \"Whole-exome and Sanger sequencing, 14-3-3 interaction disruption assay, EGFR protein levels, POMC mRNA levels, siRNA knockdown in primary cultures\",\n      \"journal\": \"Cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods confirming mechanism, large cohort, replicated across multiple labs\",\n      \"pmids\": [\"25675982\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"In Drosophila, USP8 deubiquitylates and stabilizes Hrs (ESCRT-0); in Ubpy-null cells Hrs becomes ubiquitylated and degraded in lysosomes, disrupting ESCRT-0 sorting machinery and causing accumulation of signaling proteins in enlarged aberrant endosomes.\",\n      \"method\": \"Drosophila Ubpy null genetics, co-immunoprecipitation, ubiquitination assay, endosomal morphology analysis\",\n      \"journal\": \"Development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic null model plus Co-IP plus ubiquitination assay, single lab\",\n      \"pmids\": [\"24574010\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"USP8 deubiquitinates and stabilizes the long isoform of FLIP (FLIPL) but not the short isoform; USP8 depletion induces FLIPL destabilization and promotes death receptor-mediated extrinsic apoptosis via enhanced DISC and TNFR1 complex II formation and caspase-8/3 activation.\",\n      \"method\": \"Co-immunoprecipitation, in vitro deubiquitination assay, siRNA knockdown, apoptosis assays (Annexin V, caspase activity), DISC complex immunoprecipitation\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro deubiquitination plus Co-IP plus functional apoptosis assay, single lab\",\n      \"pmids\": [\"27321185\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"USP8 promotes VEGFR2 deubiquitination; USP8 depletion in endothelial cells alters VEGFR2 ubiquitination and causes VEGFR2 accumulation in endosome-lysosome system with production of a unique extracellular domain proteolytic fragment, and impairs VEGF-A-stimulated signal transduction.\",\n      \"method\": \"siRNA knockdown, VEGFR2 ubiquitination assay, endosomal localization, VEGFR2 proteolytic fragment analysis, VEGF-A signaling readout\",\n      \"journal\": \"Traffic\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function with multiple mechanistic readouts, single lab\",\n      \"pmids\": [\"26459808\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"USP8 interacts and co-localizes with α-synuclein in endosomal membranes and deubiquitinates K63-linked chains from α-synuclein both in cells and after purification; Usp8 knockdown in Drosophila and human cells increases lysosomal degradation of α-synuclein; in dopaminergic neurons, Usp8 protects against α-synuclein-induced locomotor deficits and cell loss.\",\n      \"method\": \"Co-immunoprecipitation, in vitro/in-cell deubiquitination assay with K63 specificity, siRNA knockdown with lysosomal degradation assay, Drosophila genetics (locomotor, neuronal loss)\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro deubiquitination plus Co-IP plus Drosophila in vivo genetics plus human cell loss-of-function, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"27444016\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"EGFR kinase directly phosphorylates USP8 on Tyr-717 and Tyr-810; these phosphorylations elevate USP8 deubiquitinase activity, which stabilizes the trichoplein-Aurora A pathway to suppress ciliogenesis; EGFR knockdown and serum starvation induce ciliogenesis through downregulation of this USP8-trichoplein-Aurora A signal.\",\n      \"method\": \"In vitro kinase assay with EGFR and USP8, phospho-specific mutant analysis, trichoplein/Aurora A stability assay, ciliogenesis assay, zebrafish usp8 KO\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinase assay establishing direct phosphorylation plus functional pathway cascade plus in vivo zebrafish validation, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"29472535\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"USP8 deubiquitinates HIF1α, counteracting pVHL-mediated HIF1α ubiquitination; USP8 maintains basal HIF1α expression in normoxia, and this HIF1α deubiquitination is required for ciliogenesis through repression of Rabaptin5, which controls endosome trafficking.\",\n      \"method\": \"siRNA screen for ciliogenesis genes, HIF1α ubiquitination assay, epistasis with pVHL, ciliogenesis assay, Rabaptin5 expression assay\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA screen with mechanistic follow-up (ubiquitination and epistasis assays), single lab\",\n      \"pmids\": [\"24378640\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"NMDAR activation causes dephosphorylation and activation of USP8 in neurons; activated USP8 deubiquitinates AMPARs; surface AMPAR levels and synaptic strength are inversely regulated by Nedd4-1 and USP8; USP8 levels decrease during homeostatic downscaling, while Nedd4-1 increases.\",\n      \"method\": \"NMDAR activation, phosphorylation assay, co-immunoprecipitation, surface AMPAR biotinylation, electrophysiology (synaptic strength), USP8/Nedd4-1 protein level analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus phosphorylation assay plus electrophysiology, single lab\",\n      \"pmids\": [\"25505317\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"USP8 forms a ubiquitin-dependent tripartite complex with Nrdp1 (E3 ligase) and Clec16a (which encodes an E3 ligase promoting non-degradative ubiquitin conjugates to direct mitophagy effectors); this complex is essential for β-cell mitophagy; lenalidomide inhibits Clec16a and destabilizes the complex, impairing β-cell mitophagy and insulin secretion.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, mitophagy assay, β-cell oxygen consumption and insulin secretion assay, pharmacological inhibition\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP establishing tripartite complex plus functional mitophagy and metabolic assays, single lab\",\n      \"pmids\": [\"29180353\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Crystal structure of the 14-3-3ζ protein in complex with the USP8 Ser718-phosphorylated motif was determined; fluorescence polarization and isothermal titration calorimetry quantified the interaction affinity; Cushing's disease mutations in USP8 impair 14-3-3 binding.\",\n      \"method\": \"X-ray crystallography, fluorescence polarization, isothermal titration calorimetry\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — high-resolution crystal structure with biophysical quantification, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"29473952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"USP8 deubiquitinates and stabilizes SHANK3 (and SHANK1) in neurons; USP8 overexpression enhances SHANK3/SHANK1 protein levels via deubiquitination and increases dendritic spine density; USP8 is essential for activity-dependent changes in SHANK3 protein levels.\",\n      \"method\": \"Co-immunoprecipitation, in vitro deubiquitination assay, USP8 overexpression, USP8 knockdown, dendritic spine counting, synaptic activity modulation\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus deubiquitination assay plus neuronal gain/loss-of-function, single lab\",\n      \"pmids\": [\"29735556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"CHMP1B is ubiquitinated within its flexible loop and is deubiquitinated by USP8; CHMP1B ubiquitination is induced by EGF stimulation; CHMP1B ubiquitination is necessary for EGFR trafficking and wing development in Drosophila; USP8 deubiquitination of CHMP1B may favor its assembly into ESCRT-III polymers.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, Drosophila genetics (wing phenotype), EGF-stimulated CHMP1B ubiquitination assay\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus in vivo Drosophila genetics plus stimulated ubiquitination assay, single lab\",\n      \"pmids\": [\"29933386\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"USP8 interacts with and deubiquitinates SQSTM1/p62 preferentially removing K11-linked ubiquitin chains at K420 within the UBA domain; this deubiquitination inhibits p62 degradation and suppresses autophagic flux; the K420R mutant abolishes USP8 effects.\",\n      \"method\": \"Co-immunoprecipitation, in vitro deubiquitination assay with linkage specificity, K420R mutant analysis, autophagic flux assay\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro deubiquitination with site and linkage specificity plus functional autophagy assay plus mutagenesis, single lab\",\n      \"pmids\": [\"31241013\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"USP8 deubiquitinates EPG5 by removing K63-linked ubiquitin chains at K252, leading to enhanced EPG5-LC3 interaction and autophagic flux maintenance in embryonic stem cells; USP8-EPG5 interaction is through the Coiled-coil domain of EPG5.\",\n      \"method\": \"Co-immunoprecipitation (Coiled-coil domain mapping), in vitro deubiquitination assay with K63 specificity, K252 site identification, EPG5-LC3 interaction assay, autophagic flux assay in ESCs\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro deubiquitination with site and linkage specificity plus Co-IP domain mapping plus functional autophagy assay, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"30931944\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"USP8 interacts with and deubiquitinates TRAF6, TAB2, TAK1, p62, and BECN1; USP8 deubiquitinates K63-linked ubiquitination of TAK1; USP8 knockout in liver cancer cells increases NF-κB activation and autophagy in response to TLR4/LPS stimulation, enhancing cancer progression and metastasis.\",\n      \"method\": \"Co-immunoprecipitation, K63-linked ubiquitination assay of TAK1, USP8 knockout (CRISPR), NF-κB reporter, invasion/metastasis assay, xenograft\",\n      \"journal\": \"Translational oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus K63 ubiquitination assay plus KO functional assay, single lab\",\n      \"pmids\": [\"34688043\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"H2S promotes S-sulfhydration of USP8 at specific cysteine residues; S-sulfhydration of USP8 is decreased under hyperglycemia/hyperlipidemia; H2S-mediated USP8 sulfhydration enhances USP8 deubiquitinase activity toward parkin and promotes USP8-parkin interaction, facilitating parkin translocation to mitochondria and mitophagy formation in diabetic cardiomyopathy.\",\n      \"method\": \"S-sulfhydration detection assay, dithiothreitol reversal of sulfhydration, co-immunoprecipitation (USP8-parkin), ubiquitination assay of parkin, mitophagy assay, db/db mouse model\",\n      \"journal\": \"Aging and disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — post-translational modification assay with functional reversal plus Co-IP plus mitophagy readout, single lab\",\n      \"pmids\": [\"32257541\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"USP8 inhibition in macrophages increases expression of Nrdp1 (E3 ligase for TLR4), which downregulates TLR4 and MyD88 protein levels and inhibits IKKβ/IκBα phosphorylation, thereby reducing NF-κB p65 nuclear translocation and pro-inflammatory cytokine production; USP8 opposes TLR4/MyD88/NF-κB signaling.\",\n      \"method\": \"In vivo LPS mouse model, intracerebroventricular USP8 administration, TLR4 knockout mice, TLR4 inhibitor, Western blot for NF-κB pathway components, cytokine measurement\",\n      \"journal\": \"Brain, behavior, and immunity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo mouse model with pathway epistasis (TLR4 KO), single lab\",\n      \"pmids\": [\"32335193\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"USP8 interacts with and deubiquitinates TAK1 via K63-linked ubiquitination in liver cells; USP8 promotes mRNA stability of USP8 through PTBP1/MALAT1 axis; USP8 stabilizes TAK1 and its depletion promotes TAK1 degradation, pyroptosis, and M1 macrophage polarization contributing to liver fibrosis.\",\n      \"method\": \"Co-immunoprecipitation, protein degradation assay, ubiquitination assay, RNA pulldown, RIP assay, methylated RNA immunoprecipitation, gain/loss-of-function\",\n      \"journal\": \"Cell death discovery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination assay plus RNA stability assay, single lab\",\n      \"pmids\": [\"34839365\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"USP8 deubiquitinates the leptin receptor (LepRb), inhibiting its lysosomal degradation and enhancing surface localization; USP8 is in complex with LepRb; leptin stimulation increases USP8 activity and induces USP8 gene expression via CREB-dependent transcription; increased USP8 expression enhances MAPK/ERK pathway activation and glutamatergic synapse formation in hippocampal neurons in a LepRb-dependent manner.\",\n      \"method\": \"Co-immunoprecipitation, surface receptor assay, USP8 activity assay, dominant-negative CREB, shRNA knockdown, synapse formation assay\",\n      \"journal\": \"Endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus activity assay plus transcriptional regulation assay plus functional synaptogenesis, single lab\",\n      \"pmids\": [\"31199479\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"USP8 interacts with and deubiquitinates Cx43 (connexin-43), reducing both monoubiquitination and polyubiquitination of Cx43 to prevent autophagy-mediated degradation; USP8 knockdown decreases Cx43 protein levels and suppresses intercellular dye transfer (gap junction communication).\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, siRNA knockdown, dye transfer assay for gap junction function\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination assay plus functional gap junction assay, single lab\",\n      \"pmids\": [\"29626091\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Inhibition of USP8 in Drosophila PINK1 KO model normalizes elevated Mitofusin (MFN) protein levels; a targeted DUB RNAi screen identified USP8 as prominently influencing MFN levels; USP8 inhibition in PINK1-deficient models improves mitochondrial function, locomotor performance, lifespan, and prevents dopaminergic neuron loss.\",\n      \"method\": \"RNAi DUB screen for MFN levels, genetic USP8 inhibition, pharmacological USP8 inhibition, PINK1 KO Drosophila, mitochondrial function assay, dopaminergic neuron counting\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi screen validated in vivo with multiple functional readouts, single lab\",\n      \"pmids\": [\"30988163\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"USP8 directly deubiquitinates and stabilizes the type II TGF-β receptor TβRII, leading to increased TβRII expression at the plasma membrane and in tumor-derived extracellular vesicles; USP8 promotes TGF-β/SMAD-induced EMT, invasion, and metastasis; elevated TβRII+ extracellular vesicles mediate T cell exhaustion; pharmacological USP8 inhibition reduces TβRII stability and TβRII+ circulating EVs.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, TβRII surface expression assay, extracellular vesicle isolation and characterization, EMT/invasion assay, T cell exhaustion assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination assay plus multiple functional mechanistic assays (EMT, EV, T cell), single lab with multiple orthogonal methods\",\n      \"pmids\": [\"35811497\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"USP8 inhibition increases PD-L1 protein abundance by elevating TRAF6-mediated K63-linked ubiquitination of PD-L1 to antagonize its K48-linked ubiquitination and degradation; USP8 inhibition also activates NF-κB signaling to trigger innate immune response and MHC-I expression.\",\n      \"method\": \"K63/K48 ubiquitination assays of PD-L1, TRAF6 pathway analysis, NF-κB activation assay, MHC-I expression assay, tumor immunotherapy mouse models\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — linkage-specific ubiquitination assays plus NF-κB pathway analysis plus in vivo tumor models, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"35361799\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"USP8 deubiquitinates ESCRT-III proteins CHMP2B and Shrub/CHMP4 in Drosophila germline; loss of USP8 causes ectopic ESCRT-III recruitment at intercellular bridges converting incomplete cell divisions to complete cytokinesis; a Shrub/CHMP4 variant that cannot be ubiquitinated fails to localize at abscission bridges; overexpression of USP8 in germline stem cells converts complete to incomplete cytokinesis.\",\n      \"method\": \"Drosophila genetics (usp8 mutant, overexpression), ubiquitination-resistant CHMP4 mutant analysis, ESCRT localization at intercellular bridges, cytokinesis assay\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Drosophila genetics with gain/loss-of-function plus ubiquitination-resistant mutant establishing ESCRT-III as direct target, rigorous mechanistic study\",\n      \"pmids\": [\"35587967\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP8 interacts with and deubiquitinates GPX4, leading to GPX4 stabilization; USP8 inhibition destabilizes GPX4 and sensitizes cancer cells to ferroptosis; homozygous USP8 deletion in intestinal epithelial cells causes lipid peroxidation and cell death.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination/stability assay, USP8 conditional knockout mouse, ferroptosis assay (lipid peroxidation), in vitro cancer cell ferroptosis, in vivo tumor model\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination/stability assay plus conditional KO mouse plus multiple functional assays, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"38598341\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP8 is recruited to stress granules (SGs) upon dsDNA stimulation and cleaves K27-linked ubiquitin chains from the intrinsically disordered region (IDR) of DDX3X, enhancing DDX3X condensation and liquid-liquid phase separation; enhanced DDX3X LLPS promotes cGAS phase separation and activation, potentiating cGAS-STING signaling and type I interferonopathy.\",\n      \"method\": \"Co-immunoprecipitation, K27-linkage-specific ubiquitination assay of DDX3X, stress granule localization assay, LLPS assay, cGAS activation assay, USP8 inhibitor in Trex1-/- mice\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — linkage-specific deubiquitination assay plus LLPS assay plus in vivo Trex1 KO model plus stress granule localization, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"38795350\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"USP8 depletion causes aberrant accumulation of K63-linked ubiquitin chains on endosomes; TAB2/3 (decoder for K63-Ub) is recruited to endosomes, activating TAK1-NF-κB signaling; p62 is also recruited to endosomes activating Keap1-Nrf2; oxidative stress suppresses USP8 activity, causing K63-Ub accumulation on endosomes and TAB2 recruitment triggering inflammatory cytokine expression.\",\n      \"method\": \"USP8 depletion, K63-linked ubiquitin chain accumulation assay on endosomes, TAB2/p62 endosomal recruitment assay, NF-κB and Nrf2 reporter assays, oxidative stress treatment\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mechanistic epistasis establishing K63-Ub/TAB2/TAK1-NF-κB and K63-Ub/p62/Nrf2 pathways downstream of USP8 on endosomes, multiple readouts, single lab\",\n      \"pmids\": [\"38180476\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"USP8 stabilizes O-GlcNAc transferase (OGT) by inhibiting K48-specific poly-ubiquitination of OGT at K117; SLK-mediated phosphorylation of USP8 at S716 is required for USP8-OGT interaction; OGT O-GlcNAcylates SLC7A11 at Ser26, enabling cystine import; USP8 inhibition reduces OGT stability, decreases SLC7A11 O-GlcNAcylation, and induces ferroptosis in HCC.\",\n      \"method\": \"Co-immunoprecipitation, K48-specific ubiquitination assay at OGT K117, phosphorylation site mutagenesis (S716), O-GlcNAcylation assay of SLC7A11 at Ser26, cystine import assay, ferroptosis assay\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — site-specific ubiquitination and phosphorylation assays plus O-GlcNAcylation site identified plus functional ferroptosis assay, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"37867237\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"USP8 directly deubiquitinates β-catenin, inhibiting K48-specific poly-ubiquitination, and stabilizes β-catenin protein; the USP domain of USP8 interacts with the ARM domain of β-catenin; USP8 depletion decreases β-catenin protein levels, β-catenin target gene expression, and promotes ferroptosis resistance.\",\n      \"method\": \"Co-immunoprecipitation (domain mapping of USP8 USP domain and β-catenin ARM domain), K48-specific ubiquitination assay, TOP-luciferase reporter, siRNA knockdown, ferroptosis assay\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP domain mapping plus ubiquitination assay plus reporter assay, single lab\",\n      \"pmids\": [\"37311739\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"USP8 directly interacts with and deubiquitinates Nrf2 by removing K48-linked polyubiquitin chains, stabilizing Nrf2 expression; this enhances Nrf2 signaling activation and promotes gemcitabine resistance in pancreatic cancer.\",\n      \"method\": \"Co-immunoprecipitation, K48-specific ubiquitination assay of Nrf2, siRNA/overexpression, in vivo xenograft\",\n      \"journal\": \"Biomedicine & pharmacotherapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus linkage-specific ubiquitination assay, single lab\",\n      \"pmids\": [\"37639742\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"USP8 (also known as UBPY) is a multidomain deubiquitinating enzyme whose catalytic activity is regulated by 14-3-3 binding to a phospho-Ser680/Ser718 motif (inhibitory during interphase, relieved in M phase and by Cushing's disease gain-of-function mutations) and by EGFR/Src-mediated tyrosine phosphorylation; it localizes to endosomes via its N-terminal MIT domain that interacts with CHMP/ESCRT-III proteins, where it deubiquitinates cargo receptors (EGFR, CXCR4, VEGFR2, LepRb, TβRII, ENaC, KCa3.1, BACE1, ERBB2) and endosomal machinery components (STAM, Hrs, CHMP1B, ESCRT-III subunits) to regulate receptor trafficking, recycling, and lysosomal degradation; beyond endosomes, USP8 deubiquitinates diverse substrates including parkin (K6-linked chains, required for mitophagy), α-synuclein (K63-linked, reducing lysosomal degradation), GPX4 (stabilizing ferroptosis defense), p62/SQSTM1 (K11 at K420, suppressing autophagy), FLIPL (suppressing apoptosis), BRIT1 (K63-linked, enabling DNA damage repair), SHANK3 (stabilizing synaptic scaffolds), Smoothened (promoting Hedgehog signaling), CLOCK (suppressing circadian transcription), HIF1α (maintaining normoxic levels for ciliogenesis), TβRII (promoting TGF-β/SMAD signaling), OGT (stabilizing cystine import machinery), Nrf2, β-catenin, DDX3X (facilitating cGAS condensation), and TAK1; accumulation of K63-linked ubiquitin chains on endosomes upon USP8 depletion aberrantly activates TAK1-NF-κB and Keap1-Nrf2 inflammatory/stress pathways through TAB2/3 and p62 recruitment, identifying USP8 as a gatekeeper preventing misdirected ubiquitin signaling from endosomes.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"USP8 (UBPY) is a multidomain deubiquitinating isopeptidase that cleaves both K48- and K63-linked polyubiquitin chains and governs the ubiquitin economy of the endosomal system, where it controls receptor trafficking, recycling, and lysosomal degradation [#0, #5]. It is recruited to endosomes through an N-terminal MIT domain that binds ESCRT-III CHMP proteins (CHMP1A/1B/7); this localization is required for its function but dispensable for catalysis, and the enzyme engages the ESCRT-0 machinery by binding STAM1/2 SH3 domains through central RXXK motifs, with STAM in turn stimulating its activity [#9, #11]. At endosomes USP8 deubiquitinates the cargo receptor EGFR and stabilizes ESCRT components such as STAM and Hrs to set receptor sorting dynamics, and it cooperates with HD-PTP/PTPN23 to hand EGFR from ESCRT-0 to ESCRT-III for delivery into intralumenal vesicles [#4, #5, #11, #17, #28]. Beyond EGFR, USP8 deubiquitinates a broad panel of membrane proteins and channels—CXCR4, VEGFR2, BACE1, ENaC, KCa3.1, the leptin receptor, and TβRII—to oppose their lysosomal degradation and tune their surface abundance and downstream signaling [#12, #19, #20, #30, #45, #48]. Its catalytic output is gated by phosphorylation-dependent 14-3-3 binding at a Ser680/Ser718 motif that inhibits activity during interphase and is relieved in M phase, while EGFR/Src-mediated tyrosine phosphorylation at Tyr717/Tyr810 elevates activity [#10, #32, #36]. Gain-of-function USP8 mutations clustered in the 14-3-3 motif cause Cushing's disease by disrupting 14-3-3 inhibition, enhancing EGFR deubiquitination and sustaining EGF signaling and POMC/ACTH expression in corticotroph adenomas [#21, #27]. USP8 also extends to non-endosomal substrates: it removes K6-linked chains from parkin to enable mitophagy [#22], deubiquitinates SHANK3 and AMPARs at synapses [#34, #37], processes K63 chains on α-synuclein and BRIT1 [#23, #31], and stabilizes effectors such as GPX4, OGT/SLC7A11, β-catenin, and Nrf2 [#51, #54, #55, #56]. By restraining endosomal K63-ubiquitin accumulation, USP8 acts as a gatekeeper preventing TAB2/3–TAK1–NF-κB and p62–Keap1–Nrf2 signaling from being aberrantly triggered from endosomes [#53].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established that USP8 is a catalytically active ubiquitin isopeptidase whose abundance and activity are coupled to cell proliferation, framing it as a regulator of the ubiquitin-proteasome system rather than a passive enzyme.\",\n      \"evidence\": \"in vitro ubiquitin cleavage with recombinant protein plus antisense microinjection with S-phase readout\",\n      \"pmids\": [\"9628861\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No substrate identified at this stage\", \"Mechanism linking activity to S-phase entry undefined\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Connected USP8 to endocytic trafficking by identifying its non-canonical SH3-binding motif interaction with the ESCRT-0 adaptor STAM, anchoring it to growth factor receptor complexes at early endosomes.\",\n      \"evidence\": \"Far Western screening and mutagenic mapping of the SH3-binding motif with in vitro binding assays\",\n      \"pmids\": [\"10982817\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of the STAM interaction not yet demonstrated\", \"Endosomal recruitment determinant not yet mapped\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Showed USP8 can act as a stabilizing deubiquitinase for a binding partner (CDC25Mm/Ras-GRF1), extending its role beyond chain disassembly to controlling substrate half-life.\",\n      \"evidence\": \"yeast two-hybrid, GST pulldown, Co-IP and co-transfection ubiquitination assay\",\n      \"pmids\": [\"11500497\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, ortholog-based\", \"Physiological context of CDC25 stabilization unclear\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Demonstrated reciprocal regulation between USP8 and an E3 ligase (Nrdp1), with catalytic activity required to stabilize the partner, defining a DUB–E3 stabilization module.\",\n      \"evidence\": \"affinity chromatography, Co-IP, domain mapping, and catalytic-mutant stability assays\",\n      \"pmids\": [\"15314180\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Linkage type of Nrdp1 ubiquitin not defined\", \"Downstream consequence of Nrdp1 stabilization not addressed\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identified EGFR as a direct endosomal substrate, establishing USP8 as a regulator of receptor tyrosine kinase ubiquitination and trafficking.\",\n      \"evidence\": \"in vitro deubiquitination assay, gain/loss-of-function, and endosomal co-localization of catalytic-dead USP8 with EGFR\",\n      \"pmids\": [\"16120644\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Directionality of effect on degradation became contested (see #6)\", \"Ubiquitin linkage on EGFR not resolved here\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Resolved the biochemical scope and broad endosomal role of USP8: it processes both K48- and K63-linked chains, and its loss destabilizes its partner STAM while disrupting MVE morphology and RTK degradation.\",\n      \"evidence\": \"siRNA knockdown, in vitro chain-cleavage assays, electron microscopy, and EGFR/Met degradation assays (plus parallel work on Eps15 and Src-dependent tyrosine phosphorylation)\",\n      \"pmids\": [\"16520378\", \"17121848\", \"16771824\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether USP8 net promotes or restrains EGFR degradation remained discrepant between studies\", \"Mechanism of endosome enlargement upon depletion not fully defined\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Provided the structural framework for USP8 regulation: a helix-swapped N-terminal dimer, a rhodanese–Nrdp1 interface, and a catalytic domain in an autoinhibited closed conformation requiring substrate-induced activation.\",\n      \"evidence\": \"X-ray crystallography of three USP8 domains and the Nrdp1-rhodanese complex\",\n      \"pmids\": [\"17035239\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No full-length structure\", \"Conformational activation not captured in an active state\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined the two pillars of spatial and activity control: the MIT domain mediates ESCRT-III/CHMP-dependent endosomal targeting, while phospho-Ser680-dependent 14-3-3 binding inhibits catalysis and is relieved in M phase.\",\n      \"evidence\": \"MIT deletion with CHMP binding and siRNA rescue assays; Co-IP/MS, phosphatase and phospho-antibody analyses with in vitro deubiquitination in the presence of 14-3-3\",\n      \"pmids\": [\"17711858\", \"17720156\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How cell-cycle phosphatases target Ser680 not defined\", \"Relationship between MIT targeting and 14-3-3 gating not integrated\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Mapped USP8 into the ESCRT-0 checkpoint mechanism, showing it sets EGFR and CXCR4 ubiquitination dynamics via multiple STAM-binding RXXK motifs and opposes specific E3 ligases (AIP4) at endosomes.\",\n      \"evidence\": \"domain mutagenesis of RXXK motifs, Hrs/AIP4 epistasis, endosomal localization, and surface receptor degradation assays; plus ERBB2 chimera and MIT/Src-dependent tyrosine phosphorylation work\",\n      \"pmids\": [\"20736164\", \"20876529\", \"21044682\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor-specific differences in ubiquitin-status dependence unexplained\", \"Precise step of the early-to-recycling transition controlled by USP8 not defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Generalized USP8 to developmental and circadian signaling, deubiquitinating Smoothened to promote Hedgehog surface accumulation and deubiquitinating CLOCK to restrain CLK/CYC circadian transcription.\",\n      \"evidence\": \"in vivo Drosophila RNAi screen, ubiquitination assays, Co-IP, localization, and circadian/Hh pathway activity readouts\",\n      \"pmids\": [\"22253573\", \"23154984\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Smo/CLOCK effects are endosome-dependent unclear\", \"Conservation of CLOCK regulation in mammals not tested\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Expanded the trafficking interactome and substrate range: USP8 is recruited by HD-PTP to transfer EGFR between ESCRT complexes, is itself an RNF41 substrate, and deubiquitinates BACE1, ENaC, and HIF1α to control trafficking, channel surface levels, and ciliogenesis.\",\n      \"evidence\": \"Co-IP, ILV sorting assays, reciprocal ubiquitination/epistasis, site-specific ubiquitination (BACE1 K501), oocyte electrophysiology, and HIF1α/pVHL epistasis\",\n      \"pmids\": [\"23477725\", \"23750007\", \"27302062\", \"23297398\", \"24378640\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How substrate selectivity is achieved among many endosomal cargos unresolved\", \"Direct vs indirect effects on HIF1α not fully separated\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Linked USP8 to organelle quality control, DNA repair, immune development, and disease genetics: K6-chain removal from parkin enables mitophagy, K63-chain removal from BRIT1 enables HR repair, T-cell USP8 controls thymocyte maturation, and Cushing's disease mutations cause 14-3-3-resistant gain of function.\",\n      \"evidence\": \"linkage-specific in vitro deubiquitination, mitophagy and HR assays, conditional/BRUCE-mutant mouse models, exome sequencing, and catalytic/POMC reporter assays\",\n      \"pmids\": [\"25216678\", \"25733871\", \"26214742\", \"25485838\", \"24828152\", \"24894536\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanistic basis of linkage preference (K6, K63) not structurally explained\", \"How a single DUB serves such divergent compartments unaddressed\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Established the mechanism of Cushing's disease gain-of-function and broadened substrates: mutations disrupt 14-3-3 to protect EGFR and drive ACTH; USP8 also stabilizes Hrs, FLIPL, and VEGFR2, controlling endosomal sorting, apoptosis, and angiogenic signaling.\",\n      \"evidence\": \"sequencing cohorts with 14-3-3 disruption and EGFR/POMC assays; Drosophila Ubpy-null genetics; in vitro deubiquitination and apoptosis/DISC assays; VEGFR2 ubiquitination and signaling assays\",\n      \"pmids\": [\"25675982\", \"24574010\", \"27321185\", \"26459808\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why corticotrophs are selectively vulnerable to USP8 hyperactivity unclear\", \"Isoform selectivity (FLIPL vs FLIPS) mechanism undefined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Refined activity control and neuronal/structural roles: EGFR directly phosphorylates USP8 at Tyr717/Tyr810 to raise activity in a ciliogenesis-suppressing trichoplein-Aurora A axis, a 14-3-3ζ:phospho-Ser718 structure was solved, and USP8 stabilizes SHANK3 and deubiquitinates ESCRT-III CHMP1B.\",\n      \"evidence\": \"in vitro kinase assays, phospho-mutant analysis, X-ray crystallography with FP/ITC, neuronal gain/loss-of-function, and Drosophila CHMP1B ubiquitination genetics\",\n      \"pmids\": [\"29472535\", \"29473952\", \"29735556\", \"29933386\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Integration of tyrosine activation with 14-3-3 inhibition not mechanistically unified\", \"Structural basis for catalytic-domain activation still missing\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Positioned USP8 as a regulator of autophagy and metabolic/neuronal signaling: linkage- and site-specific deubiquitination of p62 (K11 at K420) and EPG5 (K63 at K252) tunes autophagic flux, while LepRb deubiquitination links it to leptin/CREB signaling and synaptogenesis.\",\n      \"evidence\": \"in vitro deubiquitination with linkage/site specificity, autophagic flux assays, Co-IP domain mapping, and receptor/transcriptional/synapse assays\",\n      \"pmids\": [\"31241013\", \"30931944\", \"31199479\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Opposing autophagy effects (p62 vs EPG5) not reconciled into one model\", \"Determinants of K11 vs K63 chain selectivity unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined USP8 as a node in cancer immune evasion and ESCRT-dependent cytokinesis: it stabilizes TβRII to drive TGF-β-mediated EMT and T-cell exhaustion, its inhibition rewires PD-L1/NF-κB/MHC-I immunity, and germline ESCRT-III deubiquitination controls abscission.\",\n      \"evidence\": \"Co-IP/ubiquitination assays, EV characterization, EMT and T-cell exhaustion assays, K63/K48 PD-L1 ubiquitination with tumor models, and Drosophila ESCRT-III cytokinesis genetics\",\n      \"pmids\": [\"35811497\", \"35361799\", \"35587967\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Therapeutic window of USP8 inhibition across opposing immune outcomes unclear\", \"How ESCRT-III ubiquitination state dictates polymer assembly not fully defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified USP8 as a guardian of ferroptosis defense and against misdirected endosomal ubiquitin signaling: it stabilizes GPX4, OGT/SLC7A11, β-catenin and Nrf2 to resist ferroptosis, deubiquitinates DDX3X to potentiate cGAS-STING, and prevents endosomal K63-Ub from triggering TAK1-NF-κB and Keap1-Nrf2 inflammation.\",\n      \"evidence\": \"Co-IP, site/linkage-specific ubiquitination assays, conditional KO mice, ferroptosis and LLPS assays, and endosomal K63-Ub/TAB2/p62 recruitment epistasis\",\n      \"pmids\": [\"38598341\", \"37867237\", \"37311739\", \"37639742\", \"38795350\", \"38180476\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How oxidative stress mechanistically inactivates USP8 to release endosomal signaling not fully defined\", \"Hierarchy among the many ferroptosis-relevant substrates unestablished\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how a single deubiquitinase achieves substrate- and linkage-selectivity across endosomes, mitochondria, the nucleus, synapses, and stress granules, and how its competing phospho/tyrosine/sulfhydration inputs are integrated into a unified activation logic.\",\n      \"evidence\": \"no single study in the timeline reconciles substrate selectivity with the multiple regulatory modifications\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of substrate-specificity determinants\", \"No integrated regulatory model spanning 14-3-3, tyrosine phosphorylation, SLK-S716, and S-sulfhydration\", \"Compartment-specific targeting beyond the MIT/ESCRT axis undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 4, 5, 22, 39, 40, 48, 51, 54, 55]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 5, 22]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 18, 35]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [4, 5, 9, 11, 17, 53]},\n      {\"term_id\": \"GO:0005769\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [29, 39]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [4, 5, 11, 17]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 12, 15, 30, 48]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [22, 39, 40]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [3, 5, 51, 54, 55, 56]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [26, 49, 53]}\n    ],\n    \"complexes\": [\n      \"ESCRT-0 (STAM/Hrs)\",\n      \"ESCRT-III (CHMP)\",\n      \"USP8-Nrdp1-Clec16a complex\",\n      \"BRUCE-USP8-BRIT1 complex\"\n    ],\n    \"partners\": [\n      \"STAM\",\n      \"CHMP1B\",\n      \"Nrdp1\",\n      \"HD-PTP\",\n      \"EGFR\",\n      \"RNF41\",\n      \"14-3-3\",\n      \"parkin\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}