Affinage

USP27X

Ubiquitin carboxyl-terminal hydrolase 27 · UniProt A6NNY8

Length
438 aa
Mass
49.6 kDa
Annotated
2026-04-28
16 papers in source corpus 12 papers cited in narrative 12 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

USP27X is a deubiquitinase that stabilizes diverse protein substrates by removing K48- or K63-linked polyubiquitin chains, thereby preventing proteasomal degradation and modulating signaling outputs across epithelial-mesenchymal transition, apoptosis, innate immunity, cell cycle progression, chromatin regulation, and glycolytic metabolism. It deubiquitinates and stabilizes Snail1 downstream of TGF-β to drive EMT and metastasis (PMID:30341066), stabilizes the pro-apoptotic BH3-only protein Bim to promote apoptosis upon ERK pathway modulation (PMID:27013495), stabilizes cGAS via K48-linked chain removal to sustain cGAS–STING antiviral signaling (PMID:31534008), and conversely dampens RIG-I signaling by removing activating K63-linked ubiquitin from RIG-I (PMID:32027733). Upstream kinases regulate USP27X activity: GSK3β phosphorylates USP27X to enhance CBX2 deubiquitination (PMID:38030604), and PIM2 phosphorylates USP27X to augment MYC stabilization and aerobic glycolysis (PMID:38969771). Loss-of-function missense variants in USP27X cause X-linked intellectual disability (XLID105) by disrupting both catalytic deubiquitylating activity and protein–protein interactions (PMID:38182161).

Mechanistic history

Synthesis pass · year-by-year structured walk · 10 steps
  1. 2016 High

    Identification of USP27X as a deubiquitinase for the pro-apoptotic protein Bim established its first known substrate and linked it to regulation of apoptosis downstream of ERK signaling.

    Evidence Reciprocal Co-IP, ubiquitination assays, and gain/loss-of-function apoptosis readouts in multiple cell lines including NSCLC cells treated with EGFR inhibitors

    PMID:27013495

    Open questions at the time
    • Structural basis of USP27X recognition of phosphorylated Bim not determined
    • Whether USP27X deubiquitinates other BH3-only family members unknown
  2. 2018 High

    Discovery that USP27X stabilizes the EMT transcription factor Snail1 downstream of TGF-β broadened its substrate repertoire beyond apoptosis regulators and established a role in tumor invasion and metastasis.

    Evidence siRNA screen, Co-IP, ubiquitination assays, TGF-β stimulation, migration/invasion assays, and xenograft metastasis models

    PMID:30341066

    Open questions at the time
    • Whether USP27X also deubiquitinates other EMT transcription factors (e.g., Slug, Twist) not tested
    • Direct demonstration of TGF-β-dependent transcriptional regulation of USP27X promoter lacking
  3. 2018 Medium

    Identification of Cyclin E as a USP27X substrate linked the enzyme to cell cycle control and hepatocellular carcinoma proliferation.

    Evidence Co-IP, ubiquitination assays, knockdown experiments, cell growth/invasion assays, and tumor xenograft models

    PMID:29497124

    Open questions at the time
    • Ubiquitin chain linkage specificity on Cyclin E not characterized
    • Relationship to FBXW7-mediated Cyclin E degradation not resolved
  4. 2019 High

    Demonstration that USP27X removes K48-linked ubiquitin from cGAS to sustain cGAS–STING–IFN-β signaling established its role in innate DNA-sensing antiviral immunity.

    Evidence Co-IP, K48-linkage-specific ubiquitination assays, Usp27x knockout mouse macrophages with cGAMP quantification, TBK1/IRF3 phosphorylation, and HSV-1 infection challenge

    PMID:31534008

    Open questions at the time
    • Which E3 ligase USP27X opposes on cGAS not identified
    • In vivo systemic antiviral phenotype of Usp27x knockout mice not fully characterized
  5. 2020 High

    Showing that USP27X removes K63-linked activating ubiquitin from RIG-I to suppress type I interferon responses revealed that USP27X can exert opposing effects on innate immune pathways depending on ubiquitin linkage type and substrate.

    Evidence siRNA library screen, Co-IP, K63-linkage-specific ubiquitination assays, interferon reporter assays

    PMID:32027733

    Open questions at the time
    • How substrate selectivity between cGAS and RIG-I is determined remains unknown
    • Whether USP27X cleaves both K48 and K63 chains with equal catalytic efficiency not biochemically resolved
  6. 2022 Medium

    Identification of the histone methyltransferase SETD3 as a USP27X substrate extended its functional reach to epigenetic regulation and HCC tumorigenesis.

    Evidence Co-IP, ubiquitination assays, knockdown, proliferation and tumor growth assays

    PMID:35018513

    Open questions at the time
    • Downstream histone methylation targets affected by SETD3 stabilization not mapped
    • Single-lab finding without independent replication
  7. 2023 Medium

    Discovery that GSK3β phosphorylates USP27X to enhance its interaction with CBX2 revealed a kinase-dependent mechanism for modulating DUB substrate selectivity.

    Evidence Mass spectrometry identification, Co-IP, in vitro kinase assay, ubiquitination assays

    PMID:38030604

    Open questions at the time
    • Phosphorylation site(s) on USP27X and their structural consequences not fully characterized
    • Whether GSK3β regulation extends to other USP27X substrates not tested
  8. 2024 Medium

    Demonstration that PIM2 phosphorylates USP27X to enhance MYC deubiquitination and promote glycolysis established a second kinase-DUB regulatory axis and connected USP27X to metabolic reprogramming in cancer.

    Evidence Co-IP, in vitro kinase assays, ubiquitination assays, MYC stability assays, glycolysis measurements, PIM2-knockout mouse model

    PMID:38969771

    Open questions at the time
    • Whether PIM2 and GSK3β phosphorylate the same or distinct sites on USP27X unknown
    • Quantitative contribution of USP27X relative to other MYC-directed DUBs (e.g., USP28, USP36) not compared
  9. 2024 Medium

    Functional characterization of XLID105-associated missense variants established that USP27X loss-of-function in humans causes X-linked intellectual disability through impaired catalytic activity and disrupted protein interactions.

    Evidence Clinical genetics, DUB activity assays, protein-protein interaction assays, and cell biology experiments with patient-derived variants

    PMID:38182161

    Open questions at the time
    • Neurodevelopmental substrates of USP27X that are critical for brain function not identified
    • Animal models recapitulating the XLID phenotype not reported
    • Whether all XLID105 variants share the same mechanism (catalytic vs. PPI defect) not resolved
  10. 2024 Medium

    Identification of PFKFB3 as a USP27X substrate linked its deubiquitinating activity directly to glycolytic flux regulation in HCC, with CTCF acting as an upstream transcriptional activator of USP27X.

    Evidence Co-IP, ubiquitination assays, knockdown/overexpression, glycolysis assays, ChIP for CTCF binding, in vivo tumor models

    PMID:39746496

    Open questions at the time
    • Whether CTCF-mediated transcriptional regulation of USP27X is context-specific not determined
    • Relative importance of PFKFB3 vs. MYC stabilization for USP27X-driven glycolysis not dissected

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural basis for USP27X substrate recognition, the mechanism by which upstream phosphorylation events alter its catalytic activity or substrate selectivity, and the identity of the neurodevelopmental substrates whose deubiquitination is critical for intellectual function remain unresolved.
  • No crystal or cryo-EM structure of USP27X alone or in complex with substrates
  • Neurodevelopmental substrates and pathways disrupted in XLID105 not identified
  • Comprehensive phosphosite mapping and its effect on catalytic parameters not performed

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016787 hydrolase activity 11 GO:0140096 catalytic activity, acting on a protein 9
Localization
GO:0005829 cytosol 3
Pathway
R-HSA-392499 Metabolism of proteins 9 R-HSA-162582 Signal Transduction 4 R-HSA-168256 Immune System 2 R-HSA-5357801 Programmed Cell Death 2 R-HSA-1640170 Cell Cycle 1
Partners
BCL2L11CBX2CCNE1DDX58MB21D1MYCPFKFB3SNAI1

Evidence

Reading pass · 12 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2018 USP27X is a deubiquitinase that directly interacts with and stabilizes Snail1 by removing ubiquitin chains, preventing its proteasomal degradation. USP27X is upregulated by TGFβ during EMT and is required for TGFβ-induced Snail1 expression and mesenchymal marker induction. USP27X depletion impairs Snail1-dependent cell migration, invasion, metastasis, and increases cisplatin sensitivity. siRNA screen, protein stability assays, co-immunoprecipitation, ubiquitination assays, TGFβ stimulation, migration/invasion assays, xenograft metastasis models Cancer research High 30341066
2016 USP27X binds Bim upon ERK-dependent phosphorylation and cleaves ubiquitin from phosphorylated Bim, stabilizing it and counteracting ERK-driven Bim degradation. Overexpression of USP27X reduces ERK-dependent Bim ubiquitination, induces apoptosis in cells with active Raf/ERK signaling, and enhances apoptosis upon ERK pathway inhibition. Loss of USP27X reduces apoptosis in NSCLC cells treated with EGFR inhibitors. Co-immunoprecipitation, overexpression and knockdown, ubiquitination assays, apoptosis assays, PMA stimulation, ERK/EGFR inhibitor treatment EMBO reports High 27013495
2019 USP27X interacts with the cytosolic DNA sensor cGAS and cleaves K48-linked polyubiquitin chains from cGAS, stabilizing it. Knockout of Usp27x in mouse macrophages accelerates cGAS turnover, decreases cGAMP production, reduces phosphorylation of TBK1 and IRF3, decreases IFN-β production, and impairs innate antiviral responses against HSV-1. Co-immunoprecipitation, ubiquitination assays (K48-linkage specificity), Usp27x knockout mice macrophages, cGAMP quantification, phosphorylation assays, viral infection experiments Journal of immunology High 31534008
2020 USP27X negatively regulates RIG-I-mediated antiviral signaling by removing K63-linked polyubiquitin chains from RIG-I, thereby reducing type I interferon responses to RNA viruses. siRNA library screen, functional overexpression/knockdown assays, Co-immunoprecipitation, linkage-specific ubiquitination assays (K63), interferon reporter assays PLoS pathogens High 32027733
2018 USP27X (referred to as USP27) interacts with Cyclin E, negatively regulates its ubiquitination, and stabilizes it, promoting cell cycle progression and hepatocellular carcinoma growth. Co-immunoprecipitation, ubiquitination assays, knockdown experiments, cell growth and invasion assays, tumor xenograft models Oncogene Medium 29497124
2019 Inhibition of Cathepsin K increases USP27X expression, which in turn stabilizes Bim protein. Cathepsin K inhibition also decreases Raptor, leading to mitochondrial ROS production; this ROS increase is required for USP27X-mediated Bim stabilization, as mitochondria-specific superoxide scavengers prevent this effect. siRNA knockdown of USP27X, Western blot for Bim and USP27X, ROS measurement, mitochondrial ROS scavengers, xenograft tumor model Redox biology Medium 31901727
2022 USP27X (referred to as USP27) interacts with the histone methyltransferase SETD3, negatively regulates its ubiquitination, and stabilizes it, thereby promoting HCC cell proliferation and tumorigenesis. Co-immunoprecipitation, ubiquitination assays, knockdown experiments, proliferation and tumor growth assays Cellular and molecular life sciences Medium 35018513
2023 GSK3β directly binds and phosphorylates USP27X, enhancing the interaction between USP27X and its substrate CBX2 and leading to further stabilization of CBX2 protein through deubiquitination. Mass spectrometry identified USP27X as a deubiquitinating enzyme targeting CBX2. Mass spectrometry, Co-immunoprecipitation, overexpression/knockdown, ubiquitination assays, in vitro kinase assay for GSK3β phosphorylation of USP27X Cell death & disease Medium 38030604
2024 PIM2 phosphorylates USP27X, enhancing its deubiquitylating activity toward MYC, which stabilizes MYC protein and promotes HK2-mediated aerobic glycolysis in breast cancer. This axis was validated in PIM2-knockout mice. Co-immunoprecipitation, in vitro kinase assays, ubiquitination assays, MYC stability assays, glycolysis measurements, PIM2-knockout mouse model Oncogene Medium 38969771
2024 USP27X stabilizes PFKFB3, a key glycolytic enzyme, through deubiquitination, thereby increasing glycolytic activity and facilitating HCC progression. CTCF transcriptionally upregulates USP27 expression by binding its promoter. Co-immunoprecipitation, ubiquitination assays, knockdown/overexpression, glycolysis assays, ChIP for CTCF binding, in vivo tumor models Cellular signalling Medium 39746496
2024 XLID105-associated missense variants in USP27X disrupt protein function via distinct mechanisms: altered protein-protein interactions in developmentally relevant complexes and reduced deubiquitylating activity, as demonstrated by functional biochemical and cell biology assays. Clinical genetics, bioinformatics, biochemical assays (deubiquitylating activity assays), protein-protein interaction assays, cell biology experiments with patient-derived variants Life science alliance Medium 38182161
2025 A USP27X missense variant (p.Thr86Met) identified in an individual with XLID-105 is detrimental to both the expression level and deubiquitination activity of USP27X protein, as assessed by in vitro functional assays. In vitro functional assays for deubiquitination activity, Western blot for protein expression Journal of human genetics Low 40596734

Source papers

Stage 0 corpus · 16 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2018 TGFβ-Activated USP27X Deubiquitinase Regulates Cell Migration and Chemoresistance via Stabilization of Snail1. Cancer research 93 30341066
2019 Cutting Edge: USP27X Deubiquitinates and Stabilizes the DNA Sensor cGAS to Regulate Cytosolic DNA-Mediated Signaling. Journal of immunology (Baltimore, Md. : 1950) 60 31534008
2018 USP27-mediated Cyclin E stabilization drives cell cycle progression and hepatocellular tumorigenesis. Oncogene 49 29497124
2016 The deubiquitinase Usp27x stabilizes the BH3-only protein Bim and enhances apoptosis. EMBO reports 47 27013495
2019 Cathepsin K inhibition-induced mitochondrial ROS enhances sensitivity of cancer cells to anti-cancer drugs through USP27x-mediated Bim protein stabilization. Redox biology 36 31901727
2021 Overexpression of the Ubiquitin Specific Proteases USP43, USP41, USP27x and USP6 in Osteosarcoma Cell Lines: Inhibition of Osteosarcoma Tumor Growth and Lung Metastasis Development by the USP Antagonist PR619. Cells 30 34571917
2020 USP27X negatively regulates antiviral signaling by deubiquitinating RIG-I. PLoS pathogens 23 32027733
2022 Stabilization of SETD3 by deubiquitinase USP27 enhances cell proliferation and hepatocellular carcinoma progression. Cellular and molecular life sciences : CMLS 20 35018513
2024 SP1-activated USP27X-AS1 promotes hepatocellular carcinoma progression via USP7-mediated AKT stabilisation. Clinical and translational medicine 11 38279869
2023 Phosphorylation of USP27X by GSK3β maintains the stability and oncogenic functions of CBX2. Cell death & disease 7 38030604
2024 USP27X variants underlying X-linked intellectual disability disrupt protein function via distinct mechanisms. Life science alliance 6 38182161
2024 Phosphorylation of USP27X by PIM2 promotes glycolysis and breast cancer progression via deubiquitylation of MYC. Oncogene 6 38969771
2024 USP27 promotes glycolysis and hepatocellular carcinoma progression by stabilizing PFKFB3 through deubiquitination. Cellular signalling 4 39746496
2024 MiR-214 promotes the antitumor effect of NK cells in colorectal cancer liver metastasis through USP27X/Bim. Cytotechnology 1 39435421
2025 A novel USP27X missense variant identified in an individual with intellectual disability. Journal of human genetics 0 40596734
2024 [Two new cases of X-linked intellectual developmental disorder-105 linked to a previously unreported pathogenic variant in the USP27X gene]. Revista de neurologia 0 39007861