Emerging Roles of USP18: From Biology to Pathophysiology

Eukaryotic proteomes are enormously sophisticated through versatile post-translational modifications (PTMs) of proteins. A large variety of code generated via PTMs of proteins by ubiquitin (ubiquitination) and ubiquitin-like proteins (Ubls), such as interferon (IFN)-stimulated gene 15 (ISG15), small ubiquitin-related modifier (SUMO) and neural precursor cell expressed, developmentally downregulated 8 (NEDD8), not only provides distinct signals but also orchestrates a plethora of biological processes, thereby underscoring the necessity for sophisticated and fine-tuned mechanisms of code regulation. Deubiquitinases (DUBs) play a pivotal role in the disassembly of the complex code and removal of the signal. Ubiquitin-specific protease 18 (USP18), originally referred to as UBP43, is a major DUB that reverses the PTM of target proteins by ISG15 (ISGylation). Intriguingly, USP18 is a multifaceted protein that not only removes ISG15 or ubiquitin from conjugated proteins in a deconjugating activity-dependent manner but also acts as a negative modulator of type I IFN signaling, irrespective of its catalytic activity. The function of USP18 has become gradually clear, but not yet been completely addressed. In this review, we summarize recent advances in our understanding of the multifaceted roles of USP18. We also highlight new insights into how USP18 is implicated not only in physiology but also in pathogenesis of various human diseases, involving infectious diseases, neurological disorders, and cancers. Eventually, we integrate a discussion of the potential of therapeutic interventions for targeting USP18 for disease treatment.

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Small‐molecule inhibitors of ubiquitin‐specific protease 7 enhance type‐I interferon antiviral efficacy by destabilizing SOCS1

Immunology ◽

10.1111/imm.13147 ◽

2019 ◽

Vol 159 (3) ◽

pp. 309-321

Author(s):

Yukang Yuan ◽

Ying Miao ◽

Chenhua Zeng ◽

Jin Liu ◽

Xiangjie Chen ◽

...

Keyword(s):

Small Molecule ◽

Small Molecule Inhibitors ◽

Type I Interferon ◽

Type I ◽

Antiviral Efficacy ◽

Specific Protease ◽

Ubiquitin Specific Protease

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Herpes Simplex Virus 1 UL36USP Antagonizes Type I Interferon-Mediated Antiviral Innate Immunity

Journal of Virology ◽

10.1128/jvi.01161-18 ◽

2018 ◽

Vol 92 (19) ◽

Cited By ~ 14

Author(s):

Hui Yuan ◽

Jia You ◽

Hongjuan You ◽

Chunfu Zheng

Keyword(s):

Innate Immune ◽

Type I ◽

Type I Ifn ◽

Herpes Simplex Virus 1 ◽

Type I Ifns ◽

Specific Protease ◽

Ubiquitin Specific Protease ◽

Simplex Virus ◽

Antiviral Innate Immunity ◽

Hsv 1

ABSTRACT Type I interferons (IFNs), as major components of the innate immune system, play a vital role in host resistance to a variety of pathogens. Canonical signaling mediated by type I IFNs activates the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway through binding to the IFN-α/β receptor (IFNAR), resulting in transcription of IFN-stimulated genes (ISGs). However, viruses have evolved multiple strategies to evade this process. Here, we report that herpes simplex virus 1 (HSV-1) ubiquitin-specific protease (UL36USP) abrogates the type I IFN-mediated signaling pathway independent of its deubiquitinase (DUB) activity. In this study, ectopically expressed UL36USP inhibited IFN-β-induced activation of ISRE promoter and transcription of ISGs, and overexpression of UL36USP lacking DUB activity did not influence this effect. Furthermore, UL36USP was demonstrated to antagonize IFN-β-induced activation of JAKs and STATs via specifically binding to the IFNAR2 subunit and blocking the interaction between JAK1 and IFNAR2. More importantly, knockdown of HSV-1 UL36USP restored the formation of JAK1-IFNAR2 complex. These findings underline the roles of UL36USP-IFNAR2 interaction in counteracting the type I IFN-mediated signaling pathway and reveal a novel evasion mechanism of antiviral innate immunity by HSV-1. IMPORTANCE Type I IFNs mediate transcription of numerous antiviral genes, creating a remarkable antiviral state in the host. Viruses have evolved various mechanisms to evade this response. Our results indicated that HSV-1 encodes a ubiquitin-specific protease (UL36USP) as an antagonist to subvert type I IFN-mediated signaling. UL36USP was identified to significantly inhibit IFN-β-induced signaling independent of its deubiquitinase (DUB) activity. The underlying mechanism of UL36USP antagonizing type I IFN-mediated signaling was to specifically bind with IFNAR2 and disassociate JAK1 from IFNAR2. For the first time, we identify UL36USP as a crucial suppressor for HSV-1 to evade type I IFN-mediated signaling. Our findings also provide new insights into the innate immune evasion by HSV-1 and will facilitate our understanding of host-virus interplay.

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Proinflammatory Effects of Ubiquitin-Specific Protease 5 (USP5) in Rheumatoid Arthritis Fibroblast-Like Synoviocytes

Mediators of Inflammation ◽

10.1155/2020/8295149 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Xiao-Bo Luo ◽

Jian-Cheng Xi ◽

Zhen Liu ◽

Yu Long ◽

Li-tao Li ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Tumor Necrosis Factor Receptor ◽

Dependent Manner ◽

Autoimmune Inflammatory Disease ◽

Specific Protease ◽

Inflammatory Processes ◽

Ubiquitin Specific Protease ◽

Signaling Activation ◽

Fibroblast Like Synoviocytes

Rheumatoid arthritis (RA) is a worldwide chronic autoimmune inflammatory disease which is affecting approximately 1% of the total population. It is characterized by abnormal proliferation of fibroblast-like synoviocytes (FLS) and increased production of proinflammatory cytokines. In the current study, we were aiming to investigate the role of ubiquitin-specific protease 5 (USP5) in the inflammatory process in RA-FLS. Expression of USP5 was found upregulated in RA-FLS compared with that in osteoarthritis- (OA-) FLS, and IL-1β stimulation increased USP5 expression in a time-dependent manner. Furthermore, we found that USP5 overexpression significantly aggravated proinflammatory cytokine production and related nuclear factor κB (NF-κB) signaling activation. Consistently, silencing of USP5 decreased the release of cytokines and inhibited the activation of NF-κB. In addition, USP5 was found to interact with tumor necrosis factor receptor-associated factor 6 (TRAF6) and remove its K48-linked polyubiquitination chains therefore stabilizing TRAF6. Our data showed that a USP5-positive cell regulates inflammatory processes in RA-FLS and suggested USP5 as a potential target for RA treatment.

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The Ubiquitin-Specific Protease 18 Promotes Hepatitis C Virus Production by Increasing Viral Infectivity

Mediators of Inflammation ◽

10.1155/2019/3124745 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Yujia Li ◽

Max Xuezhong Ma ◽

Bo Qin ◽

Liang-Tzung Lin ◽

Christopher D. Richardson ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Virus Entry ◽

Virus Production ◽

Type I ◽

Viral Infectivity ◽

Wild Type ◽

Cellular Environment ◽

Specific Protease ◽

Ubiquitin Specific Protease

Background and Aims. Ubiquitin-specific protease 18 (USP18) is involved in immunoregulation and response to interferon- (IFN-) based treatment in patients chronically infected with hepatitis C virus (HCV). We investigated whether and how its upregulation alters HCV infection. Methods. Overexpression of wild-type (USP18 WT) or catalytically inactive mutant (USP18 C64S) USP18 was examined for effects on HCV replication in the absence and presence of IFNα or IFNλ using both the HCV-infective model and replicon cells. The IFN signaling pathway was assessed via STAT1 phosphorylation (western blot) and downstream ISG expression (real-time PCR). Mechanistic roles were sought by quantifying microRNA-122 levels and J6/JFH1 infectivity of Huh7.5 cells. Results. We found that overexpression of either USP18 WT or USP18 C64S stimulated HCV production and blunted the anti-HCV effect of IFNα and IFNλ in the infective model but not in the replicon system. Overexpressed USP18 showed no effect on Jak/STAT signaling nor on microRNA-122 expression. However, USP18 upregulation markedly increased J6/JFH1 infectivity and promoted the expression of the key HCV entry factor CD81 on Huh7.5 cells. Conclusions. USP18 stimulates HCV production and blunts the effect of both type I and III IFNs by fostering a cellular environment characterized by upregulation of CD81, promoting virus entry and infectivity.

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Ubiquitin-specific protease 4 (USP4) targets TRAF2 and TRAF6 for deubiquitination and inhibits TNFα-induced cancer cell migration

Biochemical Journal ◽

10.1042/bj20111358 ◽

2012 ◽

Vol 441 (3) ◽

pp. 979-987 ◽

Cited By ~ 91

Author(s):

Ning Xiao ◽

Hui Li ◽

Jian Luo ◽

Rui Wang ◽

Haiquan Chen ◽

...

Keyword(s):

Cell Migration ◽

Cancer Cell ◽

Signalling Pathway ◽

Negative Regulator ◽

Dependent Manner ◽

Cancer Cell Migration ◽

Specific Protease ◽

Ubiquitin Specific Protease

TRAF [TNF (tumour necrosis factor)-receptor-associated factor] 2 and 6 are essential adaptor proteins for the NF-κB (nuclear factor κB) signalling pathway, which play important roles in inflammation and immune response. Polyubiquitination of TRAF2 and TRAF6 is critical to their activities and functions in TNFα- and IL (interleukin)-1β-induced NF-κB activation. However, the regulation of TRAF2 and TRAF6 by deubiquitination remains incompletely understood. In the present study, we identified USP (ubiquitin-specific protease) 4 as a novel deubiquitinase targeting TRAF2 and TRAF6 for deubiquitination. We found that USP4 specifically interacts with TRAF2 and TRAF6, but not TRAF3. Moreover, USP4 associates with TRAF6 both in vitro and in vivo, independent of its deubiquitinase activity. The USP domain is responsible for USP4 to interact with TRAF6. Ectopic expression of USP4 inhibits the TRAF2- and TRAF6-stimulated NF-κB reporter gene and negatively regulates the TNFα-induced IκBα (inhibitor of NF-κBα) degradation and NF-κB activation. Knockdown of USP4 significantly increased TNFα-induced cytokine expression. Furthermore, we found that USP4 deubiquitinates both TRAF2 and TRAF6 in vivo and in vitro in a deubiquitinase activity-dependent manner. Importantly, the results of the present study showed that USP4 is a negative regulator of TNFα- and IL-1β-induced cancer cell migration. Taken together, the present study provides a novel insight into the regulation of the NF-κB signalling pathway and uncovers a previously unknown function of USP4 in cancer.

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Calcium/Calmodulin Regulates Ubiquitination of the Ubiquitin-specific Protease TRE17/USP6

Journal of Biological Chemistry ◽

10.1074/jbc.m505220200 ◽

2005 ◽

Vol 280 (43) ◽

pp. 35967-35973 ◽

Cited By ~ 32

Author(s):

Chuanlu Shen ◽

Ying Ye ◽

Sarah E. Robertson ◽

Alan W. Lau ◽

Don-On D. Mak ◽

...

Keyword(s):

Point Mutations ◽

Calcium Ionophore ◽

Rab Gtpase ◽

Ionophore A23187 ◽

Dependent Manner ◽

C Terminus ◽

Specific Protease ◽

Ubiquitin Specific Protease

The TRE17 (USP6/TRE-2) oncogene induces tumorigenesis in both humans and mice. However, little is known regarding its regulation or mechanism of transformation. TRE17 encodes a TBC (Tre-2/Bub2/Cdc16)/Rab GTPase-activating protein homology domain at its N terminus and a ubiquitin-specific protease at its C terminus. In the current study, we identified the ubiquitous calcium (Ca2+)-binding protein calmodulin (CaM) as a novel binding partner for TRE17. CaM bound directly to TRE17 in a Ca2+-dependent manner both in vitro and in vivo. The CaM-binding site was mapped to two hydrophobic motifs near the C terminus of the TBC domain. Point mutations within these motifs significantly reduced the interaction of TRE17 with CaM. We further found that TRE17 is monoubiquitinated and promotes its own deubiquitination in vivo. CaM binding-deficient mutants of TRE17 exhibited significantly reduced monoubiquitination, suggesting that binding of Ca2+/CaM to TRE17 promotes this modification. Consistent with this notion, treatment of cells with the CaM inhibitor W7 reduced levels of TRE17 monoubiquitination. Interestingly, the calcium ionophore A23187 induced accumulation of a polyubiquitinated TRE17 species. The effect of A23187 was attenuated in CaM binding-deficient mutants of TRE17. Taken together, these studies indicate a role for Ca2+/CaM in regulating ubiquitination through direct interaction with TRE17.

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Ubiquitin-specific Protease 15 Negatively Regulates Virus-induced Type I Interferon Signaling via Catalytically-dependent and -independent Mechanisms

Scientific Reports ◽

10.1038/srep11220 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 30

Author(s):

Huan Zhang ◽

Dang Wang ◽

Huijuan Zhong ◽

Rui Luo ◽

Min Shang ◽

...

Keyword(s):

Type I Interferon ◽

Type I ◽

Interferon Signaling ◽

Specific Protease ◽

Ubiquitin Specific Protease

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GSK-3β regulates cell growth, migration, and angiogenesis via Fbw7 and USP28-dependent degradation of HIF-1α

Blood ◽

10.1182/blood-2011-08-375014 ◽

2012 ◽

Vol 119 (5) ◽

pp. 1292-1301 ◽

Cited By ~ 92

Author(s):

Daniela Flügel ◽

Agnes Görlach ◽

Thomas Kietzmann

Keyword(s):

Ubiquitin Ligase ◽

Glycogen Synthase ◽

Glycogen Synthase Kinase 3 ◽

Dependent Manner ◽

Hypoxic Conditions ◽

Specific Protease ◽

Ubiquitin Specific Protease ◽

Cancer Phenotypes ◽

Gsk 3Β ◽

Dependent Processes

Abstract The hypoxia-inducible transcription factor-1α (HIF-1α) is a major regulator of angiogenesis, carcinogenesis, and various processes by which cells adapt to hypoxic conditions. Therefore, the identification of critical players regulating HIF-1α is not only important for the understanding of angiogenesis and different cancer phenotypes, but also for unraveling new therapeutic options. We report a novel mechanism by which HIF-1α is degraded after glycogen synthase kinase-3 (GSK-3)–induced phosphorylation and recruitment of the ubiquitin ligase and tumor suppressor F-box and WD protein Fbw7. Further, experiments with GSK-3β and Fbw7-deficient cells revealed that GSK-3β and Fbw7-dependent HIF-1α degradation can be antagonized by ubiquitin-specific protease 28 (USP28). In agreement with this, Fbw7 and USP28 reciprocally regulated cell migration and angiogenesis in an HIF-1α–dependent manner. Therefore, we have identified a new pathway that could be targeted at the level of GSK-3, Fbw7, or USP28 to influence HIF-1α–dependent processes like angiogenesis and metastasis.

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The Non-structural Protein NSs of SFTSV Causes Cytokine Storm Through the Hyper-activation of NF-κB

Molecular and Cellular Biology ◽

10.1128/mcb.00542-20 ◽

2020 ◽

Author(s):

Jumana Khalil ◽

Shintaro Yamada ◽

Yuta Tsukamoto ◽

Hiroto Abe ◽

Masayuki Shimojima ◽

...

Keyword(s):

Inflammatory Cytokines ◽

Pharmacological Intervention ◽

Type I ◽

Dependent Manner ◽

Cytokine Storm ◽

Structural Protein ◽

Cytokines And Chemokines ◽

Activity Dependent

Severe fever with thrombocytopenia syndrome (SFTS) virus (SFTSV) is an emerging highly pathogenic phlebovirus. The syndrome is characterized by the substantial production of inflammatory cytokines and chemokines, described as cytokine storm, which correlates with multi-organ failure and high mortality. SFSTV nonstructural (NSs) protein was suggested to mediate the pathogenesis by inhibiting antiviral interferon signaling in the host. However, whether SFTSV NSs protein mediates the induction of fatal cytokine storm remains unaddressed. We demonstrated that SFTSV NSs promotes the hyper-induction of cytokine/chemokine genes in vitro, reminiscent of cytokine storm. Using gene deletion and pharmacological intervention, we found that the induced cytokine storm is driven by the transcription factor NF-κB. Our investigation revealed that TANK-binding kinase 1 (TBK1) suppresses NF-κB signaling and cytokine/chemokine induction in its kinase activity-dependent manner, and that NSs sequesters TBK1 to prevent it from suppressing NF-κB, thereby promoting the activation of NF-κB and its target cytokine/chemokine genes. Of note, NF-κB inhibition suppressed the induction of pro-inflammatory cytokines in SFTSV-infected type I interferon (IFN-I) receptor 1-deficient (Ifnar1-/-) mice. These findings establish the essential role of NSs in SFTS pathogenesis and suggest NF-κB as a possible therapeutic target.

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