Deubiquitinating enzymes(DUBs)are key enzymes capable of cleaving ubiquitin chains and synergizing with ubiquitination modifications to regulate the function of key proteins andmaintain normal physiological functions....Deubiquitinating enzymes(DUBs)are key enzymes capable of cleaving ubiquitin chains and synergizing with ubiquitination modifications to regulate the function of key proteins andmaintain normal physiological functions.OTUDs are a key subfamily of the ovarian tumor protease(OTU)family,with important DUB activities,and include mainly OTUD1,OTUD2,OTUD3,OTUD4,OTUD5,OTUD6A,and OTUD6B.In recent years,research on OTUD proteins has been gradually emphasized,and their aberrant expression has demonstrated significant research value in many diseases,such as cancer,immune abnormalities,neurological disorders,and embryonic developmental abnormalities.Therefore,a comprehensive understanding of the regulatory mechanisms of OTUD proteins and their use as therapeutic targets for diseases is of great value.This article focuses on the role of individual OTUD proteins in cancer progression and antiviral response.Importantly,in the context of cancer,we elaborate on their deubiquitinated protein targets and summarize the signaling mechanisms by which they promote or inhibit cancer progression.In the future,targeting OTUD proteins may become a therapeutic direction for cancer,and this review may be useful for research related to OTUD proteins and cancer.At present,there is a lack of research on targeted inhibitors or activators of OTUDs.More in vivo and in vitro studies on OTUDs may contribute to the development of inhibitors or agonists targeting OTUDs.Of course,when conducting these studies,researchers also need to pay attention to the impact of OTUDs on the host’s antiviral immune response.展开更多
Objectives:Deubiquitinase OTUB2 plays a critical role in the progression of various tumors.However,its specific role in triple-negative breast cancer(TNBC)remains unclear.This study aims to elucidate the biological fu...Objectives:Deubiquitinase OTUB2 plays a critical role in the progression of various tumors.However,its specific role in triple-negative breast cancer(TNBC)remains unclear.This study aims to elucidate the biological function of OTUB2 in TNBC and uncover the underlying mechanisms.Methods:First,we found that the expression of OTUB2 was upregulated in TNBC by bioinformatics analysis,we then validated its expression in TNBC tissues and cells using immunohistochemistry(IHC)and qPCR and plotted the survival curves by Kaplan-Meier method.Gene set enrichment analysis(GSEA)suggested that OTUB2 may be involved in tumor proliferation and metastasis.Further functional assays,including Cell Counting Kit-8(CCK-8),colony formation,Transwell,and wound healing assays,were performed to assess the effects of OTUB2 overexpression and knockdown on TNBC cell proliferation and migration.Additionally,UbiBrowser 2.0 was used to identify OTUB2 substrate proteins and western blotting was conducted to clarify the molecular mechanisms involved.Results:Our results demonstrated that OTUB2 expression was elevated in TNBC and associated with poor prognosis.Overexpression of OTUB2 enhanced the proliferation and migration of TNBC cells,while its knockdown inhibited these processes.Moreover,OTUB2 stabilized tumor necrosis factor receptor-associated factor 6(TRAF6)by deubiquitinating it,leading to activation of the protein kinase B(AKT)pathway.Conclusions:OTUB2 exerts its promoting effects on the progression of TNBC by activating the TRAF6/AKT pathway.展开更多
Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes(DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. ...Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes(DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme(E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.展开更多
DNA is the hereditary material in humans and almost all other organisms. It is essential for maintaining accurate transmission of genetic information. In the life cycle, DNA replication, cell division, or genome damag...DNA is the hereditary material in humans and almost all other organisms. It is essential for maintaining accurate transmission of genetic information. In the life cycle, DNA replication, cell division, or genome damage, including that caused by endogenous and exogenous agents, may cause DNA aberrations. Of all forms of DNA damage, DNA double-strand breaks(DSBs) are the most serious. If the repair function is defective, DNA damage may cause gene mutation, genome instability, and cell chromosome loss, which in turn can even lead to tumorigenesis. DNA damage can be repaired through multiple mechanisms. Homologous recombination(HR) and non-homologous end joining(NHEJ) are the two main repair mechanisms for DNA DSBs. Increasing amounts of evidence reveal that protein modifications play an essential role in DNA damage repair.Protein deubiquitination is a vital post-translational modification which removes ubiquitin molecules or polyubiquitinated chains from substrates in order to reverse the ubiquitination reaction. This review discusses the role of deubiquitinating enzymes(DUBs) in repairing DNA DSBs. Exploring the molecular mechanisms of DUB regulation in DSB repair will provide new insights to combat human diseases and develop novel therapeutic approaches.展开更多
The p53 tumor suppressor protein coordinates the cellular responses to a broad range of cellular stresses, leading to DNA repair, cell cycle arrest or apoptosis. The stability of p53 is essential for its tumor suppres...The p53 tumor suppressor protein coordinates the cellular responses to a broad range of cellular stresses, leading to DNA repair, cell cycle arrest or apoptosis. The stability of p53 is essential for its tumor suppressor function, which is tightly controlled by ubiquitin-dependent degradation primarily through its negative regulator mudne double minute 2 （Mdm2）. To better understand the regulation of p53, we tested the interaction between p53 and USP11 using co-immunoprecipitation. The results show that USP11, an ubiquitin-specific protease, forms specific complexes with p53 and stabilizes p53 by deubiquitinating it. Moreover, down-regulation of USP11 dramatically attenuated p53 in- duction in response to DNA damage stress. These findings reveal that USP11 is a novel regulator of p53, which is required for p53 activation in response to DNA damage.展开更多
Gastric cancer(GC)is a pervasive malignant tumor with a high incidence rate,and its mortality in late stages poses a significant threat to global public health.Despite advancements in diagnosis and treatment,the progn...Gastric cancer(GC)is a pervasive malignant tumor with a high incidence rate,and its mortality in late stages poses a significant threat to global public health.Despite advancements in diagnosis and treatment,the prognosis for advanced GC remains poor.The progression of GC is closely associated with immune system dysfunction,particularly the role of the immune checkpoint programmed death ligand 1(PD-L1),which is a key mediator of immune evasion and a promising target for immunotherapy.The ubiquitin proteasome system(UPS),including ubiquitinases and deubiquitinases,is primarily responsible for the degradation of programmed death 1(PD-1)/PD-L1)proteins and plays an indispensable role in the malignant progression and metastasis of GC.This review synthesizes research on GC immunity,the role of DUBs in regulating PD-L1 stability and immune evasion,and major immunotherapies such as immune checkpoint inhibitors(ICIs),with a focus on the promising DUB inhibitors which may improve the efficacy of GC immunotherapies.In recent years,various ICIs have been widely used in immunotherapy,significantly improving the clinical prognosis of cancer patients.However,immunotherapy also faces many challenges.Meanwhile,multiple DUBs have been shown to directly bind to PD-L1,inducing its deubiquitination and stabilization,leading to the development of malignant tumors.The efficacy of ICIs is closely related to PD-1/PD-L1.Therefore,inhibiting these DUBs can make tumor cells sensitive to immune surveillance and enhance the effectiveness of ICIs.Therefore,in-depth exploration of the combination therapy of DUBs inhibitors and ICIs is of great significance for improving the prognosis of GC.展开更多
Deubiquitinating enzymes(DUBs) or deubiquitinases facilitate the escape of multiple proteins from ubiquitin-proteasome degradation and are critical for regulating protein expression levels in vivo.Therefore,dissecting...Deubiquitinating enzymes(DUBs) or deubiquitinases facilitate the escape of multiple proteins from ubiquitin-proteasome degradation and are critical for regulating protein expression levels in vivo.Therefore,dissecting the underlying mechanism of DUB recognition is needed to advance the development of drugs related to DUB signaling pathways.To data,extensive studies on the ubiquitin chain specificity of DUBs have been reported,but substrate protein recognition is still not clearly understood.As a breakthrough,the scaffolding role may be significant to substrate protein selectivity.From this perspective,we systematically characterized the scaffolding proteins and complexes contributing to DUB substrate selectivity.Furthermore,we proposed a deubiquitination complex platform(DCP) as a potentially generic mechanism for DUB substrate recognition based on known examples,which might fill the gaps in the understanding of DUB substrate specificity.展开更多
Cilia are microtubule-based organelles projecting from the cell surface with important sensory and motility functions.Ciliary defects are associated with diverse diseases collectively known as ciliopathies.However,the...Cilia are microtubule-based organelles projecting from the cell surface with important sensory and motility functions.Ciliary defects are associated with diverse diseases collectively known as ciliopathies.However,the molecular mechanisms that govern ciliogenesis remain not fully understood.Here,we demonstrate that ubiquitin-specific protease 21(USP21)is indispensable for cilium formation through its deubiquitinating activity.Usp21 knockout mice exhibit ciliary defects in multiple organs,such as the kidney,liver,and trachea.Our data also reveal a constant localization of USP21 at the centrosome and basal body during ciliogenesis.Mechanistically,USP21 interacts with dihydropyrimidinase-like 2(DPYSL2)at the centrosome and removes lysine 48-linked ubiquitination from DPYSL2.Loss of USP21 leads to the proteasomal degradation of DPYSL2 and causes a significant reduction in its centrosome abundance,ultimately resulting in ciliary defects.These findings thus identify a critical role for the USP21–DPYSL2 axis in ciliogenesis and have important implications for health and disease.展开更多
Stimulator of interferon genes(STING)is an adaptor protein that is critical for effective innate antiviral and antitumor immunity.The activity of STING is heavily regulated by protein ubiquitination,which is fine-tune...Stimulator of interferon genes(STING)is an adaptor protein that is critical for effective innate antiviral and antitumor immunity.The activity of STING is heavily regulated by protein ubiquitination,which is fine-tuned by both E3 ubiquitin ligases and deubiquitinases.Here,we report that the deubiquitinase OTUD5 interacts with STING,cleaves its K48-linked polyubiquitin chains,and promotes its stability.Consistently,knockout of OTUD5 resulted in faster turnover of STING and subsequently impaired type I IFN signaling following cytosolic DNA stimulation.More importantly,Lyz2-Cre Otud5^(fl/Y) mice and CD11-Cre Otud5^(fl/Y) mice showed more susceptibility to herpes simplex virus type 1(HSV-1)infection and faster development of melanomas than their corresponding control littermates,indicating that OTUD5 is indispensable for STING-mediated antiviral and antitumor immunity.Our data suggest that OTUD5 is a novel checkpoint in the cGAS-STING cytosolic DNA sensing pathway.展开更多
Oral squamous cell carcinoma(OSCC)is the most common head and neck malignancy worldwide,accounting for more than 90%of all oral cancers,and is characterized by high invasiveness and poor long-term prognosis.Its etiolo...Oral squamous cell carcinoma(OSCC)is the most common head and neck malignancy worldwide,accounting for more than 90%of all oral cancers,and is characterized by high invasiveness and poor long-term prognosis.Its etiology is multifactorial,involving tobacco use,alcohol consumption,and human papillomavirus(HPV)infection.Oral leukoplakia and erythroplakia are the main precancerous lesions lesions,with oral leukoplakia being the most common.Both OSCC and premalignant lesions are closely associated with aberrant activation of multiple signaling pathways.Post-translational modifications(such as ubiquitination and deubiquitination)play key roles in regulating these pathways by controlling protein stability and activity.Growing evidence indicates that dysregulated ubiquitination/deubiquitination can mediate OSCC initiation and progression via aberrant activation of signaling pathways.The ubiquitination/deubiquitination process mainly involves E3 ligases(E3s)that catalyze substrate ubiquitination,deubiquitinating enzymes(DUBs)that remove ubiquitin chains,and the 26S proteasome complex that degrades ubiquitinated substrates.Abnormal expression or mutation of E3s and DUBs can lead to altered stability of critical tumorrelated proteins,thereby driving OSCC initiation and progression.Therefore,understanding the aberrantly activated signaling pathways in OSCC and the ubiquitination/deubiquitination mechanisms within these pathways will help elucidate the molecular mechanisms and improve OSCC treatment by targeting relevant components.Here,we summarize four aberrantly activated signaling pathways in OSCC―the PI3K/AKT/mTOR pathway,Wnt/β-catenin pathway,Hippo pathway,and canonical NF-κB pathway―and systematically review the regulatory mechanisms of ubiquitination/deubiquitination within these pathways,along with potential drug targets.PI3K/AKT/mTOR pathway is aberrantly activated in approximately 70%of OSCC cases.It is modulated by E3s(e.g.,FBXW7 and NEDD4)and DUBs(e.g.,USP7 and USP10):FBXW7 and USP10 inhibit signaling,while NEDD4 and USP7 potentiate it.Aberrant activation of the Wnt/β-catenin pathway leads toβ-catenin nuclear translocation and induction of cell proliferation.This pathway is modulated by E3s(e.g.,c-Cbl and RNF43)and DUBs(e.g.,USP9X and USP20):c-Cbl and RNF43 inhibit signaling,while USP9X and USP20 potentiate it.Hippo pathway inactivation permits YAP/TAZ to enter the nucleus and promotes cancer cell metastasis.This pathway is modulated by E3s(e.g.,CRL4^(DCAF1) and SIAH2)and DUBs(e.g.,USP1 and USP21):CRL4^(DCAF1) and SIAH2 inhibit signaling,while USP1 and USP21 potentiate it.Persistent activation of the canonical NF-κB pathway is associated with an inflammatory microenvironment and chemotherapy resistance.This pathway is modulated by E3s(e.g.,TRAF6 and LUBAC)and DUBs(e.g.,A20 and CYLD):A20 and CYLD inhibit signaling,while TRAF6 and LUBAC potentiate it.Targeting these E3s and DUBs provides directions for OSCC drug research.Small-molecule inhibitors such as YCH2823(a USP7 inhibitor),GSK2643943A(a USP20 inhibitor),and HOIPIN-8(a LUBAC inhibitor)have shown promising antitumor activity in preclinical models;PROTAC molecules,by binding to surface sites of target proteins and recruiting E3s,achieve targeted ubiquitination and degradation of proteins insensitive to small-molecule inhibitors,for example,PU7-1-mediated USP7 degradation,offering new strategies to overcome traditional drug limitations.Currently,NX-1607(a Cbl-b inhibitor)has entered phase I clinical trials,with preliminary results confirming its safety and antitumor activity.Future research on aberrant E3s and DUBs in OSCC and the development of highly specific inhibitors will be of great significance for OSCC precision therapy.展开更多
Parkinson's disease(PD)is a severe neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons.Emerging evidence suggests that deubiquitinating enzymes(DUBs),which regulate protein hom...Parkinson's disease(PD)is a severe neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons.Emerging evidence suggests that deubiquitinating enzymes(DUBs),which regulate protein homeostasis through the cleavage of ubiquitin chains,play critical roles in PD pathogenesis.In this study,we discovered that a DUB,ovarian tumor deubiquitinase 6A(OTUD6A),was significantly upregulated in both PD patients and PD mouse models.Notably,OTUD6A deficiency effectively protected dopaminergic neurons from degeneration and improved motor deficits in both acute and chronic PD mouse models.Through comprehensive mass spectrometry analysis and co-immunoprecipitation assays,we identified that actin gamma 1(ACTG1)serves as a key substrate of OTUD6A.Mechanistically,OTUD6A specifically interacts with the 8–181 aa domain of ACTG1 and preferentially cleaves K48-linked polyubiquitin chains,thereby enhancing ACTG1 protein stability in neuronal cells.The stabilized ACTG1 subsequently binds to p53 and facilitates its nuclear translocation,leading to the transcriptional activation of pro-apoptotic genes and promoting neuronal apoptosis.Collectively,our findings demonstrate that OTUD6A promotes dopaminergic neuron degeneration and PD progression by deubiquitinating and stabilizing ACTG1,which in turn activates a p53-dependent apoptotic pathway.These findings identify OTUD6A as a potential therapeutic target for PD intervention.展开更多
Activity-based Ubiquitin probes(Ub-ABPs)carrying a reporter group have emerged as effective tools for the investigation of deubiquitinating enzymes(DUBs),such as studying the molecular mechanism of DUBs,profiling new ...Activity-based Ubiquitin probes(Ub-ABPs)carrying a reporter group have emerged as effective tools for the investigation of deubiquitinating enzymes(DUBs),such as studying the molecular mechanism of DUBs,profiling new DUBs.But so far,the synthesis of commonly used biotin-bearing Ub-ABPs is a technical challenge.Here,we report a one-pot semi-synthetic strategy for the acquiring of Ub-ABPs carrying a biotin tag through sequential enzymatic ligation,N-S acyl transfer and aminolysis reaction without any purification steps.These probes enable to capture the different family of DUBs for enrichment and immunoblotting using the attached biotin tag.展开更多
Dysregulation of components of the ubiqutin system has been linked to many diseases including melanoma. This is vital since the post-translational modification of different proteins via direct ubiquitin attachment is ...Dysregulation of components of the ubiqutin system has been linked to many diseases including melanoma. This is vital since the post-translational modification of different proteins via direct ubiquitin attachment is an important process for various cellular processes. CYLD is a tumor suppressor gene and deubiquitinating enzyme, which can remove polyubiquitin chains from their specific substrate and interfere with different signaling pathways. CYLD is frequently downregulated or even lost in melanoma cell lines or tissues compared to melanocytes. Down-regulation of CYLD leads to sustained oncogenic signaling that promotes melanoma progression and metastasis. In this review, we summarize the recent insights into the mechanisms which are responsible for the down-regulation of CYLD levels in melanoma and the signaling interactions of the CYLD gene product in melanoma. We argue that these recent insights into CYLD function invite the development of novel molecular strategies for melanoma prevention and treatment.展开更多
Infections by coronaviruses such as severe acute respiratory syndrome （SARS） coronavirus （SCoV） and mouse hepatitis virus A59 （MHV-A59） result in very little type I interferon （IFN） production by host cells, w...Infections by coronaviruses such as severe acute respiratory syndrome （SARS） coronavirus （SCoV） and mouse hepatitis virus A59 （MHV-A59） result in very little type I interferon （IFN） production by host cells, which is potentially responsible for the rapid viral growth and severe immunopathology associated with SARS. However, the molecular mechanisms for the low IFN production in cells infected with coronaviruses remain unclear. Here, we provide evidence that Papain-like protease domain 2 （PLP2）, a catalytic domain of the nonstructural protein 3 （nsp3） of MHV-A59, can bind to IRF3, cause its deubiquitination and prevent its nuclear translocation. As a consequence, co-expression of PLP2 strongly inhibits CARDIF-, TBK1- and IRF3-mediated IFNp reporter activities. In addition, we show that wild-type PLP2 but not the mutant PLP2 lacking the deubiquitinase （DUB） activity can reduce IFN induction and promote viral growth in cells infected with VSV. Thus, our study uncovered a viral DUB which coronaviruses may use to escape from the host innate antiviral responses.展开更多
Aim： To study the incidence of single nucleotide polymorphisms in ubiquitin-specific protease 26 （USP26） gene and its involvement in idiopathic male infertility in China. Methods： Routine semen analysis was perfor...Aim： To study the incidence of single nucleotide polymorphisms in ubiquitin-specific protease 26 （USP26） gene and its involvement in idiopathic male infertility in China. Methods： Routine semen analysis was performed. Infertility factors such as immunological, infectious and biochemical disorders were examined to select patients with idiopathic infertility. DNA was isolated from peripheral blood of the selected patients and control population, which were examined for mutations using polymerase chain reaction-single strand conformation polymorphism analysis. Furthermore, nucleotide sequences were sequenced in some patients and controls. Results： Of 41 infertile men, 9 （22.0%, P = 0.01） had changes in USP26 gene on the X chromosome. A compound mutation （364insACA; 460G→A） was detected in 8 patients （19.5%, P = 0.01） and a 1044T→A substitution was found in 1 patient （2.4%, P 〉 0.05）. All three variations led to changes in the coding amino acids. Two substitutions predict some changes： 460G→ A changes a valine into an isoleucine, and 1044T → A substitutes a leucine for a phenylalanine. Another insertion of three nucleotides ACA causes an insertion of threonine. No other changes were found in the remaining patients and fertile controls. Conclusion： The USP26 gene might be of importance in male reproduction. Mutations in this gene might be associated with male infertility, and might negatively affect testicular function. Further research on this issue is in progress.展开更多
Viral infection initiates a series of signaling cascades that activate the transcription factors nuclear factor kappa B and interferon regulatory factor 3, which collaborate to induce transcription of genes for type I...Viral infection initiates a series of signaling cascades that activate the transcription factors nuclear factor kappa B and interferon regulatory factor 3, which collaborate to induce transcription of genes for type I interferons （IFNs） and other cytokines. Here we report that the deubiquitinating enzyme ubiquitin-specific protease 17 （USP17） is required for virus-induced RIG-I- and melanoma differentiation-associated protein-5 （MDA5）-mediated type I IFN signaling. Knockdown of endogenous USP17 inhibited virus-, cytoplasmic poly（I：C）- and poly（dA：dT）-induced activation of the IFN-β promoter and cellular antiviral responses. We further found that knockdown of USP17 inhibited RIG-I- and MDA5-induced but not downstream activator-induced activation of the IFN-β promoter, which was correlated with an increase in ubiquitination levels of RIG-I and MDA5. Taken together, our findings suggest that USP17 functions through deubiquitination of RIG-I and MDA5 to regulate virus-induced type I IFN signaling.展开更多
As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein qual...As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein quality control. However, the structural and biochemical properties of K-branched ubiquitin chains have not been well examined. Here we employed the synthetic linkage-and length-defined K-branched ubiquitin chains to examine their binding and hydrolysis properties in vitro. Quantitatively affinity determination of ubiquitin chains to the proteasome ubiquitin receptor S5 a indicated that the S5 a exhibited preference binding to K-branched chains over K-linked chains, but not K-conjugated chains. In addition, deubiquitination experiments were carried out and the results showed that K-branched chains were preferably hydrolyzed by proteasome-associated deubiquitinase Rpnll than homotypic Kor K-linked chains.展开更多
Deubiquitinating enzymes （DUBs） play an important role in ubiquitin-dependent processes as negative regulators of protein ubiquitination. Ubiquitin-specific protease 26 （USP26） is a member of this family. The expr...Deubiquitinating enzymes （DUBs） play an important role in ubiquitin-dependent processes as negative regulators of protein ubiquitination. Ubiquitin-specific protease 26 （USP26） is a member of this family. The expression of Usp26 in mammalian testis and in other tissues has yet to be fully elucidated. To study the expression of Usp26 mRNA and protein in various murine tissues, reverse transcription （RT）-PCR and immunohistochemistry analyses were carried out. The RT-PCR analysis showed that the Usp26 transcript was expressed in all of the tested tissues. USP26 protein localization was examined by immunohistochemistry, and it was shown that USP26 was not detectable at 20 days postpartum, with the expression restricted to the cytoplasm of condensing spermatids （steps 9-16）, Leydig cells and nerve fibers in the brain. In addition, the USP26 protein was detected at moderate levels in myocardial ceils, the corpus of epidydimis, epithelium of the renal tubules and the seminal gland of postnatal day 35 mice. Its spatial and temporal expression pattern suggests that Usp26 may play an important role in development or function of the testis and brain. Further research into these possibilities is in progress.展开更多
Objective Obesity-induced kidney injury contributes to the development of diabetic nephropathy(DN).Here,we identified the functions of ubiquitin-specific peptidase 19(USP19)in HK-2 cells exposed to a combination of hi...Objective Obesity-induced kidney injury contributes to the development of diabetic nephropathy(DN).Here,we identified the functions of ubiquitin-specific peptidase 19(USP19)in HK-2 cells exposed to a combination of high glucose(HG)and free fatty acid(FFA)and determined its association with TGF-beta-activated kinase 1(TAK1).Methods HK-2 cells were exposed to a combination of HG and FFA.USP19 mRNA expression was detected by quantitative RT-PCR(qRT-PCR),and protein analysis was performed by immunoblotting(IB).Cell growth was assessed by Cell Counting Kit-8(CCK-8)viability and 5-ethynyl-2′-deoxyuridine(EdU)proliferation assays.Cell cycle distribution and apoptosis were detected by flow cytometry.The USP19/TAK1 interaction and ubiquitinated TAK1 levels were assayed by coimmunoprecipitation(Co-IP)assays and IB.Results In HG+FFA-challenged HK-2 cells,USP19 was highly expressed.USP19 knockdown attenuated HG+FFA-triggered growth inhibition and apoptosis promotion in HK-2 cells.Moreover,USP19 knockdown alleviated HG+FFA-mediated PTEN-induced putative kinase 1(PINK1)/Parkin pathway inactivation and increased mitochondrial reactive oxygen species(ROS)generation in HK-2 cells.Mechanistically,USP19 stabilized the TAK1 protein through deubiquitination.Importantly,increased TAK1 expression reversed the USP19 knockdown-mediated phenotypic changes and PINK1/Parkin pathway activation in HG+FFA-challenged HK-2 cells.Conclusion The findings revealed that USP19 plays a crucial role in promoting HK-2 cell dysfunction induced by combined stimulation with HG and FFAs by stabilizing TAK1,providing a potential therapeutic strategy for combating DN.展开更多
Doxorubicin(Dox)is an anthracycline drug widely applied in various malignancies.However,the fatal cardiotoxicity induced by Dox limits its clinical application.Post-transcriptional protein modification via ubiquitinat...Doxorubicin(Dox)is an anthracycline drug widely applied in various malignancies.However,the fatal cardiotoxicity induced by Dox limits its clinical application.Post-transcriptional protein modification via ubiquitination/deubiquitination in cardiomyocytes mediates the pathophysiological process in Dox-induced cardiotoxicity(DIC).In this study,we aimed to clarify the regulatory role and mechanism of a deubiquitinating enzyme,ubiquitin-specific peptidase 13(USP13),in DIC.RNA-seq analysis and experimental examinations identified that cardiomyocyte-derived USP13 positively correlated with DIC.Mice with cardiac-specific deletion of USP13 were subjected to Dox modeling.Adeno-associated virus serotype 9(AAV9)carrying cTNT promoter was constructed to overexpress USP13 in mouse heart tissues.Cardiomyocyte-specific knockout of USP13 exacerbated DIC,while its overexpression mitigated DIC in mice.Mechanistically,USP13 deubiquitinates the stimulator of interferon genes(STING)and promotes the autolysosome-related degradation of STING,subsequently alleviating cardiomyocyte inflammation and death.Our study suggests that USP13 serves a cardioprotective role in DIC and indicates USP13 as a potential therapeutic target for DIC treatment.展开更多
文摘Deubiquitinating enzymes(DUBs)are key enzymes capable of cleaving ubiquitin chains and synergizing with ubiquitination modifications to regulate the function of key proteins andmaintain normal physiological functions.OTUDs are a key subfamily of the ovarian tumor protease(OTU)family,with important DUB activities,and include mainly OTUD1,OTUD2,OTUD3,OTUD4,OTUD5,OTUD6A,and OTUD6B.In recent years,research on OTUD proteins has been gradually emphasized,and their aberrant expression has demonstrated significant research value in many diseases,such as cancer,immune abnormalities,neurological disorders,and embryonic developmental abnormalities.Therefore,a comprehensive understanding of the regulatory mechanisms of OTUD proteins and their use as therapeutic targets for diseases is of great value.This article focuses on the role of individual OTUD proteins in cancer progression and antiviral response.Importantly,in the context of cancer,we elaborate on their deubiquitinated protein targets and summarize the signaling mechanisms by which they promote or inhibit cancer progression.In the future,targeting OTUD proteins may become a therapeutic direction for cancer,and this review may be useful for research related to OTUD proteins and cancer.At present,there is a lack of research on targeted inhibitors or activators of OTUDs.More in vivo and in vitro studies on OTUDs may contribute to the development of inhibitors or agonists targeting OTUDs.Of course,when conducting these studies,researchers also need to pay attention to the impact of OTUDs on the host’s antiviral immune response.
基金supported by the National Natural Science Foundation of China(No.82373380,Xinhua Xie).
文摘Objectives:Deubiquitinase OTUB2 plays a critical role in the progression of various tumors.However,its specific role in triple-negative breast cancer(TNBC)remains unclear.This study aims to elucidate the biological function of OTUB2 in TNBC and uncover the underlying mechanisms.Methods:First,we found that the expression of OTUB2 was upregulated in TNBC by bioinformatics analysis,we then validated its expression in TNBC tissues and cells using immunohistochemistry(IHC)and qPCR and plotted the survival curves by Kaplan-Meier method.Gene set enrichment analysis(GSEA)suggested that OTUB2 may be involved in tumor proliferation and metastasis.Further functional assays,including Cell Counting Kit-8(CCK-8),colony formation,Transwell,and wound healing assays,were performed to assess the effects of OTUB2 overexpression and knockdown on TNBC cell proliferation and migration.Additionally,UbiBrowser 2.0 was used to identify OTUB2 substrate proteins and western blotting was conducted to clarify the molecular mechanisms involved.Results:Our results demonstrated that OTUB2 expression was elevated in TNBC and associated with poor prognosis.Overexpression of OTUB2 enhanced the proliferation and migration of TNBC cells,while its knockdown inhibited these processes.Moreover,OTUB2 stabilized tumor necrosis factor receptor-associated factor 6(TRAF6)by deubiquitinating it,leading to activation of the protein kinase B(AKT)pathway.Conclusions:OTUB2 exerts its promoting effects on the progression of TNBC by activating the TRAF6/AKT pathway.
基金Supported by NIH/NCI,No.R00 CA127134 and No.R01CA160474a Department of Defense,No.W81XWH-10-1-1029,to Dai MSA Grant from Medical Research Foundation(MRF)of Oregon,to Sun XX
文摘Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes(DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme(E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.
基金supported by the National Natural Science Foundation of China (Nos. 91749115 and 81872298)the Natural Science Foundation of Jiangxi Province (No. 20181BAB205044), China。
文摘DNA is the hereditary material in humans and almost all other organisms. It is essential for maintaining accurate transmission of genetic information. In the life cycle, DNA replication, cell division, or genome damage, including that caused by endogenous and exogenous agents, may cause DNA aberrations. Of all forms of DNA damage, DNA double-strand breaks(DSBs) are the most serious. If the repair function is defective, DNA damage may cause gene mutation, genome instability, and cell chromosome loss, which in turn can even lead to tumorigenesis. DNA damage can be repaired through multiple mechanisms. Homologous recombination(HR) and non-homologous end joining(NHEJ) are the two main repair mechanisms for DNA DSBs. Increasing amounts of evidence reveal that protein modifications play an essential role in DNA damage repair.Protein deubiquitination is a vital post-translational modification which removes ubiquitin molecules or polyubiquitinated chains from substrates in order to reverse the ubiquitination reaction. This review discusses the role of deubiquitinating enzymes(DUBs) in repairing DNA DSBs. Exploring the molecular mechanisms of DUB regulation in DSB repair will provide new insights to combat human diseases and develop novel therapeutic approaches.
基金Project supported by the Key Project of Colleges and Universities in Fujian Province Serving the Construction of the West-strait(No.A101)the Foundation for the 2013 Research Plan of University Key Teacher Domestic Visitor of the Ministry of Educationthe Foundation for the Second Batch of Key Teacher of Quanzhou Normal College(the personnel department of QNC[2012]No.1),China
文摘The p53 tumor suppressor protein coordinates the cellular responses to a broad range of cellular stresses, leading to DNA repair, cell cycle arrest or apoptosis. The stability of p53 is essential for its tumor suppressor function, which is tightly controlled by ubiquitin-dependent degradation primarily through its negative regulator mudne double minute 2 （Mdm2）. To better understand the regulation of p53, we tested the interaction between p53 and USP11 using co-immunoprecipitation. The results show that USP11, an ubiquitin-specific protease, forms specific complexes with p53 and stabilizes p53 by deubiquitinating it. Moreover, down-regulation of USP11 dramatically attenuated p53 in- duction in response to DNA damage stress. These findings reveal that USP11 is a novel regulator of p53, which is required for p53 activation in response to DNA damage.
文摘Gastric cancer(GC)is a pervasive malignant tumor with a high incidence rate,and its mortality in late stages poses a significant threat to global public health.Despite advancements in diagnosis and treatment,the prognosis for advanced GC remains poor.The progression of GC is closely associated with immune system dysfunction,particularly the role of the immune checkpoint programmed death ligand 1(PD-L1),which is a key mediator of immune evasion and a promising target for immunotherapy.The ubiquitin proteasome system(UPS),including ubiquitinases and deubiquitinases,is primarily responsible for the degradation of programmed death 1(PD-1)/PD-L1)proteins and plays an indispensable role in the malignant progression and metastasis of GC.This review synthesizes research on GC immunity,the role of DUBs in regulating PD-L1 stability and immune evasion,and major immunotherapies such as immune checkpoint inhibitors(ICIs),with a focus on the promising DUB inhibitors which may improve the efficacy of GC immunotherapies.In recent years,various ICIs have been widely used in immunotherapy,significantly improving the clinical prognosis of cancer patients.However,immunotherapy also faces many challenges.Meanwhile,multiple DUBs have been shown to directly bind to PD-L1,inducing its deubiquitination and stabilization,leading to the development of malignant tumors.The efficacy of ICIs is closely related to PD-1/PD-L1.Therefore,inhibiting these DUBs can make tumor cells sensitive to immune surveillance and enhance the effectiveness of ICIs.Therefore,in-depth exploration of the combination therapy of DUBs inhibitors and ICIs is of great significance for improving the prognosis of GC.
基金supported by National Natural Science Foundation of China(No.U21A20420 to Bo Yang)Zhejiang Provincial Natural Science Foundation(No.LR22H310002 to Ji Cao,China)。
文摘Deubiquitinating enzymes(DUBs) or deubiquitinases facilitate the escape of multiple proteins from ubiquitin-proteasome degradation and are critical for regulating protein expression levels in vivo.Therefore,dissecting the underlying mechanism of DUB recognition is needed to advance the development of drugs related to DUB signaling pathways.To data,extensive studies on the ubiquitin chain specificity of DUBs have been reported,but substrate protein recognition is still not clearly understood.As a breakthrough,the scaffolding role may be significant to substrate protein selectivity.From this perspective,we systematically characterized the scaffolding proteins and complexes contributing to DUB substrate selectivity.Furthermore,we proposed a deubiquitination complex platform(DCP) as a potentially generic mechanism for DUB substrate recognition based on known examples,which might fill the gaps in the understanding of DUB substrate specificity.
基金supported by the National Natural Science Foundation of China(32300694,32270807,32170829,and 31900538)the Shandong Natural Science Foundation(2022HWYQ-075)the Taishan Scholar Foundation of Shandong Province(tsqn202211109).
文摘Cilia are microtubule-based organelles projecting from the cell surface with important sensory and motility functions.Ciliary defects are associated with diverse diseases collectively known as ciliopathies.However,the molecular mechanisms that govern ciliogenesis remain not fully understood.Here,we demonstrate that ubiquitin-specific protease 21(USP21)is indispensable for cilium formation through its deubiquitinating activity.Usp21 knockout mice exhibit ciliary defects in multiple organs,such as the kidney,liver,and trachea.Our data also reveal a constant localization of USP21 at the centrosome and basal body during ciliogenesis.Mechanistically,USP21 interacts with dihydropyrimidinase-like 2(DPYSL2)at the centrosome and removes lysine 48-linked ubiquitination from DPYSL2.Loss of USP21 leads to the proteasomal degradation of DPYSL2 and causes a significant reduction in its centrosome abundance,ultimately resulting in ciliary defects.These findings thus identify a critical role for the USP21–DPYSL2 axis in ciliogenesis and have important implications for health and disease.
基金This work was supported by grants from the National Natural Science Foundation of China(31730026,81930039,and 81525012).
文摘Stimulator of interferon genes(STING)is an adaptor protein that is critical for effective innate antiviral and antitumor immunity.The activity of STING is heavily regulated by protein ubiquitination,which is fine-tuned by both E3 ubiquitin ligases and deubiquitinases.Here,we report that the deubiquitinase OTUD5 interacts with STING,cleaves its K48-linked polyubiquitin chains,and promotes its stability.Consistently,knockout of OTUD5 resulted in faster turnover of STING and subsequently impaired type I IFN signaling following cytosolic DNA stimulation.More importantly,Lyz2-Cre Otud5^(fl/Y) mice and CD11-Cre Otud5^(fl/Y) mice showed more susceptibility to herpes simplex virus type 1(HSV-1)infection and faster development of melanomas than their corresponding control littermates,indicating that OTUD5 is indispensable for STING-mediated antiviral and antitumor immunity.Our data suggest that OTUD5 is a novel checkpoint in the cGAS-STING cytosolic DNA sensing pathway.
文摘Oral squamous cell carcinoma(OSCC)is the most common head and neck malignancy worldwide,accounting for more than 90%of all oral cancers,and is characterized by high invasiveness and poor long-term prognosis.Its etiology is multifactorial,involving tobacco use,alcohol consumption,and human papillomavirus(HPV)infection.Oral leukoplakia and erythroplakia are the main precancerous lesions lesions,with oral leukoplakia being the most common.Both OSCC and premalignant lesions are closely associated with aberrant activation of multiple signaling pathways.Post-translational modifications(such as ubiquitination and deubiquitination)play key roles in regulating these pathways by controlling protein stability and activity.Growing evidence indicates that dysregulated ubiquitination/deubiquitination can mediate OSCC initiation and progression via aberrant activation of signaling pathways.The ubiquitination/deubiquitination process mainly involves E3 ligases(E3s)that catalyze substrate ubiquitination,deubiquitinating enzymes(DUBs)that remove ubiquitin chains,and the 26S proteasome complex that degrades ubiquitinated substrates.Abnormal expression or mutation of E3s and DUBs can lead to altered stability of critical tumorrelated proteins,thereby driving OSCC initiation and progression.Therefore,understanding the aberrantly activated signaling pathways in OSCC and the ubiquitination/deubiquitination mechanisms within these pathways will help elucidate the molecular mechanisms and improve OSCC treatment by targeting relevant components.Here,we summarize four aberrantly activated signaling pathways in OSCC―the PI3K/AKT/mTOR pathway,Wnt/β-catenin pathway,Hippo pathway,and canonical NF-κB pathway―and systematically review the regulatory mechanisms of ubiquitination/deubiquitination within these pathways,along with potential drug targets.PI3K/AKT/mTOR pathway is aberrantly activated in approximately 70%of OSCC cases.It is modulated by E3s(e.g.,FBXW7 and NEDD4)and DUBs(e.g.,USP7 and USP10):FBXW7 and USP10 inhibit signaling,while NEDD4 and USP7 potentiate it.Aberrant activation of the Wnt/β-catenin pathway leads toβ-catenin nuclear translocation and induction of cell proliferation.This pathway is modulated by E3s(e.g.,c-Cbl and RNF43)and DUBs(e.g.,USP9X and USP20):c-Cbl and RNF43 inhibit signaling,while USP9X and USP20 potentiate it.Hippo pathway inactivation permits YAP/TAZ to enter the nucleus and promotes cancer cell metastasis.This pathway is modulated by E3s(e.g.,CRL4^(DCAF1) and SIAH2)and DUBs(e.g.,USP1 and USP21):CRL4^(DCAF1) and SIAH2 inhibit signaling,while USP1 and USP21 potentiate it.Persistent activation of the canonical NF-κB pathway is associated with an inflammatory microenvironment and chemotherapy resistance.This pathway is modulated by E3s(e.g.,TRAF6 and LUBAC)and DUBs(e.g.,A20 and CYLD):A20 and CYLD inhibit signaling,while TRAF6 and LUBAC potentiate it.Targeting these E3s and DUBs provides directions for OSCC drug research.Small-molecule inhibitors such as YCH2823(a USP7 inhibitor),GSK2643943A(a USP20 inhibitor),and HOIPIN-8(a LUBAC inhibitor)have shown promising antitumor activity in preclinical models;PROTAC molecules,by binding to surface sites of target proteins and recruiting E3s,achieve targeted ubiquitination and degradation of proteins insensitive to small-molecule inhibitors,for example,PU7-1-mediated USP7 degradation,offering new strategies to overcome traditional drug limitations.Currently,NX-1607(a Cbl-b inhibitor)has entered phase I clinical trials,with preliminary results confirming its safety and antitumor activity.Future research on aberrant E3s and DUBs in OSCC and the development of highly specific inhibitors will be of great significance for OSCC precision therapy.
基金supported by the National Natural Science Foundation of China(21961142009 to Guang Liang and 82501725 to Xia Zhao)Hangzhou Natural Science Foundation(2024SZRYBH090002to Xia Zhao)Medical and Health Science and Technology Project of Zhejiang Province(2025KY1032 to Xia Zhao).
文摘Parkinson's disease(PD)is a severe neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons.Emerging evidence suggests that deubiquitinating enzymes(DUBs),which regulate protein homeostasis through the cleavage of ubiquitin chains,play critical roles in PD pathogenesis.In this study,we discovered that a DUB,ovarian tumor deubiquitinase 6A(OTUD6A),was significantly upregulated in both PD patients and PD mouse models.Notably,OTUD6A deficiency effectively protected dopaminergic neurons from degeneration and improved motor deficits in both acute and chronic PD mouse models.Through comprehensive mass spectrometry analysis and co-immunoprecipitation assays,we identified that actin gamma 1(ACTG1)serves as a key substrate of OTUD6A.Mechanistically,OTUD6A specifically interacts with the 8–181 aa domain of ACTG1 and preferentially cleaves K48-linked polyubiquitin chains,thereby enhancing ACTG1 protein stability in neuronal cells.The stabilized ACTG1 subsequently binds to p53 and facilitates its nuclear translocation,leading to the transcriptional activation of pro-apoptotic genes and promoting neuronal apoptosis.Collectively,our findings demonstrate that OTUD6A promotes dopaminergic neuron degeneration and PD progression by deubiquitinating and stabilizing ACTG1,which in turn activates a p53-dependent apoptotic pathway.These findings identify OTUD6A as a potential therapeutic target for PD intervention.
基金supported by the National Key R&D Program of China(No.2017YFA0505400)the National Natural Science Foundation of China(Nos.21877024,21972214 and 22277020)。
文摘Activity-based Ubiquitin probes(Ub-ABPs)carrying a reporter group have emerged as effective tools for the investigation of deubiquitinating enzymes(DUBs),such as studying the molecular mechanism of DUBs,profiling new DUBs.But so far,the synthesis of commonly used biotin-bearing Ub-ABPs is a technical challenge.Here,we report a one-pot semi-synthetic strategy for the acquiring of Ub-ABPs carrying a biotin tag through sequential enzymatic ligation,N-S acyl transfer and aminolysis reaction without any purification steps.These probes enable to capture the different family of DUBs for enrichment and immunoblotting using the attached biotin tag.
基金supported by the Swedish Society for Medical Research,Swedish Cancer Foundation,Swedish Medical Research Council,Royal Physiographic Society in Lund,BioCARE,Cancer Foundation,SUS Research Foundationsby funding from the European Research Council(ERC),under the European Union’s Seventh Framework Programme for Research and Technology Development,Grant Agreement No.[260460].
文摘Dysregulation of components of the ubiqutin system has been linked to many diseases including melanoma. This is vital since the post-translational modification of different proteins via direct ubiquitin attachment is an important process for various cellular processes. CYLD is a tumor suppressor gene and deubiquitinating enzyme, which can remove polyubiquitin chains from their specific substrate and interfere with different signaling pathways. CYLD is frequently downregulated or even lost in melanoma cell lines or tissues compared to melanocytes. Down-regulation of CYLD leads to sustained oncogenic signaling that promotes melanoma progression and metastasis. In this review, we summarize the recent insights into the mechanisms which are responsible for the down-regulation of CYLD levels in melanoma and the signaling interactions of the CYLD gene product in melanoma. We argue that these recent insights into CYLD function invite the development of novel molecular strategies for melanoma prevention and treatment.
基金These authors contributed equally to this work. We thank Drs S Vaidya and E Chow （University of California Los Angeles, USA） for their help in setting up critical experimental systems. We greatly thank Dr K Holmes （University of Colorado Health Sciences Center, USA） for sharing with us 17C1-1 cell line and helping to optimize the protocol to produce high titered MHV-A59 virus stock. We also thank Drs R Baric and L Su （University of North Carolina, USA） for the gift of MHV-A59 and guidance of virus infection. We thank Dr K Lim （National Neuroscience Institute, Singapore） for the gift of Ubi plasmids. We thank Dr M Wathelet （University of Cincinnati College of Medicine, USA） for sharing the nsp3 construct. Also we thank Dr G Gao （Institute of Biophysics, CAS） for providing us with VSV. This research was partly supported by grants from the National Natural Science Foundation of China （30728006） to Genhong Cheng and the National Basic Research Program of MOST （2004BA519A61, 2006CB504300, 2007DFC30190） to Hong Tang.
文摘Infections by coronaviruses such as severe acute respiratory syndrome （SARS） coronavirus （SCoV） and mouse hepatitis virus A59 （MHV-A59） result in very little type I interferon （IFN） production by host cells, which is potentially responsible for the rapid viral growth and severe immunopathology associated with SARS. However, the molecular mechanisms for the low IFN production in cells infected with coronaviruses remain unclear. Here, we provide evidence that Papain-like protease domain 2 （PLP2）, a catalytic domain of the nonstructural protein 3 （nsp3） of MHV-A59, can bind to IRF3, cause its deubiquitination and prevent its nuclear translocation. As a consequence, co-expression of PLP2 strongly inhibits CARDIF-, TBK1- and IRF3-mediated IFNp reporter activities. In addition, we show that wild-type PLP2 but not the mutant PLP2 lacking the deubiquitinase （DUB） activity can reduce IFN induction and promote viral growth in cells infected with VSV. Thus, our study uncovered a viral DUB which coronaviruses may use to escape from the host innate antiviral responses.
基金Acknowledgment We thank the laboratory, clinical and paramedical staff of the center of Reproductive Medicine, and the Departmerit of Forensic Medicine, Pathology for their assistance. We especially thank Dr Sheng-Bin Li for practical support. This study was supported by National Natural Science Foundation of China （No. 30471735） and Science ＆ Technique Research Intensive Project of Education Ministry of China （No.105157） and Sci-Technical Development Project of Shaanxi Province, China （2005K15-G2, 2006K15-G4）.
文摘Aim： To study the incidence of single nucleotide polymorphisms in ubiquitin-specific protease 26 （USP26） gene and its involvement in idiopathic male infertility in China. Methods： Routine semen analysis was performed. Infertility factors such as immunological, infectious and biochemical disorders were examined to select patients with idiopathic infertility. DNA was isolated from peripheral blood of the selected patients and control population, which were examined for mutations using polymerase chain reaction-single strand conformation polymorphism analysis. Furthermore, nucleotide sequences were sequenced in some patients and controls. Results： Of 41 infertile men, 9 （22.0%, P = 0.01） had changes in USP26 gene on the X chromosome. A compound mutation （364insACA; 460G→A） was detected in 8 patients （19.5%, P = 0.01） and a 1044T→A substitution was found in 1 patient （2.4%, P 〉 0.05）. All three variations led to changes in the coding amino acids. Two substitutions predict some changes： 460G→ A changes a valine into an isoleucine, and 1044T → A substitutes a leucine for a phenylalanine. Another insertion of three nucleotides ACA causes an insertion of threonine. No other changes were found in the remaining patients and fertile controls. Conclusion： The USP26 gene might be of importance in male reproduction. Mutations in this gene might be associated with male infertility, and might negatively affect testicular function. Further research on this issue is in progress.
基金Acknowledgments We thank the members of our laboratory for discussions. This work was supported by grants from the National Basic Re- search Program of China （973 Program） （2006CB504301 and 2010CB911802） and the National Natural Science Foundation of China （30921001 and 30700417）.
文摘Viral infection initiates a series of signaling cascades that activate the transcription factors nuclear factor kappa B and interferon regulatory factor 3, which collaborate to induce transcription of genes for type I interferons （IFNs） and other cytokines. Here we report that the deubiquitinating enzyme ubiquitin-specific protease 17 （USP17） is required for virus-induced RIG-I- and melanoma differentiation-associated protein-5 （MDA5）-mediated type I IFN signaling. Knockdown of endogenous USP17 inhibited virus-, cytoplasmic poly（I：C）- and poly（dA：dT）-induced activation of the IFN-β promoter and cellular antiviral responses. We further found that knockdown of USP17 inhibited RIG-I- and MDA5-induced but not downstream activator-induced activation of the IFN-β promoter, which was correlated with an increase in ubiquitination levels of RIG-I and MDA5. Taken together, our findings suggest that USP17 functions through deubiquitination of RIG-I and MDA5 to regulate virus-induced type I IFN signaling.
基金supported by the National Natural Science Foundation of China(Nos. U1732161, 91753120)
文摘As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein quality control. However, the structural and biochemical properties of K-branched ubiquitin chains have not been well examined. Here we employed the synthetic linkage-and length-defined K-branched ubiquitin chains to examine their binding and hydrolysis properties in vitro. Quantitatively affinity determination of ubiquitin chains to the proteasome ubiquitin receptor S5 a indicated that the S5 a exhibited preference binding to K-branched chains over K-linked chains, but not K-conjugated chains. In addition, deubiquitination experiments were carried out and the results showed that K-branched chains were preferably hydrolyzed by proteasome-associated deubiquitinase Rpnll than homotypic Kor K-linked chains.
基金Acknowledgment We thank the laboratory, clinical and paramedical staff of the center of Reproductive Medicine, and the Department of Pathology for their assistance. This study was supported by the National Natural Science Foundation of China （30471735 and 30700654） and the Sci-Technical Development Project of Shanxi Province, China （2006K 15-G4）.
文摘Deubiquitinating enzymes （DUBs） play an important role in ubiquitin-dependent processes as negative regulators of protein ubiquitination. Ubiquitin-specific protease 26 （USP26） is a member of this family. The expression of Usp26 in mammalian testis and in other tissues has yet to be fully elucidated. To study the expression of Usp26 mRNA and protein in various murine tissues, reverse transcription （RT）-PCR and immunohistochemistry analyses were carried out. The RT-PCR analysis showed that the Usp26 transcript was expressed in all of the tested tissues. USP26 protein localization was examined by immunohistochemistry, and it was shown that USP26 was not detectable at 20 days postpartum, with the expression restricted to the cytoplasm of condensing spermatids （steps 9-16）, Leydig cells and nerve fibers in the brain. In addition, the USP26 protein was detected at moderate levels in myocardial ceils, the corpus of epidydimis, epithelium of the renal tubules and the seminal gland of postnatal day 35 mice. Its spatial and temporal expression pattern suggests that Usp26 may play an important role in development or function of the testis and brain. Further research into these possibilities is in progress.
基金supported by Natural Science Foundation of Shaanxi Province(No.2023-JC-YB-743 and No.2021JQ-905).
文摘Objective Obesity-induced kidney injury contributes to the development of diabetic nephropathy(DN).Here,we identified the functions of ubiquitin-specific peptidase 19(USP19)in HK-2 cells exposed to a combination of high glucose(HG)and free fatty acid(FFA)and determined its association with TGF-beta-activated kinase 1(TAK1).Methods HK-2 cells were exposed to a combination of HG and FFA.USP19 mRNA expression was detected by quantitative RT-PCR(qRT-PCR),and protein analysis was performed by immunoblotting(IB).Cell growth was assessed by Cell Counting Kit-8(CCK-8)viability and 5-ethynyl-2′-deoxyuridine(EdU)proliferation assays.Cell cycle distribution and apoptosis were detected by flow cytometry.The USP19/TAK1 interaction and ubiquitinated TAK1 levels were assayed by coimmunoprecipitation(Co-IP)assays and IB.Results In HG+FFA-challenged HK-2 cells,USP19 was highly expressed.USP19 knockdown attenuated HG+FFA-triggered growth inhibition and apoptosis promotion in HK-2 cells.Moreover,USP19 knockdown alleviated HG+FFA-mediated PTEN-induced putative kinase 1(PINK1)/Parkin pathway inactivation and increased mitochondrial reactive oxygen species(ROS)generation in HK-2 cells.Mechanistically,USP19 stabilized the TAK1 protein through deubiquitination.Importantly,increased TAK1 expression reversed the USP19 knockdown-mediated phenotypic changes and PINK1/Parkin pathway activation in HG+FFA-challenged HK-2 cells.Conclusion The findings revealed that USP19 plays a crucial role in promoting HK-2 cell dysfunction induced by combined stimulation with HG and FFAs by stabilizing TAK1,providing a potential therapeutic strategy for combating DN.
基金supported by National Natural Science Foundation of China(82271347 to Gaojun Wu and U24A20814 to Guang Liang).
文摘Doxorubicin(Dox)is an anthracycline drug widely applied in various malignancies.However,the fatal cardiotoxicity induced by Dox limits its clinical application.Post-transcriptional protein modification via ubiquitination/deubiquitination in cardiomyocytes mediates the pathophysiological process in Dox-induced cardiotoxicity(DIC).In this study,we aimed to clarify the regulatory role and mechanism of a deubiquitinating enzyme,ubiquitin-specific peptidase 13(USP13),in DIC.RNA-seq analysis and experimental examinations identified that cardiomyocyte-derived USP13 positively correlated with DIC.Mice with cardiac-specific deletion of USP13 were subjected to Dox modeling.Adeno-associated virus serotype 9(AAV9)carrying cTNT promoter was constructed to overexpress USP13 in mouse heart tissues.Cardiomyocyte-specific knockout of USP13 exacerbated DIC,while its overexpression mitigated DIC in mice.Mechanistically,USP13 deubiquitinates the stimulator of interferon genes(STING)and promotes the autolysosome-related degradation of STING,subsequently alleviating cardiomyocyte inflammation and death.Our study suggests that USP13 serves a cardioprotective role in DIC and indicates USP13 as a potential therapeutic target for DIC treatment.
