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Combs LR, Combs J, McKenna R, Toth Z. Protein Degradation by Gammaherpesvirus RTAs: More Than Just Viral Transactivators. Viruses 2023; 15:730. [PMID: 36992439 PMCID: PMC10055789 DOI: 10.3390/v15030730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a member of the Gammaherpesvirus subfamily that encodes several viral proteins with intrinsic E3 ubiquitin ligase activity or the ability to hijack host E3 ubiquitin ligases to modulate the host's immune response and to support the viral life cycle. This review focuses specifically on how the immediate-early KSHV protein RTA (replication and transcription activator) hijacks the host's ubiquitin-proteasome pathway (UPP) to target cellular and viral factors for protein degradation to allow for robust lytic reactivation. Notably, RTA's targets are either potent transcription repressors or they are activators of the innate and adaptive immune response, which block the lytic cycle of the virus. This review mainly focuses on what is currently known about the role of the E3 ubiquitin ligase activity of KSHV RTA in the regulation of the KSHV life cycle, but we will also discuss the potential role of other gammaherpesviral RTA homologs in UPP-mediated protein degradation.
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Affiliation(s)
- Lauren R. Combs
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
| | - Jacob Combs
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
- UF Genetics Institute, Gainesville, FL 32610, USA
- UF Health Cancer Center, Gainesville, FL 32610, USA
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2
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STAT6/VDR Axis Mitigates Lung Inflammatory Injury by Promoting Nrf2 Signaling Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:2485250. [PMID: 35047105 PMCID: PMC8763503 DOI: 10.1155/2022/2485250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/17/2021] [Accepted: 12/14/2021] [Indexed: 11/18/2022]
Abstract
Lung inflammatory injury is a global public health concern. It is characterized by infiltration of diverse inflammatory cells and thickening of pulmonary septum along with oxidative stress to airway epithelial cells. STAT6 is a nuclear transcription factor that plays a crucial role in orchestrating the immune response, but its function in tissue inflammatory injury has not been comprehensively studied. Here, we demonstrated that STAT6 activation can protect against particle-induced lung inflammatory injury by resisting oxidative stress. Specifically, genetic ablation of STAT6 was observed to worsen particle-induced lung injury mainly by disrupting the lungs' antioxidant capacity, as reflected by the downregulation of the Nrf2 signaling pathway, an increase in malondialdehyde levels, and a decrease in glutathione levels. Vitamin D receptor (VDR) has been previously proved to positively regulate Nrf2 signals. In this study, silencing VDR expression in human bronchial epithelial BEAS-2B cells consistently suppressed autophagy-mediated activation of the Nrf2 signaling pathway, thereby aggravating particle-induced cell damage. Mechanically, STAT6 activation promoted the nuclear translocation of VDR, which increased the transcription of autophagy-related genes and induced Nrf2 signals, and silencing VDR abolished these effects. Our research provides important insights into the role of STAT6 in oxidative damage and reveals its potential underlying mechanism. This information not only deepens the appreciation of STAT6 but also opens new avenues for the discovery of therapies for inflammatory respiratory system disorders.
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3
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Expression of Concern: Nuclear Localization and Cleavage of STAT6 Is Induced by Kaposi's Sarcoma-Associated Herpesvirus for Viral Latency. PLoS Pathog 2021; 17:e1010047. [PMID: 34910774 PMCID: PMC8673609 DOI: 10.1371/journal.ppat.1010047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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4
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Proteomic Profiling Identifies Kaposi's Sarcoma-Associated Herpesvirus (KSHV)-Encoded LANA SIM-Associated Proteins in Hypoxia. mSystems 2021; 6:e0110921. [PMID: 34726485 PMCID: PMC8562486 DOI: 10.1128/msystems.01109-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hypoxia signaling is a key regulator in the development and progression of many types of human malignancies, including viral cancers. The latency-associated nuclear antigen (LANA), encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) during latency, is a multifunctional protein that plays an essential role in viral episome maintenance and lytic gene silencing for inducing tumorigenesis. Although our previous studies have shown that LANA contains a SUMO-interacting motif (LANASIM), and hypoxia reduces SUMOylated KAP1 association with LANASIM, the physiological proteomic network of LANASIM-associated cellular proteins in response to hypoxia is still unclear. In this study, we individually established cell lines stably expressing wild-type LANA (LANAWT) and its SIM-deleted mutant (LANAdSIM) and treated them with or without hypoxia, followed by coimmunoprecipitation and mass spectrometry analysis to systemically identify the hypoxia-responsive profile of LANASIM-associated cellular proteins. We found that in hypoxia, the number of cellular proteins associated with LANAWT instead of LANAdSIM was dramatically increased. Functional network analysis revealed that two major pathways, which included cytoskeleton organization and DNA/RNA binding and processing pathways, were significantly enriched for 28 LANASIM-associated proteins in response to hypoxia. HNRNPU was one of the proteins consistently identified that interacted with LANASIM in different proteomic screening systems and responded to hypoxia. This study provides a proteomic profile of LANASIM-associated proteins in hypoxia and facilitates our understanding of the role of the collaboration between viral infection and the hypoxia response in inducing viral persistence and tumorigenesis. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) has been reported to be involved in the regulation of host proteins in response to hypoxic stress. LANA, one of the key latent proteins, contains a SUMO-interacting motif (LANASIM) and reduces the association with SUMOylated KAP1 upon hypoxic treatment. However, the physiological systematic network of LANASIM-associated cellular proteins in hypoxia is still unclear. Here, we revealed two major pathways, which included cytoskeleton organization and DNA/RNA binding and processing pathways, that were significantly enriched for 28 LANASIM-associated proteins in hypoxia. This discovery not only provides a proteomic profile of LANASIM-associated proteins in hypoxia but also facilitates our understanding of the collaboration between viral infection and hypoxic stress in inducing viral persistence and tumorigenesis.
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Karpathiou G, Habougit C, Peoc'h M. STAT6 is not expressed in Kaposi sarcoma. Ann Diagn Pathol 2021; 55:151836. [PMID: 34626935 DOI: 10.1016/j.anndiagpath.2021.151836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 09/24/2021] [Indexed: 10/20/2022]
Affiliation(s)
| | - Cyril Habougit
- Pathology Department, University Hospital of Saint-Etienne, France
| | - Michel Peoc'h
- Pathology Department, University Hospital of Saint-Etienne, France
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6
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Karpathiou G, Papoudou-Bai A, Ferrand E, Dumollard JM, Peoc'h M. STAT6: A review of a signaling pathway implicated in various diseases with a special emphasis in its usefulness in pathology. Pathol Res Pract 2021; 223:153477. [PMID: 33991851 DOI: 10.1016/j.prp.2021.153477] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/17/2022]
Abstract
Signal Transducer and Activator of Transcription 6 (STAT6), belonging to a family of seven similar members is primarily stimulated by interleukin(IL)-4 and IL-13, and acts as a T helper type 2 (Th2)-inducing factor. Thus, it is implicated in the pathophysiology of various allergic conditions, such as asthma, atopic dermatitis, eosinophilic esophagitis and food allergies, but also in tumor microenvironment regulation. Furthermore, certain forms of lymphomas, notably the Hodgkin lymphoma group, the primary mediastinal and primary central nervous system lymphoma, as well as some follicular and T cell lymphomas are associated with dysregulation of the STAT6 pathway. STAT6 immunohistochemical expression also serves as a surrogate marker in the diagnosis of solitary fibrous tumor, despite not directly responsible for the tumorigenic effect. These pathophysiological implications of the STAT6 pathway, its diagnostic or prognostic role in pathology, as well its immunohistochemical detection with different antibodies will be discussed in this review.
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Affiliation(s)
| | | | - Elise Ferrand
- Pathology Department, University Hospital of Saint-Etienne, France
| | | | - Michel Peoc'h
- Pathology Department, University Hospital of Saint-Etienne, France
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7
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The roles of post-translational modifications and coactivators of STAT6 signaling in tumor growth and progression. Future Med Chem 2020; 12:1945-1960. [DOI: 10.4155/fmc-2020-0224] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Signal transducers and activators of transcription 6 (STAT6) are highly expressed in various tumors and associated with tumorigenesis, immunosuppression, proliferation, metastasis and poor prognosis in human cancers. In response to IL-4/13, STAT6 is phosphorylated, dimerizes and triggers transcriptional regulation after recruitment of coactivators to transcriptosome, such as CBP/p300, SRC-1, PARP-14 and PSF. Post-translational modifications, including phosphorylation, ubiquitination, ADP-ribosylation and acetylation, have been explored for molecular mechanisms of STAT6 in tumor development and management. STAT6 has been developed as a specific biomarker for distinguishing and diagnosing tumor phenotypes, although it is observed to be frequently mutated in metastatic tumors. In this article, we focus mainly on the structural characteristics of STAT6 and its role in tumor growth and progression.
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Abstract
Viruses commonly antagonize the antiviral type I interferon response by targeting signal transducer and activator of transcription 1 (STAT1) and STAT2, key mediators of interferon signaling. Other STAT family members mediate signaling by diverse cytokines important to infection, but their relationship with viruses is more complex. Importantly, virus-STAT interaction can be antagonistic or stimulatory depending on diverse viral and cellular factors. While STAT antagonism can suppress immune pathways, many viruses promote activation of specific STATs to support viral gene expression and/or produce cellular conditions conducive to infection. It is also becoming increasingly clear that viruses can hijack noncanonical STAT functions to benefit infection. For a number of viruses, STAT function is dynamically modulated through infection as requirements for replication change. Given the critical role of STATs in infection by diverse viruses, the virus-STAT interface is an attractive target for the development of antivirals and live-attenuated viral vaccines. Here, we review current understanding of the complex and dynamic virus-STAT interface and discuss how this relationship might be harnessed for medical applications.
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Regulation of KSHV Latency and Lytic Reactivation. Viruses 2020; 12:v12091034. [PMID: 32957532 PMCID: PMC7551196 DOI: 10.3390/v12091034] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/10/2020] [Accepted: 09/12/2020] [Indexed: 02/06/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is associated with three malignancies— Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman’s disease (MCD). Central to the pathogenesis of these diseases is the KSHV viral life cycle, which is composed of a quiescent latent phase and a replicative lytic phase. While the establishment of latency enables persistent KSHV infection and evasion of the host immune system, lytic replication is essential for the dissemination of the virus between hosts and within the host itself. The transition between these phases, known as lytic reactivation, is controlled by a complex set of environmental, host, and viral factors. The effects of these various factors converge on the regulation of two KSHV proteins whose functions facilitate each phase of the viral life cycle—latency-associated nuclear antigen (LANA) and the master switch of KSHV reactivation, replication and transcription activator (RTA). This review presents the current understanding of how the transition between the phases of the KSHV life cycle is regulated, how the various phases contribute to KSHV pathogenesis, and how the viral life cycle can be exploited as a therapeutic target.
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Zhu Q, Ding L, Zi Z, Gao S, Wang C, Wang Y, Zhu C, Yuan Z, Wei F, Cai Q. Viral-Mediated AURKB Cleavage Promotes Cell Segregation and Tumorigenesis. Cell Rep 2020; 26:3657-3671.e5. [PMID: 30917319 DOI: 10.1016/j.celrep.2019.02.106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 01/04/2019] [Accepted: 02/27/2019] [Indexed: 12/31/2022] Open
Abstract
Aurora kinase B (AURKB), a central regulator of chromosome segregation and cytokinesis, is aberrantly expressed in various cancer cells. However, the relationship of AURKB and oncogenic viruses in cancer progression remains unclear. Here, we reveal that N-cleaved isoforms of AURKB exist in several oncovirus-associated tumor cells and patient cancer tissues, including Kaposi's sarcoma-associated herpesvirus (KSHV), Epstein-Barr virus (EBV), and human papillomavirus virus (HPV). Mechanistically, in KSHV-infected tumor cells, the latent viral antigen LANA cleaves AURKB at Asp76 in a serine protease-dependent manner. The N'-AURKB relocalizes to the spindle pole and promotes the metaphase-to-telophase transition in mitotic cells. Introduction of N'-AURKB but not C'-AURKB promotes colony formation and malignant growth of tumor cells in vitro and in vivo using a murine xenograft model. Altogether, our findings uncover a proteolytic cleavage mechanism by which oncoviruses induce cancer cell segregation and tumorigenesis.
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Affiliation(s)
- Qing Zhu
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Ling Ding
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhenguo Zi
- ShengYushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shujun Gao
- Hospital and Institute of Obstetrics and Gynecology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Chong Wang
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yuyan Wang
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Caixia Zhu
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhenghong Yuan
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Fang Wei
- ShengYushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiliang Cai
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China; Expert Workstation, Baoji Central Hospital, Baoji, 721008 Shaanxi Province, China.
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STUB1 is targeted by the SUMO-interacting motif of EBNA1 to maintain Epstein-Barr Virus latency. PLoS Pathog 2020; 16:e1008447. [PMID: 32176739 PMCID: PMC7105294 DOI: 10.1371/journal.ppat.1008447] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/30/2020] [Accepted: 03/01/2020] [Indexed: 12/31/2022] Open
Abstract
Latent Epstein-Barr virus (EBV) infection is strongly associated with several malignancies, including B-cell lymphomas and epithelial tumors. EBNA1 is a key antigen expressed in all EBV-associated tumors during latency that is required for maintenance of the EBV episome DNA and the regulation of viral gene transcription. However, the mechanism utilized by EBV to maintain latent infection at the levels of posttranslational regulation remains largely unclear. Here, we report that EBNA1 contains two SUMO-interacting motifs (SIM2 and SIM3), and mutation of SIM2, but not SIM3, dramatically disrupts the EBNA1 dimerization, while SIM3 contributes to the polySUMO2 modification of EBNA1 at lysine 477 in vitro. Proteomic and immunoprecipitation analyses further reveal that the SIM3 motif is required for the EBNA1-mediated inhibitory effects on SUMO2-modified STUB1, SUMO2-mediated degradation of USP7, and SUMO1-modified KAP1. Deletion of the EBNASIM motif leads to functional loss of both EBNA1-mediated viral episome maintenance and lytic gene silencing. Importantly, hypoxic stress induces the SUMO2 modification of EBNA1, and in turn the dissociation of EBNA1 with STUB1, KAP1 and USP7 to increase the SUMO1 modification of both STUB1 and KAP1 for reactivation of lytic replication. Therefore, the EBNA1SIM motif plays an essential role in EBV latency and is a potential therapeutic target against EBV-associated cancers. The Small Ubiquitin-related modifier (SUMO) modification of proteins is a reversible post-translational regulation involved in control of gene transcription, among other functions. Epstein-Barr virus (EBV) infects most people worldwide and contributes to the development of several types of cancers due to its ability to induce cell proliferation and survival. EBNA1 is expressed in all forms of EBV-associated tumors. In this study, we found that EBNA1 contains a SUMO-interacting motif (SIM) named EBNA1SIM, which is required for EBNA1 to exert inhibitory effects on a SUMO2-modified complex (SC2) including STUB1, KAP1 and USP7. Disruption of EBNA1SIM leads to loss of both EBNA1-mediated viral episome maintenance and lytic gene silencing. Importantly, hypoxia-mediated reactivation of viral lytic replication induces the EBNA1 dissociation from STUB1 in the SC2 complex. This discovery not only opens a new insight on the interplay between host and virus, but it also provides a therapeutic target specific against EBV-associated cancers.
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12
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Broussard G, Damania B. KSHV: Immune Modulation and Immunotherapy. Front Immunol 2020; 10:3084. [PMID: 32117196 PMCID: PMC7025529 DOI: 10.3389/fimmu.2019.03084] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 12/17/2019] [Indexed: 12/21/2022] Open
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is associated with KS, primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). To ensure its own survival and propagation, KSHV employs an extensive network of viral proteins to subvert the host immune system, resulting in lifelong latent infection. Modulation of cellular and systemic immune defenses allows KSHV to persist in the host, which may eventually lead to the progression of KSHV-associated cancers. Due to KSHV's reliance on modifying immune responses to efficiently infect its host, immunotherapy is an attractive option for treating KSHV-associated malignancies. In this review, we will focus on the mechanisms by which KSHV evades the immune system and the current immune-related clinical strategies to treat KSHV-associated disease.
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Affiliation(s)
- Grant Broussard
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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13
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Cao L, Zhang X, Wang Y, Bao Y, Tang F. A case of solitary fibrous tumor/hemangiopericytoma in the central nervous system with papillary morphology. Neuropathology 2019; 39:141-146. [PMID: 30864263 DOI: 10.1111/neup.12541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/03/2019] [Accepted: 01/25/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Lijuan Cao
- Department of PathologyHuashan Hospital of Fudan University Shanghai China
| | - Xialing Zhang
- Department of PathologyHuashan Hospital of Fudan University Shanghai China
| | - Yin Wang
- Department of PathologyHuashan Hospital of Fudan University Shanghai China
| | - Yun Bao
- Department of PathologyHuashan Hospital of Fudan University Shanghai China
| | - Feng Tang
- Department of PathologyHuashan Hospital of Fudan University Shanghai China
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Gu F, Wang C, Wei F, Wang Y, Zhu Q, Ding L, Xu W, Zhu C, Cai C, Qian Z, Yuan Z, Robertson E, Cai Q. STAT6 degradation and ubiquitylated TRIML2 are essential for activation of human oncogenic herpesvirus. PLoS Pathog 2018; 14:e1007416. [PMID: 30532138 PMCID: PMC6287816 DOI: 10.1371/journal.ppat.1007416] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/17/2018] [Indexed: 01/01/2023] Open
Abstract
Aberrations in STAT6-mediated signaling are linked to the development of multiple cancer types. Increasing evidence has shown that activation of human oncogenic herpesvirus lytic replication is crucial for viral tumorigenesis. However, the role of STAT6 in herpesvirus lytic replication remains elusive. Here, by using Kaposi’s sarcoma-associated herpesvirus (KSHV) as a model, we revealed that RTA, the master regulator of lytic replication, interacts with STAT6 and promotes lysine 48 (K48) and K63-linked ubiquitylation of STAT6 for degradation via the proteasome and lysosome systems. Moreover, degradation of STAT6 is dramatically associated with the increased ubiquitylated form of tripartite motif family like 2 (TRIML2, a tumor suppressor) for prolonged cell survival and virion production, which is also commonly observed in lytic activation of Epstein-Barr virus, herpes simplex virus 1 and cytomegalovirus. These results suggest that degradation of STAT6 is important for the lytic activation of KSHV and as such, may be an attractive therapeutic target. STAT6 is a transcriptional factor that plays an important role in the extracellular cytokine and virus-mediated immune response. Extensive studies have revealed that the dysregulation of STAT6 is linked to the pathological features of virus-associated cancers. However, the molecular mechanism of STAT6 regulation by tumor viruses is still unknown. Here, we report that the degradation of STAT6 is induced and required for the lytic activation of human herpesviruses including oncogenic γ-herpesviruses (KSHV and EBV) and α/β-herpesviruses (HSV1 and HCMV). Importantly, this effect is highly dependent on the expression of viral lytic antigens (i.e., RTA in KSHV). This study reveals the central role of STAT6 in controlling the switch from latency to lytic replication of herpesviruses.
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Affiliation(s)
- Feng Gu
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Chong Wang
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Fang Wei
- ShengYushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Yuyan Wang
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Qing Zhu
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Ling Ding
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Wenjia Xu
- Unit of Herpesvirus and Molecular Virology, Key Laboratory of Molecular Virology &Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, P. R. China
| | - Caixia Zhu
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Cankun Cai
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Zhikang Qian
- Unit of Herpesvirus and Molecular Virology, Key Laboratory of Molecular Virology &Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, P. R. China
| | - Zhenghong Yuan
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
| | - Erle Robertson
- Department of Otorhinolaryngology-Head and Neck Surgery, Department of Microbiology, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States of America
| | - Qiliang Cai
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai, P. R. China
- * E-mail:
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Duan Z, Xu H, Ji X, Zhao J, Xu H, Hu Y, Deng S, Hu S, Liu X. Importin α5 negatively regulates importin β1-mediated nuclear import of Newcastle disease virus matrix protein and viral replication and pathogenicity in chicken fibroblasts. Virulence 2018. [PMID: 29532715 PMCID: PMC5955436 DOI: 10.1080/21505594.2018.1449507] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The matrix (M) protein of Newcastle disease virus (NDV) is demonstrated to localize in the nucleus via intrinsic nuclear localization signal (NLS), but cellular proteins involved in the nuclear import of NDV M protein and the role of M's nuclear localization in the replication and pathogenicity of NDV remain unclear. In this study, importin β1 was screened to interact with NDV M protein by yeast two-hybrid screening. This interaction was subsequently confirmed by co-immunoprecipitation and pull-down assays. In vitro binding studies indicated that the NLS region of M protein and the amino acids 336–433 of importin β1 that belonged to the RanGTP binding region were important for binding. Importantly, a recombinant virus with M/NLS mutation resulted in a pathotype change of NDV and attenuated viral replication and pathogenicity in chicken fibroblasts and SPF chickens. In agreement with the binding data, nuclear import of NDV M protein in digitonin-permeabilized HeLa cells required both importin β1 and RanGTP. Interestingly, importin α5 was verified to interact with M protein through binding importin β1. However, importin β1 or importin α5 depletion by siRNA resulted in different results, which showed the obviously cytoplasmic or nuclear accumulation of M protein and the remarkably decreased or increased replication ability and pathogenicity of NDV in chicken fibroblasts, respectively. Our findings therefore demonstrate for the first time the nuclear import mechanism of NDV M protein and the negative regulation role of importin α5 in importin β1-mediated nuclear import of M protein and the replication and pathogenicity of a paramyxovirus.
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Affiliation(s)
- Zhiqiang Duan
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Haixu Xu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xinqin Ji
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Jiafu Zhao
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Houqiang Xu
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Yan Hu
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shanshan Deng
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shunlin Hu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xiufan Liu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
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16
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Wang C, Zhou H, Xue Y, Liang J, Narita Y, Gerdt C, Zheng AY, Jiang R, Trudeau S, Peng CW, Gewurz BE, Zhao B. Epstein-Barr Virus Nuclear Antigen Leader Protein Coactivates EP300. J Virol 2018; 92:e02155-17. [PMID: 29467311 PMCID: PMC5899200 DOI: 10.1128/jvi.02155-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 02/10/2018] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus nuclear antigen (EBNA) leader protein (EBNALP) is one of the first viral genes expressed upon B-cell infection. EBNALP is essential for EBV-mediated B-cell immortalization. EBNALP is thought to function primarily by coactivating EBNA2-mediated transcription. Chromatin immune precipitation followed by deep sequencing (ChIP-seq) studies highlight that EBNALP frequently cooccupies DNA sites with host cell transcription factors (TFs), in particular, EP300, implicating a broader role in transcription regulation. In this study, we investigated the mechanisms of EBNALP transcription coactivation through EP300. EBNALP greatly enhanced EP300 transcription activation when EP300 was tethered to a promoter. EBNALP coimmunoprecipitated endogenous EP300 from lymphoblastoid cell lines (LCLs). EBNALP W repeat serine residues 34, 36, and 63 were required for EP300 association and coactivation. Deletion of the EP300 histone acetyltransferase (HAT) domain greatly reduced EBNALP coactivation and abolished the EBNALP association. An EP300 bromodomain inhibitor also abolished EBNALP coactivation and blocked the EP300 association with EBNALP. EBNALP sites cooccupied by EP300 had significantly higher ChIP-seq signals for sequence-specific TFs, including SPI1, RelA, EBF1, IRF4, BATF, and PAX5. EBNALP- and EP300-cooccurring sites also had much higher H3K4me1 and H3K27ac signals, indicative of activated enhancers. EBNALP-only sites had much higher signals for DNA looping factors, including CTCF and RAD21. EBNALP coactivated reporters under the control of NF-κB or SPI1. EP300 inhibition abolished EBNALP coactivation of these reporters. Clustered regularly interspaced short palindromic repeat interference targeting of EBNALP enhancer sites significantly reduced target gene expression, including that of EP300 itself. These data suggest a previously unrecognized mechanism by which EBNALP coactivates transcription through subverting of EP300 and thus affects the expression of LCL genes regulated by a broad range of host TFs.IMPORTANCE Epstein-Barr virus was the first human DNA tumor virus discovered over 50 years ago. EBV is causally linked to ∼200,000 human malignancies annually. These cancers include endemic Burkitt lymphoma, Hodgkin lymphoma, lymphoma/lymphoproliferative disease in transplant recipients or HIV-infected people, nasopharyngeal carcinoma, and ∼10% of gastric carcinoma cases. EBV-immortalized human B cells faithfully model key aspects of EBV lymphoproliferative diseases and are useful models of EBV oncogenesis. EBNALP is essential for EBV to transform B cells and transcriptionally coactivates EBNA2 by removing repressors from EBNA2-bound DNA sites. Here, we found that EBNALP can also modulate the activity of the key transcription activator EP300, an acetyltransferase that activates a broad range of transcription factors. Our data suggest that EBNALP regulates a much broader range of host genes than was previously appreciated. A small-molecule inhibitor of EP300 abolished EBNALP coactivation of multiple target genes. These findings suggest novel therapeutic approaches to control EBV-associated lymphoproliferative diseases.
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Affiliation(s)
- Chong Wang
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Hufeng Zhou
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Yong Xue
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jun Liang
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Yohei Narita
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Catherine Gerdt
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Amy Y Zheng
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Runsheng Jiang
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Stephen Trudeau
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Chih-Wen Peng
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Benjamin E Gewurz
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Bo Zhao
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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17
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The regulatory role of protein phosphorylation in human gammaherpesvirus associated cancers. Virol Sin 2017; 32:357-368. [PMID: 29116588 PMCID: PMC6704201 DOI: 10.1007/s12250-017-4081-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/23/2017] [Indexed: 12/12/2022] Open
Abstract
Activation of specific sets of protein kinases by intracellular signal molecules
has become more and more apparent in the past decade. Phosphorylation, one of key
posttranslational modification events, is activated by kinase or regulatory protein
and is vital for controlling many physiological functions of eukaryotic cells such
as cell proliferation, differentiation, malignant transformation, and signal
transduction mediated by external stimuli. Moreovers, the reversible modification of
phosphorylation and dephosphorylation can result in different features of the target
substrate molecules including DNA binding, protein-protein interaction, subcellular
location and enzymatic activity, and is often hijacked by viral infection.
Epstein-Barr virus (EBV) and Kaposi’s sarcomaassociated herpesvirus (KSHV), two
human oncogenic gamma-herpesviruses, are shown to tightly associate with many
malignancies. In this review, we summarize the recent progresses on understanding of
molecular properties and regulatory modes of cellular and viral proteins
phosphorylation influenced by these two tumor viruses, and highlight the potential
therapeutic targets and strategies against their related cancers. ![]()
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