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Xing J, Hu C, Che S, Lan Y, Huang L, Liu L, Yin Y, Li H, Liao M, Qi W. USP1-Associated Factor 1 Modulates Japanese Encephalitis Virus Replication by Governing Autophagy and Interferon-Stimulated Genes. Microbiol Spectr 2023; 11:e0318622. [PMID: 36988464 PMCID: PMC10269463 DOI: 10.1128/spectrum.03186-22] [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: 08/13/2022] [Accepted: 03/07/2023] [Indexed: 03/30/2023] Open
Abstract
Japanese encephalitis virus (JEV) is a typical mosquito-borne flavivirus that can cause central nervous system diseases in humans and animals. Host factors attempt to limit virus replication when the viruses invade the host by using various strategies for replication. It is essential to clarify the host factors that affect the life cycle of JEV and explore its underlying mechanism. Here, we found that USP1-associated factor 1 (UAF1; also known as WD repeat-containing protein 48) modulated JEV replication. We found that JEV propagation significantly increased in UAF1-depleted Huh7 cells. Moreover, we found that knockdown of UAF1 activated cell autophagic flux in further functional analysis. Subsequently, we demonstrated that autophagy can be induced by JEV, which promotes viral replication by inhibiting interferon-stimulated gene (ISG) expression in Huh7 cells. The knockdown of UAF1 reduced ISG expression during JEV infection. To explore the possible roles of autophagy in UAF1-mediated inhibition of JEV propagation, we knocked out ATG7 to generate autophagy-deficient cells and found that depletion of UAF1 failed to promote JEV replication in ATG7 knockout cells. Moreover, in ATG7-deficient Huh7 cells, interference with UAF1 expression did not lead to the induction of autophagy. Taken together, these findings indicate that UAF1 is a critical regulator of autophagy and reveal a mechanism by which UAF1 knockdown activates autophagy to promote JEV replication. IMPORTANCE Host factors play an essential role in virus replication and pathogenesis. Although UAF1 is well known to form complexes with ubiquitin-specific proteases, little is known about the function of the UAF1 protein itself. In this study, we confirmed that UAF1 is involved in JEV replication. Notably, we discovered a novel function for UAF1 in regulating autophagy. Furthermore, we demonstrated that UAF1 modulated JEV replication through its autophagy regulation. This study is the first description of the novel function of UAF1 in regulating autophagy, and it clarifies the underlying mechanism of the antiviral effect of UAF1 against JEV. These results provide a new mechanistic insight into the functional annotation of UAF1 and provide a potential target for increasing virus production during vaccine production.
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Affiliation(s)
- Jinchao Xing
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
- Key Laboratory of Zoonoses Prevention and Control of Guangdong Province, Guangzhou, China
| | - Chen Hu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
- Key Laboratory of Zoonoses Prevention and Control of Guangdong Province, Guangzhou, China
| | - Siqi Che
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yixin Lan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Lihong Huang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Lele Liu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
| | - Youqin Yin
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
| | - Huanan Li
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
| | - Ming Liao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
- Key Laboratory of Zoonoses Prevention and Control of Guangdong Province, Guangzhou, China
| | - Wenbao Qi
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis, Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
- Key Laboratory of Zoonoses Prevention and Control of Guangdong Province, Guangzhou, China
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Byers NM, Burns PL, Stuchlik O, Reed MS, Ledermann JP, Pohl J, Powers AM. Identification of mosquito proteins that differentially interact with alphavirus nonstructural protein 3, a determinant of vector specificity. PLoS Negl Trop Dis 2023; 17:e0011028. [PMID: 36696390 PMCID: PMC9876241 DOI: 10.1371/journal.pntd.0011028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 12/17/2022] [Indexed: 01/26/2023] Open
Abstract
Chikungunya virus (CHIKV) and the closely related onyong-nyong virus (ONNV) are arthritogenic arboviruses that have caused significant, often debilitating, disease in millions of people. However, despite their kinship, they are vectored by different mosquito subfamilies that diverged 180 million years ago (anopheline versus culicine subfamilies). Previous work indicated that the nonstructural protein 3 (nsP3) of these alphaviruses was partially responsible for this vector specificity. To better understand the cellular components controlling alphavirus vector specificity, a cell culture model system of the anopheline restriction of CHIKV was developed along with a protein expression strategy. Mosquito proteins that differentially interacted with CHIKV nsP3 or ONNV nsP3 were identified. Six proteins were identified that specifically bound ONNV nsP3, ten that bound CHIKV nsP3 and eight that interacted with both. In addition to identifying novel factors that may play a role in virus/vector processing, these lists included host proteins that have been previously implicated as contributing to alphavirus replication.
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Affiliation(s)
- Nathaniel M. Byers
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
- * E-mail:
| | - Paul L. Burns
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Olga Stuchlik
- Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Matthew S. Reed
- Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jeremy P. Ledermann
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Jan Pohl
- Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Ann M. Powers
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
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A Comparative Quantitative Proteomic Analysis of HCMV-Infected Cells Highlights pUL138 as a Multifunctional Protein. Molecules 2020; 25:molecules25112520. [PMID: 32481657 PMCID: PMC7321164 DOI: 10.3390/molecules25112520] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/15/2020] [Accepted: 05/21/2020] [Indexed: 02/02/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread virus that can establish life-long latent infection in large populations. The establishment of latent infection prevents HCMV from being cleared by host cells, and HCMV reactivation from latency can cause severe disease and death in people with immature or compromised immune systems. To establish persistent and latent infection in healthy individuals, HCMV encodes a large array of proteins that can modulate different components and pathways of host cells. It has been reported that pUL138 encoded by the UL133-UL138 polycistronic locus promotes latent infection in primary CD34+ hematopoietic progenitor cells (HPCs) infected in vitro. In this study, recombinant HCMV HanUL138del was constructed by deleting the UL138 locus of Han, a clinical HCMV strain. Then, a comparative quantitative proteomic analysis of Han- and HanUL138del-infected MRC5 cells was performed to study the effect of pUL138 on host cells in the context of HCMV infection. Our results indicated that, during the early phase of HCMV infection, the innate immune response was differentially activated, while during the late phase of HCMV infection, multiple host proteins were differentially expressed between Han- and HanUL138del-infected cells, and these proteins are involved in the oxidation-reduction process, ER to Golgi vesicle-mediated transport, and extracellular matrix organization. Among these proteins, STEAP3, BORCS7, FAM172A, RELL1, and WDR48 were further demonstrated to affect HCMV infection. Our study provides a systematic view of the effect of pUL138 on the host cell proteome and highlights the proposition that multiple biological processes or host factors may be involved in the overall role of the UL133-UL138 polycistronic locus in HCMV persistence.
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Bayliss RJ, Piguet V. Masters of manipulation: Viral modulation of the immunological synapse. Cell Microbiol 2018; 20:e12944. [PMID: 30123959 PMCID: PMC6492149 DOI: 10.1111/cmi.12944] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/01/2018] [Accepted: 08/14/2018] [Indexed: 02/06/2023]
Abstract
In order to thrive, viruses have evolved to manipulate host cell machinery for their own benefit. One major obstacle faced by pathogens is the immunological synapse. To enable efficient replication and latency in immune cells, viruses have developed a range of strategies to manipulate cellular processes involved in immunological synapse formation to evade immune detection and control T-cell activation. In vitro, viruses such as human immunodeficiency virus 1 and human T-lymphotropic virus type 1 utilise structures known as virological synapses to aid transmission of viral particles from cell to cell in a process termed trans-infection. The formation of the virological synapse provides a gateway for virus to be transferred between cells avoiding the extracellular space, preventing antibody neutralisation or recognition by complement. This review looks at how viruses are able to subvert intracellular signalling to modulate immune function to their advantage and explores the role synapse formation has in viral persistence and cell-to-cell transmission.
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Affiliation(s)
- Rebecca J. Bayliss
- Division of Infection and Immunity, School of MedicineCardiff UniversityCardiffUK
| | - Vincent Piguet
- Division of Infection and Immunity, School of MedicineCardiff UniversityCardiffUK
- Division of Dermatology, Department of MedicineUniversity of TorontoTorontoOntarioCanada
- Division of DermatologyWomen's College HospitalTorontoOntarioCanada
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Zheng H, Wang M, Zhao C, Wu S, Yu P, Lü Y, Wang T, Ai Y. Characterization of the deubiquitination activity and substrate specificity of the chicken ubiquitin-specific protease 1/USP associated factor 1 complex. PLoS One 2017; 12:e0186535. [PMID: 29091922 PMCID: PMC5665528 DOI: 10.1371/journal.pone.0186535] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 10/03/2017] [Indexed: 12/02/2022] Open
Abstract
Deubiquitinases (DUBs) are essential regulators of intracellular processes involving ubiquitin (Ub) modification. The human DUB ubiquitin-specific protease 1 (hUSP1) interacts with human USP-associated factor 1 (hUAF1), and helps to regulate processes such as DNA damage repair. Previously, we identified a chicken USP1 homologue (chUSP1) during an investigation into the properties of Marek's disease virus (MDV). However, chUSP1's deubiquitination activity, interaction with chUAF1, and substrate specificity remained unknown. In the present study, we expressed and purified both chUAF1 and chUSP1 with or without putative catalytic core mutations using the Bac-to-Bac system, before investigating their deubiquitination activity and kinetics using various substrates. chUSP1 was shown to interact with chUAF1 both in cellular assays in which the two proteins were co-expressed, and in in vitro assays using purified proteins. Heterodimerization with chUAF1 increased the deubiquitination activity of chUSP1 up to 54-fold compared with chUSP1 alone. The chUSP1 mutants C91S, H603A, and D758A reduced the deubiquitination activity of the chUSP1/chUAF1 complex by 10-, 7-, and 33-fold, respectively, while the C91A and H594A chUSP1 mutants eliminated deubiquitination activity of the chUSP1/chUAF1 complex completely. This suggests that C91 and H594, but not D758, are essential for chUSP1 deubiquitination activity, and that a nucleophilic group at position 91 is needed for the deubiquitination reaction. The chUSP1/chUAF1 complex was found to have distinct substrate preferences; efficient hydrolysis of Ub dimers with K11-, K48-, and K63-linkages was seen, with weaker hydrolysis observed with K6-, K27-, and K33-linkages and no hydrolysis seen with a K29-linkage. Furthermore, other Ub-like substrates were disfavored by the complex. No activity was seen with SUMO1-GST, SUMO2- and SUMO3-dimers, ISG15-Rho, FAT10-Rho, or Ufm1-Rho, and only weak activity was observed with NEDD8-Rho. Overall, the data presented here characterize the activity and substrate preferences of chUSP1, and thus may facilitate future studies on its in vivo role.
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Affiliation(s)
- Hainan Zheng
- College of Animal Science, Jilin University, Changchun, China
| | - Mengyun Wang
- College of Animal Science, Jilin University, Changchun, China
| | - Chengcheng Zhao
- Institute of Translational Medicine, Jilin University, Changchun, China
| | - Shanli Wu
- College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Peifeng Yu
- College of Animal Science, Jilin University, Changchun, China
| | - Yan Lü
- College of Animal Science, Jilin University, Changchun, China
| | - Tiedong Wang
- College of Animal Science, Jilin University, Changchun, China
- * E-mail: (YXA); (TDW)
| | - Yongxing Ai
- College of Animal Science, Jilin University, Changchun, China
- * E-mail: (YXA); (TDW)
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Banerjee S, Uppal T, Strahan R, Dabral P, Verma SC. The Modulation of Apoptotic Pathways by Gammaherpesviruses. Front Microbiol 2016; 7:585. [PMID: 27199919 PMCID: PMC4847483 DOI: 10.3389/fmicb.2016.00585] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 04/11/2016] [Indexed: 12/11/2022] Open
Abstract
Apoptosis or programmed cell death is a tightly regulated process fundamental for cellular development and elimination of damaged or infected cells during the maintenance of cellular homeostasis. It is also an important cellular defense mechanism against viral invasion. In many instances, abnormal regulation of apoptosis has been associated with a number of diseases, including cancer development. Following infection of host cells, persistent and oncogenic viruses such as the members of the Gammaherpesvirus family employ a number of different mechanisms to avoid the host cell’s “burglar” alarm and to alter the extrinsic and intrinsic apoptotic pathways by either deregulating the expressions of cellular signaling genes or by encoding the viral homologs of cellular genes. In this review, we summarize the recent findings on how gammaherpesviruses inhibit cellular apoptosis via virus-encoded proteins by mediating modification of numerous signal transduction pathways. We also list the key viral anti-apoptotic proteins that could be exploited as effective targets for novel antiviral therapies in order to stimulate apoptosis in different types of cancer cells.
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Affiliation(s)
- Shuvomoy Banerjee
- Amity Institute of Virology and Immunology, Amity University Noida, India
| | - Timsy Uppal
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Roxanne Strahan
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Prerna Dabral
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Subhash C Verma
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
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7
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Gao Y, Nai W, Yang L, Lu Z, Shi P, Jin H, Wen H, Wang G. Construction of an immunorelated protein-protein interaction network for clarifying the mechanism of burn. Burns 2015; 42:405-13. [PMID: 26739088 DOI: 10.1016/j.burns.2015.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 06/20/2015] [Accepted: 06/24/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND AIM Severe burn is known to induce a series of pathological responses resulting in increased susceptibility to systemic inflammatory response and multiple organ failure, but the underlying molecular mechanism remains unclear at present. The main aim of this study was to expand our understanding of the events leading to circulating leukocyte response after burn by subjecting the gene expression profiles to a bioinformatic analysis. MATERIALS AND METHODS Comprehensive gene expression analysis was performed to identify differentially expressed genes (DEGs) using the expression profile GSE7404 (Mus musculus, circulating leukocyte, 25% of total body surface area (TBSA), full thickness) downloaded from the Gene Expression Omnibus, followed by the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. In addition, a postburn protein-protein interaction (PPI) network was constructed to identify potential biomarkers. RESULTS Maximum changes in the gene expression profile were detected 1 day post burn. Separate Gene Ontology (GO) functional enrichment analysis for upregulated and downregulated DEGs revealed significant alterations of genes related to biological process such as "response to stimuli," "metabolic," "cellular and immune system processes," "biological regulation," and "death" in the leukocyte transcriptome after the burn. The KEGG pathway enrichment analysis showed that the upregulated DEGs were significantly enriched in the nodes of immunorelated and signal transduction-related pathways, and the downregulated genes were significantly enriched for the immunorelated pathways. The PPI network and module analysis revealed that, 1 day after the burn, lymphocyte-specific protein tyrosine kinase (Lck) (downregulated), Jun (upregulated), Cd19 (downregulated), Stat1 (downregulated), and Cdk1 (upregulated) were located centrally in both the PPI network and modules. CONCLUSIONS Based on an integrated bioinformatic analysis, we concluded that Lck, Jun, Cd19, Stat1, and Cdk1 may be critical 1 day after the burn. These findings expand our understanding of the molecular mechanisms of this important pathological process. Further studies are needed to support our work, focused on identifying candidate biomarkers with sufficient predictive power to act as prognostic and therapeutic biomarkers for burn injury.
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Affiliation(s)
- Yanbin Gao
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Wenqing Nai
- Department of Health Management, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Lei Yang
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
| | - Zhiyang Lu
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Pengwei Shi
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Hui Jin
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Huangding Wen
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Guifang Wang
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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Ohashi M, Holthaus AM, Calderwood MA, Lai CY, Krastins B, Sarracino D, Johannsen E. The EBNA3 family of Epstein-Barr virus nuclear proteins associates with the USP46/USP12 deubiquitination complexes to regulate lymphoblastoid cell line growth. PLoS Pathog 2015; 11:e1004822. [PMID: 25855980 PMCID: PMC4391933 DOI: 10.1371/journal.ppat.1004822] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 03/19/2015] [Indexed: 11/29/2022] Open
Abstract
The Epstein-Barr virus (EBV) nuclear proteins EBNA3A, EBNA3B, and EBNA3C interact with the cell DNA binding protein RBPJ and regulate cell and viral genes. Repression of the CDKN2A tumor suppressor gene products p16INK4A and p14ARF by EBNA3A and EBNA3C is critical for EBV mediated transformation of resting B lymphocytes into immortalized lymphoblastoid cell lines (LCLs). To define the composition of endogenous EBNA3 protein complexes, we generated lymphoblastoid cell lines (LCLs) expressing flag-HA tagged EBNA3A, EBNA3B, or EBNA3C and used tandem affinity purification to isolate each EBNA3 complex. Our results demonstrated that each EBNA3 protein forms a distinct complex with RBPJ. Mass-spectrometry revealed that the EBNA3A and EBNA3B complexes also contained the deubquitylation complex consisting of WDR48, WDR20, and USP46 (or its paralog USP12) and that EBNA3C complexes contained WDR48. Immunoprecipitation confirmed that EBNA3A, EBNA3B, and EBNA3C association with the USP46 complex. Using chromatin immunoprecipitation, we demonstrate that WDR48 and USP46 are recruited to the p14ARF promoter in an EBNA3C dependent manner. Mapping studies were consistent with WDR48 being the primary mediator of EBNA3 association with the DUB complex. By ChIP assay, WDR48 was recruited to the p14ARF promoter in an EBNA3C dependent manner. Importantly, WDR48 associated with EBNA3A and EBNA3C domains that are critical for LCL growth, suggesting a role for USP46/USP12 in EBV induced growth transformation. Epstein-Barr virus (EBV) is a gammaherpesvirus implicated in the pathogenesis of multiple malignancies, including Burkitt lymphoma, Hodgkin lymphoma, post-transplant lymphoproliferative disease (PTLD), nasopharyngeal carcinoma, and gastric carcinoma. EBV infection of resting B-lymphocytes drives them to proliferate as lymphoblastoid cell lines (LCLs), an in vitro model of PTLD. LCLs express a limited EBV gene repertoire, including six nuclear proteins (EBNA1, 2, 3A, 3B, 3C, and LP), three integral membrane proteins (LMP1, 2A, and 2B), and more than 30 micro RNAs. EBNA2 and the EBNA3 proteins are transcription factors that regulate viral and cell gene expression through the cell DNA binding protein RBPJ. In this study, we established LCLs transformed by recombinant EBV genomes in which a Flag-HA epitope tag is fused in-frame to the C-terminus of EBNA3A, EBNA3B or EBNA3C. Using these LCLs, we purified endogenous EBNA3 complexes and identified the USP46 deubiquitinating enzyme (DUB) and its associated chaperones WDR48 and WDR20 as EBNA3 binding proteins. We find that EBNA3s interact primarily with the WDR48 protein and that loss of WDR48 interaction with EBNA3A or EBNA3C impairs LCL growth. This study represents the first characterization of EBNA3 complexes from LCLs and implicates the USP46 DUB complex in EBNA3 mediated gene regulation.
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Affiliation(s)
- Makoto Ohashi
- Departments of Medicine and Oncology (McArdle Laboratory for Cancer Research), University of Wisconsin, Madison, Wisconsin, United States of America
| | - Amy M. Holthaus
- Infectious Disease Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael A. Calderwood
- Infectious Disease Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Chiou-Yan Lai
- Infectious Disease Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bryan Krastins
- Biomarker Research Initiatives in Mass Spectrometry (BRIMS), Thermo Fisher Scientific, Cambridge, Massachusetts, United States of America
| | - David Sarracino
- Biomarker Research Initiatives in Mass Spectrometry (BRIMS), Thermo Fisher Scientific, Cambridge, Massachusetts, United States of America
| | - Eric Johannsen
- Departments of Medicine and Oncology (McArdle Laboratory for Cancer Research), University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
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Artificial Recruitment of UAF1-USP Complexes by a PHLPP1-E1 Chimeric Helicase Enhances Human Papillomavirus DNA Replication. J Virol 2015; 89:6227-39. [PMID: 25833051 DOI: 10.1128/jvi.00560-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 03/18/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The E1 helicase from anogenital human papillomavirus (HPV) types interacts with the cellular WD repeat-containing protein UAF1 in complex with the deubiquitinating enzyme USP1, USP12, or USP46. This interaction stimulates viral DNA replication and is required for maintenance of the viral episome in keratinocytes. E1 associates with UAF1 through a short UAF1-binding site (UBS) located within the N-terminal 40 residues of the protein. Here, we investigated if the E1 UBS could be replaced by the analogous domain from an unrelated protein, the pleckstrin homology domain and leucine-rich repeat protein phosphatase 1 (PHLPP1). We found that PHLPP1 and E1 interact with UAF1 in a mutually exclusive manner and mapped the minimal PHLPP1 UBS (PUBS) to a 100-amino-acid region sufficient for assembly into UAF1-USP complexes. Similarly to the E1 UBS, overexpression of PUBS in trans inhibited HPV DNA replication, albeit less efficiently. Characterization of a PHLPP1-E1 chimeric helicase revealed that PUBS could partially substitute for the E1 UBS in enhancing viral DNA replication and that the stimulatory effect of PUBS likely involves recruitment of UAF1-USP complexes, as it was abolished by mutations that weaken UAF1-binding and by overexpression of catalytically inactive USPs. Although functionally similar to the E1 UBS, PUBS is larger in size and requires both the WD repeat region and C-terminal ubiquitin-like domain of UAF1 for interaction, in contrast to E1, which does not contact the latter. Overall, this comparison of two heterologous UBSs indicates that these domains function as transferable protein interaction modules and provide further evidence that the association of E1 with UAF1-containing deubiquitinating complexes stimulates HPV DNA replication. IMPORTANCE The E1 protein from anogenital HPV types interacts with the UAF1-associated deubiquitinating enzymes USP1, USP12, and USP46 to stimulate replication of the viral genome. Little is known about the molecular nature of the E1-UAF1 interaction and, more generally, how UAF1-USP complexes recognize their substrate proteins. To address this question, we characterized the UAF1-binding site (UBS) of PHLPP1, a protein unrelated to E1. Using a PHLPP1-E1 chimeric helicase, we show that the PHLPP1 UBS (PUBS) can partially substitute for the E1 UBS in stimulating HPV DNA replication. This stimulation required conserved sequences in PUBS that meditate its interaction with UAF1, including a motif common to the E1 UBS. These results indicate that UAF1-binding sequences function as transferable protein interaction modules and provide further evidence that UAF1-USP complexes stimulate HPV DNA replication.
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Novarino G, Fenstermaker AG, Zaki MS, Hofree M, Silhavy JL, Heiberg AD, Abdellateef M, Rosti B, Scott E, Mansour L, Masri A, Kayserili H, Al-Aama JY, Abdel-Salam GMH, Karminejad A, Kara M, Kara B, Bozorgmehri B, Ben-Omran T, Mojahedi F, El Din Mahmoud IG, Bouslam N, Bouhouche A, Benomar A, Hanein S, Raymond L, Forlani S, Mascaro M, Selim L, Shehata N, Al-Allawi N, Bindu P, Azam M, Gunel M, Caglayan A, Bilguvar K, Tolun A, Issa MY, Schroth J, Spencer EG, Rosti RO, Akizu N, Vaux KK, Johansen A, Koh AA, Megahed H, Durr A, Brice A, Stevanin G, Gabriel SB, Ideker T, Gleeson JG. Exome sequencing links corticospinal motor neuron disease to common neurodegenerative disorders. Science 2014; 343:506-511. [PMID: 24482476 PMCID: PMC4157572 DOI: 10.1126/science.1247363] [Citation(s) in RCA: 399] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hereditary spastic paraplegias (HSPs) are neurodegenerative motor neuron diseases characterized by progressive age-dependent loss of corticospinal motor tract function. Although the genetic basis is partly understood, only a fraction of cases can receive a genetic diagnosis, and a global view of HSP is lacking. By using whole-exome sequencing in combination with network analysis, we identified 18 previously unknown putative HSP genes and validated nearly all of these genes functionally or genetically. The pathways highlighted by these mutations link HSP to cellular transport, nucleotide metabolism, and synapse and axon development. Network analysis revealed a host of further candidate genes, of which three were mutated in our cohort. Our analysis links HSP to other neurodegenerative disorders and can facilitate gene discovery and mechanistic understanding of disease.
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Affiliation(s)
- Gaia Novarino
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ali G. Fenstermaker
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Maha S. Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Center, Cairo 12311, Egypt
| | - Matan Hofree
- Department of Computer Science and Engineering and Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jennifer L. Silhavy
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Andrew D. Heiberg
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mostafa Abdellateef
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Basak Rosti
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Eric Scott
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lobna Mansour
- Department of Pediatric Neurology, Neurometabolic Unit, Cairo University Children’s Hospital, Cairo 406, Egypt
| | - Amira Masri
- Division of Child Neurology, Department of Pediatrics, University of Jordan, Amman 11942, Jordan
| | - Hulya Kayserili
- Istanbul University, Istanbul Medical Faculty, Medical Genetics Department, 34093 Istanbul, Turkey
| | - Jumana Y. Al-Aama
- Department of Genetic Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Ghada M. H. Abdel-Salam
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Center, Cairo 12311, Egypt
| | | | - Majdi Kara
- Department of Pediatrics, Tripoli Children’s Hospital, Tripoli, Libya
| | - Bulent Kara
- Kocaeli University, Medical Faculty, Department of Pediatric Neurology, 41380 Umuttepe, Kocaeli, Turkey
| | - Bita Bozorgmehri
- Kariminejad-Najmabadi Pathology and Genetics Center, Tehran, Iran
| | - Tawfeg Ben-Omran
- Clinical and Metabolic Genetics Division, Department of Pediatrics, Hamad Medical Corporation, Doha 3050, Qatar
| | - Faezeh Mojahedi
- Mashhad Medical Genetic Counseling Center, 91767 Mashhad, Iran
| | - Iman Gamal El Din Mahmoud
- Department of Pediatric Neurology, Neurometabolic Unit, Cairo University Children’s Hospital, Cairo 406, Egypt
| | - Naima Bouslam
- Université Mohammed V Souissi, Equipe de Recherchéde Maladies Neurodégéneratives (ERMN) and Centre de Recherche en Épidémiologie Clinique et Essais Thérapeutiques (CRECET), 6402 Rabat, Morocco
| | - Ahmed Bouhouche
- Université Mohammed V Souissi, Equipe de Recherchéde Maladies Neurodégéneratives (ERMN) and Centre de Recherche en Épidémiologie Clinique et Essais Thérapeutiques (CRECET), 6402 Rabat, Morocco
| | - Ali Benomar
- Université Mohammed V Souissi, Equipe de Recherchéde Maladies Neurodégéneratives (ERMN) and Centre de Recherche en Épidémiologie Clinique et Essais Thérapeutiques (CRECET), 6402 Rabat, Morocco
| | - Sylvain Hanein
- Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225; UPMC Univ Paris VI UMR_S975, 75013 Paris, France
| | - Laure Raymond
- Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225; UPMC Univ Paris VI UMR_S975, 75013 Paris, France
| | - Sylvie Forlani
- Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225; UPMC Univ Paris VI UMR_S975, 75013 Paris, France
| | - Massimo Mascaro
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Laila Selim
- Department of Pediatric Neurology, Neurometabolic Unit, Cairo University Children’s Hospital, Cairo 406, Egypt
| | - Nabil Shehata
- Department of Pediatrics and Neonatology, Saudi German Hospital, Post Office Box 84348, Riyadh, Kingdom of Saudi Arabia
| | - Nasir Al-Allawi
- Department of Pathology, School of Medicine, University of Dohuk, Dohuk, Iraq
| | - P.S. Bindu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Matloob Azam
- Department of Pediatrics and Child Neurology, Wah Medical College, Wah Cantt, Pakistan
| | - Murat Gunel
- Department of Genetics and Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ahmet Caglayan
- Department of Genetics and Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Kaya Bilguvar
- Department of Genetics and Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Aslihan Tolun
- Department of Molecular Biology and Genetics, Bogazici University, 34342 Istanbul, Turkey
| | - Mahmoud Y. Issa
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Center, Cairo 12311, Egypt
| | - Jana Schroth
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emily G. Spencer
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rasim O. Rosti
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Naiara Akizu
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Keith K. Vaux
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anide Johansen
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alice A. Koh
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hisham Megahed
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Center, Cairo 12311, Egypt
| | - Alexandra Durr
- Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225; UPMC Univ Paris VI UMR_S975, 75013 Paris, France
- Assistance Publique–Hôpitaux de Paris, Fédération de Génétique, Pitié-Salpêtrière Hospital, 75013 Paris, France
| | - Alexis Brice
- Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225; UPMC Univ Paris VI UMR_S975, 75013 Paris, France
- Assistance Publique–Hôpitaux de Paris, Fédération de Génétique, Pitié-Salpêtrière Hospital, 75013 Paris, France
- Institut du Cerveau et de la Moelle Épinière, 75013 Paris, France
| | - Giovanni Stevanin
- Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225; UPMC Univ Paris VI UMR_S975, 75013 Paris, France
- Assistance Publique–Hôpitaux de Paris, Fédération de Génétique, Pitié-Salpêtrière Hospital, 75013 Paris, France
- Institut du Cerveau et de la Moelle Épinière, 75013 Paris, France
- Laboratoire de Neurogénétique, Ecole Pratique des Hautes Etudes, Institut du Cerveau et de la Moelle Épinière, 75013 Paris, France
| | - Stacy B. Gabriel
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Trey Ideker
- Department of Computer Science and Engineering and Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joseph G. Gleeson
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
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11
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Abstract
Calpains regulate a wide spectrum of biological functions, including migration, adhesion, apoptosis, secretion, and autophagy, through the modulating cleavage of specific substrates. Ubiquitous microcalpain (μ-calpain) and millicalpain (m-calpain) are heterodimers composed of catalytic subunits encoded, respectively, by CAPN1 and CAPN2 and a regulatory subunit encoded by CAPNS1. Here we show that calpain is required for the stability of the deubiquitinating enzyme USP1 in several cell lines. USP1 modulates DNA replication polymerase choice and repair by deubiquitinating PCNA. The ubiquitinated form of the USP1 substrate PCNA is stabilized in CAPNS1-depleted U2OS cells and mouse embryonic fibroblasts (MEFs), favoring polymerase-η loading on chromatin and increased mutagenesis. USP1 degradation directed by the cell cycle regulator APC/C(cdh1), which marks USP1 for destruction in the G1 phase, is upregulated in CAPNS1-depleted cells. USP1 stability can be rescued upon forced expression of calpain-activated Cdk5/p25, previously reported as a cdh1 repressor. These data suggest that calpain stabilizes USP1 by activating Cdk5, which in turn inhibits cdh1 and, consequently, USP1 degradation. Altogether these findings point to a connection between the calpain system and the ubiquitin pathway in the regulation of DNA damage response and place calpain at the interface between cell cycle modulation and DNA repair.
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12
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Two nuclear localization signals in USP1 mediate nuclear import of the USP1/UAF1 complex. PLoS One 2012; 7:e38570. [PMID: 22701671 PMCID: PMC3368879 DOI: 10.1371/journal.pone.0038570] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 05/07/2012] [Indexed: 01/06/2023] Open
Abstract
The human deubiquitinase USP1 plays important roles in cancer-related processes, such as the DNA damage response, and the maintenance of the undifferentiated state of osteosarcoma cells. USP1 deubiquitinase activity is critically regulated by its interaction with the WD40 repeat-containing protein UAF1. Inhibiting the function of the USP1/UAF1 complex sensitizes cancer cells to chemotherapy, suggesting that this complex is a relevant anticancer target. Intriguingly, whereas UAF1 has been reported to locate in the cytoplasm, USP1 is a nuclear protein, although the sequence motifs that mediate its nuclear import have not been functionally characterized. Here, we identify two nuclear localization signals (NLSs) in USP1 and show that these NLSs mediate the nuclear import of the USP1/UAF1 complex. Using a cellular relocation assay based on these results, we map the UAF1-binding site to a highly conserved 100 amino acid motif in USP1. Our data support a model in which USP1 and UAF1 form a complex in the cytoplasm that subsequently translocates to the nucleus through import mediated by USP1 NLSs. Importantly, our findings have practical implications for the development of USP1-directed therapies. First, the UAF1-interacting region of USP1 identified here might be targeted to disrupt the USP1/UAF1 interaction with therapeutic purposes. On the other hand, we describe a cellular relocation assay that can be easily implemented in a high throughput setting to search for drugs that may dissociate the USP1/UAF1 complex.
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13
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Species restriction of Herpesvirus saimiri and Herpesvirus ateles: Human lymphocyte transformation correlates with distinct signaling properties of viral oncoproteins. Virus Res 2012; 165:179-89. [DOI: 10.1016/j.virusres.2012.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/06/2012] [Accepted: 02/16/2012] [Indexed: 01/05/2023]
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14
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Katsch K, de Jong SJ, Albrecht JC, Steger J, Genth H, Posern G, Biesinger B. Actin-dependent activation of serum response factor in T cells by the viral oncoprotein tip. Cell Commun Signal 2012; 10:5. [PMID: 22385615 PMCID: PMC3310822 DOI: 10.1186/1478-811x-10-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 03/03/2012] [Indexed: 01/05/2023] Open
Abstract
Serum response factor (SRF) acts as a multifunctional transcription factor regulated by mutually exclusive interactions with ternary complex factors (TCFs) or myocardin-related transcription factors (MRTFs). Binding of Rho- and actin-regulated MRTF:SRF complexes to target gene promoters requires an SRF-binding site only, whereas MAPK-regulated TCF:SRF complexes in addition rely on flanking sequences present in the serum response element (SRE). Here, we report on the activation of an SRE luciferase reporter by Tip, the viral oncoprotein essentially contributing to human T-cell transformation by Herpesvirus saimiri. SRE activation in Tip-expressing Jurkat T cells could not be attributed to triggering of the MAPK pathway. Therefore, we further analyzed the contribution of MRTF complexes. Indeed, Tip also activated a reporter construct responsive to MRTF:SRF. Activation of this reporter was abrogated by overexpression of a dominant negative mutant of the MRTF-family member MAL. Moreover, enrichment of monomeric actin suppressed the Tip-induced reporter activity. Further upstream, the Rho-family GTPase Rac, was found to be required for MRTF:SRF reporter activation by Tip. Initiation of this pathway was strictly dependent on Tip's ability to interact with Lck and on the activity of this Src-family kinase. Independent of Tip, T-cell stimulation orchestrates Src-family kinase, MAPK and actin pathways to induce SRF. These findings establish actin-regulated transcription in human T cells and suggest its role in viral oncogenesis.
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Affiliation(s)
- Kristin Katsch
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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15
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Inhibition of human papillomavirus DNA replication by an E1-derived p80/UAF1-binding peptide. J Virol 2012; 86:3486-500. [PMID: 22278251 DOI: 10.1128/jvi.07003-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The papillomavirus E1 helicase is recruited by E2 to the viral origin, where it assembles into a double hexamer that orchestrates replication of the viral genome. We previously identified the cellular WD40 repeat-containing protein p80/UAF1 as a novel interaction partner of E1 from anogenital human papillomavirus (HPV) types. p80 was found to interact with the first 40 residues of HPV type 31 (HPV31) E1, and amino acid substitutions within this domain abrogated the maintenance of the viral episome in keratinocytes. In this study, we report that these p80-binding substitutions reduce by 70% the ability of E1 to support transient viral DNA replication without affecting its interaction with E2 and assembly at the origin in vivo. Microscopy studies revealed that p80 is relocalized from the cytoplasm to discrete subnuclear foci by E1 and E2. Chromatin immunoprecipitation assays further revealed that p80 is recruited to the viral origin in an E1- and E2-dependent manner. Interestingly, overexpression of a 40-amino-acid-long p80-binding peptide, derived from HPV31 E1, was found to inhibit viral DNA replication by preventing the recruitment of endogenous p80 to the origin. Mutant peptides defective for p80 interaction were not inhibitory, demonstrating the specificity of this effect. Characterization of this E1 peptide by nuclear magnetic resonance (NMR) showed that it is intrinsically disordered in solution, while mapping studies indicated that the WD repeats of p80 are required for E1 interaction. These results provide additional evidence for the requirement for p80 in anogenital HPV DNA replication and highlight the potential of E1-p80 interaction as a novel antiviral target.
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16
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Yang K, Moldovan GL, Vinciguerra P, Murai J, Takeda S, D'Andrea AD. Regulation of the Fanconi anemia pathway by a SUMO-like delivery network. Genes Dev 2011; 25:1847-58. [PMID: 21896657 DOI: 10.1101/gad.17020911] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The USP1/UAF1 complex deubiquitinates the Fanconi anemia protein FANCD2, thereby promoting homologous recombination and DNA cross-link repair. How USP1/UAF1 is targeted to the FANCD2/FANCI heterodimer has remained unknown. Here we show that UAF1 contains a tandem repeat of SUMO-like domains in its C terminus (SLD1 and SLD2). SLD2 binds directly to a SUMO-like domain-interacting motif (SIM) on FANCI. Deletion of the SLD2 sequence of UAF1 or mutation of the SIM on FANCI disrupts UAF1/FANCI binding and inhibits FANCD2 deubiquitination and DNA repair. The USP1/UAF1 complex also deubiquitinates PCNA-Ub, and deubiquitination requires the PCNA-binding protein hELG1. The SLD2 sequence of UAF1 binds to a SIM on hELG1, thus targeting the USP1/UAF1 complex to its PCNA-Ub substrate. We propose that the regulated targeting of USP1/UAF1 to its DNA repair substrates, FANCD2-Ub and PCNA-Ub, by SLD-SIM interactions coordinates homologous recombination and translesion DNA synthesis.
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Affiliation(s)
- Kailin Yang
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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17
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Kim Y, Kwon EK, Jeon JH, So I, Kim IG, Choi MS, Kim IS, Choi JK, Jung JU, Cho NH. Activation of the STAT6 transcription factor in Jurkat T-cells by the herpesvirus saimiri Tip protein. J Gen Virol 2011; 93:330-340. [PMID: 22012462 DOI: 10.1099/vir.0.036087-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Herpesvirus saimiri (HVS), a T-lymphotropic monkey herpesvirus, induces fulminant T-cell lymphoma in non-natural primate hosts. In addition, it can immortalize human T-cells in vitro. HVS tyrosine kinase-interacting protein (Tip) is an essential viral gene required for T-cell transformation both in vitro and in vivo. In this study, we found that Tip interacts with the STAT6 transcription factor and induces phosphorylation of STAT6 in T-cells. The interaction with STAT6 requires the Tyr(127) residue and Lck-binding domain of Tip, which are indispensable for interleukin (IL)-2-independent T-cell transformation by HVS. It was also demonstrated that Tip induces nuclear translocation of STAT6, as well as activation of STAT6-dependent transcription in Jurkat T-cells. Interestingly, the phosphorylated STAT6 mainly colocalized with vesicles containing Tip within T-cells, but was barely detectable in the nucleus. However, nuclear translocation of phospho-STAT6 and transcriptional activation of STAT6 by IL-4 stimulation were not affected significantly in T-cells expressing Tip. Collectively, these findings suggest that the constitutive activation of STAT6 by Tip in T-cells may contribute to IL-2-independent T-cell transformation by HVS.
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Affiliation(s)
- Yuri Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Eun-Kyung Kwon
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ju-Hong Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - In-Gyu Kim
- Department of Biochemistry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Myung-Sik Choi
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Jongno-Gu, Seoul 110-799, Republic of Korea
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ik-Sang Kim
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Jongno-Gu, Seoul 110-799, Republic of Korea
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Joong-Kook Choi
- Division of Biochemistry, College of Medicine, Chungbuk National University, Cheongju 361-763, Republic of Korea
| | - Jae Ung Jung
- Molecular Microbiology and Immunology, University of Southern California, School of Medicine, 2011 Zonal Avenue, HMR401, Los Angeles, CA 90033, USA
| | - Nam-Hyuk Cho
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Jongno-Gu, Seoul 110-799, Republic of Korea
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
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18
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Kingston D, Chang H, Ensser A, Lee HR, Lee J, Lee SH, Jung JU, Cho NH. Inhibition of retromer activity by herpesvirus saimiri tip leads to CD4 downregulation and efficient T cell transformation. J Virol 2011; 85:10627-38. [PMID: 21849449 PMCID: PMC3187508 DOI: 10.1128/jvi.00757-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 08/08/2011] [Indexed: 11/20/2022] Open
Abstract
The mammalian retromer is an evolutionally conserved protein complex composed of a vacuolar protein sorting trimer (Vps 26/29/35) that participates in cargo recognition and a sorting nexin (SNX) dimer that binds to endosomal membranes. The retromer plays an important role in efficient retrograde transport for endosome-to-Golgi retrieval of the cation-independent mannose-6-phosphate receptor (CI-MPR), a receptor for lysosomal hydrolases, and other endosomal proteins. This ultimately contributes to the control of cell growth, cell adhesion, and cell migration. The herpesvirus saimiri (HVS) tyrosine kinase-interacting protein (Tip), required for the immortalization of primary T lymphocytes, targets cellular signaling molecules, including Lck tyrosine kinases and the p80 endosomal trafficking protein. Despite the pronounced effects of HVS Tip on T cell signal transduction, the details of its activity on T cell immortalization remain elusive. Here, we report that the amino-terminal conserved, glutamate-rich sequence of Tip specifically interacts with the retromer subunit Vps35 and that this interaction not only causes the redistribution of Vps35 from the early endosome to the lysosome but also drastically inhibits retromer activity, as measured by decreased levels of CI-MPR and lower activities of cellular lysosomal hydrolases. Physiologically, the inhibition of intracellular retromer activity by Tip is ultimately linked to the downregulation of CD4 surface expression and to the efficient in vitro immortalization of primary human T cells to interleukin-2 (IL-2)-independent permanent growth. Therefore, HVS Tip uniquely targets the retromer complex to impair the intracellular trafficking functions of infected cells, ultimately contributing to efficient T cell transformation.
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Affiliation(s)
- Dior Kingston
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102
- Institute for Research in Biomedicine, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland
| | - Heesoon Chang
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102
- Molecular Microbiology & Immunology, University of Southern California, School of Medicine, 2011 Zonal Avenue, HMR401, Los Angeles, California 90033
| | - Armin Ensser
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91054 Erlangen, Germany
| | - Hye-Ra Lee
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102
- Molecular Microbiology & Immunology, University of Southern California, School of Medicine, 2011 Zonal Avenue, HMR401, Los Angeles, California 90033
| | - Jongsoo Lee
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102
- Molecular Microbiology & Immunology, University of Southern California, School of Medicine, 2011 Zonal Avenue, HMR401, Los Angeles, California 90033
| | - Sun-Hwa Lee
- Molecular Microbiology & Immunology, University of Southern California, School of Medicine, 2011 Zonal Avenue, HMR401, Los Angeles, California 90033
| | - Jae Ung Jung
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102
- Molecular Microbiology & Immunology, University of Southern California, School of Medicine, 2011 Zonal Avenue, HMR401, Los Angeles, California 90033
| | - Nam-Hyuk Cho
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102
- Department of Microbiology and Immunology, Seoul National University College of Medicine, and Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Jongno-Gu, Seoul 110-799, Republic of Korea
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19
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Sigalov AB. The SCHOOL of nature: IV. Learning from viruses. SELF/NONSELF 2010; 1:282-298. [PMID: 21487503 PMCID: PMC3062383 DOI: 10.4161/self.1.4.13279] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/04/2010] [Accepted: 08/05/2010] [Indexed: 02/05/2023]
Abstract
During the co-evolution of viruses and their hosts, the latter have equipped themselves with an elaborate immune system to defend themselves from the invading viruses. In order to establish a successful infection, replicate and persist in the host, viruses have evolved numerous strategies to counter and evade host antiviral immune responses as well as exploit them for productive viral replication. These strategies include those that modulate signaling mediated by cell surface receptors. Despite tremendous advancement in recent years, the exact molecular mechanisms underlying these critical points in viral pathogenesis remain unknown. In this work, based on a novel platform of receptor signaling, the Signaling Chain HOmoOLigomerization (SCHOOL) platform, I suggest specific mechanisms used by different viruses such as human immunodeficiency virus (HIV), cytomegalovirus (CMV), severe acute respiratory syndrome coronavirus, human herpesvirus 6 and others, to modulate receptor signaling. I also use the example of HIV and CMV to illustrate how two unrelated enveloped viruses use a similar SCHOOL mechanism to modulate the host immune response mediated by two functionally different receptors: T cell antigen receptor and natural killer cell receptor, NKp30. This suggests that it is very likely that similar general mechanisms can be or are used by other viral and possibly non-viral pathogens. Learning from viruses how to target cell surface receptors not only helps us understand viral strategies to escape from the host immune surveillance, but also provides novel avenues in rational drug design and the development of new therapies for immune disorders.
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20
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Hidalgo-Curtis C, Apperley JF, Stark A, Stark A, Jeng M, Gotlib J, Chase A, Cross NCP, Grand FH. Fusion of PDGFRB to two distinct loci at 3p21 and a third at 12q13 in imatinib-responsive myeloproliferative neoplasms. Br J Haematol 2010; 148:268-73. [PMID: 20085582 DOI: 10.1111/j.1365-2141.2009.07955.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We identified four patients who presented with BCR-ABL1 negative myeloproliferative neoplasms and cytogenetically visible abnormalities of chromosome band 5q31-35. Fluorescence in situ hybridization indicated that the platelet-derived growth factor receptor beta gene (PDGFRB) was disrupted in all four cases and 5' rapid amplification of cDNA ends identified in-frame mRNA fusions between PDGFRB and WDR48 (3p21), GOLGA4 (3p21) and BIN2 (12q13). Strikingly, all three genes encode proteins involving intracellular trafficking. Imatinib, a known inhibitor of PDGFRbeta, selectively blocked the growth of t(3;5) myeloid colonies and produced clinically significant responses in all patients. We conclude that PDGFRB fuses to diverse partner genes in atypical myeloproliferative neoplasms (MPNs). Although very rare, identification of these fusions is critical for proper management of affected individuals.
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Manolios N, Ali M, Bender V. T-cell antigen receptor (TCR) transmembrane peptides: A new paradigm for the treatment of autoimmune diseases. Cell Adh Migr 2010; 4:273-83. [PMID: 20431344 DOI: 10.4161/cam.4.2.11909] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cell surface membranes are generally considered as inert and hydrophobic providing a stable physical barrier that anchor proteins and maintain cellular homeostasis between the intra- and the extra-cellular environment. The integral proteins that transverse membranes do so once or multiple times and can function alone or as part of a larger complex. Far from being inert, there is a multiplicity of biophysical factors that drive protein-protein and protein-lipid interactions within membranes that are being increasingly recognised as very important for cellular function. Unravelling these "hot-spots" on the contact surface of transmembrane (TM) proteins and targeting peptides to these sites to interrupt the cohesive interaction between the proteins provides both an enormous challenge and a huge therapeutic potential that as yet remains unrecognized. Indeed, with biopharmaceutical research on the rise, TM peptides may prove a useful innovation. Using the T-cell antigen receptor (TCR) as a model system of multi-subunits interacting at the TM via electrostatic charges the potential for peptides as therapeutic agents to interfere with normal immune responses is discussed. The principles of such can be extended to other similar receptor systems including those involved in cancer or infection.
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Affiliation(s)
- Nicholas Manolios
- Department of Rheumatology, Westmead Hospital, Westmead, NSW, Australia.
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22
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Sigalov AB. New therapeutic strategies targeting transmembrane signal transduction in the immune system. Cell Adh Migr 2010; 4:255-67. [PMID: 20519929 DOI: 10.4161/cam.4.2.10746] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Single-chain receptors and multi-chain immune recognition receptors (SRs and MIRRs, respectively) represent families of structurally related but functionally different surface receptors expressed on different cells. In contrast to SRs, a distinctive and common structural characteristic of MIRR family members is that the extracellular recognition domains and intracellular signaling domains are located on separate subunits. How extracellular ligand binding triggers MIRRs and initiates intracellular signal transduction processes is not clear. A novel model of immune signaling, the Signaling Chain HOmoOLigomerization (SCHOOL) model, suggests that the homooligomerization of receptor intracellular signaling domains represents a necessary and sufficient condition for receptor triggering. In this review, I demonstrate striking similarities between a consensus model of SR signaling and the SCHOOL model of MIRR signaling and show how these models, together with the lessons learned from viral pathogenesis, provide a molecular basis for novel pharmacological approaches targeting inter- and intrareceptor transmembrane interactions as universal therapeutic targets for a diverse variety of immune and other disorders.
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Affiliation(s)
- Alexander B Sigalov
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA.
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23
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Vesicle traffic to the immunological synapse: a multifunctional process targeted by lymphotropic viruses. Curr Top Microbiol Immunol 2010; 340:191-207. [PMID: 19960315 DOI: 10.1007/978-3-642-03858-7_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The site of contact between T lymphocytes and antigen-presenting cells becomes, upon antigen recognition, an organized junction named the immunological synapse. Various T cell organelles polarize, together with microtubules, toward the antigen-presenting cell. Among them, intracellular vesicular compartments, such as the Golgi apparatus, the recycling endosomal compartment, or cytotoxic granules help to build the immunological synapse and ensure effector functions, such as polarized secretion of cytokines by helper T cells, or exocytosis of lytic granules by cytotoxic T cells. Lymphotropic retroviruses, such as the human immunodeficiency virus type 1, the human T cell leukemia virus type 1, or the Herpesvirus saimiri, can subvert some of the vesicle traffic mechanisms impeding the generation and function of the immunological synapses. This review focuses on the polarization of vesicle traffic, its regulation, and its role in maintaining the structure and function of the immunological synapse. We discuss how some lymphotropic viruses target the vesicle traffic in T lymphocytes, inhibiting the formation of immunological synapses and modulating the response of infected T cells.
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Gorska MM, Liang Q, Karim Z, Alam R. Uncoordinated 119 protein controls trafficking of Lck via the Rab11 endosome and is critical for immunological synapse formation. THE JOURNAL OF IMMUNOLOGY 2009; 183:1675-84. [PMID: 19592652 DOI: 10.4049/jimmunol.0900792] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The activation of T cells through the TCR is essential for development of the adaptive immune response. TCR does not have any enzymatic activity and relies on the plasma membrane-associated lymphocyte-specific protein tyrosine kinase (Lck) for initiation of signaling. Here we uncover a mechanism that is responsible for plasma membrane targeting of Lck. We show that Lck is transported to the membrane via a specific endosomal compartment. The transport depends on the adaptor protein Uncoordinated 119 (Unc119), on the GTPase rat brain 11 (Rab11), and on the actin cytoskeleton. Unc119 regulates the activation of Rab11. Consequently, Unc119 orchestrates the recruitment of the actin-based motor protein, myosin 5B, and the organization of multiprotein complexes on endosomes. The Unc119-regulated pathway is essential for immunological synapse formation and T cell activation.
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Affiliation(s)
- Magdalena M Gorska
- Division of Allergy and Immunology, Department of Medicine, National Jewish Health, Denver, CO 80206, USA
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26
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Min CK, Bang SY, Cho BA, Choi YH, Yang JS, Lee SH, Seong SY, Kim KW, Kim S, Jung JU, Choi MS, Kim IS, Cho NH. Role of amphipathic helix of a herpesviral protein in membrane deformation and T cell receptor downregulation. PLoS Pathog 2008; 4:e1000209. [PMID: 19023411 PMCID: PMC2581436 DOI: 10.1371/journal.ppat.1000209] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 10/16/2008] [Indexed: 11/18/2022] Open
Abstract
Lipid rafts are membrane microdomains that function as platforms for signal transduction and membrane trafficking. Tyrosine kinase interacting protein (Tip) of T lymphotropic Herpesvirus saimiri (HVS) is targeted to lipid rafts in T cells and downregulates TCR and CD4 surface expression. Here, we report that the membrane-proximal amphipathic helix preceding Tip's transmembrane (TM) domain mediates lipid raft localization and membrane deformation. In turn, this motif directs Tip's lysosomal trafficking and selective TCR downregulation. The amphipathic helix binds to the negatively charged lipids and induces liposome tubulation, the TM domain mediates oligomerization, and cooperation of the membrane-proximal helix with the TM domain is sufficient for localization to lipid rafts and lysosomal compartments, especially the mutivesicular bodies. These findings suggest that the membrane-proximal amphipathic helix and TM domain provide HVS Tip with the unique ability to deform the cellular membranes in lipid rafts and to downregulate TCRs potentially through MVB formation.
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Affiliation(s)
- Chan-Ki Min
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
| | - Sun-Young Bang
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
| | - Bon-A Cho
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
| | - Yun-Hui Choi
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
| | - Jae-Seong Yang
- Department of Life Science and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Kyungbuk, Korea
| | - Sun-Hwa Lee
- Seoul National University Hospital, Innovative Research Institute for Cell Therapy, Chongno-Gu, Seoul, Korea
| | - Seung-Yong Seong
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
- Seoul National University Hospital, Innovative Research Institute for Cell Therapy, Chongno-Gu, Seoul, Korea
| | - Ki Woo Kim
- National Instrumentation Center for Environmental Management, Seoul National University, Gwanak-Gu, Seoul, Korea
| | - Sanguk Kim
- Department of Life Science and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Kyungbuk, Korea
| | - Jae Ung Jung
- Department of Molecular Microbiology and Immunology, University of Southern California School of Medicine, Los Angeles, California, United States of America
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
| | - Ik-Sang Kim
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Korea
- * E-mail:
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Strasner AB, Natarajan M, Doman T, Key D, August A, Henderson AJ. The Src kinase Lck facilitates assembly of HIV-1 at the plasma membrane. THE JOURNAL OF IMMUNOLOGY 2008; 181:3706-13. [PMID: 18714047 DOI: 10.4049/jimmunol.181.5.3706] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HIV type 1 (HIV-1) assembly and egress are driven by the viral protein Gag and occur at the plasma membrane in T cells. Recent evidence indicates that secretory vesicles and machinery are essential components of virus packaging in both T cells and macrophages. However, the pathways and cellular mediators of Gag targeting to the plasma membrane are not well characterized. Lck, a lymphoid specific Src kinase critical for T cell activation, is found in the plasma membrane as well as various intracellular compartments and it has been suggested to influence HIV-1 replication. To investigate Lck as a potential regulator of Gag targeting, we assessed HIV-1 replication and Gag-induced virus-like particle release in the presence and absence of Lck. Release of HIV-1 and virus-like particles was reduced in the absence of Lck. This decrease in replication was not due to altered HIV-1 infection, transcription or protein translation. However, in T cells lacking Lck, HIV-1 accumulated intracellularly. In addition, expressing Lck in HeLa cells promoted HIV-1 Gag plasma membrane localization. Palmitoylation of the Lck unique domain, which is essential for directing Lck to the plasma membrane, was critical for its effect on HIV-1 replication. Furthermore, HIV-1 Gag directly interacted with the Lck unique domain in the context of infected cells. These results indicate that Lck plays a key role in targeting HIV-1 Gag to the plasma membrane in T cells.
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Affiliation(s)
- Amy B Strasner
- Intergrated Bioscience Program in Immunobiology, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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Sanchez-Pulido L, Devos D, Sung ZR, Calonje M. RAWUL: a new ubiquitin-like domain in PRC1 ring finger proteins that unveils putative plant and worm PRC1 orthologs. BMC Genomics 2008; 9:308. [PMID: 18588675 PMCID: PMC2447854 DOI: 10.1186/1471-2164-9-308] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 06/27/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Polycomb group (PcG) proteins are a set of chromatin-modifying proteins that play a key role in epigenetic gene regulation. The PcG proteins form large multiprotein complexes with different activities. The two best-characterized PcG complexes are the PcG repressive complex 1 (PRC1) and 2 (PRC2) that respectively possess histone 2A lysine 119 E3 ubiquitin ligase and histone 3 lysine 27 methyltransferase activities. While PRC2-like complexes are conserved throughout the eukaryotic kingdoms, PRC1-like complexes have only been described in Drosophila and vertebrates. Since both complexes are required for the gene silencing mechanism in Drosophila and vertebrates, how PRC1 function is realized in organisms that apparently lack PRC1 such as plants, is so far unknown. In vertebrates, PRC1 includes three proteins, Ring1B, Ring1A, and Bmi-1 that form an E3 ubiquitin ligase complex. These PRC1 proteins have an N-terminally located Ring finger domain associated to a poorly characterized conserved C-terminal region. RESULTS We obtained statistically significant evidences of sequence similarity between the C-terminal region of the PRC1 Ring finger proteins and the ubiquitin (Ubq)-like family proteins, thus defining a new Ubq-like domain, the RAWUL domain. In addition, our analysis revealed the existence of plant and worm proteins that display the conserved combination of a Ring finger domain at the N-terminus and a RAWUL domain at the C-terminus. CONCLUSION Analysis of the conserved domain architecture among PRC1 Ring finger proteins revealed the existence of long sought PRC1 protein orthologs in these organisms, suggesting the functional conservation of PRC1 throughout higher eukaryotes.
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Affiliation(s)
- Luis Sanchez-Pulido
- Centro Nacional de Biotecnología (CNB-CSIC). Cantoblanco, E-28049 Madrid, Spain.
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NF-kappaB activation by the viral oncoprotein StpC enhances IFN-gamma production in T cells. Immunol Cell Biol 2008; 86:622-30. [PMID: 18560378 DOI: 10.1038/icb.2008.43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Interferon-gamma (IFN-gamma) is an essential regulator of innate and adaptive immune responses and a hallmark of the Th1 T-cell subset. It is produced at high levels by human T lymphocytes upon transformation with Herpesvirus saimiri, which depends on the expression of the viral oncoproteins saimiri transformation-associated protein of subgroup C (StpC) and tyrosine kinase-interacting protein (Tip). Here, we show that IFN-gamma production was induced by Tip in Jurkat T cells. StpC by itself did not affect IFN-gamma expression, but enhanced the effect of Tip. Our results substantiated the findings that StpC induces NF-kappaB activation and demonstrated that other transcription factors, including NFAT, AP-1 and serum response element regulators, were not activated by StpC in unstimulated T cells. Studies using StpC mutants deficient in NF-kappaB activation, dominant negative IkappaBalpha and constitutively active IKK2, established the importance of NF-kappaB in StpC-mediated upregulation of IFN-gamma production. These observations suggest that NF-kappaB induction by StpC contributes to the Th1-like phenotype of virus-transformed human T cells.
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Cohn MA, Kowal P, Yang K, Haas W, Huang TT, Gygi SP, D'Andrea AD. A UAF1-containing multisubunit protein complex regulates the Fanconi anemia pathway. Mol Cell 2008; 28:786-97. [PMID: 18082604 DOI: 10.1016/j.molcel.2007.09.031] [Citation(s) in RCA: 261] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 06/13/2007] [Accepted: 09/22/2007] [Indexed: 11/26/2022]
Abstract
The deubiquitinating enzyme USP1 controls the cellular levels of the DNA damage response protein Ub-FANCD2, a key protein of the Fanconi anemia DNA repair pathway. Here we report the purification of a USP1 multisubunit protein complex from HeLa cells containing stoichiometric amounts of a WD40 repeat-containing protein, USP1 associated factor 1 (UAF1). In vitro reconstitution of USP1 deubiquitinating enzyme activity, using either ubiquitin-7-amido-4-methylcoumarin (Ub-AMC) or purified monoubiquitinated FANCD2 protein as substrates, demonstrates that UAF1 functions as an activator of USP1. UAF1 binding increases the catalytic turnover (kcat) but does not increase the affinity of the USP1 enzyme for the substrate (KM). Moreover, we show that DNA damage results in an immediate shutoff of transcription of the USP1 gene, leading to a rapid decline in the USP1/UAF1 protein complex. Taken together, our results describe a mechanism of regulation of the deubiquitinating enzyme, USP1, and of DNA repair.
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Affiliation(s)
- Martin A Cohn
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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Côté-Martin A, Moody C, Fradet-Turcotte A, D'Abramo CM, Lehoux M, Joubert S, Poirier GG, Coulombe B, Laimins LA, Archambault J. Human papillomavirus E1 helicase interacts with the WD repeat protein p80 to promote maintenance of the viral genome in keratinocytes. J Virol 2008; 82:1271-83. [PMID: 18032488 PMCID: PMC2224424 DOI: 10.1128/jvi.01405-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Accepted: 11/12/2007] [Indexed: 02/02/2023] Open
Abstract
Due to the limited coding capacity of their small genomes, human papillomaviruses (HPV) rely extensively on host factors for the completion of their life cycles. Accordingly, most HPV proteins, including the replicative helicase E1, engage in multiple protein interactions. The fact that conserved regions of E1 have not yet been ascribed a function prompted us to use tandem affinity protein purification (TAP) coupled to mass spectrometry to identify novel targets of this helicase. This method led to the discovery of a novel interaction between the N-terminal 40 amino acids of HPV type 11 (HPV11) E1 and the cellular WD repeat protein p80 (WDR48). We found that interaction with p80 is conserved among E1 proteins from anogenital HPV but not among cutaneous or animal types. Colocalization studies showed that E1 can redistribute p80 from the cytoplasm to the nucleus in a manner that is dependent on the E1 nuclear localization signal. Three amino acid substitutions in E1 proteins from HPV11 and -31 were identified that abrogate binding to p80 and its relocalization to the nucleus. In HPV31 E1, these substitutions reduced but did not completely abolish transient viral DNA replication. HPV31 genomes encoding two of the mutant E1 proteins were not maintained as episomes in immortalized primary keratinocytes, whereas one encoding the third mutant protein was maintained at a very low copy number. These findings suggest that the interaction of E1 with p80 is required for efficient maintenance of the viral episome in undifferentiated keratinocytes.
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Affiliation(s)
- Alexandra Côté-Martin
- Laboratory of Molecular Virology, Institut de Recherches Cliniques de Montréal, 110 Pine Avenue West, Montreal, Quebec, Canada
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Downregulation of the T-cell receptor complex and impairment of T-cell activation by human herpesvirus 6 u24 protein. J Virol 2007; 82:602-8. [PMID: 17977973 DOI: 10.1128/jvi.01571-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have performed a screen aimed at identifying human herpesvirus 6 (HHV-6)-encoded proteins that modulate immune recognition. Here we show that the U24 protein encoded by HHV-6 variant A downregulates cell surface expression of the T-cell receptor (TCR)/CD3 complex, a complex essential to T-cell activation and the generation of an immune adaptive response. In the presence of U24, the TCR/CD3 complex is endocytosed but is not recycled back to the plasma membrane. Instead, it accumulates in early and late endosomes. Interestingly, whereas CD3 downregulation from the cell surface is normally associated with T-cell activation, U24 downregulates CD3 independently of T-cell activation. Moreover, we found that U24-expressing T cells are resistant to activation by antigen-presenting cells. HHV-6 has evolved a unique mechanism of inhibition of T-cell activation that may impair the establishment of an adaptive immune response. Furthermore, lymphocyte activation creates an environment favorable to the reactivation and replication of lymphotropic herpesviruses. Thus, by inhibiting T-cell activation, HHV-6 might limit its reactivation and thus minimize immune recognition.
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Cho NH, Kingston D, Chang H, Kwon EK, Kim JM, Lee JH, Chu H, Choi MS, Kim IS, Jung JU. Association of herpesvirus saimiri tip with lipid raft is essential for downregulation of T-cell receptor and CD4 coreceptor. J Virol 2007; 80:108-18. [PMID: 16352535 PMCID: PMC1317525 DOI: 10.1128/jvi.80.1.108-118.2006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Lipid rafts are membrane microdomains that are proposed to function as platforms for both receptor signaling and trafficking. Our previous studies have demonstrated that Tip of herpesvirus saimiri (HVS), which is a T-lymphotropic tumor virus, is constitutively targeted to lipid rafts and interacts with cellular Lck tyrosine kinase and p80 WD repeat-containing endosomal protein. Through the interactions with Lck and p80, HVS Tip modulates diverse T-cell functions, which leads to the downregulation of T-cell receptor (TCR) and CD4 coreceptor surface expression, the inhibition of TCR signal transduction, and the activation of STAT3 transcription factor. In this study, we investigated the functional significance of Tip association with lipid rafts. We found that Tip expression remarkably increased lipid raft fractions in human T cells by enhancing the recruitment of lipid raft-resident proteins. Genetic analysis showed that the carboxyl-terminal transmembrane, but not p80 and Lck interaction, of Tip was required for the lipid raft localization and that lipid raft localization of Tip was necessary for the efficient downregulation of TCR and CD4 surface expression. Correlated with this, treatment with Filipin III, a lipid raft-disrupting agent, effectively reversed the downregulation of CD3 and CD4 surface expression induced by Tip. On the other hand, Tip mutants that were no longer present in lipid rafts were still capable of inhibiting TCR signaling and activating STAT3 transcription factor activity as efficiently as wild-type (wt) Tip. These results indicate that the association of Tip with lipid rafts is essential for the downregulation of TCR and CD4 surface expression but not for the inhibition of TCR signal transduction and the activation of STAT3 transcription factor. These results also suggest that the signaling and targeting activities of HVS Tip rely on functionally and genetically separable mechanisms, which may independently modulate T-cell function for viral persistence or pathogenesis.
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Affiliation(s)
- Nam-Hyuk Cho
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102, USA.
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35
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Heck E, Friedrich U, Gack MU, Lengenfelder D, Schmidt M, Müller-Fleckenstein I, Fleckenstein B, Ensser A, Biesinger B. Growth transformation of human T cells by herpesvirus saimiri requires multiple Tip-Lck interaction motifs. J Virol 2006; 80:9934-42. [PMID: 17005671 PMCID: PMC1617286 DOI: 10.1128/jvi.01112-06] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lymphoma induction and T-cell transformation by herpesvirus saimiri strain C488 depends on two viral oncoproteins, StpC and Tip. The major interaction partner of Tip is the protein tyrosine kinase Lck, a key regulator of T-cell activation. The Lck binding domain (LBD) of Tip comprises two interaction motifs, a proline-rich SH3 domain-binding sequence (SH3B) and a region with homology to the C terminus of Src family kinase domains (CSKH). In addition, biophysical binding analyses with purified Lck-SH2 domain suggest the phosphorylated tyrosine residue 127 of Tip (pY127) as a potential third Lck interaction site. Here, we addressed the relevance of the individual binding motifs, SH3B, CSKH, and pY127, for Tip-Lck interaction and for human T-cell transformation. Both motifs within the LBD displayed Lck binding activities and cooperated to achieve a highly efficient interaction, while pY127, the major tyrosine phosphorylation site of Tip, did not enhance Lck binding in T cells. Herpesvirus saimiri strain C488 recombinants lacking one or both LBD motifs of Tip lost their transforming potential on human cord blood lymphocytes. Recombinant virus expressing Tip with a mutation at position Y127 was still able to transform human T lymphocytes but, in contrast to wild-type virus, was strictly dependent on exogenous interleukin-2. Thus, the strong Lck binding mediated by cooperation of both LBD motifs was essential for the transformation of human T cells by herpesvirus saimiri C488. The major tyrosine phosphorylation site Y127 of Tip was particularly required for transformation in the absence of exogenous interleukin-2, suggesting its involvement in cytokine signaling pathways.
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Affiliation(s)
- Elke Heck
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schlossgarten 4, D-91054 Erlangen, Germany
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36
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Brinkmann MM, Schulz TF. Regulation of intracellular signalling by the terminal membrane proteins of members of the Gammaherpesvirinae. J Gen Virol 2006; 87:1047-1074. [PMID: 16603506 DOI: 10.1099/vir.0.81598-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The human gamma(1)-herpesvirus Epstein-Barr virus (EBV) and the gamma(2)-herpesviruses Kaposi's sarcoma-associated herpesvirus (KSHV), rhesus rhadinovirus (RRV), herpesvirus saimiri (HVS) and herpesvirus ateles (HVA) all contain genes located adjacent to the terminal-repeat region of their genomes, encoding membrane proteins involved in signal transduction. Designated 'terminal membrane proteins' (TMPs) because of their localization in the viral genome, they interact with a variety of cellular signalling molecules, such as non-receptor protein tyrosine kinases, tumour-necrosis factor receptor-associated factors, Ras and Janus kinase (JAK), thereby initiating further downstream signalling cascades, such as the MAPK, PI3K/Akt, NF-kappaB and JAK/STAT pathways. In the case of TMPs expressed during latent persistence of EBV and HVS (LMP1, LMP2A, Stp and Tip), their modulation of intracellular signalling pathways has been linked to the provision of survival signals to latently infected cells and, hence, a contribution to occasional cellular transformation. In contrast, activation of similar pathways by TMPs of KSHV (K1 and K15) and RRV (R1), expressed during lytic replication, may extend the lifespan of virus-producing cells, alter their migration and/or modulate antiviral immune responses. Whether R1 and K1 contribute to the oncogenic properties of KSHV and RRV has not been established satisfactorily, despite their transforming qualities in experimental settings.
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Affiliation(s)
- Melanie M Brinkmann
- Institut für Virologie, Medizinische Hochschule Hannover, Carl-Neuberg Str. 1, D-30625 Hannover, Germany
| | - Thomas F Schulz
- Institut für Virologie, Medizinische Hochschule Hannover, Carl-Neuberg Str. 1, D-30625 Hannover, Germany
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Abstract
Acute T-lymphoproliferative syndromes are caused by herpesvirus saimiri (HVS) and ateles in neotropical primates; by alcelaphine herpesvirus-1 and ovine herpesvirus-2 strains in domestic cattle and other ungulates; and by the α-herpesvirus of Marek's disease in chickens. T-cell lymphoproliferation caused by these herpesviruses has short incubation periods and a rapid course when compared with retroviral disease. The B-lymphotropic Epstein–Barr virus (EBV) is also associated with some human T-cell malignancies. Analogous to EBV in B cells, HVS isolates of the subgroup C are uniquely capable of transforming human and Old World primate T lymphocytes to continuous growth in cell culture and can provide useful tools for T-cell immunology or gene transfer. Signal transduction pathways stimulated by the viral oncoproteins seem to converge at related cellular effector proteins, in total providing a proproliferative signal. However, the viral oncoproteins most likely evolved to evade immune recognition and to support persistent infection in the natural host, where these viruses are frequently apathogenic.
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Affiliation(s)
- Armin Ensser
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institut für Klinische und Molekulare Virologie, Schlossgarten 4, 91054 Erlangen, Germany
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38
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Albrecht JC, Müller-Fleckenstein I, Schmidt M, Fleckenstein B, Biesinger B. Tyrosine phosphorylation of the Tio oncoprotein is essential for transformation of primary human T cells. J Virol 2005; 79:10507-13. [PMID: 16051843 PMCID: PMC1182665 DOI: 10.1128/jvi.79.16.10507-10513.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T cells are transformed to antigen-independent permanent growth in vitro upon infection with herpesvirus saimiri subgroup C strains. The viral oncoproteins required for this process, StpC and Tip, could be replaced by Tio, the oncoprotein of herpesvirus ateles. Here we demonstrate that proliferation of lymphocytes transformed with Tio-recombinant herpesvirus saimiri required the activity of Src family kinases. Src kinases had previously been identified as interaction partners of Tio. This interaction was now shown to be independent of any of the four tyrosine residues of Tio but to be dependent on an SH3-binding motif. Mutations within this motif abrogated the transforming capabilities of Tio-recombinant herpesvirus saimiri. Furthermore, kinase interaction resulted in the phosphorylation of Tio on a single tyrosine residue at position 136. Mutation of this residue in the viral context revealed that this phosphorylation site, but none of the other tyrosine residues, was required for T-cell transformation. These data indicate that the interaction of Tio with a Src kinase is essential for both the initiation and the maintenance of T-cell transformation by recombinant herpesvirus saimiri. The requirement for the tyrosine phosphorylation site at position 136 suggests a role for Tio beyond simple deregulation of the kinase.
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Affiliation(s)
- Jens-Christian Albrecht
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schlossgarten 4, D-91054 Erlangen, Germany.
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39
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Abstract
gamma2-Herpesviruses, also termed rhadinoviruses, have long been known as animal pathogens causing lymphoproliferative diseases such as malignant catarrhal fever in cattle or T-cell lymphoma in certain Neotropical primates. The rhadinovirus prototype is Herpesvirus saimiri (HVS), a T-lymphotropic agent of squirrel monkeys (Saimiri sciureus); Herpesvirus ateles (HVA) is closely related to HVS. The first human rhadinovirus, human herpesvirus type 8 (HHV-8), was discovered a decade ago in Kaposi's sarcoma (KS) biopsies. It was found to be strongly associated with all forms of KS, as well as with multicentric Castleman's disease and primary effusion lymphoma (PEL). Since DNA of this virus is regularly found in all KS forms, and specifically in the spindle cells of KS, it was also termed KS-associated herpesvirus (KSHV). Several simian rhadinoviruses related to KSHV have been discovered in various Old World primates, though they seem only loosely associated with pathogenicity or tumor induction. In contrast, HVS and HVA cause T-cell lymphoma in numerous non-natural primate hosts; HVS strains of the subgroup C are capable of transforming human and simian T-lymphocytes to continuous growth in cell culture and can provide useful tools for T-cell immunology or gene transfer. Here, we describe their natural history, genome structure, biology, and pathogenesis in T-cell transformation and oncogenesis.
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Affiliation(s)
- Armin Ensser
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
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40
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Heck E, Lengenfelder D, Schmidt M, Müller-Fleckenstein I, Fleckenstein B, Biesinger B, Ensser A. T-cell growth transformation by herpesvirus saimiri is independent of STAT3 activation. J Virol 2005; 79:5713-20. [PMID: 15827186 PMCID: PMC1082769 DOI: 10.1128/jvi.79.9.5713-5720.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Herpesvirus saimiri (saimirine herpesvirus 2) (HVS), a T-lymphotropic tumor virus, induces lymphoproliferative disease in several species of New World primates. In addition, strains of HVS subgroup C are able to transform T cells of Old World primates, including humans, to permanently growing T-cell lines. In concert with the Stp oncoprotein, the tyrosine kinase-interacting protein (Tip) of HVS C488 is required for T-cell transformation in vitro and lymphoma induction in vivo. Tip was previously shown to interact with the protein tyrosine kinase Lck. Constitutive activation of signal transducers and activators of transcription (STATs) has been associated with oncogenesis and has also been detected in HVS-transformed T-cell lines. Furthermore, Tip contains a putative consensus YXPQ binding motif for the SH2 (src homology 2) domains of STAT1 and STAT3. Tip tyrosine phosphorylation at this site was required for binding of STATs and induction of STAT-dependent transcription. Here we sought to address the relevance of STAT activation for transformation of human T cells by introducing a tyrosine-to-phenylalanine mutation in the YXPQ motif of Tip of HVS C488. Unexpectedly, the recombinant virus was still able to transform human T lymphocytes, but it had lost its capability to activate STAT3 as well as STAT1. This demonstrates that growth transformation by HVS is independent of STAT3 activation.
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Affiliation(s)
- Elke Heck
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Schlossgarten 4, D-91054 Erlangen, Germany
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41
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Abstract
Herpesvirus saimiri (Saimiriine herpesvirus-2), a gamma2-herpesvirus (rhadinovirus) of non-human primates, causes T-lymphoproliferative diseases in susceptible organisms and transforms human and non-human T lymphocytes to continuous growth in vitro in the absence of stimulation. T cells transformed by H. saimiri retain many characteristics of intact T lymphocytes, such as the sensitivity to interleukin-2 and the ability to recognize the corresponding antigens. As a result, H. saimiri is widely used in immunobiology for immortalization of various difficult-to-obtain and/or -to-maintain T cells in order to obtain useful experimental models. In particular, H. saimiri-transformed human T cells are highly susceptible to infection with HIV-1 and -2. This makes them a convenient tool for propagation of poorly replicating strains of HIV, including primary clinical isolates. Therefore, the mechanisms mediating transformation of T cells by H. saimiri are of considerable interest. A single transformation-associated protein, StpA or StpB, mediates cell transformation by H. saimiri strains of group A or B, respectively. Strains of group C, which exhibit the highest oncogenic potential, have two proteins involved in transformation-StpC and Tip. Both proteins have been shown to dramatically affect signal transduction pathways leading to the activation of crucial transcription factors. This review is focused on the biological effects and molecular mechanisms of action of proteins involved in H. saimiri-dependent transformation.
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MESH Headings
- Animals
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Gene Expression Regulation, Viral/genetics
- HIV-1/genetics
- HIV-1/metabolism
- Herpesviridae Infections/genetics
- Herpesviridae Infections/metabolism
- Herpesvirus 2, Saimiriine/genetics
- Herpesvirus 2, Saimiriine/metabolism
- Humans
- Lymphoma, T-Cell/genetics
- Lymphoma, T-Cell/metabolism
- Models, Biological
- Oncogene Proteins, Viral/biosynthesis
- Oncogene Proteins, Viral/genetics
- Tumor Virus Infections/genetics
- Tumor Virus Infections/metabolism
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Affiliation(s)
- Alexander Y Tsygankov
- Department of Microbiology and Immunology, Temple University School of Medicine, 3400 N. Broad Street, Philadelphia, PA 19104, USA.
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42
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Cook HL, Lytle JR, Mischo HE, Li MJ, Rossi JJ, Silva DP, Desrosiers RC, Steitz JA. Small Nuclear RNAs Encoded by Herpesvirus saimiri Upregulate the Expression of Genes Linked to T Cell Activation in Virally Transformed T Cells. Curr Biol 2005; 15:974-9. [PMID: 15916956 DOI: 10.1016/j.cub.2005.04.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 04/14/2005] [Accepted: 04/19/2005] [Indexed: 11/20/2022]
Abstract
Seven small nuclear RNAs of the Sm class are encoded by Herpesvirus saimiri (HVS), a gamma Herpesvirus that causes aggressive T cell leukemias and lymphomas in New World primates and efficiently transforms T cells in vitro. The Herpesvirus saimiri U RNAs (HSURs) are the most abundant viral transcripts in HVS-transformed, latently infected T cells but are not required for viral replication or transformation in vitro. We have compared marmoset T cells transformed with wild-type or a mutant HVS lacking the most highly conserved HSURs, HSURs 1 and 2. Microarray and Northern analyses reveal that HSUR 1 and 2 expression correlates with significant increases in a small number of host mRNAs, including the T cell-receptor beta and gamma chains, the T cell and natural killer (NK) cell-surface receptors CD52 and DAP10, and intracellular proteins--SKAP55, granulysin, and NKG7--linked to T cell and NK cell activation. Upregulation of three of these transcripts was rescued after transduction of deletion-mutant-HVS-transformed cells with a lentiviral vector carrying HSURs 1 and 2. These changes indicate an unexpected role for the HSURs in regulating a remarkably defined and physiologically relevant set of host targets involved in the activation of virally transformed T cells during latency.
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MESH Headings
- Animals
- Antigens, CD/metabolism
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Antigens, Neoplasm/metabolism
- Base Pairing
- Blotting, Northern
- Blotting, Western
- CD52 Antigen
- Callithrix
- Cell Line, Tumor
- Flow Cytometry
- Genetic Vectors
- Genome, Viral
- Glycoproteins/metabolism
- Herpesvirus 2, Saimiriine/genetics
- Herpesvirus 2, Saimiriine/metabolism
- Lentivirus
- Lymphocyte Activation/genetics
- Lymphocyte Activation/physiology
- Membrane Proteins/metabolism
- Microarray Analysis
- Oncogene Proteins, Viral/metabolism
- RNA, Small Nuclear/genetics
- RNA, Small Nuclear/metabolism
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Immunologic/metabolism
- T-Lymphocytes/physiology
- Transduction, Genetic
- Up-Regulation/genetics
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Affiliation(s)
- Heidi L Cook
- Howard Hughes Medical Institute, Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06536, USA
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43
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Cho NH, Feng P, Lee SH, Lee BS, Liang X, Chang H, Jung JU. Inhibition of T cell receptor signal transduction by tyrosine kinase-interacting protein of Herpesvirus saimiri. ACTA ACUST UNITED AC 2004; 200:681-7. [PMID: 15337788 PMCID: PMC2212737 DOI: 10.1084/jem.20040924] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
T cells play a central role in orchestrating immunity against pathogens, particularly viruses. Thus, impairing T cell activation is an important strategy employed by viruses to escape host immune control. The tyrosine kinase–interacting protein (Tip) of the T lymphotropic Herpesvirus saimiri (HVS) is constitutively present in lipid rafts and interacts with cellular Lck tyrosine kinase and p80 endosomal protein. Here we demonstrate that, due to the sequestration of Lck by HVS Tip, T cell receptor (TCR) stimulation fails to activate ZAP70 tyrosine kinase and to initiate downstream signaling events. TCR ζ chains in Tip-expressing T cells were initially phosphorylated to recruit ZAP70 molecule upon TCR stimulation, but the recruited ZAP70 kinase was not subsequently phosphorylated, resulting in TCR complexes that were stably associated with inactive ZAP70 kinase. Consequently, Tip expression not only markedly inhibited TCR-mediated intracellular signal transduction but also blocked TCR engagement with major histocompatibility complexes on the antigen-presenting cells and immunological synapse formation. These results demonstrate that a lymphotropic herpesvirus has evolved a novel mechanism to deregulate T cell activation to disarm host immune surveillance. This process contributes to the establishment and maintenance of viral latency.
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Affiliation(s)
- Nam-Hyuk Cho
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, MA 01772, USA
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44
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Lee SH, Chung YH, Cho NH, Gwack Y, Feng P, Jung JU. Modulation of T-cell receptor signal transduction by herpesvirus signaling adaptor protein. Mol Cell Biol 2004; 24:5369-82. [PMID: 15169900 PMCID: PMC419894 DOI: 10.1128/mcb.24.12.5369-5382.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Because of its central regulatory role, T-cell receptor (TCR) signal transduction is a common target of viruses. We report here the identification of a small signaling protein, ORF5, of the T-lymphotropic tumor virus herpesvirus saimiri (HVS). ORF5 is predicted to contain 89 to 91 amino acids with an amino-terminal myristoylation site and six SH2 binding motifs, showing structural similarity to cellular LAT (linker for activation of T cells). Sequence analysis showed that, despite extensive sequence variation, the myristoylation site and SH2 binding motifs were completely conserved among 13 different ORF5 isolates. Upon TCR stimulation, ORF5 was efficiently tyrosine phosphorylated and subsequently interacted with cellular SH2-containing signaling proteins Lck, Fyn, SLP-76, and p85 through its tyrosine residues. ORF5 expression resulted in the marked augmentation of TCR signal transduction activity, evidenced by increased cellular tyrosine phosphorylation, intracellular calcium mobilization, CD69 surface expression, interleukin-2 production, and activation of the NF-AT, NF-kappa B, and AP-1 transcription factors. Despite its structural similarity to cellular LAT, however, ORF5 could only partially substitute for LAT function in TCR signal transduction. These results demonstrate that HVS utilizes a novel signaling protein, ORF5, to activate TCR signal transduction. This activation probably facilitates viral gene expression and, thereby, persistent infection.
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Affiliation(s)
- Sun-Hwa Lee
- Department o fMicrobiology and Molecular Genetics and Tumor Virology Division, New England Regional Primate Research Center, Harvard Medical School, Southborough, MA 01772-9102, USA
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45
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Eckstein AK, Quadbeck B, Tews S, Mann K, Krüger C, Mohr CH, Steuhl KP, Esser J, Gieseler RK. Thyroid associated ophthalmopathy: evidence for CD4(+) gammadelta T cells; de novo differentiation of RFD7(+) macrophages, but not of RFD1(+) dendritic cells; and loss of gammadelta and alphabeta T cell receptor expression. Br J Ophthalmol 2004; 88:803-8. [PMID: 15148216 PMCID: PMC1772193 DOI: 10.1136/bjo.2003.035915] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
AIM To characterise periorbital immune cells (stages, kinetics) in active and inactive thyroid associated ophthalmopathy (A-TAO; I-TAO). METHODS In orbital tissue cryosections of patients with A-TAO (n = 15), I-TAO (n = 11), and healthy controls (n = 14), adipose and fibrovascular areas were evaluated for MHC II(+) cells, CD45(+) total leukocytes, myeloid cells (CD33(+) monocytes; CD14(+) macrophages; mature RFD7(+) macrophages; RFD1(+) dendritic cells (DCs)), and lymphoid cells (CD4(+) T cells; alphabeta and gammadelta T cells; CD20(+) B cells). Results are expressed as medians and 5% confidence intervals. RESULTS In fibrovascular septae, a surge of CD33(+) immigrants clearly correlating with disease activity generated significantly increased (p<0.05) percentages of CD14(+) and RFD7(+) macrophages. Intriguingly, CD4(+) cells were mostly gammadelta T cells, while alphabeta T helper cells were much less frequent. Successful treatment rendering TAO inactive apparently downregulates monocyte influx, macrophage differentiation, and T cell receptor expression. Similar trends were recorded for adipose tissue. Interestingly, RFD1(+) DCs were completely absent from all conditions examined. CONCLUSION A-TAO coincides with periorbital monocyte infiltration and de novo differentiation of macrophages, but not DCs. The authors discuss a novel potential role for inflammatory CD4(+) gammadelta T cells in TAO. Successful treatment apparently downregulates orbital monocyte recruitment and effects functional T cell knockout.
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Affiliation(s)
- A K Eckstein
- Department of Ophthalmology, Essen University Hospital, Essen, Germany
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46
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Hasham MG, Tsygankov AY. Tip, an Lck-interacting protein of Herpesvirus saimiri, causes Fas- and Lck-dependent apoptosis of T lymphocytes. Virology 2004; 320:313-29. [PMID: 15016553 DOI: 10.1016/j.virol.2003.11.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Revised: 11/19/2003] [Accepted: 11/24/2003] [Indexed: 11/21/2022]
Abstract
Saimiriine herpesvirus-2 (Herpesvirus saimiri) transforms T lymphocytes, including human, to continuous growth in vitro. H. saimiri-induced transformation is becoming an important tool of T-cell biology, including studies of HIV replication. Two proteins of H. saimiri subgroup C, Tip and StpC, are essential for T-cell transformation. In spite of the important role of these proteins, their biological functions and the molecular mechanisms of their action remain insufficiently understood. To further elucidate the effects of Tip on T cells, we transduced T lymphocytes, using an efficient lentiviral gene transfer system, to express Tip in the absence of other H. saimiri proteins. Our results indicate that Tip specifically inhibits IL-2 production by human T lymphocytes. Furthermore, Tip promotes T-cell apoptosis, which appears to be the reason for the observed decrease in IL-2 production. Finally, the apoptotic effect of Tip in T cells is mediated by Fas and requires the presence of active Lck in the cell.
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Affiliation(s)
- Muneer G Hasham
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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47
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Sorokina EM, Merlo JJ, Tsygankov AY. Molecular mechanisms of the effect of herpesvirus saimiri protein StpC on the signaling pathway leading to NF-kappaB activation. J Biol Chem 2004; 279:13469-77. [PMID: 14724292 DOI: 10.1074/jbc.m305250200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Herpesvirus saimiri (Saimiriine herpesvirus-2) causes lethal T lymphoproliferative diseases in the susceptible species and transforms T lymphocytes to continuous growth in vitro. H. saimiri-induced transformation of T cells is becoming an important experimental tool of biomedical research. Two proteins of H. saimiri subgroup C, Tip and StpC, are essential for T cell transformation by this virus. It has been shown previously that StpC transforms fibroblasts, activates NF-kappaB, and binds to tumor necrosis factor (TNF)-receptor-associated factor (TRAF) proteins, but the molecular mechanism of its action remains insufficiently understood. This study further characterized the effect of StpC on NF-kappaB. First, StpC activates NF-kappaB via the consensus pathway involving activation of I-kappaB kinase and subsequent phosphorylation and degradation of I-kappaB in both T lymphoid and epithelial cells. Second, triggering of this pathway by StpC in both T lymphoid and epithelial cells is dependent on the presence of functional NF-kappaB-inducing kinase (NIK). Third, StpC physically interacts with TRAF in epithelial cells, and the effect of StpC on NF-kappaB activity in these cells requires the presence of functional TRAF. Finally the effect of StpC is completely independent of TNF-alpha, a well described stimulus of NF-kappaB activity. Moreover it appears that StpC uncouples stimulation of NF-kappaB activity from TNF-alpha stimulation. Overall these results argue that the effect of StpC on NF-kappaB is similar to the effects of other viral proteins, "usurping" the TRAF/NIK/I-kappaB kinase pathway, and reinforce the notion that the role of StpC in cell transformation by H. saimiri may be mediated by signaling that results in NF-kappaB activation.
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Affiliation(s)
- Elena M Sorokina
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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48
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Alaniz RC, Sandall S, Thomas EK, Wilson CB. Increased Dendritic Cell Numbers Impair Protective Immunity to Intracellular Bacteria Despite Augmenting Antigen-Specific CD8+T Lymphocyte Responses. THE JOURNAL OF IMMUNOLOGY 2004; 172:3725-35. [PMID: 15004177 DOI: 10.4049/jimmunol.172.6.3725] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dendritic cells (DCs) reside in tissues, where they function as sentinels, providing an essential link between innate and adaptive immunity. Increasing the numbers of DCs in vivo augments T cell responses, and can cause dramatic CTL-dependent tumor regression. To determine whether greater DC numbers promoted T cell-mediated protection in the context of host defense against intracellular bacteria, we treated mice with Flt3 ligand (Flt3-L) to increase DCs in vivo and challenged them with Listeria monocytogenes. Unexpectedly, after primary challenge with Listeria, the overall control of Listeria infection was impaired in Flt3-L-treated mice, which had greater bacterial burden and mortality than controls. Similar results were obtained when DC numbers were increased by treatment with polyethylene glycol-conjugated GM-CSF rather than Flt3-L and in mice infected with Mycobacterium tuberculosis. Impaired protection was not due to dysfunctional T cell responses, as Flt3-L-treated mice had a greater frequency and absolute number of Ag-specific CD8+ T cells, which produced IFN-gamma, exhibited cytolytic activity, and transferred protection. The increased Listeria burden in Flt3-L-treated mice was preferentially associated with DCs, which were unable to kill Listeria and more resistant to CTL lysis compared with macrophages in vitro. Although we cannot exclude the possibility that other potential effects, in addition to increased numbers of DCs, are shared by Flt3-L and polyethylene glycol-conjugated GM-CSF and contributed to the increase in susceptibility observed in treated mice, these results support the notion that DC numbers must be properly controlled within physiological limits to optimize host defense to intracellular bacterial pathogens.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Animals
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- Cell Count
- Cell Division/immunology
- Cells, Cultured
- Cytotoxicity, Immunologic
- Dendritic Cells/immunology
- Dendritic Cells/microbiology
- Dendritic Cells/pathology
- Epitopes, T-Lymphocyte/immunology
- Female
- Granulocyte-Macrophage Colony-Stimulating Factor/administration & dosage
- Humans
- Immunity, Cellular
- Immunity, Innate
- Immunosuppressive Agents/administration & dosage
- Injections, Intraperitoneal
- Intracellular Fluid/immunology
- Intracellular Fluid/microbiology
- Ligands
- Listeria monocytogenes/growth & development
- Listeria monocytogenes/immunology
- Listeriosis/immunology
- Listeriosis/microbiology
- Listeriosis/pathology
- Membrane Proteins/administration & dosage
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Polyethylene Glycols/administration & dosage
- Tuberculosis/immunology
- Tuberculosis/microbiology
- Tuberculosis/pathology
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Affiliation(s)
- Robert C Alaniz
- Department of Immunology, University of Washington, Seattle, WA 98195, USA
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49
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Park J, Cho NH, Choi JK, Feng P, Choe J, Jung JU. Distinct roles of cellular Lck and p80 proteins in herpesvirus saimiri Tip function on lipid rafts. J Virol 2003; 77:9041-51. [PMID: 12885920 PMCID: PMC167239 DOI: 10.1128/jvi.77.16.9041-9051.2003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid rafts are proposed to function as platforms for both receptor signaling and trafficking. Following interaction with antigenic peptides, the T-cell receptor (TCR) rapidly translocates to lipid rafts, where it transmits signals and subsequently undergoes endocytosis. The Tip protein of herpesvirus saimiri (HVS), which is a T-lymphotropic tumor virus, interacts with cellular Lck tyrosine kinase and p80, a WD domain-containing endosomal protein. Interaction of Tip with p80 induces enlarged vesicles and recruits Lck and TCR complex into these vesicles for trafficking. We report here that Tip is constitutively present in lipid rafts and that Tip interaction with p80 but not with Lck is necessary for its efficient localization in lipid rafts. The Tip-Lck interaction was required for recruitment of the TCR complex to lipid rafts, and the Tip-p80 interaction was critical for the aggregation and internalization of lipid rafts. These results suggest the potential mechanism for Tip-mediated TCR downregulation: Tip interacts with Lck to recruit TCR complex to lipid rafts, and it subsequently interacts with p80 to initiate the aggregation and internalization of the lipid raft domain and thereby downregulate the TCR complex. Thus, the signaling and targeting functions of HVS Tip rely on two functionally and genetically separable mechanisms that independently target cellular Lck tyrosine kinase and p80 endosomal protein.
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Affiliation(s)
- Junsoo Park
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772-9102, USA
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