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Šimičić P, Batović M, Stojanović Marković A, Židovec-Lepej S. Deciphering the Role of Epstein-Barr Virus Latent Membrane Protein 1 in Immune Modulation: A Multifaced Signalling Perspective. Viruses 2024; 16:564. [PMID: 38675906 PMCID: PMC11054855 DOI: 10.3390/v16040564] [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: 01/29/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024] Open
Abstract
The disruption of antiviral sensors and the evasion of immune defences by various tactics are hallmarks of EBV infection. One of the EBV latent gene products, LMP1, was shown to induce the activation of signalling pathways, such as NF-κB, MAPK (JNK, ERK1/2, p38), JAK/STAT and PI3K/Akt, via three subdomains of its C-terminal domain, regulating the expression of several cytokines responsible for modulation of the immune response and therefore promoting viral persistence. The aim of this review is to summarise the current knowledge on the EBV-mediated induction of immunomodulatory molecules by the activation of signal transduction pathways with a particular focus on LMP1-mediated mechanisms. A more detailed understanding of the cytokine biology molecular landscape in EBV infections could contribute to the more complete understanding of diseases associated with this virus.
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Affiliation(s)
- Petra Šimičić
- Department of Oncology and Nuclear Medicine, Sestre Milosrdnice University Hospital Center, Vinogradska cesta 29, 10 000 Zagreb, Croatia;
| | - Margarita Batović
- Department of Clinical Microbiology and Hospital Infections, Dubrava University Hospital, Avenija Gojka Šuška 6, 10 000 Zagreb, Croatia;
| | - Anita Stojanović Marković
- Department of Immunological and Molecular Diagnostics, University Hospital for Infectious Diseases “Dr. Fran Mihaljević”, Mirogojska 8, 10 000 Zagreb, Croatia
| | - Snjezana Židovec-Lepej
- Department of Immunological and Molecular Diagnostics, University Hospital for Infectious Diseases “Dr. Fran Mihaljević”, Mirogojska 8, 10 000 Zagreb, Croatia
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2
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Giehler F, Ostertag MS, Sommermann T, Weidl D, Sterz KR, Kutz H, Moosmann A, Feller SM, Geerlof A, Biesinger B, Popowicz GM, Kirchmair J, Kieser A. Epstein-Barr virus-driven B cell lymphoma mediated by a direct LMP1-TRAF6 complex. Nat Commun 2024; 15:414. [PMID: 38195569 PMCID: PMC10776578 DOI: 10.1038/s41467-023-44455-w] [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: 01/25/2022] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) drives viral B cell transformation and oncogenesis. LMP1's transforming activity depends on its C-terminal activation region 2 (CTAR2), which induces NF-κB and JNK by engaging TNF receptor-associated factor 6 (TRAF6). The mechanism of TRAF6 recruitment to LMP1 and its role in LMP1 signalling remains elusive. Here we demonstrate that TRAF6 interacts directly with a viral TRAF6 binding motif within CTAR2. Functional and NMR studies supported by molecular modeling provide insight into the architecture of the LMP1-TRAF6 complex, which differs from that of CD40-TRAF6. The direct recruitment of TRAF6 to LMP1 is essential for NF-κB activation by CTAR2 and the survival of LMP1-driven lymphoma. Disruption of the LMP1-TRAF6 complex by inhibitory peptides interferes with the survival of EBV-transformed B cells. In this work, we identify LMP1-TRAF6 as a critical virus-host interface and validate this interaction as a potential therapeutic target in EBV-associated cancer.
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Affiliation(s)
- Fabian Giehler
- Research Unit Signaling and Translation, Helmholtz Center Munich - German Research Center for Environmental Health, 85764, Neuherberg, Germany
- Research Unit Gene Vectors, Helmholtz Center Munich - German Research Center for Environmental Health, 81377, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Michael S Ostertag
- Institute of Structural Biology, Helmholtz Center Munich - German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Thomas Sommermann
- Immune Regulation and Cancer, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Daniel Weidl
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Kai R Sterz
- Research Unit Gene Vectors, Helmholtz Center Munich - German Research Center for Environmental Health, 81377, Munich, Germany
| | - Helmut Kutz
- Research Unit Gene Vectors, Helmholtz Center Munich - German Research Center for Environmental Health, 81377, Munich, Germany
| | - Andreas Moosmann
- Research Unit Gene Vectors, Helmholtz Center Munich - German Research Center for Environmental Health, 81377, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
- Department of Medicine III, University Hospital, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Stephan M Feller
- Institute of Molecular Medicine, Martin-Luther-University Halle-Wittenberg, 06120, Halle, Germany
| | - Arie Geerlof
- Institute of Structural Biology, Helmholtz Center Munich - German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Brigitte Biesinger
- Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Grzegorz M Popowicz
- Institute of Structural Biology, Helmholtz Center Munich - German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Johannes Kirchmair
- Universität Hamburg, Department of Informatics, Center for Bioinformatics (ZBH), 20146, Hamburg, Germany
- Department of Pharmaceutical Sciences, Division of Pharmaceutical Chemistry, University of Vienna, 1090, Vienna, Austria
| | - Arnd Kieser
- Research Unit Signaling and Translation, Helmholtz Center Munich - German Research Center for Environmental Health, 85764, Neuherberg, Germany.
- Research Unit Gene Vectors, Helmholtz Center Munich - German Research Center for Environmental Health, 81377, Munich, Germany.
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany.
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Wu L, Huang J, Trivedi P, Sun X, Yu H, He Z, Zhang X. Zinc finger myeloid Nervy DEAF-1 type (ZMYND) domain containing proteins exert molecular interactions to implicate in carcinogenesis. Discov Oncol 2022; 13:139. [PMID: 36520265 PMCID: PMC9755447 DOI: 10.1007/s12672-022-00597-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Morphogenesis and organogenesis in the low organisms have been found to be modulated by a number of proteins, and one of such factor, deformed epidermal auto-regulatory factor-1 (DEAF-1) has been initially identified in Drosophila. The mammalian homologue of DEAF-1 and structurally related proteins have been identified, and they formed a family with over 20 members. The factors regulate gene expression through association with co-repressors, recognition of genomic marker, to exert histone modification by catalyze addition of some chemical groups to certain amino acid residues on histone and non-histone proteins, and degradation host proteins, so as to regulate cell cycle progression and execution of cell death. The formation of fused genes during chromosomal translocation, exemplified with myeloid transforming gene on chromosome 8 (MTG8)/eight-to-twenty one translocation (ETO) /ZMYND2, MTG receptor 1 (MTGR1)/ZMYND3, MTG on chromosome 16/MTGR2/ZMYND4 and BS69/ZMYND11 contributes to malignant transformation. Other anomaly like copy number variation (CNV) of BS69/ZMYND11 and promoter hyper methylation of BLU/ZMYND10 has been noted in malignancies. It has been reported that when fusing with Runt-related transcription factor 1 (RUNX1), the binding of MTG8/ZMYND2 with co-repressors is disturbed, and silencing of BLU/ZMYND10 abrogates its ability to inhibition of cell cycle and promotion of apoptotic death. Further characterization of the implication of ZMYND proteins in carcinogenesis would enhance understanding of the mechanisms of occurrence and early diagnosis of tumors, and effective antitumor efficacy.
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Affiliation(s)
- Longji Wu
- Department of Pathophysiology, School of Basic Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Songshan Lake Scientific and Industrial Park, Dongguan, 523808, Guangdong, People's Republic of China
- Chinese-American Tumor Institute, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong, People's Republic of China
- Institute of Modern Biology, Nanjing University, Nanjing, Jiangsu, China
| | - Jing Huang
- Department of Pathophysiology, School of Basic Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Songshan Lake Scientific and Industrial Park, Dongguan, 523808, Guangdong, People's Republic of China
- Chinese-American Tumor Institute, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong, People's Republic of China
| | - Pankaj Trivedi
- Department of Experimental Medicine, La Sapienza University, Rome, Italy
| | - Xuerong Sun
- Institute of Aging, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong, People's Republic of China
| | - Hongbing Yu
- Chinese-American Tumor Institute, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong, People's Republic of China
| | - Zhiwei He
- Department of Pathophysiology, School of Basic Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Songshan Lake Scientific and Industrial Park, Dongguan, 523808, Guangdong, People's Republic of China
- Chinese-American Tumor Institute, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong, People's Republic of China
| | - Xiangning Zhang
- Department of Pathophysiology, School of Basic Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Songshan Lake Scientific and Industrial Park, Dongguan, 523808, Guangdong, People's Republic of China.
- Chinese-American Tumor Institute, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, Guangdong, People's Republic of China.
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New Look of EBV LMP1 Signaling Landscape. Cancers (Basel) 2021; 13:cancers13215451. [PMID: 34771613 PMCID: PMC8582580 DOI: 10.3390/cancers13215451] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/01/2021] [Accepted: 10/26/2021] [Indexed: 01/18/2023] Open
Abstract
Simple Summary Epstein-Barr Virus (EBV) infection is associated with various lymphomas and carcinomas as well as other diseases in humans. The transmembrane protein LMP1 plays versatile roles in EBV life cycle and pathogenesis, by perturbing, reprograming, and regulating a large range of host cellular mechanisms and functions, which have been increasingly disclosed but not fully understood so far. We summarize recent research progress on LMP1 signaling, including the novel components LIMD1, p62, and LUBAC in LMP1 signalosome and LMP1 novel functions, such as its induction of p62-mediated selective autophagy, regulation of metabolism, induction of extracellular vehicles, and activation of NRF2-mediated antioxidative defense. A comprehensive understanding of LMP1 signal transduction and functions may allow us to leverage these LMP1-regulated cellular mechanisms for clinical purposes. Abstract The Epstein–Barr Virus (EBV) principal oncoprotein Latent Membrane Protein 1 (LMP1) is a member of the Tumor Necrosis Factor Receptor (TNFR) superfamily with constitutive activity. LMP1 shares many features with Pathogen Recognition Receptors (PRRs), including the use of TRAFs, adaptors, and kinase cascades, for signal transduction leading to the activation of NFκB, AP1, and Akt, as well as a subset of IRFs and likely the master antioxidative transcription factor NRF2, which we have gradually added to the list. In recent years, we have discovered the Linear UBiquitin Assembly Complex (LUBAC), the adaptor protein LIMD1, and the ubiquitin sensor and signaling hub p62, as novel components of LMP1 signalosome. Functionally, LMP1 is a pleiotropic factor that reprograms, balances, and perturbs a large spectrum of cellular mechanisms, including the ubiquitin machinery, metabolism, epigenetics, DNA damage response, extracellular vehicles, immune defenses, and telomere elongation, to promote oncogenic transformation, cell proliferation and survival, anchorage-independent cell growth, angiogenesis, and metastasis and invasion, as well as the development of the tumor microenvironment. We have recently shown that LMP1 induces p62-mediated selective autophagy in EBV latency, at least by contributing to the induction of p62 expression, and Reactive Oxygen Species (ROS) production. We have also been collecting evidence supporting the hypothesis that LMP1 activates the Keap1-NRF2 pathway, which serves as the key antioxidative defense mechanism. Last but not least, our preliminary data shows that LMP1 is associated with the deregulation of cGAS-STING DNA sensing pathway in EBV latency. A comprehensive understanding of the LMP1 signaling landscape is essential for identifying potential targets for the development of novel strategies towards targeted therapeutic applications.
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Ponnusamy R, Khatri R, Correia PB, Wood CD, Mancini EJ, Farrell PJ, West MJ. Increased association between Epstein-Barr virus EBNA2 from type 2 strains and the transcriptional repressor BS69 restricts EBNA2 activity. PLoS Pathog 2019; 15:e1007458. [PMID: 31283782 PMCID: PMC6638984 DOI: 10.1371/journal.ppat.1007458] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 07/18/2019] [Accepted: 06/09/2019] [Indexed: 12/20/2022] Open
Abstract
Natural variation separates Epstein-Barr virus (EBV) into type 1 and type 2 strains. Type 2 EBV is less transforming in vitro due to sequence differences in the EBV transcription factor EBNA2. This correlates with reduced activation of the EBV oncogene LMP1 and some cell genes. Transcriptional activation by type 1 EBNA2 can be suppressed through the binding of two PXLXP motifs in its transactivation domain (TAD) to the dimeric coiled-coil MYND domain (CC-MYND) of the BS69 repressor protein (ZMYND11). We identified a third conserved PXLXP motif in type 2 EBNA2. We found that type 2 EBNA2 peptides containing this motif bound BS69CC-MYND efficiently and that the type 2 EBNA2TAD bound an additional BS69CC-MYND molecule. Full-length type 2 EBNA2 also bound BS69 more efficiently in pull-down assays. Molecular weight analysis and low-resolution structures obtained using small-angle X-ray scattering showed that three BS69CC-MYND dimers bound two molecules of type 2 EBNA2TAD, in line with the dimeric state of full-length EBNA2 in vivo. Importantly, mutation of the third BS69 binding motif in type 2 EBNA2 improved B-cell growth maintenance and the transcriptional activation of the LMP1 and CXCR7 genes. Our data indicate that increased association with BS69 restricts the function of type 2 EBNA2 as a transcriptional activator and driver of B cell growth and may contribute to reduced B-cell transformation by type 2 EBV. Epstein-Barr virus (EBV) drives the development of many human cancers worldwide including specific types of lymphoma and carcinoma. EBV infects B lymphocytes and immortalises them, thus contributing to lymphoma development. The virus promotes B lymphocyte growth and survival by altering the level at which hundreds of genes are expressed. The EBV protein EBNA2 is known to activate many growth-promoting genes. Natural variation in the sequence of EBNA2 defines the two main EBV strains: type 1 and type 2. Type 2 strains immortalise B lymphocytes less efficiency and activate some growth genes poorly, although the mechanism of this difference is unclear. We now show that sequence variation in type 2 EBNA2 creates a third site of interaction for the repressor protein (BS69, ZMYND11). We have characterised the complex formed between type 2 EBNA2 and BS69 and show that three dimers of BS69 form a bridged complex with two molecules of type 2 EBNA2. We demonstrate that mutation of the additional BS69 interaction site in type 2 EBNA2 improves its growth-promoting and gene induction function. Our results therefore highlight a molecular mechanism that may contribute to the different B lymphocyte growth promoting activities of EBV strains. This aids our understanding of immortalisation by EBV.
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Affiliation(s)
- Rajesh Ponnusamy
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Ritika Khatri
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Paulo B. Correia
- Section of Virology, Imperial College London, London, United Kingdom
| | - C. David Wood
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Erika J. Mancini
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Paul J. Farrell
- Section of Virology, Imperial College London, London, United Kingdom
| | - Michelle J. West
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
- * E-mail:
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Cheerathodi MR, Meckes DG. The Epstein-Barr virus LMP1 interactome: biological implications and therapeutic targets. Future Virol 2018; 13:863-887. [PMID: 34079586 DOI: 10.2217/fvl-2018-0120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The oncogenic potential of Epstein-Barr virus (EBV) is mostly attributed to latent membrane protein 1 (LMP1), which is essential and sufficient for transformation of fibroblast and primary lymphocytes. LMP1 expression results in the activation of multiple signaling cascades like NF-ΚB and MAP kinases that trigger cell survival and proliferative pathways. LMP1 specific signaling events are mediated through the recruitment of a number of interacting proteins to various signaling domains. Based on these properties, LMP1 is an attractive target to develop effective therapeutics to treat EBV-related malignancies. In this review, we focus on LMP1 interacting proteins, associated signaling events, and potential targets that could be exploited for therapeutic strategies.
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Affiliation(s)
- Mujeeb R Cheerathodi
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306
| | - David G Meckes
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306
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Sun X, Chen J, Zhang Y, Munisha M, Dougan S, Sun Y. Mga Modulates Bmpr1a Activity by Antagonizing Bs69 in Zebrafish. Front Cell Dev Biol 2018; 6:126. [PMID: 30324105 PMCID: PMC6172302 DOI: 10.3389/fcell.2018.00126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 09/10/2018] [Indexed: 12/12/2022] Open
Abstract
MAX giant associated protein (MGA) is a dual transcriptional factor containing both T-box and bHLHzip DNA binding domains. In vitro studies have shown that MGA functions as a transcriptional repressor or activator to regulate transcription of promotors containing either E-box or T-box binding sites. BS69 (ZMYND11), a multidomain-containing (i.e., PHD, BROMO, PWWP, and MYND) protein, has been shown to selectively recognizes histone variant H3.3 lysine 36 trimethylation (H3.3K36me3), modulates RNA Polymerase II elongation, and functions as RNA splicing regulator. Mutations in MGA or BS69 have been linked to multiple cancers or neural developmental disorders. Here, by TALEN and CRISPR/Cas9-mediated loss of gene function assays, we show that zebrafish Mga and Bs69 are required to maintain proper Bmp signaling during early embryogenesis. We found that Mga protein localized in the cytoplasm modulates Bmpr1a activity by physical association with Zmynd11/Bs69. The Mynd domain of Bs69 specifically binds the kinase domain of Bmpr1a and interferes with its phosphorylation and activation of Smad1/5/8. Mga acts to antagonize Bs69 and facilitate the Bmp signaling pathway by disrupting the Bs69–Bmpr1a association. Functionally, Bmp signaling under control of Mga and Bs69 is required for properly specifying the ventral tailfin cell fate.
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Affiliation(s)
- Xiaoyun Sun
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Ji Chen
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yanyong Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Mumingjiang Munisha
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Scott Dougan
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Yuhua Sun
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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Togi S, Hatano Y, Muromoto R, Kawanishi E, Ikeda O, Hirashima K, Kon S, Kitai Y, Yasui T, Oritani K, Matsuda T. Caspase-dependent cleavage regulates protein levels of Epstein-Barr virus-derived latent membrane protein 1. FEBS Lett 2016; 590:808-18. [DOI: 10.1002/1873-3468.12119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/21/2016] [Accepted: 02/23/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Sumihito Togi
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Yosuke Hatano
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Ryuta Muromoto
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Eri Kawanishi
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Osamu Ikeda
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Koki Hirashima
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Shigeyuki Kon
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Yuichi Kitai
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
| | - Teruhito Yasui
- Department of Molecular Immunology; Research Institute for Microbial Diseases; Osaka University; Suita Osaka Japan
| | - Kenji Oritani
- Department of Hematology and Oncology; Graduate School of Medicine; Osaka University; Suita Osaka Japan
| | - Tadashi Matsuda
- Department of Immunology; Graduate School of Pharmaceutical Sciences; Hokkaido University; Kita-Ku Sapporo Japan
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Harter MR, Liu CD, Shen CL, Gonzalez-Hurtado E, Zhang ZM, Xu M, Martinez E, Peng CW, Song J. BS69/ZMYND11 C-Terminal Domains Bind and Inhibit EBNA2. PLoS Pathog 2016; 12:e1005414. [PMID: 26845565 PMCID: PMC4742278 DOI: 10.1371/journal.ppat.1005414] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/04/2016] [Indexed: 12/20/2022] Open
Abstract
Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) plays an important role in driving immortalization of EBV-infected B cells through regulating the expression of many viral and cellular genes. We report a structural study of the tumor suppressor BS69/ZMYND11 C-terminal region, comprised of tandem coiled-coil-MYND domains (BS69CC-MYND), in complex with an EBNA2 peptide containing a PXLXP motif. The coiled-coil domain of BS69 self-associates to bring two separate MYND domains in close proximity, thereby enhancing the BS69 MYND-EBNA2 interaction. ITC analysis of BS69CC-MYND with a C-terminal fragment of EBNA2 further suggests that the BS69CC-MYND homodimer synergistically binds to the two EBNA2 PXLXP motifs that are respectively located in the conserved regions CR7 and CR8. Furthermore, we showed that EBNA2 interacts with BS69 and down-regulates its expression at both mRNA and protein levels in EBV-infected B cells. Ectopic BS69CC-MYND is recruited to viral target promoters through interactions with EBNA2, inhibits EBNA2-mediated transcription activation, and impairs proliferation of lymphoblastoid cell lines (LCLs). Substitution of critical residues in the MYND domain impairs the BS69-EBNA2 interaction and abolishes the BS69 inhibition of the EBNA2-mediated transactivation and LCL proliferation. This study identifies the BS69 C-terminal domains as an inhibitor of EBNA2, which may have important implications in development of novel therapeutic strategies against EBV infection. Since the discovery of Epstein-Barr virus (EBV) 50 years ago, the etiologic links between EBV and a variety of human cancers have gained wide recognition. It is estimated that >90% of the worldwide population carry this virus, which causes over 200,000 cancers across the world every year. One of the key proteins in driving immortalization of EBV-infected B cells is Epstein-Barr virus nuclear antigen 2 (EBNA2), which regulates the expression of many cellular and viral genes. However, the molecular mechanism underlying the interactions between EBNA2 and cellular transcriptional regulators remains enigmatic. Here, we determined the crystal structure of the coiled-coil and MYND tandem domains of BS69/ZMYND11, a candidate tumor suppressor, in complex with an EBNA2 peptide containing a PXLXP motif. We found that the coiled-coil and MYND domains of BS69 cooperate in binding to EBNA2. We also showed that EBNA2 interacts with BS69 and down-regulates its expression at both mRNA and protein levels in EBV-associated B cells. Ectopic BS69 coiled-coil-MYND dual domain is recruited to viral target promoters through interaction with EBNA2, inhibits EBNA2-mediated transcription activation, and impairs proliferation of lymphoblastoid cell lines (LCLs). Together, this study identifies the BS69 C-terminal domains as an inhibitor of EBNA2.
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Affiliation(s)
- Matthew R. Harter
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Cheng-Der Liu
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Chih-Lung Shen
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Elsie Gonzalez-Hurtado
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
- MARC U-STAR Program, University of California, Riverside, Riverside, California, United States of America
| | - Zhi-Min Zhang
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Muyu Xu
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Ernest Martinez
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
- MARC U-STAR Program, University of California, Riverside, Riverside, California, United States of America
| | - Chih-Wen Peng
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
- * E-mail: (CWP); (JS)
| | - Jikui Song
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
- * E-mail: (CWP); (JS)
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Abstract
Almost exactly twenty years after the discovery of Epstein-Barr virus (EBV), the latent membrane protein 1 (LMP1) entered the EBV stage, and soon thereafter, it was recognized as the primary transforming gene product of the virus. LMP1 is expressed in most EBV-associated lymphoproliferative diseases and malignancies, and it critically contributes to pathogenesis and disease phenotypes. Thirty years of LMP1 research revealed its high potential as a deregulator of cellular signal transduction pathways leading to target cell proliferation and the simultaneous subversion of cell death programs. However, LMP1 has multiple roles beyond cell transformation and immortalization, ranging from cytokine and chemokine induction, immune modulation, the global alteration of gene and microRNA expression patterns to the regulation of tumor angiogenesis, cell-cell contact, cell migration, and invasive growth of tumor cells. By acting like a constitutively active receptor, LMP1 recruits cellular signaling molecules associated with tumor necrosis factor receptors such as tumor necrosis factor receptor-associated factor (TRAF) proteins and TRADD to mimic signals of the costimulatory CD40 receptor in the EBV-infected B lymphocyte. LMP1 activates NF-κB, mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3-K), IRF7, and STAT pathways. Here, we review LMP1's molecular and biological functions, highlighting the interface between LMP1 and the cellular signal transduction network as an important factor of virus-host interaction and a potential therapeutic target.
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Ersing I, Bernhardt K, Gewurz BE. NF-κB and IRF7 pathway activation by Epstein-Barr virus Latent Membrane Protein 1. Viruses 2013; 5:1587-606. [PMID: 23793113 PMCID: PMC3717723 DOI: 10.3390/v5061587] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 12/22/2022] Open
Abstract
The principal Epstein-Barr virus (EBV) oncoprotein, Latent Membrane Protein 1 (LMP1), is expressed in most EBV-associated human malignancies. LMP1 mimics CD40 receptor signaling to provide infected cells with constitutive NF-κB, MAP kinase, IRF7, and PI3 kinase pathway stimulation. EBV-transformed B-cells are particularly dependent on constitutive NF-κB activity, and rapidly undergo apoptosis upon NF-κB blockade. Here, we review LMP1 function, with special attention to current understanding of the molecular mechanisms of LMP1-mediated NF-κB and IRF7 pathway activation. Recent advances include the elucidation of transmembrane motifs important for LMP1 trafficking and ligand-independent signaling, analysis of genome-wide LMP1 gene targets, and the identification of novel cell proteins that mediate LMP1 NF-κB and IRF7 pathway activation.
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Affiliation(s)
| | | | - Benjamin E. Gewurz
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-011-617-525-4263; Fax: +1-011-615-525-4251
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12
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Shkoda A, Town JA, Griese J, Romio M, Sarioglu H, Knöfel T, Giehler F, Kieser A. The germinal center kinase TNIK is required for canonical NF-κB and JNK signaling in B-cells by the EBV oncoprotein LMP1 and the CD40 receptor. PLoS Biol 2012; 10:e1001376. [PMID: 22904686 PMCID: PMC3419181 DOI: 10.1371/journal.pbio.1001376] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 07/06/2012] [Indexed: 01/04/2023] Open
Abstract
TNIK has an important function in physiological activation and viral transformation of human B-cells by interacting with the TRAF6 adapter complex and mediating NF-κB and JNK signal transduction. The tumor necrosis factor-receptor-associated factor 2 (TRAF2)- and Nck-interacting kinase (TNIK) is a ubiquitously expressed member of the germinal center kinase family. The TNIK functions in hematopoietic cells and the role of TNIK-TRAF interaction remain largely unknown. By functional proteomics we identified TNIK as interaction partner of the latent membrane protein 1 (LMP1) signalosome in primary human B-cells infected with the Epstein-Barr tumor virus (EBV). RNAi-mediated knockdown proved a critical role for TNIK in canonical NF-κB and c-Jun N-terminal kinase (JNK) activation by the major EBV oncoprotein LMP1 and its cellular counterpart, the B-cell co-stimulatory receptor CD40. Accordingly, TNIK is mandatory for proliferation and survival of EBV-transformed B-cells. TNIK forms an activation-induced complex with the critical signaling mediators TRAF6, TAK1/TAB2, and IKKβ, and mediates signalosome formation at LMP1. TNIK directly binds TRAF6, which bridges TNIK's interaction with the C-terminus of LMP1. Separate TNIK domains are involved in NF-κB and JNK signaling, the N-terminal TNIK kinase domain being essential for IKKβ/NF-κB and the C-terminus for JNK activation. We therefore suggest that TNIK orchestrates the bifurcation of both pathways at the level of the TRAF6-TAK1/TAB2-IKK complex. Our data establish TNIK as a novel key player in TRAF6-dependent JNK and NF-κB signaling and a transducer of activating and transforming signals in human B-cells. The germinal center kinase family member TNIK was discovered in a yeast-two-hybrid screen for interaction partners of the adapter proteins TRAF2 and Nck, and here we show it is one of the missing molecular players in two key signaling pathways in B-lymphocytes. We found that TNIK is crucial for the activities of the CD40 receptor on Bcells and its viral mimic, the latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV). EBV is a human DNA tumor virus that is associated with various malignancies. It targets and transforms B-cells by hijacking the cellular signaling machinery via its oncogene LMP1. In normal Bcell physiology, the CD40 receptor is central to the immune response by mediating B-cell activation and proliferation. TNIK turns out to be an organizer of the LMP1- and CD40-induced signaling complexes by interacting with the TRAF6 adapter protein, well known for its role in linking distinct signaling pathways. Through this mechanism the two receptors depend on TNIK to activate the canonical NF-κB and JNK signal transduction pathways, which are important for the physiological activation of B-cells (a process that enables antibody production), as well as for their transformation into tumor cells. TNIK thus constitutes a key player in the transmission of physiological and pathological signals in human B-cells that might serve as a future therapeutic target against B-cell malignancies.
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Affiliation(s)
- Anna Shkoda
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Jennifer A. Town
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Janine Griese
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Michael Romio
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Hakan Sarioglu
- Research Unit Protein Science, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Thomas Knöfel
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Fabian Giehler
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
| | - Arnd Kieser
- Research Unit Gene Vectors, Helmholtz Zentrum München - German Research Center for Environmental Health, München, Germany
- * E-mail:
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13
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Dawson CW, Port RJ, Young LS. The role of the EBV-encoded latent membrane proteins LMP1 and LMP2 in the pathogenesis of nasopharyngeal carcinoma (NPC). Semin Cancer Biol 2012; 22:144-53. [PMID: 22249143 DOI: 10.1016/j.semcancer.2012.01.004] [Citation(s) in RCA: 221] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/02/2012] [Accepted: 01/03/2012] [Indexed: 02/08/2023]
Abstract
Although frequently expressed in EBV-positive malignancies, the contribution of the oncogenic latent membrane proteins, LMP1 and LMP2, to the pathogenesis of nasopharyngeal carcinoma (NPC) is not fully defined. As a key effector in EBV-driven B cell transformation and an established "transforming" gene, LMP1 displays oncogenic properties in rodent fibroblasts and induces profound morphological and phenotypic effects in epithelial cells. LMP1 functions as a viral mimic of the TNFR family member, CD40, engaging a number of signalling pathways that induce morphological and phenotypic alterations in epithelial cells. Although LMP2A plays an essential role in maintaining viral latency in EBV infected B cells, its role in epithelial cells is less clear. Unlike LMP1, LMP2A does not display "classical" transforming functions in rodent fibroblasts but its ability to engage a number of potentially oncogenic cell signalling pathways suggests that LMP2A can also participate in EBV-induced epithelial cell growth transformation. Here we review the effects of LMP1 and LMP2 on various aspects of epithelial cell behaviour highlighting key aspects that may contribute to the pathogenesis of NPC.
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Affiliation(s)
- Christopher W Dawson
- Birmingham Cancer Research UK Cancer Centre, School of Cancer Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
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14
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Schmitz ML, Weber A, Roxlau T, Gaestel M, Kracht M. Signal integration, crosstalk mechanisms and networks in the function of inflammatory cytokines. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:2165-75. [PMID: 21787809 DOI: 10.1016/j.bbamcr.2011.06.019] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 12/20/2022]
Abstract
Infection or cell damage triggers the release of pro-inflammatory cytokines such as interleukin(IL)-1α or β and tumor necrosis factor (TNF)α which are key mediators of the host immune response. Following their identification and the elucidation of central signaling pathways, recent results show a highly complex crosstalk between various cytokines and their signaling effectors. The molecular mechanisms controlling signaling thresholds, signal integration and the function of feed-forward and feedback loops are currently revealed by combining methods from biochemistry, genetics and in silico analysis. Increasing evidence is mounted that defects in information processing circuits or their components can be causative for chronic or overshooting inflammation. As progress in biosciences has always benefitted from the use of well-studied model systems, research on inflammatory cytokines may function as a paradigm to reveal general principles of signal integration, crosstalk mechanisms and signaling networks.
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Affiliation(s)
- M Lienhard Schmitz
- Institute of Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany.
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15
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Arcipowski KM, Stunz LL, Graham JP, Kraus ZJ, Bush TJV, Bishop GA. Molecular mechanisms of TNFR-associated factor 6 (TRAF6) utilization by the oncogenic viral mimic of CD40, latent membrane protein 1 (LMP1). J Biol Chem 2011; 286:9948-55. [PMID: 21262968 PMCID: PMC3060549 DOI: 10.1074/jbc.m110.185983] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 01/19/2011] [Indexed: 11/06/2022] Open
Abstract
Latent membrane protein 1 (LMP1), encoded by Epstein-Barr virus, is required for EBV-mediated B cell transformation and plays a significant role in the development of posttransplant B cell lymphomas. LMP1 has also been implicated in exacerbation of autoimmune diseases such as systemic lupus erythematosus. LMP1 is a constitutively active functional mimic of the tumor necrosis factor receptor superfamily member CD40, utilizing tumor necrosis factor receptor-associated factor (TRAF) adaptor proteins to induce signaling. However, LMP1-mediated B cell activation is amplified and sustained compared with CD40. We have previously shown that LMP1 and CD40 use TRAFs 1, 2, 3, and 5 differently. TRAF6 is important for CD40 signaling, but the role of TRAF6 in LMP1 signaling in B cells is not clear. Although TRAF6 binds directly to CD40, TRAF6 interaction with LMP1 in B cells has not been characterized. Here we tested the hypothesis that TRAF6 is a critical regulator of LMP1 signaling in B cells, either as part of a receptor-associated complex and/or as a cytoplasmic adaptor protein. Using TRAF6-deficient B cells, we determined that TRAF6 was critical for LMP1-mediated B cell activation. Although CD40-mediated TRAF6-dependent signaling does not require the TRAF6 receptor-binding domain, we found that LMP1 signaling required the presence of this domain. Furthermore, TRAF6 was recruited to the LMP1 signaling complex via the TRAF1/2/3/5 binding site within the cytoplasmic domain of LMP1.
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MESH Headings
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/virology
- CD40 Antigens/genetics
- CD40 Antigens/immunology
- CD40 Antigens/metabolism
- Cell Transformation, Viral/genetics
- Cell Transformation, Viral/immunology
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/immunology
- Herpesvirus 4, Human/metabolism
- Lupus Erythematosus, Systemic/genetics
- Lupus Erythematosus, Systemic/immunology
- Lupus Erythematosus, Systemic/metabolism
- Lupus Erythematosus, Systemic/virology
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/immunology
- Lymphoma, B-Cell/metabolism
- Lymphoma, B-Cell/virology
- Mice
- Mice, Knockout
- Molecular Mimicry/genetics
- Molecular Mimicry/immunology
- Protein Structure, Tertiary
- Signal Transduction/immunology
- TNF Receptor-Associated Factor 6/genetics
- TNF Receptor-Associated Factor 6/immunology
- TNF Receptor-Associated Factor 6/metabolism
- Viral Matrix Proteins/genetics
- Viral Matrix Proteins/immunology
- Viral Matrix Proteins/metabolism
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Affiliation(s)
- Kelly M. Arcipowski
- From the Interdisciplinary Graduate Programs in Molecular and Cellular Biology and
| | | | | | | | | | - Gail A. Bishop
- From the Interdisciplinary Graduate Programs in Molecular and Cellular Biology and
- Immunology and
- the Departments of Microbiology and
- Internal Medicine, University of Iowa and
- the Veterans Affairs Medical Center, Iowa City, Iowa 52242
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16
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Shinohara H, Kurosaki T. Comprehending the complex connection between PKCbeta, TAK1, and IKK in BCR signaling. Immunol Rev 2010; 232:300-18. [PMID: 19909372 DOI: 10.1111/j.1600-065x.2009.00836.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The transcription factor nuclear factor-kappaB (NF-kappaB) contributes to many events in the immune system. Characterization of NF-kappaB has facilitated our understanding of immune cell differentiation, survival, proliferation, and effector functions. Intense research continues to elucidate the role of NF-kappaB, which is shared in several receptor signaling pathways, such as Toll-like receptors, the tumor necrosis factor receptor, and antigen receptors. The specificity of cellular responses emanating from stimulation of these receptors is determined by post-translational modification, or 'fine tuning', which regulates spatiotemporal dynamics of downstream signaling. Understanding the fine tuning mechanisms of NF-kappaB activation is crucial for insights into biological regulation and for understanding how cellular signaling pathways are tightly regulated to guide different cell fates. In this review, we focus on recent advances that illuminate the fine tuning mechanisms of NF-kappaB activation by BCR signaling and have increased our comprehension of complex signal systems.
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Affiliation(s)
- Hisaaki Shinohara
- Laboratory for Lymphocyte Differentiation, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa, Japan.
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17
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Zeng S, Chen J, Shen H. Controlling of bone morphogenetic protein signaling. Cell Signal 2010; 22:888-93. [DOI: 10.1016/j.cellsig.2009.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 12/31/2009] [Indexed: 01/13/2023]
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18
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Yang H, Zhang C, Zhao X, Wu Q, Fu X, Yu B, Shao Y, Guan M, Zhang W, Wan J, Huang X. Analysis of copy number variations of BS69 in multiple types of hematological malignancies. Ann Hematol 2010; 89:959-64. [DOI: 10.1007/s00277-010-0966-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 04/12/2010] [Indexed: 10/19/2022]
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19
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BS69 cooperates with TRAF3 in the regulation of Epstein-Barr virus-derived LMP1/CTAR1-induced NF-κB activation. FEBS Lett 2010; 584:865-72. [DOI: 10.1016/j.febslet.2010.01.060] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/13/2010] [Accepted: 01/27/2010] [Indexed: 11/19/2022]
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20
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Takaki H, Oshiumi H, Sasai M, Kawanishi T, Matsumoto M, Seya T. Oligomerized TICAM-1 (TRIF) in the cytoplasm recruits nuclear BS69 to enhance NF-kappaB activation and type I IFN induction. Eur J Immunol 2010; 39:3469-76. [PMID: 19795416 DOI: 10.1002/eji.200939878] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although adenovirus 5 E1A-binding protein (BS69) is a nuclear protein acting as a transcriptional repressor, we found by an yeast two-hybrid and human cell immunoprecipitation another cytoplasmic function for this protein. BS69 bound Toll-interleukin 1 receptor domain (TIR)-containing adaptor molecule-1 (TICAM-1) (also named TRIF), an adaptor protein that couples with TLR3 around the endosome. BS69 translocated from the nucleus to the cytoplasm when cells were stimulated with dsRNA or transfected with TICAM-1. Confocal analysis of cells with over-expressed TICAM-1 or those stimulated with dsRNA revealed the characteristic "TICAM-1 speckle", which reflects signalosome formation necessary for the activation of NF-kappaB and IFN-regulatory factor (IRF)-3. BS69 was involved in the TICAM-1 complex, and the activation of NF-kappaB/IRF-3 followed by cytokine production was augmented in the presence of BS69 overexpression. Knockdown of endogenous BS69 resulted in a decrease of IFN-beta induction, suggesting that BS69 is a positive regulator for the TLR3-TICAM-1 pathway. These results, together with a recent report showing the negative regulatory properties of BS69 in NF-kappaB activation by EBV-derived latent membrane protein 1, suggest that BS69 harbors dual modes of cytoplasmic NF-kappaB regulation, positively in the TICAM-1 pathway and negatively in the latent membrane protein 1 pathway.
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Affiliation(s)
- Hiromi Takaki
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, Japan
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21
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Yu B, Shao Y, Zhang C, Chen Y, Zhong Q, Zhang J, Yang H, Zhang W, Wan J. BS69 undergoes SUMO modification and plays an inhibitory role in muscle and neuronal differentiation. Exp Cell Res 2009; 315:3543-53. [DOI: 10.1016/j.yexcr.2009.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Revised: 09/05/2009] [Accepted: 09/11/2009] [Indexed: 01/08/2023]
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22
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Ikeda O, Sekine Y, Mizushima A, Oritani K, Yasui T, Fujimuro M, Muromoto R, Nanbo A, Matsuda T. BS69 negatively regulates the canonical NF-kappaB activation induced by Epstein-Barr virus-derived LMP1. FEBS Lett 2009; 583:1567-74. [PMID: 19379743 DOI: 10.1016/j.febslet.2009.04.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 04/02/2009] [Accepted: 04/09/2009] [Indexed: 11/18/2022]
Abstract
Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) activates NF-kappaB signaling pathways through the two C-terminal regions, CTAR1 and CTAR2. BS69 has previously been shown to be involved in LMP1-induced c-Jun N-terminal kinase activation through CTAR2 by interacting with tumor necrosis factor (TNFR) receptor-associated factor 6. In the present study, our manipulation of BS69 expression clearly indicates that BS69 negatively regulates LMP1-mediated NF-kappaB activation and up-regulates IL-6 mRNA expression and IkappaB degradation. Our immunoprecipitation experiments suggest that BS69 decreases complex formation between LMP1 and TNFR-associated death domain protein (TRADD).
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Affiliation(s)
- Osamu Ikeda
- Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-Ku Kita 12 Nishi 6, Sapporo, Japan
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23
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Kieser A. Pursuing different 'TRADDes': TRADD signaling induced by TNF-receptor 1 and the Epstein-Barr virus oncoprotein LMP1. Biol Chem 2009; 389:1261-71. [PMID: 18713013 DOI: 10.1515/bc.2008.144] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The pro-apoptotic tumor necrosis factor (TNF)-receptor 1-associated death domain protein (TRADD) was initially identified as the central signaling adapter molecule of TNF-receptor 1 (TNFR1). Upon stimulation with the pro-inflammatory cytokine TNFalpha, TRADD is recruited to the activated TNFR1 by direct interaction between the death domains of both molecules. TRADD mediates TNFR1 activation of NF-kappaB and c-Jun N-terminal kinase (JNK), as well as caspase-dependent apoptosis. Surprisingly, TRADD is also recruited by latent membrane protein 1 (LMP1), the major oncoprotein of the human Epstein-Barr tumor virus. By mimicking a constitutively active receptor, LMP1 is essential for B-cell transformation by the virus, activating NF-kappaB, phosphatidylinositol 3-kinase, JAK/STAT and mitogen-activated protein kinase signaling. In contrast to TNFR1, LMP1's interaction with TRADD is independent of a functional death domain. The unique structure of the LMP1-TRADD complex dictates an unusual type of TRADD-dependent NF-kappaB signaling and subverts TRADD's potential to induce apoptosis. This article provides an overview of TNFR1 and LMP1 signal transduction with a focus on TRADD's functions in apoptotic and transforming signaling, incorporating recent results from TRADD RNAi and knockout studies.
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Affiliation(s)
- Arnd Kieser
- Abteilung Genvektoren, Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt, Marchioninistrasse 25, D-81377 München, Germany.
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24
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Luo W, Yan G, Li L, Wang Z, Liu H, Zhou S, Liu S, Tang M, Yi W, Dong Z, Cao Y. Epstein–Barr virus latent membrane protein 1 mediates serine 25 phosphorylation and nuclear entry of annexin A2 via PI‐PLC–PKCα/PKCβ pathway. Mol Carcinog 2008; 47:934-46. [DOI: 10.1002/mc.20445] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Wei Luo
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Guangrong Yan
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Lili Li
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Zhenlian Wang
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Haidan Liu
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Shanghui Zhou
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Sufang Liu
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Min Tang
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Wei Yi
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, Austin, Minnesota, 55912
| | - Ya Cao
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, P.R. China
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25
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STAP-2 negatively regulates both canonical and noncanonical NF-kappaB activation induced by Epstein-Barr virus-derived latent membrane protein 1. Mol Cell Biol 2008; 28:5027-42. [PMID: 18573890 DOI: 10.1128/mcb.00194-08] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The signal-transducing adaptor protein 2 (STAP-2) is a recently identified adaptor protein that contains a pleckstrin homology (PH) and Src homology 2 (SH2)-like domains, as well as a proline-rich domain in its C-terminal region. In previous studies, we demonstrated that STAP-2 binds to MyD88 and IKK-alpha or IKK-beta and modulates NF-kappaB signaling in macrophages. In the present study, we found that ectopic expression of STAP-2 inhibited Epstein-Barr virus (EBV) LMP1-mediated NF-kappaB signaling and interleukin-6 expression. Indeed, STAP-2 associated with LMP1 through its PH and SH2-like domains, and these proteins interacted with each other in EBV-positive human B cells. We found, furthermore, that STAP-2 regulated LMP1-mediated NF-kappaB signaling through direct or indirect interactions with the tumor necrosis factor receptor (TNFR)-associated factor 3 (TRAF3) and TNFR-associated death domain (TRADD) proteins. STAP-2 mRNA was induced by the expression of LMP1 in human B cells. Furthermore, transient expression of STAP-2 in EBV-positive human B cells decreased cell growth. Finally, STAP-2 knockout mouse embryonic fibroblasts showed enhanced LMP1-induced cell growth. These results suggest that STAP-2 acts as an endogenous negative regulator of EBV LMP1-mediated signaling through TRAF3 and TRADD.
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26
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Abstract
Tumor necrosis factor receptor associated factors (TRAFs) play a variety of interesting and important roles in the regulation of B lymphocyte function. They act both as cytoplasmic regulatory molecules, and as signal transducers for receptors involved in both innate and adaptive humoral immune responses. In this brief review, we highlight the current state of knowledge of the diverse roles of TRAF molecules in the functions of B lymphocytes.
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Affiliation(s)
- Ping Xie
- Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA
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27
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The ID proteins contribute to the growth of rodent fibroblasts during LMP1-mediated transformation. Virology 2008; 376:258-69. [PMID: 18456300 DOI: 10.1016/j.virol.2007.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 09/14/2007] [Accepted: 12/03/2007] [Indexed: 12/17/2022]
Abstract
LMP1 induces the expression of two members of the family of Id proteins, Id1 and Id3, and affects cell cycle regulation by decreasing the expression of the cyclin dependent kinase inhibitor, p27, and increasing levels and phosphorylation of cdk2 and Rb. In the present study, the contribution of the Id proteins to LMP1-mediated transformation was determined. Although LMP1 effectively inhibited p27 expression, the Id proteins alone did not affect expression of p27, cdk2, and Rb. Neither Id1 nor Id3 was sufficient to transform Rat-1 cells and inhibition of Id1 expression did not affect LMP1-induced morphologic transformation of Rat-1 cells or reduction of p27. However, reduced Id expression resulted in smaller foci and impaired the growth rate of Rat-1 cells. These data indicate that overexpression of the Id proteins is not sufficient for the effects of LMP1 on the cell cycle but that inhibition of Id expression does affect the growth of LMP1-transformed and parental Rat1 cells.
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28
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Intrinsic structural disorder in adenovirus E1A: a viral molecular hub linking multiple diverse processes. J Virol 2008; 82:7252-63. [PMID: 18385237 DOI: 10.1128/jvi.00104-08] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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29
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Schneider F, Neugebauer J, Griese J, Liefold N, Kutz H, Briseño C, Kieser A. The viral oncoprotein LMP1 exploits TRADD for signaling by masking its apoptotic activity. PLoS Biol 2008; 6:e8. [PMID: 18198944 PMCID: PMC2174972 DOI: 10.1371/journal.pbio.0060008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 12/04/2007] [Indexed: 01/14/2023] Open
Abstract
The tumor necrosis factor (TNF)-receptor 1–associated death domain protein (TRADD) mediates induction of apoptosis as well as activation of NF-κB by cellular TNF-receptor 1 (TNFR1). TRADD is also recruited by the latent membrane protein 1 (LMP1) oncoprotein of Epstein-Barr virus, but its role in LMP1 signaling has remained enigmatic. In human B lymphocytes, we have generated, to our knowledge, the first genetic knockout of TRADD to investigate TRADD's role in LMP1 signal transduction. Our data from TRADD-deficient cells demonstrate that TRADD is a critical signaling mediator of LMP1 that is required for LMP1 to recruit and activate I-κB kinase β (IKKβ). However, in contrast to TNFR1, LMP1-induced TRADD signaling does not induce apoptosis. Searching for the molecular basis for this observation, we characterized the 16 C-terminal amino acids of LMP1 as an autonomous and unique virus-derived TRADD-binding domain. Replacing the death domain of TNFR1 by LMP1′s TRADD-binding domain converts TNFR1 into a nonapoptotic receptor that activates NF-κB through a TRAF6-dependent pathway, like LMP1 but unlike wild-type TNFR1. Thus, the unique interaction of LMP1 with TRADD encodes the transforming phenotype of viral TRADD signaling and masks TRADD's pro-apoptotic function. For viral infection to succeed, viral proteins must interact with the cellular signaling machinery of its target cell. An oncoprotein encoded by the Epstein-Barr virus (EBV) called latent membrane protein 1 (LMP1) is a primary contributor to the transformation of human B cells by the virus and the development of EBV-associated B cell malignancies by recruiting signaling molecules provided by the host. One such molecule, the cellular adapter protein TRADD, is among the few direct interaction partners of LMP1. But because TRADD promotes cell death (apoptosis) in the cellular tumor necrosis factor-receptor 1 (TNFR1) signaling pathway, it seems counterintuitive that TRADD could play a role in LMP1 biology, since LMP1 promotes cell survival and proliferation. We provide genetic evidence that TRADD is critical for LMP1 to assemble its transforming signaling network. LMP1 requires TRADD to recruit and activate I-κB kinase β and, thus, to induce canonical NF-κB signaling. Simultaneously, LMP1 masks TRADD's pro-apoptotic activity. We show that LMP1 carries a unique and autonomous viral TRADD-binding domain, which dictates an unusual structure of the LMP1-TRADD complex and the nonapoptotic phenotype of TRADD signaling, irrespective of the receptor context in which this domain is located. Thus, DNA tumor viruses alter the functional properties of cellular signaling molecules to exploit them for their own purpose of cell transformation. A unique Epstein Barr virus-derived protein interaction domain uses the cellular death domain protein TRADD to assemble its transforming signaling complex and dictates a transferable nonapoptitic phenotype of TRADD signaling.
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Affiliation(s)
- Frank Schneider
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
| | - Julia Neugebauer
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
| | - Janine Griese
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
| | - Nicola Liefold
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
| | - Helmut Kutz
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
| | - Cinthia Briseño
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
| | - Arnd Kieser
- Department of Gene Vectors, GSF–National Research Center for Environment and Health, Munich, Germany
- * To whom correspondence should be addressed. E-mail:
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Ju D, Wang X, Xu H, Xie Y. Genome-wide analysis identifies MYND-domain protein Mub1 as an essential factor for Rpn4 ubiquitylation. Mol Cell Biol 2008; 28:1404-12. [PMID: 18070918 PMCID: PMC2258742 DOI: 10.1128/mcb.01787-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/05/2007] [Accepted: 11/26/2007] [Indexed: 01/13/2023] Open
Abstract
The proteasome homeostasis in Saccharomyces cerevisiae is regulated by a negative feedback circuit in which the Rpn4 transcription factor upregulates the proteasome genes and is rapidly degraded by the proteasome. Previous work has identified Ubr2 and Rad6 as the cognate E3 and E2 enzymes for Rpn4 ubiquitylation. However, our recent attempts to ubiquitylate Rpn4 using purified Ubr2 and Rad6 proteins in a reconstitution system have been unsuccessful, suggesting that an additional factor is required for Rpn4 ubiquitylation. Here, we screened the entire collection of the single-gene-deletion yeast mutants generated by the Saccharomyces Genome Deletion Project and identified the mub1Delta mutant defective in ubiquitin-dependent degradation of Rpn4. An in vitro reconstitution ubiquitylation assay confirms that Mub1 is the missing factor for Rpn4 ubiquitylation. We further show that Mub1 directly interacts with Ubr2 and Rpn4. The MYND domain of Mub1 may play an important role in Rpn4 ubiquitylation. Interestingly, Mub1 itself is a short-lived protein and its degradation is dependent on the Ubr2/Rad6 ubiquitin ligase. Together, these data suggest that Mub1 and Ubr2 cooperate to transfer ubiquitin to Rpn4 from Rad6 and that Mub1 may switch from a partner to a substrate of the Ubr2/Rad6 ubiquitin ligase.
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Affiliation(s)
- Donghong Ju
- Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, 110 E. Warren Ave., Detroit, MI 48201, USA
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31
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Soni V, Cahir-McFarland E, Kieff E. LMP1 TRAFficking Activates Growth and Survival pathways. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 597:173-87. [PMID: 17633026 DOI: 10.1007/978-0-387-70630-6_14] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Epstein-Barr Virus (EBV) Latent Infection Membrane Protein 1 (LMP1) is expressed in all the EBV related malignancies. LMP1 expression is critical for transformation of human B-cells by EBV. LMP1 expression in human B cells induces activation and adhesion molecule expression and cell dumping, which are characteristic of CD40 activated B lymphocytes. In immortalized fibroblasts, LMP1 mimics aspects of activated ras in enabling serum, contact, and anchorage independent growth. Reverse genetic analyses implicate six transmembrane domains (TM), TM1-6, and two C-terminal cytosolic domains, transformation effector sites 1 and 2 (TES1 and 2) or C-terminal activation regions 1 and 2 (CTAR1 and 2) as the essential domains for LMP1 effects. The 6 transmembrane domains cause intermolecular interaction, whereas the C-terminal domains signal through tumor necrosis factor receptor (TNFR) associated factors (TRAFs) or TNFR associated death domain proteins (TRADD) and activate NF-kappaB, JNK, and p38. LMP1 TES1/CTAR1 directly recruits TRAFs 1, 2, 3 and 5 whereas LMP1 TES2/CTAR2 indirectly recruits TRAF6 via BS69. LMP1 TES1/CTAR1 activates TRAF2, NIK, IKKalpha and p52 mediated noncanonical NF-KB pathway and LMP1 TES2/CTAR2 activates TRAF6, TAB1, TAK1, IKKalpha/ IKKbeta/ IKKgamma mediated canonical NF-KB pathway. Interestingly, TRAF3 is a negative regulator of noncanonical NF-kappaB activation, although a positive role in LMP1 signaling has also been described. LMP1 mediated JNK activation is predominantly TES2/CTAR2 dependent and requires TRAF6. LMP1 specifically increases TRAF3 partitioning into lipid rafts and interestingly does not induce degradation of any of the TRAFs upon NF-kappaB activation. Studies of the chemistry and biology of LMP1-TRAF interaction mediated activation of signaling pathways are important for controlling EBV infected cell survival and growth.
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Affiliation(s)
- Vishal Soni
- Channing Laboratory and Infectious Disease Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School and University, Boston, Massachusetts 02115, USA
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Zhang W, Chan HM, Gao Y, Poon R, Wu Z. BS69 is involved in cellular senescence through the p53-p21Cip1 pathway. EMBO Rep 2007; 8:952-8. [PMID: 17721438 PMCID: PMC2002549 DOI: 10.1038/sj.embor.7401049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 07/16/2007] [Accepted: 07/16/2007] [Indexed: 11/08/2022] Open
Abstract
The multidomain-containing cellular protein BS69 interacts with adenovirus E1A and several other viral and cellular factors, and acts as a transcription repressor. Here, we show that BS69 is involved in the p53-p21Cip1-mediated senescence pathway. Knockdown of BS69 by RNA interference in human primary fibroblasts results in elevated levels of p21Cip1 and the appearance of several senescent markers, including enhanced senescence-associated beta-galactosidase activity and formation of senescence-associated heterochromatin foci. Importantly, knockdown of either p53 or p21Cip1, but not p16(INK4a) or Rb, allows cells to bypass premature senescence that is induced by BS69 knockdown. Furthermore, we show that BS69 forms complexes with both p53 and p400, and that BS69 associates with the p21Cip1 promoter through p53. Together, our data indicate that BS69 is involved in cellular senescence mainly through the p53-p21Cip1 pathway.
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Affiliation(s)
- Wei Zhang
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Ho Man Chan
- Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
| | - Yan Gao
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Randy Poon
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Zhenguo Wu
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
- Tel: +852 2358 8704; Fax: +852 2358 1552; E-mail:
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Abstract
Deletions of the 3p21.3 region are a frequent and early event in the formation of lung, breast, kidney and other cancers. Intense investigation of allelic losses and the discovery of overlapping homozygous deletions in lung and breast tumour-cell lines have defined a minimal critical 120 kb deletion region containing eight genes and likely to harbor one or more tumour-suppressor genes (TSGs). The candidate genes are HYAL2, FUS1, Ras-associated factor 1 (RASSF1), BLU/ZMYND10, NPR2L, 101F6, PL6 and CACNA2D2. Recent research indicates that several of these genes can suppress the growth of lung and other tumour cells. Furthermore, some genes (RASSF1A and BLU/ZMYND10) are very frequently inactivated by non-classical mechanisms such as promoter hypermethylation resulting in loss of expression. These data indicate that the 120 kb critical deletion region at 3p21.3 may represent a TSG cluster with preferential inactivation of particular genes depending on tumour type. The eight genes within this region and their potential role in cancer will be the focus of this review.
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Affiliation(s)
- L B Hesson
- Department of Medical and Molecular Genetics, MRC Protein Phosphorylation Unit, College of Life Sciences, Sir James Black Centre, Dow Street, University of Dundee, Dundee, UK.
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34
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Kieser A. Signal transduction by the Epstein-Barr virus oncogene latent membrane protein 1 (LMP1). ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200600116] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Yan G, Luo W, Lu Z, Luo X, Li L, Liu S, Liu Y, Tang M, Dong Z, Cao Y. Epstein–Barr virus latent membrane protein 1 mediates phosphorylation and nuclear translocation of annexin A2 by activating PKC pathway. Cell Signal 2007; 19:341-8. [PMID: 16989986 DOI: 10.1016/j.cellsig.2006.07.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 06/28/2006] [Accepted: 07/19/2006] [Indexed: 01/14/2023]
Abstract
We have previously combined phosphorylation enrichment with proteomics technology to elucidate the novel phosphoproteins in the signaling pathways triggered by Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) and shown that LMP1 can increase the phosphorylation level of annexin A2. Here, we further showed that LMP1 increased the serine, but not tyrosine, phosphorylation of annexin A2 by activating a novel signaling pathway, the protein kinase C (PKC) signaling pathway. However, LMP1 did not affect the level of annexin A2 expression. In addition, we found that LMP1 induced the nuclear entry of annexin A2 in an energy- and temperature-dependent manner, suggesting that the nuclear entry of annexin A2 is an active process. Treatment of LMP1-expressing cells with the PKC inhibitor myr-psiPKC resulted in annexin A2 being present almost exclusively at cell surface, instead of within the nucleus, suggesting that the nuclear entry of annexin A2 was associated with serine phosphorylation mediated by PKC.
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Affiliation(s)
- Guangrong Yan
- Cancer Research Institute, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
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Liu M, Xiao DS, Qian ZM. Identification of transcriptionally regulated genes in response to cellular iron availability in rat hippocampus. Mol Cell Biochem 2006; 300:139-47. [PMID: 17186380 DOI: 10.1007/s11010-006-9377-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Accepted: 11/06/2006] [Indexed: 12/11/2022]
Abstract
The present study was attempted to identify transcriptionally regulated genes of the normal neurocytes responsive to iron availability. Postnatal rat hippocampus cells were primarily cultured either under the iron-loaded or depleted conditions. These cultured cells were applied for the generation of subtracted complementary DNA libraries by the suppression subtraction hybridization (SSH) and for the subsequent identification of differentially expressed transcripts by reverse Northern blot. The differentially expressed genes were chosen to perform sequencing, and then some of them were performed by Northern blot analysis for observation of their expression in the hippocampus of rats with the different iron status. The results indicated that five unique transcripts were strong candidates for differential expression in cellular iron repletion, one of them is a novel sequence (GenBank No. AF 433878), while 26 unique transcripts were strong candidates for differential expression in cellular iron deprivation, one of them is a novel sequence (GenBank No. AY 912101). The revealed known genes responsive to iron availability were previously unknown to respond to iron availability, or have not been determined in the brain, have not even been currently determined in their physiological and biological functions. Interestingly, the proteins encoded by most of the known genes are either directly pointed to or indirectly associated with the molecules that play important, even key roles in cellular signal transduction and the cell cycle. These findings lead to the important suggestion that the cellular responses to iron availability involve extensive transcriptional regulation and cellular signal transduction. Therefore, iron may serve as a signal, which directly and/or indirectly regulates or modulates cell functions.
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Affiliation(s)
- Mei Liu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
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Yau WL, Lung HL, Zabarovsky ER, Lerman MI, Sham JST, Chua DTT, Tsao SW, Stanbridge EJ, Lung ML. Functional studies of the chromosome 3p21.3 candidate tumor suppressor geneBLU/ZMYND10 in nasopharyngeal carcinoma. Int J Cancer 2006; 119:2821-6. [PMID: 16929489 DOI: 10.1002/ijc.22232] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Chromosome 3p plays an important role in tumorigenesis in many cancers, including nasopharyngeal carcinoma (NPC). We have previously shown chromosome 3p can suppress tumor growth in vivo by using the monochromosome transfer approach, which indicated the chromosome 3p21.3 region was critical for tumor suppression. BLU/ZMYND10 is one of the candidate tumor suppressor genes mapping in the 3p21.3 critical region and is a candidate TSG for NPC. By quantitative RT-PCR, it is frequently downregulated in NPC cell lines (83%) and NPC biopsies (80%). However, no functional studies have yet verified the functional role of BLU/ZMYND10 as a tumor suppressor gene. In the current study, a gene inactivation test (GIT) utilizing a tetracycline regulation system was used to study the functional role of BLU/ZMYND10. When BLU/ZMYND10 is expressed in the absence of doxycycline, the stable transfectants were able to induce tumor suppression in nude mice. In contrast, downregulation of BLU/ZMYND10 in these tumor suppressive clones by doxycycline treatment restored the tumor formation ability. This study provides the first significant evidence to demonstrate BLU/ZMYND10 can functionally suppress tumor formation in vivo and is, therefore, likely to be one of the candidate tumor suppressor genes involved in NPC.
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Affiliation(s)
- Wing Lung Yau
- Department of Biology and Center for Cancer Research, The Hong Kong University of Science and Technology, Hong Kong (SAR), China
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