1
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Wu S, Zhao Y, Wang D, Chen Z. Mode of Action of Heat Shock Protein (HSP) Inhibitors against Viruses through Host HSP and Virus Interactions. Genes (Basel) 2023; 14:genes14040792. [PMID: 37107550 PMCID: PMC10138296 DOI: 10.3390/genes14040792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023] Open
Abstract
Misfolded proteins after stress-induced denaturation can regain their functions through correct re-folding with the aid of molecular chaperones. As a molecular chaperone, heat shock proteins (HSPs) can help client proteins fold correctly. During viral infection, HSPs are involved with replication, movement, assembly, disassembly, subcellular localization, and transport of the virus via the formation of macromolecular protein complexes, such as the viral replicase complex. Recent studies have indicated that HSP inhibitors can inhibit viral replication by interfering with the interaction of the virus with the HSP. In this review, we describe the function and classification of HSPs, the transcriptional mechanism of HSPs promoted by heat shock factors (HSFs), discuss the interaction between HSPs and viruses, and the mode of action of HSP inhibitors at two aspects of inhibiting the expression of HSPs and targeting the HSPs, and elaborate their potential use as antiviral agents.
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2
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Pley C, Lourenço J, McNaughton AL, Matthews PC. Spacer Domain in Hepatitis B Virus Polymerase: Plugging a Hole or Performing a Role? J Virol 2022; 96:e0005122. [PMID: 35412348 PMCID: PMC9093120 DOI: 10.1128/jvi.00051-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/14/2022] [Indexed: 11/25/2022] Open
Abstract
Hepatitis B virus (HBV) polymerase is divided into terminal protein, spacer, reverse transcriptase, and RNase domains. Spacer has previously been considered dispensable, merely acting as a tether between other domains or providing plasticity to accommodate deletions and mutations. We explore evidence for the role of spacer sequence, structure, and function in HBV evolution and lineage, consider its associations with escape from drugs, vaccines, and immune responses, and review its potential impacts on disease outcomes.
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Affiliation(s)
- Caitlin Pley
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - José Lourenço
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
| | - Anna L. McNaughton
- Population Health Science, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
| | - Philippa C. Matthews
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Division of Infection and Immunity, University College London, London, United Kingdom
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3
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Huang W, Li JY, Wu YY, Liao TL, Nielsen BL, Liu HJ. p17-Modulated Hsp90/Cdc37 Complex Governs Oncolytic Avian Reovirus Replication by Chaperoning p17, Which Promotes Viral Protein Synthesis and Accumulation of Viral Proteins σC and σA in Viral Factories. J Virol 2022; 96:e0007422. [PMID: 35107368 PMCID: PMC8941905 DOI: 10.1128/jvi.00074-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 01/25/2022] [Indexed: 11/20/2022] Open
Abstract
In this work we have determined that heat shock protein 90 (Hsp90) is essential for avian reovirus (ARV) replication by chaperoning the ARV p17 protein. p17 modulates the formation of the Hsp90/Cdc37 complex by phosphorylation of Cdc37, and this chaperone machinery protects p17 from ubiquitin-proteasome degradation. Inhibition of the Hsp90/Cdc37 complex by inhibitors (17-N-allylamino-17-demethoxygeldanamycin 17-AGG, and celastrol) or short hairpin RNAs (shRNAs) significantly reduced expression levels of viral proteins and virus yield, suggesting that the Hsp90/Cdc37 chaperone complex functions in virus replication. The expression levels of p17 were decreased at the examined time points (2 to 7 h and 7 to 16 h) in 17-AAG-treated cells in a dose-dependent manner while the expression levels of viral proteins σA, σC, and σNS were decreased at the examined time point (7 to 16 h). Interestingly, the expression levels of σC, σA, and σNS proteins increased along with coexpression of p17 protein. p17 together with the Hsp90/Cdc37 complex does not increase viral genome replication but enhances viral protein stability, maturation, and virus production. Virus factories of ARV are composed of nonstructural proteins σNS and μNS. We found that the Hsp90/Cdc37 chaperone complex plays an important role in accumulation of the outer-capsid protein σC, inner core protein σA, and nonstructural protein σNS of ARV in viral factories. Depletion of Hsp90 inhibited σA, σC, and p17 proteins colocalized with σNS in viral factories. This study provides novel insights into p17-modulated formation of the Hsp90/Cdc37 chaperone complex governing virus replication via stabilization and maturation of viral proteins and accumulation of viral proteins in viral factories for virus assembly. IMPORTANCE Molecular mechanisms that control stabilization of ARV proteins and the intermolecular interactions among inclusion components remain largely unknown. Here, we show that the ARV p17 is an Hsp90 client protein. The Hsp90/Cdc37 chaperone complex is essential for ARV replication by protecting p17 chaperone from ubiquitin-proteasome degradation. p17 modulates the formation of Hsp90/Cdc37 complex by phosphorylation of Cdc37, and this chaperone machinery protects p17 from ubiquitin-proteasome degradation, suggesting a feedback loop between p17 and the Hsp90/Cdc37 chaperone complex. p17 together with the Hsp90/Cdc37 complex does not increase viral genome replication but enhances viral protein stability and virus production. Depletion of Hsp90 prevented viral proteins σA, σC, and p17 from colocalizing with σNS in viral factories. Our findings elucidate that the Hsp90/Cdc37 complex chaperones p17, which, in turn, promotes the synthesis of viral proteins σA, σC, and σNS and facilitates accumulation of the outer-capsid protein σC and inner core protein σA in viral factories for virus assembly.
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Affiliation(s)
- Wei‐Ru Huang
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
- The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Jyun-Yi Li
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
- The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ying Wu
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
- The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Tsai-Ling Liao
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
- Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Ph.D. Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Brent L. Nielsen
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Hung-Jen Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
- The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Ph.D. Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
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4
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Zhang Q, Wu YF, Chen P, Liu TH, Dong ZQ, Lu C, Pan MH. Bombyx mori cell division cycle protein 37 promotes the proliferation of BmNPV. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 178:104923. [PMID: 34446199 DOI: 10.1016/j.pestbp.2021.104923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 07/06/2021] [Accepted: 07/11/2021] [Indexed: 06/13/2023]
Abstract
Cell division cycle protein 37 (Cdc37) is a molecular chaperone that actively participates in many intracellular physiological and biochemical processes as well as pathogen infection. However, the function of Cdc37 in silkworm cells under Bombyx mori nucleopolyhedrovirus (BmNPV) infection is unknown. We cloned and identified BmCdc37, a Cdc37 gene from B. mori, which is highly conserved among other species. After BmNPV infection, the expression level of the BmCdc37 gene was up-regulated and showed an expression pattern similar to the BmHsp90 gene, which relies on Cdc37 to stabilize and activate specific protein kinases. The immunofluorescence, bimolecular fluorescence complementation (BiFC), and co-immunoprecipitation (Co-IP) assays all indicated that BmCdc37 interacts with BmHsp90 in silkworm cells. Both BmCdc37 and BmHsp90 promote the reproduction of BmNPV. Co-expression of BmCdc37 and BmHsp90 was better at promoting virus proliferation than overexpression alone. These findings all indicate that BmCdc37 plays an active role in the proliferation of BmNPV.
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Affiliation(s)
- Qian Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China
| | - Yun-Fei Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China
| | - Peng Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China
| | - Tai-Hang Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Zhan-Qi Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China.
| | - Min-Hui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China.
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5
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Wang L, Zhang Q, You Q. Targeting the HSP90-CDC37-kinase chaperone cycle: A promising therapeutic strategy for cancer. Med Res Rev 2021; 42:156-182. [PMID: 33846988 DOI: 10.1002/med.21807] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 03/19/2021] [Accepted: 03/31/2021] [Indexed: 12/25/2022]
Abstract
Heat shock protein 90 (HSP90) is an indispensable molecular chaperone that facilitates the maturation of numerous oncoproteins in cancer cells, including protein kinases, ribonucleoproteins, steroid hormone receptors, and transcription factors. Although over 30 HSP90 inhibitors have steadily entered clinical trials, further clinical advancement has been restricted by their limited efficacy, inevitable heat shock response, and multiple side-effects, likely induced via an ATP inhibition mechanism. Since both ATP and various co-chaperones play essential roles in the HSP90 chaperone cycle to achieve integrated function, optimal therapeutics require an understanding of the dynamic interactions among HSP90, ATP, and cochaperones. To date, continuous research has promoted the exploration of the cochaperone cell division cycle 37 (CDC37) as a kinase-specific recognizer and has shown that the HSP90-CDC37-kinase complex is particularly relevant in cancers. Indeed, disrupting the HSP90-CDC37-kinase complex, rather than totally blocking the ATP function of HSP90, is emerging as an alternative way to avoid the limitations of current inhibitors. In this review, we first briefly introduce the HSP90-CDC37-kinase cycle and present the currently available approaches for inhibitor development targeting this cycle and provide insights into selective regulation of the kinase clients of HSP90 by more directional ways.
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Affiliation(s)
- Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, China.,Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
| | - Qiuyue Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, China.,Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, China.,Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, China
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6
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Chander Y, Kumar R, Khandelwal N, Singh N, Shringi BN, Barua S, Kumar N. Role of p38 mitogen-activated protein kinase signalling in virus replication and potential for developing broad spectrum antiviral drugs. Rev Med Virol 2021; 31:1-16. [PMID: 33450133 DOI: 10.1002/rmv.2217] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) play a key role in complex cellular processes such as proliferation, development, differentiation, transformation and apoptosis. Mammals express at least four distinctly regulated groups of MAPKs which include extracellular signal-related kinases (ERK)-1/2, p38 proteins, Jun amino-terminal kinases (JNK1/2/3) and ERK5. p38 MAPK is activated by a wide range of cellular stresses and modulates activity of several downstream kinases and transcription factors which are involved in regulating cytoskeleton remodeling, cell cycle modulation, inflammation, antiviral response and apoptosis. In viral infections, activation of cell signalling pathways is part of the cellular defense mechanism with the basic aim of inducing an antiviral state. However, viruses can exploit enhanced cell signalling activities to support various stages of their replication cycles. Kinase activity can be inhibited by small molecule chemical inhibitors, so one strategy to develop antiviral drugs is to target these cellular signalling pathways. In this review, we provide an overview on the current understanding of various cellular and viral events regulated by the p38 signalling pathway, with a special emphasis on targeting these events for antiviral drug development which might identify candidates with broad spectrum activity.
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Affiliation(s)
- Yogesh Chander
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana, India.,Department of Bio and Nano Technology, Guru Jambeshwar University of Science and Technology, Hisar, Haryana, India
| | - Ram Kumar
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana, India.,Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, India
| | - Nitin Khandelwal
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana, India.,Department of Biotechnology, GLA University, Mathura, India
| | - Namita Singh
- Department of Bio and Nano Technology, Guru Jambeshwar University of Science and Technology, Hisar, Haryana, India
| | - Brij Nandan Shringi
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, India
| | - Sanjay Barua
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana, India
| | - Naveen Kumar
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana, India
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7
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Aviner R, Frydman J. Proteostasis in Viral Infection: Unfolding the Complex Virus-Chaperone Interplay. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a034090. [PMID: 30858229 DOI: 10.1101/cshperspect.a034090] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Viruses are obligate intracellular parasites that rely on their hosts for protein synthesis, genome replication, and viral particle production. As such, they have evolved mechanisms to divert host resources, including molecular chaperones, facilitate folding and assembly of viral proteins, stabilize complex structures under constant mutational pressure, and modulate signaling pathways to dampen antiviral responses and prevent premature host death. Biogenesis of viral proteins often presents unique challenges to the proteostasis network, as it requires the rapid and orchestrated production of high levels of a limited number of multifunctional, multidomain, and aggregation-prone proteins. To overcome such challenges, viruses interact with the folding machinery not only as clients but also as regulators of chaperone expression, function, and subcellular localization. In this review, we summarize the main types of interactions between viral proteins and chaperones during infection, examine evolutionary aspects of this relationship, and discuss the potential of using chaperone inhibitors as broad-spectrum antivirals.
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Affiliation(s)
- Ranen Aviner
- Department of Biology, Stanford University, Stanford, California 94305
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, California 94305.,Department of Genetics, Stanford University, Stanford, California 94305
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8
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Heat Shock Protein 90 Ensures the Integrity of Rubella Virus p150 Protein and Supports Viral Replication. J Virol 2019; 93:JVI.01142-19. [PMID: 31484751 DOI: 10.1128/jvi.01142-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 08/21/2019] [Indexed: 12/18/2022] Open
Abstract
Two viral nonstructural proteins, p150 and p90, are expressed in rubella virus (RUBV)-infected cells and mediate viral genome replication, presumably using various host machineries. Molecular chaperones are critical host factors for the maintenance of cellular proteostasis, and certain viral proteins use this chaperone system. The RUBV p150 and p90 proteins are generated from a precursor polyprotein, p200, via processing by the protease activity of its p150 region. This processing is essential for RUBV genome replication. Here we show that heat shock protein 90 (HSP90), a molecular chaperone, is an important host factor for RUBV genome replication. The treatment of RUBV-infected cells with the HSP90 inhibitors 17-allylamino-17-desmethoxygeldanamycin (17-AAG) and ganetespib suppressed RUBV genome replication. HSP90α physically interacted with p150, but not p90. Further analyses into the mechanism of action of the HSP90 inhibitors revealed that HSP90 activity contributes to p150 functional integrity and promotes p200 processing. Collectively, our data demonstrate that RUBV p150 is a client of the HSP90 molecular chaperone and that HSP90 functions as a key host factor for RUBV replication.IMPORTANCE Accumulating evidence indicates that RNA viruses use numerous host factors during replication of their genomes. However, the host factors involved in rubella virus (RUBV) genome replication are largely unknown. In this study, we demonstrate that the HSP90 molecular chaperone is needed for the efficient replication of the RUBV genome. Further, we reveal that HSP90 interacts with RUBV nonstructural protein p150 and its precursor polyprotein, p200. HSP90 contributes to the stability of p150 and the processing of p200 via its protease domain in the p150 region. We conclude that the cellular molecular chaperone HSP90 is a key host factor for functional maturation of nonstructural proteins for RUBV genome replication. These findings provide novel insight into this host-virus interaction.
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9
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Hu J, Cheng J, Tang L, Hu Z, Luo Y, Li Y, Zhou T, Chang J, Guo JT. Virological Basis for the Cure of Chronic Hepatitis B. ACS Infect Dis 2019; 5:659-674. [PMID: 29893548 DOI: 10.1021/acsinfecdis.8b00081] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) has infected one-third of world population, and 240 million people are chronic carriers, to whom a curative therapy is still not available. Similar to other viruses, persistent HBV infection relies on the virus to exploit host cell functions to support its replication and efficiently evade host innate and adaptive antiviral immunity. Understanding HBV replication and concomitant host cell interactions is thus instrumental for development of therapeutics to disrupt the virus-host interactions critical for its persistence and cure chronic hepatitis B. Although the currently available cell culture systems of HBV infection are refractory to genome-wide high throughput screening of key host cellular factors essential for and/or regulating HBV replication, classic one-gene (or pathway)-at-a-time studies in the last several decades have already revealed many aspects of HBV-host interactions. An overview of the landscape of HBV-hepatocyte interaction indicates that, in addition to more tightly suppressing viral replication by directly targeting viral proteins, disruption of key viral-host cell interactions to eliminate or inactivate the covalently closed circular (ccc) DNA, the most stable HBV replication intermediate that exists as an episomal minichromosome in the nucleus of infected hepatocyte, is essential to achieve a functional cure of chronic hepatitis B. Moreover, therapeutic targeting of integrated HBV DNA and their transcripts may also be required to induce hepatitis B virus surface antigen (HBsAg) seroclearance and prevent liver carcinogenesis.
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Affiliation(s)
- Jin Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, 1 Tian-tan Xi-li, Beijing, 100050, China
| | - Junjun Cheng
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Liudi Tang
- Microbiology and Immunology Graduate Program, Drexel University College of Medicine, 2900 West Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Zhanying Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Yue Luo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
- Institute of Hepatology, Second Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan 410008, China
| | - Yuhuan Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, 1 Tian-tan Xi-li, Beijing, 100050, China
| | - Tianlun Zhou
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Jinhong Chang
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
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10
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Wang Y, Jin F, Li F, Qin S, Wang Y. Could targeting the heat shock protein 90 revolutionize antiviral therapy? Future Virol 2018. [DOI: 10.2217/fvl-2017-0111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Traditional antiviral strategies that target viral components are frequently associated with the generation of drug-resistant viruses. Thus, the development of novel antiviral drugs is critical. Hsp90 is a promising broad-spectrum antiviral drug target; however, whether targeting Hsp90 will revolutionize antiviral therapy remains ambiguous. Here, we summarize how Hsp90 functions in relation to its interactors, and listed the specific Hsp90 isoforms that participated in the virus life cycle. We also discuss the advantages and challenges of targeting Hsp90, taking into account antiviral activity, toxicity and the likelihood of emergence of drug-resistant viruses. Overall, we highlight that targeting Hsp90 might represent a novel and effective antiviral strategy. However, further studies are required before Hsp90 inhibitors can be used in antiviral therapy.
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Affiliation(s)
- Yiliang Wang
- Guangzhou Jinan Biomedicine Research & Development Center, Institute of Biomedicine, College of Life Science & Technology, Jinan University, Guangzhou 510632, PR China
- College of Pharmacy, Jinan University, Guangzhou 510632, PR China
| | - Fujun Jin
- Integrated Chinese and Western Medicine Postdoctoral Research Station, Jinan University, Guangzhou 510632, PR China
| | - Feng Li
- Guangzhou Jinan Biomedicine Research & Development Center, Institute of Biomedicine, College of Life Science & Technology, Jinan University, Guangzhou 510632, PR China
| | - Shurong Qin
- Guangzhou Jinan Biomedicine Research & Development Center, Institute of Biomedicine, College of Life Science & Technology, Jinan University, Guangzhou 510632, PR China
- College of Pharmacy, Jinan University, Guangzhou 510632, PR China
| | - Yifei Wang
- Guangzhou Jinan Biomedicine Research & Development Center, Institute of Biomedicine, College of Life Science & Technology, Jinan University, Guangzhou 510632, PR China
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11
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Wang Y, Jin F, Wang R, Li F, Wu Y, Kitazato K, Wang Y. HSP90: a promising broad-spectrum antiviral drug target. Arch Virol 2017; 162:3269-3282. [PMID: 28780632 DOI: 10.1007/s00705-017-3511-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 06/27/2017] [Indexed: 12/13/2022]
Abstract
The emergence of antiviral drug-resistant mutants is the most important issue in current antiviral therapy. As obligate parasites, viruses require host factors for efficient replication. An ideal therapeutic target to prevent drug-resistance development is represented by host factors that are crucial for the viral life cycle. Recent studies have indicated that heat shock protein 90 (HSP90) is a crucial host factor that is required by many viruses for multiple phases of their life cycle including viral entry, nuclear import, transcription, and replication. In this review, we summarize the most recent advances regarding HSP90 function, mechanisms of action, and molecular pathways that are associated with viral infection, and provide a comprehensive understanding of the role of HSP90 in the immune response and exosome-mediated viral transmission. In addition, several HSP90 inhibitors have entered clinical trials for specific cancers that are associated with viral infection, which further implies a crucial role for HSP90 in the malignant transformation of virus-infected cells; as such, HSP90 inhibitors exhibit excellent therapeutic potential. Finally, we describe the challenge of developing HSP90 inhibitors as anti-viral drugs.
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Affiliation(s)
- Yiliang Wang
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China.,College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Fujun Jin
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China
| | - Rongze Wang
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China.,College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Feng Li
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China.,College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Yanting Wu
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China
| | - Kaio Kitazato
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China. .,Division of Molecular Pharmacology of Infectious Agents, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan.
| | - Yifei Wang
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China.
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12
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The co-chaperone Cdc37 regulates the rabies virus phosphoprotein stability by targeting to Hsp90AA1 machinery. Sci Rep 2016; 6:27123. [PMID: 27251758 PMCID: PMC4890047 DOI: 10.1038/srep27123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/12/2016] [Indexed: 12/25/2022] Open
Abstract
Cdc37, as a kinase-specific co-chaperone of the chaperone Hsp90AA1 (Hsp90), actively aids with the maturation, stabilization and activation of the cellular or viral kinase/kinase-like targets. Phosphoprotein (P) of rabies virus (RABV) is a multifunctional, non-kinase protein involved in interferon antagonism, viral transcription and replication. Here, we demonstrated that the RABV non-kinase P is chaperoned by Cdc37 and Hsp90 during infection. We found that Cdc37 and Hsp90 affect the RABV life cycle directly. Activity inhibition and knockdown of Cdc37 and Hsp90 increased the instability of the viral P protein. Overexpression of Cdc37 and Hsp90 maintained P's stability but did not increase the yield of infectious RABV virions. We further demonstrated that the non-enzymatic polymerase cofactor P protein of all the genotypes of lyssaviruses is a target of the Cdc37/Hsp90 complex. Cdc37, phosphorylated or unphosphorylated on Ser13, aids the P protein to load onto the Hsp90 machinery, with or without Cdc37 binding to Hsp90. However, the interaction between Cdc37 and Hsp90 appears to have additional allosteric regulation of the conformational switch of Hsp90. Our study highlighted a novel mechanism in which Cdc37/Hsp90 chaperones a non-kinase target, which has significant implications for designing therapeutic targets against Rabies.
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Wang Z, Wei W, Sun CK, Chua MS, So S. Suppressing the CDC37 cochaperone in hepatocellular carcinoma cells inhibits cell cycle progression and cell growth. Liver Int 2015; 35:1403-15. [PMID: 25098386 DOI: 10.1111/liv.12651] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/01/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS The molecular cochaperone CDC37 regulates the activities of multiple protein kinases, and is an attractive broad-spectrum target in many types of cancers in which it is over-expressed. This study investigates the antitumour effects of inhibiting CDC37 in human hepatocellular carcinoma (HCC). METHODS A total of 91 patients were enrolled for CDC37 mRNA detection by using quantitative real-time PCR. Cell proliferation, gene expression changes and tumourigenicity were determined by targeting CDC37 using RNA interference in human hepatoma cell lines. RESULTS We confirmed the significant over-expression of CDC37 transcript and protein in HBV-associated HCC patients. Using a CDC37-specific small oligo-siRNA, we silenced CDC37 expression in HepG2 and Huh7 hepatoma cell lines, and observed inhibition of in vitro cell proliferation, cell cycle arrest at the G1 phase, and enhanced apoptosis. Specifically, we found concomitant down-regulation of Cyclin D1, CDK4, and pRB (S807/811 and S795) upon CDC37 suppression, which could mediate the arrest of cell cycle progression at the G1 phase. Gene expression profiling further identified several genes involved in cell proliferation, cell cycle progression, and apoptosis that are regulated by CDC37 suppression. Huh7 cells with stable knockdown of CDC37 showed decreased in vitro colony formation ability, and significantly slowed xenograft growth in vivo. CONCLUSIONS On the basis of the observed antitumour effects of inhibiting CDC37 expression, we propose that CDC37 is a promising therapeutic target in HCC. Its ability to regulate multiple pathways makes it potentially valuable in treating the heterogeneous subtypes of this malignancy.
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Affiliation(s)
- Zhanhui Wang
- Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
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Liu W, Landgraf R. Phosphorylated and unphosphorylated serine 13 of CDC37 stabilize distinct interactions between its client and HSP90 binding domains. Biochemistry 2015; 54:1493-504. [PMID: 25619116 DOI: 10.1021/bi501129g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Folding and maturation of most protein kinases require chaperone assistance. In higher eukaryotes, CDC37 is the predominant cochaperone that facilitates the transfer of kinase clients to HSP90. Kinase recognition is thought to occur through the N-terminal domain, which has, thus far, eluded structure determination. Client processing also requires the phosphorylation of the N-terminal tail at Ser13 by protein kinase CK2 (casein kinase 2). How phosphorylation alters the molecular properties of CDC37 is not understood. We show that the phosphorylation at Ser13 induces a large shift toward a more compact structure, based on ANS fluorescence, while modestly increasing secondary structure. Moreover, this transition requires interactions of the N-terminal domain and the remainder of CDC37. The stabilizing property of the phosphorylation event can be recreated in trans by a (phospho-Ser13) peptide derived from the N-terminal tail. However, the phosphorylation-induced transition is not dependent on the transferred phosphate group but rather the loss of serine-like properties at position 13. The complete absence of the N-terminal tail results in reduced secondary structure and unresponsiveness to subsequent addition of peptides. The N-terminal tail may therefore serve as an intramolecular chaperone that ensures that CDC37 assumes one of two readily interconvertible states in a manner that impacts the interaction of the client binding N-domain and the MC-domains, involved in dimerization and HSP90 binding.
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Affiliation(s)
- Wenjun Liu
- Department of Biochemistry and Molecular Biology and ‡Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine , Miami, Florida 33136, United States
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Regulation of multiple stages of hepadnavirus replication by the carboxyl-terminal domain of viral core protein in trans. J Virol 2014; 89:2918-30. [PMID: 25540387 DOI: 10.1128/jvi.03116-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED Mutational analyses have indicated that the carboxyl-terminal domain (CTD) of hepadnavirus core protein and its state of phosphorylation are critical for multiple steps in viral replication. Also, CTD interacts with host proteins in a phosphorylation state-dependent manner. To ascertain the role of CTD in viral replication without perturbing its sequence and the role of CTD-host interactions, CTD of the human hepatitis B virus (HBV) or duck hepatitis B virus (DHBV) core protein, either the wild type (WT) or with alanine or glutamic acid/aspartic acid substitutions at the phosphorylation sites, was expressed in cells replicating DHBV with the WT core protein. A dramatic decrease in phosphorylation of the DHBV core protein (DHBc) was observed when the WT and most HBV core protein CTD (HCTD) variants were coexpressed in trans, which was accompanied by a profound reduction of viral core DNA and, in particular, the double-stranded DNA. One HCTD variant that failed to change DHBc phosphorylation also had no effect on DHBV core DNA. All WT and variant HCTDs and DHBc CTDs (DCTDs) decreased the DHBV covalently closed circular (CCC) DNA. Identification of CTD-host interactions indicated that CDK2 binding by CTD may mediate its inhibitory effect on DHBc phosphorylation and reverse transcription via competition with DHBc for the host kinase, whereas importin α binding by CTD may contribute to inhibition of CCC DNA production by competitively blocking the nuclear import of viral nucleocapsids. These results suggest the possibility of blocking multiple steps of viral replication, especially CCC DNA formation, via inhibition of CTD functions. IMPORTANCE Mutational analyses have suggested that the carboxyl-terminal domain (CTD) of hepadnavirus core protein is critical for viral replication. However, results from mutational analyses are open to alternative interpretations. Also, how CTD affects virus replication remains unclear. In this study, we took an alternative approach to mutagenesis by overexpressing CTD alone in cells replicating the virus with the wild-type core protein to determine the roles of CTD in viral replication. Our results revealed that CTD can inhibit multiple stages of viral replication, and its effects may be mediated at least in part through specific host interactions. They suggest that CTD, or its mimics, may have therapeutic potential. Furthermore, our experimental approach should be broadly applicable as a complement to mutagenesis for studying protein functions and interactions while at the same time providing a means to identify the relevant interacting factors.
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Lou X, Zhang J, Liu S, Xu N, Liao DJ. The other side of the coin: the tumor-suppressive aspect of oncogenes and the oncogenic aspect of tumor-suppressive genes, such as those along the CCND-CDK4/6-RB axis. Cell Cycle 2014; 13:1677-93. [PMID: 24799665 DOI: 10.4161/cc.29082] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although cancer-regulatory genes are dichotomized to oncogenes and tumor-suppressor gene s, in reality they can be oncogenic in one situation but tumor-suppressive in another. This dual-function nature, which sometimes hampers our understanding of tumor biology, has several manifestations: (1) Most canonically defined genes have multiple mRNAs, regulatory RNAs, protein isoforms, and posttranslational modifications; (2) Genes may interact at different levels, such as by forming chimeric RNAs or by forming different protein complexes; (3) Increased levels of tumor-suppressive genes in normal cells drive proliferation of cancer progenitor cells in the same organ or tissue by imposing compensatory proliferation pressure, which presents the dual-function nature as a cell-cell interaction. All these manifestations of dual functions can find examples in the genes along the CCND-CDK4/6-RB axis. The dual-function nature also underlies the heterogeneity of cancer cells. Gene-targeting chemotherapies, including that targets CDK4, are effective to some cancer cells but in the meantime may promote growth or progression of some others in the same patient. Redefining "gene" by considering each mRNA, regulatory RNA, protein isoform, and posttranslational modification from the same genomic locus as a "gene" may help in better understanding tumor biology and better selecting targets for different sub-populations of cancer cells in individual patients for personalized therapy.
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Affiliation(s)
- Xiaomin Lou
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Ju Zhang
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Siqi Liu
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Ningzhi Xu
- Laboratory of Cell and Molecular Biology; Cancer Institute; Chinese Academy of Medical Science; Beijing, PR China
| | - D Joshua Liao
- Hormel Institute; University of Minnesota; Austin, MN USA
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Roose K, De Baets S, Schepens B, Saelens X. Hepatitis B core-based virus-like particles to present heterologous epitopes. Expert Rev Vaccines 2013; 12:183-98. [PMID: 23414409 DOI: 10.1586/erv.12.150] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Since the first effort to recombinantly express the hepatitis B core protein (HBc) in bacteria, the remarkable virion-like structure has fuelled interest in unraveling the structural and antigenic properties of this protein. Initial studies proved HBc virus-like particles to possess strong immunogenic properties, which can be conveyed to linked antigens. More than 35 years later, numerous studies have been performed using HBc as a carrier protein for antigens derived from over a dozen different pathogens and diseases. In this review, the authors highlight the intriguing features of HBc as carrier and antigen, illustrated by some examples and experimental results that underscore the value of HBc as an antigen-presenting platform. Two of these HBc fusions, targeting influenza A and malaria, have even progressed into clinical testing. In the future, the HBc-based virus-like particles platform will probably continue to be used for the display of poorly immunogenic antigens, mainly because virus-like particle formation by HBc capsomers is compatible with nearly any available recombinant gene expression system.
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Affiliation(s)
- Kenny Roose
- Department for Molecular Biomedical Research, VIB, 9052 Ghent, Belgium
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Fan H, Yan X, Zhang Y, Zhang X, Gao Y, Xu Y, Wang F, Meng S. Increased expression of Gp96 by HBx-induced NF-κB activation feedback enhances hepatitis B virus production. PLoS One 2013; 8:e65588. [PMID: 23776506 PMCID: PMC3679196 DOI: 10.1371/journal.pone.0065588] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/28/2013] [Indexed: 12/18/2022] Open
Abstract
Elevated expression of heat shock protein gp96 in hepatitis B virus (HBV)-infected patients is positively correlated with the progress of HBV-induced diseases, but little is known regarding the molecular mechanism of virus-induced gp96 expression and its impact on HBV infection. In this study, up-regulation of gp96 by HBV replication was confirmed both in vitro and in vivo. Among HBV components, HBV x protein (HBx) was found to increase gp96 promoter activity and enhance gp96 expression by using a luciferase reporter system, and western blot analysis. Further, we found that HBx-mediated regulation of gp96 expression requires a NF-κB cis-regulatory element on the gp96 promoter, and chromatin immunoprecipitation results demonstrated that HBx promotes the binding of NF-κB to the gp96 promoter. Significantly, both gain- and loss-of-function studies showed that gp96 enhances HBV production in HBV-transfected cells and a mouse model based on hydrodynamic transfection. Moreover, up-regulated gp96 expression was observed in HBV-infected patients, and gp96 levels were correlated with serum viral loads. Thus, our work demonstrates a positive feedback regulatory pathway involving gp96 and HBV, which may contribute to persistent HBV infection. Our data also indicate that modulation of gp96 function may represent a novel strategy for the intervention of HBV infection.
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Affiliation(s)
- Hongxia Fan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
| | - Xiaoli Yan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
| | - Yu Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
| | - Xiaojun Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
| | - Yanzhou Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
| | - Yaxing Xu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
| | - Fusheng Wang
- Beijing Institute of Infectious Diseases, Beijing 302 Hospital, Beijing, China
| | - Songdong Meng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China
- * E-mail:
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Chen P, Gan Y, Han N, Fang W, Li J, Zhao F, Hu K, Rayner S. Computational evolutionary analysis of the overlapped surface (S) and polymerase (P) region in hepatitis B virus indicates the spacer domain in P is crucial for survival. PLoS One 2013; 8:e60098. [PMID: 23577084 PMCID: PMC3618453 DOI: 10.1371/journal.pone.0060098] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 02/23/2013] [Indexed: 12/21/2022] Open
Abstract
Introduction The Hepatitis B Virus (HBV) genome contains four ORFs, S (surface), P (polymerase), C (core) and X. S is completely overlapped by P and as a consequence the overlapping region is subject to distinctive evolutionary constraints compared to the remainder of the genome. Specifically, a non-synonymous substitution in one coding frame may produce a synonymous substitution in the alternative frame, suggesting a possible conflict between requirements for diversifying and purifying forces. To examine how these contrasting requirements are balanced within this region, we investigated the relationship amongst positive selection sites, conserved regions, epitopes and elements of protein structure to consider how HBV balances the contrasting evolutionary pressures. Methodology/Results 323 HBV genotype D genome sequences were collected and analyzed to identify sites under positive selection and highly conserved regions. Epitopes sequences were retrieved from previously published experimental studies stored in the Immune Epitope Database. Predicted secondary structures were used to investigate the association between structure and conservation. Entropy was used as a measure of conservation and bivariate logistic regression was used to investigate the relationship between positive selection/conserved sites and epitope/secondary structure regions. Our results indicate: (i) conservation in S is primarily dictated by α-helix elements in the protein structure, (ii) variable residues are mainly located in PreS, the major hydrophilic region (MHR) and the C-terminus, (iii) epitopes in S, which are directly targeted by the host immune system, are significantly associated with sites under positive selection. Conclusions The highly variable spacer domain in P, which corresponds to PreS in S, appears to act as a harbor for the accumulation of mutations that can provide flexibility for conformational changes and responding to immune pressure.
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Affiliation(s)
- Ping Chen
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yun Gan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Na Han
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Wei Fang
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jiafu Li
- Department of Obstetrics and Gynecology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Fei Zhao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Kanghong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- Biomedical Center, Hubei University of Technology, Wuhan, China
- * E-mail: (SR); (KH)
| | - Simon Rayner
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- * E-mail: (SR); (KH)
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Wu F, Peacock SO, Rao S, Lemmon SK, Burnstein KL. Novel interaction between the co-chaperone Cdc37 and Rho GTPase exchange factor Vav3 promotes androgen receptor activity and prostate cancer growth. J Biol Chem 2012; 288:5463-74. [PMID: 23281476 DOI: 10.1074/jbc.m112.390963] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Elevated androgen receptor (AR) activity in castration-resistant prostate cancer may occur through increased levels of AR co-activator proteins. Vav3, a guanine nucleotide exchange factor, is up-regulated following progression to castration resistance in preclinical models and is overexpressed in a significant number of human prostate cancers. Vav3 is a novel co-activator of the AR. We sought to identify Vav3 binding partners in an effort to understand the molecular mechanisms underlying Vav3 enhancement of AR activity and to identify new therapeutic targets. The cell division cycle 37 homolog (Cdc37), a protein kinase-specific co-chaperone for Hsp90, was identified as a Vav3 interacting protein by yeast two-hybrid screening. Vav3-Cdc37 interaction was confirmed by GST pulldown and, for native proteins, by co-immunoprecipitation experiments in prostate cancer cells. Cdc37 potentiated Vav3 co-activation of AR transcriptional activity and Vav3 enhancement of AR N-terminal-C-terminal interaction, which is essential for optimal receptor transcriptional activity. Cdc37 increased prostate cancer cell proliferation selectively in Vav3-expressing cells. Cdc37 did not affect Vav3 nucleotide exchange activity, Vav3 protein levels, or subcellular localization. Disruption of Vav3-Cdc37 interaction inhibited Vav3 enhancement of AR transcriptional activity and AR N-C interaction. Diminished Vav3-Cdc37 interaction also caused decreased prostate cancer cell proliferation selectively in Vav3-expressing cells. Taken together, we identified a novel Vav3 interacting protein that enhances Vav3 co-activation of AR and prostate cancer cell proliferation. Vav3-Cdc37 interaction may provide a new therapeutic target in prostate cancer.
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Affiliation(s)
- Fayi Wu
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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Cyclin-dependent kinase 2 phosphorylates s/t-p sites in the hepadnavirus core protein C-terminal domain and is incorporated into viral capsids. J Virol 2012; 86:12237-50. [PMID: 22951823 DOI: 10.1128/jvi.01218-12] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Phosphorylation of the hepadnavirus core protein C-terminal domain (CTD) is important for viral RNA packaging, reverse transcription, and subcellular localization. Hepadnavirus capsids also package a cellular kinase. The identity of the host kinase that phosphorylates the core CTD or gets packaged remains to be resolved. In particular, both the human hepatitis B virus (HBV) and duck hepatitis B virus (DHBV) core CTDs harbor several conserved serine/threonine-proline (S/T-P) sites whose phosphorylation state is known to regulate CTD functions. We report here that the endogenous kinase in the HBV capsids was blocked by chemical inhibitors of the cyclin-dependent kinases (CDKs), in particular, CDK2 inhibitors. The kinase phosphorylated the HBV CTD at the serine-proline (S-P) sites. Furthermore, we were able to detect CDK2 in purified HBV capsids by immunoblotting. Purified CDK2 phosphorylated the S/T-P sites of the HBV and DHBV CTD in vitro. Inhibitors of CDKs, of CDK2 in particular, decreased both HBV and DHBV CTD phosphorylation in vivo. Moreover, CDK2 inhibitors blocked DHBV CTD phosphorylation, specifically at the S/T-P sites, in a mammalian cell lysate. These results indicate that cellular CDK2 phosphorylates the functionally critical S/T-P sites of the hepadnavirus core CTD and is incorporated into viral capsids.
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In vitro epsilon RNA-dependent protein priming activity of human hepatitis B virus polymerase. J Virol 2012; 86:5134-50. [PMID: 22379076 DOI: 10.1128/jvi.07137-11] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) replicates its DNA genome through reverse transcription of a pregenomic RNA (pgRNA) by using a multifunctional polymerase (HP). A critical function of HP is its specific recognition of a viral RNA signal termed ε (Hε) located on pgRNA, which is required for specific packaging of pgRNA into viral nucleocapsids and initiation of viral reverse transcription. HP initiates reverse transcription by using itself as a protein primer (protein priming) and Hε as the obligatory template. We have purified HP from human cells that retained Hε binding activity in vitro. Furthermore, HP purified as a complex with Hε, but not HP alone, displayed in vitro protein priming activity. While the HP-Hε interaction in vitro and in vivo required the Hε internal bulge, but not its apical loop, and was not significantly affected by the cap-Hε distance, protein priming required both the Hε apical loop and internal bulge, as well as a short distance between the cap and Hε, mirroring the requirements for RNA packaging. These studies have thus established new HBV protein priming and RNA binding assays that should greatly facilitate the dissection of the requirements and molecular mechanisms of HP-Hε interactions, RNA packaging, and protein priming.
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Ludgate L, Adams C, Hu J. Phosphorylation state-dependent interactions of hepadnavirus core protein with host factors. PLoS One 2011; 6:e29566. [PMID: 22216318 PMCID: PMC3245299 DOI: 10.1371/journal.pone.0029566] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 11/30/2011] [Indexed: 01/28/2023] Open
Abstract
Dynamic phosphorylation and dephosphorylation of the hepadnavirus core protein C-terminal domain (CTD) are required for multiple steps of the viral life cycle. It remains unknown how the CTD phosphorylation state may modulate core protein functions but phosphorylation state-dependent viral or host interactions may play a role. In an attempt to identify host factors that may interact differentially with the core protein depending on its CTD phosphorylation state, pulldown assays were performed using the CTD of the duck hepatitis B virus (DHBV) and human hepatitis B virus (HBV) core protein, either with wild type (WT) sequences or with alanine or aspartic acid substitutions at the phosphorylation sites. Two host proteins, B23 and I2PP2A, were found to interact preferentially with the alanine-substituted CTD. Furthermore, the WT CTD became competent to interact with the host proteins upon dephosphorylation. Intriguingly, the binding site on the DHBV CTD for both B23 and I2PP2A was mapped to a region upstream of the phosphorylation sites even though B23 or I2PP2A binding to this site was clearly modulated by the phosphorylation state of the downstream and non-overlapping sequences. Together, these results demonstrate a novel mode of phosphorylation-regulated protein-protein interaction and provide new insights into virus-host interactions.
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Affiliation(s)
- Laurie Ludgate
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Christina Adams
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Jianming Hu
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail:
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Geller R, Taguwa S, Frydman J. Broad action of Hsp90 as a host chaperone required for viral replication. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:698-706. [PMID: 22154817 DOI: 10.1016/j.bbamcr.2011.11.007] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 11/21/2011] [Accepted: 11/22/2011] [Indexed: 02/06/2023]
Abstract
Viruses are intracellular pathogens responsible for a vast number of human diseases. Due to their small genome size, viruses rely primarily on the biosynthetic apparatus of the host for their replication. Recent work has shown that the molecular chaperone Hsp90 is nearly universally required for viral protein homeostasis. As observed for many endogenous cellular proteins, numerous different viral proteins have been shown to require Hsp90 for their folding, assembly, and maturation. Importantly, the unique characteristics of viral replication cause viruses to be hypersensitive to Hsp90 inhibition, thus providing a novel therapeutic avenue for the development of broad-spectrum antiviral drugs. The major developments in this emerging field are hereby discussed. This article is part of a Special Issue entitled: Heat Shock Protein 90 (HSP90).
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Affiliation(s)
- Ron Geller
- Department of Biology and BioX Program, Stanford University, Stanford, CA, USA
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Shim HY, Quan X, Yi YS, Jung G. Heat shock protein 90 facilitates formation of the HBV capsid via interacting with the HBV core protein dimers. Virology 2011; 410:161-9. [DOI: 10.1016/j.virol.2010.11.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 09/26/2010] [Accepted: 11/06/2010] [Indexed: 11/24/2022]
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Reverse transcriptase- and RNA packaging signal-dependent incorporation of APOBEC3G into hepatitis B virus nucleocapsids. J Virol 2008; 82:6852-61. [PMID: 18480459 DOI: 10.1128/jvi.00465-08] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
APOBEC3G (A3G) is a cytidine deaminase that can inhibit a wide range of retroviruses, including the para-retrovirus hepatitis B virus (HBV). The antiviral function of A3G depends on its incorporation into assembling viral particles. However, it remains enigmatic how A3G is specifically packaged into a variety of unrelated viruses. By adopting a native agarose gel electrophoresis assay that can specifically measure the levels of A3G incorporation into HBV nucleocapsids, we found that A3G is specifically packaged into replication-competent HBV nucleocapsids in a fashion that is dependent on both the viral reverse transcriptase (RT) and viral RNA packaging signal, epsilon. In contrast, A3G is not incorporated into empty capsids formed in the absence of RT or epsilon. We demonstrated that the packaged A3G was protected from protease digestion by the nucleocapsids, thus confirming its interior localization. We also showed that A3G could bind RT specifically in an RNA-independent manner, which may be responsible for mediating the specific incorporation of A3G into replication-competent nucleocapsids. Finally, we provide evidence that the N-terminal domain of A3G is required for packaging into HBV nucleocapsids.
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Gao W, Hu J. Formation of hepatitis B virus covalently closed circular DNA: removal of genome-linked protein. J Virol 2007; 81:6164-74. [PMID: 17409153 PMCID: PMC1900077 DOI: 10.1128/jvi.02721-06] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis B virus (HBV) contains a small, partially double-stranded, relaxed circular (RC) DNA genome. RC DNA needs to be converted to covalently closed circular (CCC) DNA, which serves as the template for all viral RNA transcription. As a first step toward understanding how CCC DNA is formed, we analyzed the viral and host factors that may be involved in CCC DNA formation, using transient and stable DNA transfections of HBV and the related avian hepadnavirus, duck hepatitis B virus (DHBV). Our results show that HBV CCC DNA formed in hepatoma cells was derived predominantly from RC DNA with a precise junction sequence. In contrast to that of DHBV, HBV CCC DNA formation in cultured cells was accompanied by the accumulation of a RC DNA species from which the covalently attached viral reverse transcriptase (RT) protein was removed (protein-free or PF-RC DNA). Furthermore, whereas envelope deficiency led to increased CCC DNA formation in DHBV, it resulted mainly in increased PF-RC, but not CCC, DNA in HBV, suggesting that the envelope protein(s) may negatively regulate a step in CCC DNA formation that precedes deproteination in both HBV and DHBV. Interestingly, PF-RC DNA, in contrast to RT-linked RC DNA, contained, almost exclusively, mature plus-strand DNA, suggesting that the RT protein was removed preferentially from mature RC DNA.
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Affiliation(s)
- Weifan Gao
- Department of Microbiology and Immunology-H107, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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Nguyen DH, Gummuluru S, Hu J. Deamination-independent inhibition of hepatitis B virus reverse transcription by APOBEC3G. J Virol 2007; 81:4465-72. [PMID: 17314171 PMCID: PMC1900192 DOI: 10.1128/jvi.02510-06] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The APOBEC3 family of mammalian cytidine deaminases, including APOBEC3G (A3G), has been shown to function as innate antiviral factors against retroviruses and can also suppress the replication of the hepatitis B virus (HBV). The mechanism by which A3G inhibits HBV replication remains to be elucidated. In this study, we show that the inhibitory effect of APOBEC3 proteins on HBV replication was mainly at the DNA level, with only a minor effect on viral RNA packaging. The anti-HBV effect of A3G was independent of the DNA-editing function, and the mode of inhibition was not due to HBV DNA degradation. The editing-independent antiviral activity of A3G could target DNA-RNA hybrids as well as single-stranded DNA. Finally, we show that there was a preferential decrease in the accumulation of longer minus-strand DNA by A3G, compared to the shorter minus-strand DNA, and suggest that A3G exerts its inhibitory effect at very early stages during viral reverse transcription.
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Affiliation(s)
- David H Nguyen
- Department of Microbiology and Immunology-H107, The Pennsylvania State University, College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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29
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Abstract
The hepatitis B virus (HBV) particle consists of an envelope containing three related surface proteins and probably lipid and an icosahedral nucleocapsid of approximately 30 nm diameter enclosing the viral DNA genome and DNA polymerase. The capsid is formed in the cytosol of the infected cell during packaging of an RNA pregenome replication complex by multiple copies of a 21-kDa C protein. The capsid gains the ability to bud during synthesis of the viral DNA genome by reverse transcription of the pregenome in the lumen of the particle. The three envelope proteins S, M, and L shape a complex transmembrane fold at the endoplasmic reticulum, and form disulfide-linked homo- and heterodimers. The transmembrane topology of a fraction of the large envelope protein L changes post-translationally, therefore, the N terminal domain of L (preS) finally appears on both sides of the membrane. During budding at an intracellular membrane, a short linear domain in the cytosolic preS region interacts with binding sites on the capsid surface. The virions are subsequently secreted into the blood. In addition, the surface proteins can bud in the absence of capsids and form subviral lipoprotein particles of 20 nm diameter which are also secreted.
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Affiliation(s)
- Volker Bruss
- Department of Virology, University of Göttingen, Kreuzbergring 57, Göttingen 37075, Germany.
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30
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Abstract
Hepadnaviruses, including human hepatitis B virus (HBV), replicate through reverse transcription of an RNA intermediate, the pregenomic RNA (pgRNA). Despite this kinship to retroviruses, there are fundamental differences beyond the fact that hepadnavirions contain DNA instead of RNA. Most peculiar is the initiation of reverse transcription: it occurs by protein-priming, is strictly committed to using an RNA hairpin on the pgRNA, ε, as template, and depends on cellular chaperones; moreover, proper replication can apparently occur only in the specialized environment of intact nucleocapsids. This complexity has hampered an in-depth mechanistic understanding. The recent successful reconstitution in the test tube of active replication initiation complexes from purified components, for duck HBV (DHBV), now allows for the analysis of the biochemistry of hepadnaviral replication at the molecular level. Here we review the current state of knowledge at all steps of the hepadnaviral genome replication cycle, with emphasis on new insights that turned up by the use of such cell-free systems. At this time, they can, unfortunately, not be complemented by three-dimensional structural information on the involved components. However, at least for the ε RNA element such information is emerging, raising expectations that combining biophysics with biochemistry and genetics will soon provide a powerful integrated approach for solving the many outstanding questions. The ultimate, though most challenging goal, will be to visualize the hepadnaviral reverse transcriptase in the act of synthesizing DNA, which will also have strong implications for drug development.
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MESH Headings
- Animals
- Base Sequence
- Capsid/physiology
- DNA, Circular/genetics
- DNA, Circular/physiology
- DNA, Viral/genetics
- DNA, Viral/physiology
- Disease Models, Animal
- Ducks
- Hepatitis B Virus, Duck/genetics
- Hepatitis B Virus, Duck/physiology
- Hepatitis B virus/genetics
- Hepatitis B virus/physiology
- Humans
- Molecular Sequence Data
- RNA/genetics
- RNA/physiology
- RNA, Circular
- RNA, Viral/genetics
- RNA, Viral/physiology
- RNA-Directed DNA Polymerase/physiology
- Virus Replication/genetics
- Virus Replication/physiology
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Affiliation(s)
- Juergen Beck
- Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, Hugstetter Street 55, D-79106 Freiburg, Germany
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Basagoudanavar SH, Perlman DH, Hu J. Regulation of hepadnavirus reverse transcription by dynamic nucleocapsid phosphorylation. J Virol 2006; 81:1641-9. [PMID: 17135319 PMCID: PMC1797568 DOI: 10.1128/jvi.01671-06] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Reverse transcription, an essential step in the life cycle of all retroelements, is a complex, multistep process whose regulation is not yet clearly understood. We have recently shown that reverse transcription in the pararetrovirus duck hepatitis B virus is associated with complete dephosphorylation of the viral core protein, which forms the nucleocapsid wherein reverse transcription takes place. Here we present a genetic study of the role of this dynamic nucleocapsid phosphorylation in regulating viral reverse transcription. Detailed analyses of the reverse transcription products synthesized within nucleocapsids composed of core phosphorylation site mutants revealed that alanine substitutions, mimicking the nonphosphorylated state, completely blocked reverse transcription at a very early stage. In contrast, aspartate substitutions, mimicking the phosphorylated state, allowed complete first-strand DNA synthesis but were severely defective in accumulating mature double-stranded DNA. The latter defect was due to a combination of mutant nucleocapsid instability during maturation and a block in mature second-strand DNA synthesis. Thus, the reversible phosphorylation of the nucleocapsids regulates the ordered progression of reverse transcription.
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Affiliation(s)
- Suresh H Basagoudanavar
- Department of Microbiology and Immunology-H107, The Penn State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
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32
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Sohn SY, Kim SB, Kim J, Ahn BY. Negative regulation of hepatitis B virus replication by cellular Hsp40/DnaJ proteins through destabilization of viral core and X proteins. J Gen Virol 2006; 87:1883-1891. [PMID: 16760390 DOI: 10.1099/vir.0.81684-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The hepatitis B virus core protein consists of an amino-terminal capsid-assembly domain and a carboxyl-terminal RNA-binding domain. By using the yeast two-hybrid system, two Hsp40/DnaJ chaperone-family proteins, Hdj1 and hTid1, that interact with the carboxyl-terminal region (aa 94-185) of the core protein were identified. Hdj1 is the prototype member of the family and hTid1 is the human homologue of the Drosophila tumour-suppressor protein Tid56. Binding of the viral core protein with the Hsp40 proteins was confirmed by affinity chromatography and immunoprecipitation of transiently expressed proteins. Moreover, in a sucrose gradient, the precursor form of hTid1 co-sedimented with capsid-like particles composed of the full-length core protein. Unlike the general perception of the role of the cellular chaperone proteins in assisting viral protein folding and thus enhancing virus replication, ectopic expression of Hdj1 and hTid1 suppressed replication of HBV in transfected human hepatoma cells. Conversely, RNA interference-mediated knock-down of hTid1 resulted in increased HBV replication. It was found that both Hsp40 proteins specifically accelerated degradation of the viral core and HBx proteins. Our results suggest that the cellular chaperones, through destabilization of viral proteins, exert inhibitory functions on virus replication and hence may play suppressive roles in hepatocellular carcinoma.
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Affiliation(s)
- Sook-Young Sohn
- School of Life Sciences and Biotechnology, Korea University, Anamdong 5-1, Sungbuk, Seoul 136-701, Korea
| | - Sun-Bum Kim
- School of Life Sciences and Biotechnology, Korea University, Anamdong 5-1, Sungbuk, Seoul 136-701, Korea
| | - Joon Kim
- School of Life Sciences and Biotechnology, Korea University, Anamdong 5-1, Sungbuk, Seoul 136-701, Korea
| | - Byung-Yoon Ahn
- School of Life Sciences and Biotechnology, Korea University, Anamdong 5-1, Sungbuk, Seoul 136-701, Korea
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Hu J, Boyer M. Hepatitis B virus reverse transcriptase and epsilon RNA sequences required for specific interaction in vitro. J Virol 2006; 80:2141-50. [PMID: 16474122 PMCID: PMC1395402 DOI: 10.1128/jvi.80.5.2141-2150.2006] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Initiation of reverse transcription and nucleocapsid assembly in hepatitis B virus (HBV) depends on the specific recognition of an RNA signal (the packaging signal, epsilon) on the pregenomic RNA by the viral reverse transcriptase (RT). Using an in vitro reconstitution system whereby the cellular heat shock protein 90 chaperone system activates recombinant HBV RT for specific epsilon binding, we have defined the protein and RNA sequences required for specific HBV RT-epsilon interaction in vitro. Our results indicated that approximately 150 amino acid residues from the terminal protein domain and 230 from the RT domain were necessary and sufficient for epsilon binding. With respect to the epsilon RNA sequence, its internal bulge and, in particular, the first nucleotide (C) of the bulge were specifically required for RT binding. Sequences from the upper portion of the lower stem and the lower portion of the upper stem also contributed to RT binding, as did the base pairing of the upper portion and the single unpaired U residue of the upper stem. Surprisingly, the apical loop of epsilon, known to be required for RNA packaging, was entirely dispensable for RT binding. A comparison of the requirements for in vitro RT-epsilon interaction with those for in vivo pregenomic RNA (pgRNA) packaging clearly indicated that RT-epsilon interaction was necessary but not sufficient for pgRNA packaging. In addition, our results suggest that recognition of some epsilon sequences by the RT may be required specifically for viral DNA synthesis.
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Affiliation(s)
- Jianming Hu
- Department of Microbiology and Immunology, H107, The Penn State University College of Medicine, Hershey, 17033, USA.
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Guo F, Li YQ, Li SQ, Luo ZW, Zhang X, Tang DS, Zhou TH. Interaction of mouse Pem protein and cell division cycle 37 homolog. Acta Biochim Biophys Sin (Shanghai) 2005; 37:784-7. [PMID: 16270159 DOI: 10.1111/j.1745-7270.2005.00102.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Mouse Pem, a homeobox gene, encodes a protein consisting of 210 amino acid residues. To study the function of mouse Pem protein, we used the yeast two-hybrid system to screen the library of 7-day mouse embryo with full-length mouse Pem cDNA. Fifty-two colonies were obtained after 1.57 x 10(8) colonies were screened by nutrition limitation and beta-galactosidase assay. Seven individual insert fragments were obtained from the library, and three of them were identified, one of which was confirmed to be the cell division cycle 37 (Cdc37) homolog gene by sequencing. The interaction between mouse Pem and Cdc37 homolog was then confirmed by glutathione S-transferase pull-down assay, and the possible interaction model was suggested.
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Affiliation(s)
- Fen Guo
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
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35
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Abstract
The molecular chaperone Hsp90 is distinct from Hsp70 and chaperonin in that client proteins are apparently restricted to a subset of proteins categorized as cellular signaling molecules. Among these, many specific protein kinases require the assistance of Hsp90 and its co-chaperone Cdc37/p50 for their biogenesis. A series of Cdc37 deletion mutants revealed that all mutants capable of binding Raf-1 possess amino acid residues between 181 and 200. The 20-residue region is sufficient and, in particular, a five-residue segment (residue 191-195) is essential for binding to Raf-1. These five residues are present in one alpha helix (residues 184-199) in the middle of Cdc37, which is unexpectedly nested within the Hsp90-interacting domain of Cdc37, which was recently determined by crystallography, but does not seem to contribute to direct contact with Hsp90. Furthermore, an N-terminally truncated mutant of Cdc37 composed of residues 181-378 was shown to bind the N-terminal portion of Raf-1 (subdomains I-IV). This mutant can bind not only other Hsp90 client protein kinases, Akt1, Aurora B and Cdk4, but also Cdc2 and Cdk2, which to date have not been shown to physically interact with Cdc37. These results suggest that a region of Cdc37 other than the client-binding site may be responsible for discriminating client protein kinases from others.
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Affiliation(s)
- Kazuya Terasawa
- Department of Biophysics and Biochemistry, and Undergraduate Program for Bioinformatics and Systems Biology, Graduate School of Science, University of Tokyo, Japan
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36
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Perlman DH, Berg EA, O'connor PB, Costello CE, Hu J. Reverse transcription-associated dephosphorylation of hepadnavirus nucleocapsids. Proc Natl Acad Sci U S A 2005; 102:9020-5. [PMID: 15951426 PMCID: PMC1157036 DOI: 10.1073/pnas.0502138102] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatitis B viruses are pararetroviruses that contain a partially dsDNA genome and replicate this DNA through an RNA intermediate (the pregenomic RNA, pgRNA) by reverse transcription. Viral assembly begins with the packaging of the pgRNA into nucleocapsids (NCs), with subsequent reverse transcription within NCs converting the pgRNA into the characteristic dsDNA genome. Only NCs containing this dsDNA (the so-called "mature" NCs) are enveloped by the viral envelope proteins and secreted as virions; "immature" NCs, i.e., those containing pgRNA or immature reverse transcription intermediates, are excluded from virion formation. This phenomenon is thought to be caused by the emergence of an intrinsic maturation signal only on the mature NCs. To define the maturation signal, we have devised a method to separate mature from immature duck hepatitis B virus NCs and have compared them to NCs derived from secreted virions. Detailed mass spectrometric analyses revealed that the core protein from immature NCs was phosphorylated on at least six sites, whereas the core protein from mature NCs and that from secreted virions was entirely dephosphorylated. These results, together with the known requirement of core phosphorylation for pgRNA packaging and DNA synthesis, suggest that the NC undergoes a dynamic change in phosphorylation state to fulfill its multiple roles at different stages of viral replication. Although phosphorylation of the NCs is required for efficient RNA packaging and DNA synthesis by the immature NCs, dephosphorylation of the mature NCs may trigger envelopment and secretion.
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Affiliation(s)
- David H Perlman
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
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37
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Riggs DL, Cox MB, Cheung-Flynn J, Prapapanich V, Carrigan PE, Smith DF. Functional specificity of co-chaperone interactions with Hsp90 client proteins. Crit Rev Biochem Mol Biol 2005; 39:279-95. [PMID: 15763706 DOI: 10.1080/10409230490892513] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A wide array of proteins in signal transduction pathways depend on Hsp90 and other chaperone components for functional maturation, regulation, and stability. Among these Hsp90 client proteins are steroid receptors, members from other classes of transcription factors, and representatives of both serine/threonine and tyrosine kinase families. Typically, dynamic complexes form on the client protein, and these consist of Hsp90- plus bound co-chaperones that often have enzymatic activities. In addition to its direct influence on client folding, Hsp90 locally concentrates co-chaperone activity within the client complex, and dynamic exchange of co-chaperones on Hsp90 facilitates sampling of co-chaperone activities that may, or may not, act on the client protein. We are just beginning to understand the nature of biochemical and molecular interactions between co-chaperone and Hsp90-bound client. This review focuses on the differential effects of Hsp90 co-chaperones toward client protein function and on the specificity that allows co-chaperones to discriminate between even closely related clients.
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Affiliation(s)
- Daniel L Riggs
- Department of Biochemistry and Molecular Biology, Mayo Clinic Scottsdale, Scottsdale, AZ 85259, USA
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Abstract
The hepatitis B virus (HBV) is an enveloped DNA virus with an icosahedral capsid replicating via reverse transcription. The crystal structure of the capsid is known. It has a diameter of 36 nm and is formed by one protein species (C protein). The viral envelope contains three different coterminal proteins (S, M, and L proteins) spanning the membrane several times. These proteins are not only released from infected cells as components of the viral envelope but in 10,000-fold excess as subviral lipoprotein particles with a diameter of 22 nm containing no capsid. Assembly of the capsid occurs in the cytosol and results in packaging of a 3.5 kb RNA molecule together with viral and cellular factors. This newly formed capsid cannot be enveloped. Rather, synthesis of the viral DNA genome in the lumen of the capsid by reverse transcription is required to induce a budding competent state. Envelopment then takes place at an intracellular membrane of the pre-Golgi compartment. The S and the L protein, but not the M protein, is required for this process. The L protein forms two different transmembrane topologies. The isoform exposing the N-terminal part at the cytosolic side of the membrane is essential for budding. In this domain, a 22 amino acid (aa) long linear stretch has been mapped genetically to play a vital role in the morphogenetic process. This domain probably mediates the contact to the capsid. A second matrix domain was mapped to the cytosolic loop of the S protein. A similar genetic approach identified two small areas on the capsid surface, which might interact with the envelope proteins during envelopment.
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Affiliation(s)
- Volker Bruss
- Department of Virology, University of Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany.
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39
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:2911-2915. [DOI: 10.11569/wcjd.v12.i12.2911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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40
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:2907-2910. [DOI: 10.11569/wcjd.v12.i12.2907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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41
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Hu J, Flores D, Toft D, Wang X, Nguyen D. Requirement of heat shock protein 90 for human hepatitis B virus reverse transcriptase function. J Virol 2004; 78:13122-31. [PMID: 15542664 PMCID: PMC525004 DOI: 10.1128/jvi.78.23.13122-13131.2004] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The initiation of reverse transcription and nucleocapsid assembly in hepatitis B virus (HBV) depends on the specific recognition of an RNA signal (the packaging signal, epsilon) on the pregenomic RNA (pgRNA) by the viral reverse transcriptase (RT). RT-epsilon interaction in the duck hepatitis B virus (DHBV) was recently shown to require the molecular chaperone complex, the heat shock protein 90 (Hsp90). However, the requirement for RT-epsilon interaction in the human HBV has remained unknown due to the inability to obtain a purified RT protein active in specific epsilon binding. We now report that Hsp90 is also required for HBV RT-epsilon interaction. Inhibition of Hsp90 led to diminished HBV pgRNA packaging into nucleocapsids in cells, which depends on RT-epsilon interaction. Furthermore, using truncated HBV RT proteins purified from bacteria and five purified Hsp90 chaperone factors, we have developed an in vitro RT-epsilon binding assay. Our results demonstrate that Hsp90, in a dynamic process that was dependent on ATP hydrolysis, facilitated RT-epsilon interaction in HBV, as in DHBV. Specific epsilon binding required sequences from both the amino-terminal terminal protein and the carboxy-terminal RT domain. Only the cognate HBV epsilon, but not the DHBV epsilon, could bind the HBV RT proteins. Furthermore, the internal bulge, but not the apical loop, of epsilon was required for RT binding. The establishment of a defined in vitro reconstitution system has now paved the way for future biochemical and structural studies to elucidate the mechanisms of RT-epsilon interaction and chaperone activation.
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Affiliation(s)
- Jianming Hu
- Department of Microbiology and Immunology-H107, The Pennsylvania State University, 500 University Dr., Hershey, PA 17033, USA.
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42
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:2733-2736. [DOI: 10.11569/wcjd.v12.i11.2733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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43
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Zhang W, Hirshberg M, McLaughlin SH, Lazar GA, Grossmann JG, Nielsen PR, Sobott F, Robinson CV, Jackson SE, Laue ED. Biochemical and structural studies of the interaction of Cdc37 with Hsp90. J Mol Biol 2004; 340:891-907. [PMID: 15223329 DOI: 10.1016/j.jmb.2004.05.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 05/07/2004] [Accepted: 05/11/2004] [Indexed: 11/18/2022]
Abstract
The heat shock protein Hsp90 plays a key, but poorly understood role in the folding, assembly and activation of a large number of signal transduction molecules, in particular kinases and steroid hormone receptors. In carrying out these functions Hsp90 hydrolyses ATP as it cycles between ADP- and ATP-bound forms, and this ATPase activity is regulated by the transient association with a variety of co-chaperones. Cdc37 is one such co-chaperone protein that also has a role in client protein recognition, in that it is required for Hsp90-dependent folding and activation of a particular group of protein kinases. These include the cyclin-dependent kinases (Cdk) 4/6 and Cdk9, Raf-1, Akt and many others. Here, the biochemical details of the interaction of human Hsp90 beta and Cdc37 have been characterised. Small angle X-ray scattering (SAXS) was then used to study the solution structure of Hsp90 and its complexes with Cdc37. The results suggest a model for the interaction of Cdc37 with Hsp90, whereby a Cdc37 dimer binds the two N-terminal domain/linker regions in an Hsp90 dimer, fixing them in a single conformation that is presumably suitable for client protein recognition.
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Affiliation(s)
- Wei Zhang
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
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44
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Wang CH, Lang ZW, Cheng J, Wu Y, Yang YJ, Zhang LY, Dang XY. Suppression subtractive hybridization for cloning of genes transactivated by RNase H protein of HBV DNA polymerase. Shijie Huaren Xiaohua Zazhi 2004; 12:1564-1568. [DOI: 10.11569/wcjd.v12.i7.1564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To construct a subtractive cDNA library of genes transactivated by RNase H protein of hepatitis B virus (HBV) DNA polymerase with suppression subtractive hybridization (SSH) technique.
METHODS: The mRNA was isolated from HepG2 cells transfected with pcDNA3.1(-)-RNase H and pcDNA3.1(-) empty vector, respectively, and then cDNA was synthesized. After restriction enzyme RsaI digestion, small sizes cDNAs were obtained. Tester cDNA was divided into two groups and ligated to the specific adaptor 1 and adaptor 2, respectively. After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR and then was subcloned into T/A plasmid vectors to set up a subtractive library. Amplification of the library was carried out with E. coli strain JM109. The cDNA was sequenced and analyzed in GenBank with Blast search after PCR.
RESULTS: The amplified library contained 38 positive clones. Colony PCR showed that 36 clones contained 200-1 000 bp inserts. Sequence analysis suggested that 33 kinds of known and three kinds of novel cDNA sequences were the target genes transactivated by RNase H protein of HBV DNA P.
CONCLUSION: The subtractive library of genes transac-tivated by RNase H protein is successfully constructed.
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45
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:1704-1707. [DOI: 10.11569/wcjd.v12.i7.1704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
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46
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Miyata Y, Nishida E. CK2 controls multiple protein kinases by phosphorylating a kinase-targeting molecular chaperone, Cdc37. Mol Cell Biol 2004; 24:4065-74. [PMID: 15082798 PMCID: PMC387775 DOI: 10.1128/mcb.24.9.4065-4074.2004] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cdc37 is a kinase-associated molecular chaperone whose function in concert with Hsp90 is essential for many signaling protein kinases. Here, we report that mammalian Cdc37 is a pivotal substrate of CK2 (casein kinase II). Purified Cdc37 was phosphorylated in vitro on a conserved serine residue, Ser13, by CK2. Moreover, Ser13 was the unique phosphorylation site of Cdc37 in vivo. Crucially, the CK2 phosphorylation of Cdc37 on Ser13 was essential for the optimal binding activity of Cdc37 toward various kinases examined, including Raf1, Akt, Aurora-B, Cdk4, Src, MOK, MAK, and MRK. In addition, nonphosphorylatable mutants of Cdc37 significantly suppressed the association of Hsp90 with protein kinases, while the Hsp90-binding activity of the mutants was unchanged. The treatment of cells with a specific CK2 inhibitor suppressed the phosphorylation of Cdc37 in vivo and reduced the levels of Cdc37 target kinases. These results unveil a regulatory mechanism of Cdc37, identify a novel molecular link between CK2 and many crucial protein kinases via Cdc37, and reveal the molecular basis for the ability of CK2 to regulate pleiotropic cellular functions.
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Affiliation(s)
- Yoshihiko Miyata
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:925-927. [DOI: 10.11569/wcjd.v12.i4.925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
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Abstract
Cdc37 is a relatively poorly conserved and yet essential molecular chaperone. It has long been thought to function primarily as an accessory factor for Hsp90, notably directing Hsp90 to kinases as substrates. More recent discoveries challenge this simplistic view. Cdc37 client proteins other than kinases have now been found, and Cdc37 displays a variety of Hsp90-independent activities both in vitro and in vivo. It can function as a molecular chaperone by itself, interact with other Hsp90 cochaperones in the absence of Hsp90, and even support yeast growth and protein folding without its Hsp90-binding domain. Thus, for many substrates, there may be many alternative chaperone pathways involving Cdc37, Hsp90, or both.
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Affiliation(s)
- Morag MacLean
- Département de Biologie Cellulaire, Université de Genève, Sciences III, 30, quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
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