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de Souza Gama FH, Dutra LA, Hawgood M, Dos Reis CV, Serafim RAM, Ferreira MA, Teodoro BVM, Takarada JE, Santiago AS, Balourdas DI, Nilsson AS, Urien B, Almeida VM, Gileadi C, Ramos PZ, Salmazo A, Vasconcelos SNS, Cunha MR, Mueller S, Knapp S, Massirer KB, Elkins JM, Gileadi O, Mascarello A, Lemmens BBLG, Guimarães CRW, Azevedo H, Couñago RM. Novel Dihydropteridinone Derivatives As Potent Inhibitors of the Understudied Human Kinases Vaccinia-Related Kinase 1 and Casein Kinase 1δ/ε. J Med Chem 2024; 67:8609-8629. [PMID: 38780468 DOI: 10.1021/acs.jmedchem.3c02250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Vaccinia-related kinase 1 (VRK1) and the δ and ε isoforms of casein kinase 1 (CK1) are linked to various disease-relevant pathways. However, the lack of tool compounds for these kinases has significantly hampered our understanding of their cellular functions and therapeutic potential. Here, we describe the structure-based development of potent inhibitors of VRK1, a kinase highly expressed in various tumor types and crucial for cell proliferation and genome integrity. Kinome-wide profiling revealed that our compounds also inhibit CK1δ and CK1ε. We demonstrate that dihydropteridinones 35 and 36 mimic the cellular outcomes of VRK1 depletion. Complementary studies with existing CK1δ and CK1ε inhibitors suggest that these kinases may play overlapping roles in cell proliferation and genome instability. Together, our findings highlight the potential of VRK1 inhibition in treating p53-deficient tumors and possibly enhancing the efficacy of existing cancer therapies that target DNA stability or cell division.
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Affiliation(s)
| | - Luiz A Dutra
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Michael Hawgood
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Caio Vinícius Dos Reis
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Ricardo A M Serafim
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Marcos A Ferreira
- Aché Laboratórios Farmacêuticos S.A., Guarulhos, São Paulo 07034-904, Brazil
| | - Bruno V M Teodoro
- Aché Laboratórios Farmacêuticos S.A., Guarulhos, São Paulo 07034-904, Brazil
| | - Jéssica Emi Takarada
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - André S Santiago
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Dimitrios-Ilias Balourdas
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, Frankfurt am Main 60438, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Ann-Sofie Nilsson
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Bruno Urien
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Vitor M Almeida
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Carina Gileadi
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Priscila Z Ramos
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Anita Salmazo
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Stanley N S Vasconcelos
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Micael R Cunha
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Susanne Mueller
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, Frankfurt am Main 60438, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Stefan Knapp
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, Frankfurt am Main 60438, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Katlin B Massirer
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Jonathan M Elkins
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Opher Gileadi
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | | | - Bennie B L G Lemmens
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | | | - Hatylas Azevedo
- Aché Laboratórios Farmacêuticos S.A., Guarulhos, São Paulo 07034-904, Brazil
| | - Rafael M Couñago
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
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Lu J, Xing H, Wang C, Tang M, Wu C, Ye F, Yin L, Yang Y, Tan W, Shen L. Mpox (formerly monkeypox): pathogenesis, prevention, and treatment. Signal Transduct Target Ther 2023; 8:458. [PMID: 38148355 PMCID: PMC10751291 DOI: 10.1038/s41392-023-01675-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/14/2023] [Accepted: 09/21/2023] [Indexed: 12/28/2023] Open
Abstract
In 2022, a global outbreak of Mpox (formerly monkeypox) occurred in various countries across Europe and America and rapidly spread to more than 100 countries and regions. The World Health Organization declared the outbreak to be a public health emergency of international concern due to the rapid spread of the Mpox virus. Consequently, nations intensified their efforts to explore treatment strategies aimed at combating the infection and its dissemination. Nevertheless, the available therapeutic options for Mpox virus infection remain limited. So far, only a few numbers of antiviral compounds have been approved by regulatory authorities. Given the high mutability of the Mpox virus, certain mutant strains have shown resistance to existing pharmaceutical interventions. This highlights the urgent need to develop novel antiviral drugs that can combat both drug resistance and the potential threat of bioterrorism. Currently, there is a lack of comprehensive literature on the pathophysiology and treatment of Mpox. To address this issue, we conducted a review covering the physiological and pathological processes of Mpox infection, summarizing the latest progress of anti-Mpox drugs. Our analysis encompasses approved drugs currently employed in clinical settings, as well as newly identified small-molecule compounds and antibody drugs displaying potential antiviral efficacy against Mpox. Furthermore, we have gained valuable insights from the process of Mpox drug development, including strategies for repurposing drugs, the discovery of drug targets driven by artificial intelligence, and preclinical drug development. The purpose of this review is to provide readers with a comprehensive overview of the current knowledge on Mpox.
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Affiliation(s)
- Junjie Lu
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Hui Xing
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Chunhua Wang
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Mengjun Tang
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Changcheng Wu
- NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Fan Ye
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Lijuan Yin
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Yang Yang
- Shenzhen Key Laboratory of Pathogen and Immunity, National Clinical Research Center for infectious disease, State Key Discipline of Infectious Disease, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, 518112, China.
| | - Wenjie Tan
- NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
| | - Liang Shen
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China.
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Byareddy SN, Sharma K, Sachdev S, Reddy AS, Acharya A, Klaustermeier KM, Lorson CL, Singh K. Potential therapeutic targets for Mpox: the evidence to date. Expert Opin Ther Targets 2023; 27:419-431. [PMID: 37368464 PMCID: PMC10722886 DOI: 10.1080/14728222.2023.2230361] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/07/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
INTRODUCTION The global Mpox (MPX) disease outbreak caused by the Mpox virus (MPXV) in 2022 alarmed the World Health Organization (WHO) and health regulation agencies of individual countries leading to the declaration of MPX as a Public Health Emergency. Owing to the genetic similarities between smallpox-causing poxvirus and MPXV, vaccine JYNNEOS, and anti-smallpox drugs Brincidofovir and Tecovirimat were granted emergency use authorization by the United States Food and Drug Administration. The WHO also included cidofovir, NIOCH-14, and other vaccines as treatment options. AREAS COVERED This article covers the historical development of EUA-granted antivirals, resistance to these antivirals, and the projected impact of signature mutations on the potency of antivirals against currently circulating MPXV. Since a high prevalence of MPXV infections in individuals coinfected with HIV and MPXV, the treatment results among these individuals have been included. EXPERT OPINION All EUA-granted drugs have been approved for smallpox treatment. These antivirals show good potency against Mpox. However, conserved resistance mutation positions in MPXV and related poxviruses, and the signature mutations in the 2022 MPXV can potentially compromise the efficacy of the EUA-granted treatments. Therefore, MPXV-specific medications are required not only for the current but also for possible future outbreaks.
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Affiliation(s)
- Siddappa N Byareddy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | | | - Shrikesh Sachdev
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Athreya S. Reddy
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Arpan Acharya
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | | | - Christian L Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Department of Pharmaceutical Chemistry, DPSRU, New Delhi-110017
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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Linville AC, Rico AB, Teague H, Binsted LE, Smith GL, Albarnaz JD, Wiebe MS. Dysregulation of Cellular VRK1, BAF, and Innate Immune Signaling by the Vaccinia Virus B12 Pseudokinase. J Virol 2022; 96:e0039822. [PMID: 35543552 PMCID: PMC9175622 DOI: 10.1128/jvi.00398-22] [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: 03/04/2022] [Accepted: 04/18/2022] [Indexed: 11/20/2022] Open
Abstract
Poxvirus proteins remodel signaling throughout the cell by targeting host enzymes for inhibition and redirection. Recently, it was discovered that early in infection the vaccinia virus (VACV) B12 pseudokinase copurifies with the cellular kinase VRK1, a proviral factor, in the nucleus. Although the formation of this complex correlates with inhibition of cytoplasmic VACV DNA replication and likely has other downstream signaling consequences, the molecular mechanisms involved are poorly understood. Here, we further characterize how B12 and VRK1 regulate one another during poxvirus infection. First, we demonstrate that B12 is stabilized in the presence of VRK1 and that VRK1 and B12 coinfluence their respective solubility and subcellular localization. In this regard, we find that B12 promotes VRK1 colocalization with cellular DNA during mitosis and that B12 and VRK1 may be tethered cooperatively to chromatin. Next, we observe that the C-terminal tail of VRK1 is unnecessary for B12-VRK1 complex formation or its proviral activity. Interestingly, we identify a point mutation of B12 capable of abrogating interaction with VRK1 and which renders B12 nonrepressive during infection. Lastly, we investigated the influence of B12 on the host factor BAF and antiviral signaling pathways and find that B12 triggers redistribution of BAF from the cytoplasm to the nucleus. In addition, B12 increases DNA-induced innate immune signaling, revealing a new functional consequence of the B12 pseudokinase. Together, this study characterizes the multifaceted roles B12 plays during poxvirus infection that impact VRK1, BAF, and innate immune signaling. IMPORTANCE Protein pseudokinases comprise a considerable fraction of the human kinome, as well as other forms of life. Recent studies have demonstrated that their lack of key catalytic residues compared to their kinase counterparts does not negate their ability to intersect with molecular signal transduction. While the multifaceted roles pseudokinases can play are known, their contribution to virus infection remains understudied. Here, we further characterize the mechanism of how the VACV B12 pseudokinase and human VRK1 kinase regulate one another in the nucleus during poxvirus infection and inhibit VACV DNA replication. We find that B12 disrupts regulation of VRK1 and its downstream target BAF, while also enhancing DNA-dependent innate immune signaling. Combined with previous data, these studies contribute to the growing field of nuclear pathways targeted by poxviruses and provide evidence of unexplored roles of B12 in the activation of antiviral immunity.
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Affiliation(s)
- Alexandria C. Linville
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, USA
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Amber B. Rico
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, USA
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Helena Teague
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Lucy E. Binsted
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Geoffrey L. Smith
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Jonas D. Albarnaz
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Matthew S. Wiebe
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, USA
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, USA
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5
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Abstract
Poxviruses, of which vaccinia virus is the prototype, are a large family of double-stranded DNA viruses that replicate exclusively in the cytoplasm of infected cells. This physical and genetic autonomy from the host cell nucleus necessitates that these viruses encode most, if not all, of the proteins required for replication in the cytoplasm. In this review, we follow the life of the viral genome through space and time to address some of the unique challenges that arise from replicating a 195-kb DNA genome in the cytoplasm. We focus on how the genome is released from the incoming virion and deposited into the cytoplasm; how the endoplasmic reticulum is reorganized to form a replication factory, thereby compartmentalizing and helping to protect the replicating genome from immune sensors; how the cellular milieu is tailored to support high-fidelity replication of the genome; and finally, how newly synthesized genomes are faithfully and specifically encapsidated into new virions. Expected final online publication date for the Annual Review of Virology, Volume 9 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Matthew D Greseth
- Department of Biochemistry and Molecular Biology, The Medical University of South Carolina, Charleston, South Carolina, USA;
| | - Paula Traktman
- Department of Biochemistry and Molecular Biology, The Medical University of South Carolina, Charleston, South Carolina, USA; .,Department of Microbiology and Immunology, The Medical University of South Carolina, Charleston, South Carolina, USA
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The Vaccinia Virus B12 Pseudokinase Represses Viral Replication via Interaction with the Cellular Kinase VRK1 and Activation of the Antiviral Effector BAF. J Virol 2021; 95:JVI.02114-20. [PMID: 33177193 DOI: 10.1128/jvi.02114-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 10/31/2020] [Indexed: 11/20/2022] Open
Abstract
The poxviral B1 and B12 proteins are a homologous kinase-pseudokinase pair, which modulates a shared host pathway governing viral DNA replication and antiviral defense. While the molecular mechanisms involved are incompletely understood, B1 and B12 seem to intersect with signaling processes mediated by their cellular homologs termed the vaccinia-related kinases (VRKs). In this study, we expand upon our previous characterization of the B1-B12 signaling axis to gain insights into B12 function. We begin our studies by demonstrating that modulation of B12 repressive activity is a conserved function of B1 orthologs from divergent poxviruses. Next, we characterize the protein interactome of B12 using multiple cell lines and expression systems and discover that the cellular kinase VRK1 is a highly enriched B12 interactor. Using complementary VRK1 knockdown and overexpression assays, we first demonstrate that VRK1 is required for the rescue of a B1-deleted virus upon mutation of B12. Second, we find that VRK1 overexpression is sufficient to overcome repressive B12 activity during B1-deleted virus replication. Interestingly, we also evince that B12 interferes with the ability of VRK1 to phosphoinactivate the host defense protein BAF. Thus, B12 restricts vaccinia virus DNA accumulation in part by repressing the ability of VRK1 to inactivate BAF. Finally, these data establish that a B12-VRK1-BAF signaling axis forms during vaccinia virus infection and is modulated via kinases B1 and/or VRK2. These studies provide novel insights into the complex mechanisms that poxviruses use to hijack homologous cellular signaling pathways during infection.IMPORTANCE Viruses from diverse families encode both positive and negative regulators of viral replication. While their functions can sometimes be enigmatic, investigation of virus-encoded, negative regulators of viral replication has revealed fascinating aspects of virology. Studies of poxvirus-encoded genes have largely concentrated on positive regulators of their replication; however, examples of fitness gains attributed to poxvirus gene loss suggests that negative regulators of poxvirus replication also impact infection dynamics. This study focuses on the vaccinia B12 pseudokinase, a protein capable of inhibiting vaccinia DNA replication. Here, we elucidate the mechanisms by which B12 inhibits vaccinia DNA replication, demonstrating that B12 activates the antiviral protein BAF by inhibiting the activity of VRK1, a cellular modulator of BAF. Combined with previous data, these studies provide evidence that poxviruses govern their replication by employing both positive and negative regulators of viral replication.
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DiGiuseppe S, Rollins MG, Astar H, Khalatyan N, Savas JN, Walsh D. Proteomic and mechanistic dissection of the poxvirus-customized ribosome. J Cell Sci 2020; 134:jcs246603. [PMID: 32467327 PMCID: PMC7358139 DOI: 10.1242/jcs.246603] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/14/2020] [Indexed: 12/13/2022] Open
Abstract
Ribosomes are often viewed as protein synthesis machines that lack intrinsic regulatory capacity. However, studies have established that ribosomes can functionally diversify through changes in the composition of, or post-translational modifications to ribosomal subunit proteins (RPs). We recently found that poxviruses phosphorylate unique sites in the RP, receptor for activated C kinase 1 (RACK1) to enhance viral protein synthesis. Here, we developed approaches for large-scale proteomic analysis of ribosomes isolated from cells infected with different viruses. Beyond RACK1, we identified additional phosphorylation events within RPS2 and RPS28 that arise during poxvirus infection, but not other viruses tested. The modified sites lie within unstructured loop domains that position around the mRNA entry and exit channel, respectively, and site-substitution mutants revealed that each modified residue contributed differently to poxvirus replication. Our findings reveal the broader extent to which poxviruses customize host ribosomes and provide new insights into how ribosomes can functionally diversify.
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Affiliation(s)
- Stephen DiGiuseppe
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Madeline G Rollins
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Helen Astar
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Natalia Khalatyan
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jeffrey N Savas
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Derek Walsh
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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The Vaccinia Virus (VACV) B1 and Cellular VRK2 Kinases Promote VACV Replication Factory Formation through Phosphorylation-Dependent Inhibition of VACV B12. J Virol 2019; 93:JVI.00855-19. [PMID: 31341052 DOI: 10.1128/jvi.00855-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/16/2019] [Indexed: 01/08/2023] Open
Abstract
Comparative examination of viral and host protein homologs reveals novel mechanisms governing downstream signaling effectors of both cellular and viral origin. The vaccinia virus B1 protein kinase is involved in promoting multiple facets of the virus life cycle and is a homolog of three conserved cellular enzymes called vaccinia virus-related kinases (VRKs). Recent evidence indicates that B1 and VRK2 mediate a common pathway that is largely uncharacterized but appears independent of previous VRK substrates. Interestingly, separate studies described a novel role for B1 in inhibiting vaccinia virus protein B12, which otherwise impedes an early event in the viral lifecycle. Herein, we characterize the B1/VRK2 signaling axis to better understand their shared functions. First, we demonstrate that vaccinia virus uniquely requires VRK2 for viral replication in the absence of B1, unlike other DNA viruses. Employing loss-of-function analysis, we demonstrate that vaccinia virus's dependence on VRK2 is only observed in the presence of B12, suggesting that B1 and VRK2 share a pathway controlling B12. Moreover, we substantiate a B1/VRK2/B12 signaling axis by examining coprecipitation of B12 by B1 and VRK2. Employing execution point analysis, we reveal that virus replication proceeds normally through early protein translation and uncoating but stalls at replication factory formation in the presence of B12 activity. Finally, structure/function analyses of B1 and VRK2 demonstrate that enzymatic activity is essential for B1 or VRK2 to inhibit B12. Together, these data provide novel insights into B1/VRK signaling coregulation and support a model in which these enzymes modulate B12 in a phosphorylation-dependent manner.IMPORTANCE Constraints placed on viral genome size require that these pathogens must employ sophisticated, yet parsimonious mechanisms to effectively integrate with host cell signaling pathways. Poxviruses are no exception and employ several methods to balance these goals, including encoding single proteins that impact multiple downstream pathways. This study focuses on the vaccinia virus B1 protein kinase, an enzyme that promotes virus replication at multiple phases of the viral lifecycle. Herein, we demonstrate that in addition to its previously characterized functions, B1 inhibits vaccinia virus B12 protein via a phosphorylation-dependent mechanism and that this function of B1 can be complemented by the cellular B1 homolog VRK2. Combined with previous data implicating functional overlap between B1 and an additional cellular B1 homolog, VRK1, these data provide evidence of how poxviruses can be multifaceted in their mimicry of cellular proteins through the consolidation of functions of both VRK1 and VRK2 within the viral B1 protein kinase.
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9
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Phosphoproteomic analyses of kidneys of Atlantic salmon infected with Aeromonas salmonicida. Sci Rep 2019; 9:2101. [PMID: 30765835 PMCID: PMC6376026 DOI: 10.1038/s41598-019-38890-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 01/09/2019] [Indexed: 11/08/2022] Open
Abstract
Aeromonas salmonicida (A. salmonicida) is a pathogenic bacterium that causes furunculosis and poses a significant global risk, particularly in economic activities such as Atlantic salmon (Salmo salar) farming. In a previous study, we identified proteins that are significantly upregulated in kidneys of Atlantic salmon challenged with A. salmonicida. Phosphoproteomic analyses were conducted to further clarify the dynamic changes in protein phosphorylation patterns triggered by bacterial infection. To our knowledge, this is the first study to characterize phosphorylation events in proteins from A. salmonicida-infected Atlantic salmon. Overall, we identified over 5635 phosphorylation sites in 3112 proteins, and 1502 up-regulated and 77 down-regulated proteins quantified as a 1.5-fold or greater change relative to control levels. Based on the combined data from proteomic and motif analyses, we hypothesize that five prospective novel kinases (VRK3, GAK, HCK, PKCδ and RSK6) with common functions in inflammatory processes and cellular pathways to regulate apoptosis and the cytoskeleton could serve as potential biomarkers against bacterial propagation in fish. Data from STRING-based functional network analyses indicate that fga is the most central protein. Our collective findings provide new insights into protein phosphorylation patterns, which may serve as effective indicators of A. salmonicida infection in Atlantic salmon.
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Olson AT, Wang Z, Rico AB, Wiebe MS. A poxvirus pseudokinase represses viral DNA replication via a pathway antagonized by its paralog kinase. PLoS Pathog 2019; 15:e1007608. [PMID: 30768651 PMCID: PMC6395007 DOI: 10.1371/journal.ppat.1007608] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/28/2019] [Accepted: 01/31/2019] [Indexed: 12/26/2022] Open
Abstract
Poxviruses employ sophisticated, but incompletely understood, signaling pathways that engage cellular defense mechanisms and simultaneously ensure viral factors are modulated properly. For example, the vaccinia B1 protein kinase plays a vital role in inactivating the cellular antiviral factor BAF, and likely orchestrates other pathways as well. In this study, we utilized experimental evolution of a B1 deletion virus to perform an unbiased search for suppressor mutations and identify novel pathways involving B1. After several passages of the ΔB1 virus we observed a robust increase in viral titer of the adapted virus. Interestingly, our characterization of the adapted viruses reveals that mutations correlating with a loss of function of the vaccinia B12 pseudokinase provide a striking fitness enhancement to this virus. In support of predictions that reductive evolution is a driver of poxvirus adaptation, this is clear experimental evidence that gene loss can be of significant benefit. Next, we present multiple lines of evidence demonstrating that expression of full length B12 leads to a fitness reduction in viruses with a defect in B1, but has no apparent impact on wild-type virus or other mutant poxviruses. From these data we infer that B12 possesses a potent inhibitory activity that can be masked by the presence of the B1 kinase. Further investigation of B12 attributes revealed that it primarily localizes to the nucleus, a characteristic only rarely found among poxviral proteins. Surprisingly, BAF phosphorylation is reduced under conditions in which B12 is present in infected cells without B1, indicating that B12 may function in part by enhancing antiviral activity of BAF. Together, our studies of B1 and B12 present novel evidence that a paralogous kinase-pseudokinase pair can exhibit a unique epistatic relationship in a virus, perhaps serving to enhance B1 conservation during poxvirus evolution and to orchestrate yet-to-be-discovered nuclear events during infection.
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Affiliation(s)
- Annabel T. Olson
- Nebraska Center for Virology, University of Nebraska, Lincoln, NE, United States of America
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States of America
| | - Zhigang Wang
- Nebraska Center for Virology, University of Nebraska, Lincoln, NE, United States of America
| | - Amber B. Rico
- Nebraska Center for Virology, University of Nebraska, Lincoln, NE, United States of America
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE, United States of America
| | - Matthew S. Wiebe
- Nebraska Center for Virology, University of Nebraska, Lincoln, NE, United States of America
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE, United States of America
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11
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Couñago RM, Allerston CK, Savitsky P, Azevedo H, Godoi PH, Wells CI, Mascarello A, de Souza Gama FH, Massirer KB, Zuercher WJ, Guimarães CRW, Gileadi O. Structural characterization of human Vaccinia-Related Kinases (VRK) bound to small-molecule inhibitors identifies different P-loop conformations. Sci Rep 2017; 7:7501. [PMID: 28790404 PMCID: PMC5548783 DOI: 10.1038/s41598-017-07755-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/29/2017] [Indexed: 11/12/2022] Open
Abstract
The human genome encodes two active Vaccinia-related protein kinases (VRK), VRK1 and VRK2. These proteins have been implicated in a number of cellular processes and linked to a variety of tumors. However, understanding the cellular role of VRKs and establishing their potential use as targets for therapeutic intervention has been limited by the lack of tool compounds that can specifically modulate the activity of these kinases in cells. Here we identified BI-D1870, a dihydropteridine inhibitor of RSK kinases, as a promising starting point for the development of chemical probes targeting the active VRKs. We solved co-crystal structures of both VRK1 and VRK2 bound to BI-D1870 and of VRK1 bound to two broad-spectrum inhibitors. These structures revealed that both VRKs can adopt a P-loop folded conformation, which is stabilized by different mechanisms on each protein. Based on these structures, we suggest modifications to the dihydropteridine scaffold that can be explored to produce potent and specific inhibitors towards VRK1 and VRK2.
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Affiliation(s)
- Rafael M Couñago
- Structural Genomics Consortium, Universidade Estadual de Campinas - UNICAMP, Campinas, SP, Brazil. .,Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil.
| | - Charles K Allerston
- Structural Genomics Consortium and Target Discovery Institute, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Pavel Savitsky
- Structural Genomics Consortium and Target Discovery Institute, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Paulo H Godoi
- Structural Genomics Consortium, Universidade Estadual de Campinas - UNICAMP, Campinas, SP, Brazil.,Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Carrow I Wells
- Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Katlin B Massirer
- Structural Genomics Consortium, Universidade Estadual de Campinas - UNICAMP, Campinas, SP, Brazil.,Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - William J Zuercher
- Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Opher Gileadi
- Structural Genomics Consortium, Universidade Estadual de Campinas - UNICAMP, Campinas, SP, Brazil.,Structural Genomics Consortium and Target Discovery Institute, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
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12
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Deletion of the Vaccinia Virus B1 Kinase Reveals Essential Functions of This Enzyme Complemented Partly by the Homologous Cellular Kinase VRK2. J Virol 2017; 91:JVI.00635-17. [PMID: 28515294 DOI: 10.1128/jvi.00635-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 05/10/2017] [Indexed: 12/30/2022] Open
Abstract
The vaccinia virus B1 kinase is highly conserved among poxviruses and is essential for the viral life cycle. B1 exhibits a remarkable degree of similarity to vaccinia virus-related kinases (VRKs), a family of cellular kinases, suggesting that the viral enzyme has evolved to mimic VRK activity. Indeed, B1 and VRKs have been demonstrated to target a shared substrate, the DNA binding protein BAF, elucidating a signaling pathway important for both mitosis and the antiviral response. In this study, we further characterize the role of B1 during vaccinia infection to gain novel insights into its regulation and integration with cellular signaling pathways. We begin by describing the construction and characterization of the first B1 deletion virus (vvΔB1) produced using a complementing cell line expressing the viral kinase. Examination of vvΔB1 revealed that B1 is critical for the production of infectious virions in various cell types and is sufficient for BAF phosphorylation. Interestingly, the severity of the defect in DNA replication following the loss of B1 varied between cell types, leading us to posit that cellular VRKs partly complement for the absence of B1 in some cell lines. Using cell lines devoid of either VRK1 or VRK2, we tested this hypothesis and discovered that VRK2 expression facilitates DNA replication and allows later stages of the viral life cycle to proceed in the absence of B1. Finally, we present evidence that the impact of VRK2 on vaccinia virus is largely independent of BAF phosphorylation. These data support a model in which B1 and VRK2 share additional substrates important for the replication of cytoplasmic poxviruses.IMPORTANCE Viral mimicry of cellular signaling modulators provides clear evidence that the pathogen targets an important host pathway during infection. Poxviruses employ numerous viral homologs of cellular proteins, the study of which have yielded insights into signaling pathways used by both virus and cells alike. The vaccinia virus B1 protein is a homolog of cellular vaccinia virus-related kinases (VRKs) and is needed for viral DNA replication and likely other stages of the viral life cycle. However, much remains to be learned about how B1 and VRKs overlap functionally. This study utilizes new tools, including a B1 deletion virus and VRK knockout cells, to further characterize the functional links between the viral and cellular enzymes. As a result, we have discovered that B1 and VRK2 target a common set of substrates vital to productive infection of this large cytoplasmic DNA virus.
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13
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Abstract
Ribosomes have the capacity to selectively control translation through changes in their composition that enable recognition of specific RNA elements1. However, beyond differential subunit expression during development2,3, evidence for regulated ribosome specification within individual cells has remained elusive1. Here, we report that a poxvirus kinase phosphorylates serine/threonine residues in the small ribosomal subunit protein, Receptor for Activated C Kinase (RACK1) that are not phosphorylated in uninfected cells or cells infected by other viruses. These modified residues cluster in an extended loop in RACK1, phosphorylation of which selects for translation of viral or reporter mRNAs whose 5’ untranslated regions (UTRs) contain adenosine repeats, so-called polyA-leaders. Structural and phylogenetic analysis revealed that although RACK1 is highly conserved, this loop is variable and contains negatively charged amino acids in plants, where these leaders act as translational enhancers for poorly understood reasons. Phosphomimetics and inter-species chimeras demonstrated that negative charge in the RACK1 loop dictates ribosome selectivity towards viral RNAs. By converting human RACK1 to a charged, plant-like state, poxviruses remodel host ribosomes so that adenosine repeats erroneously generated by slippage of the viral RNA polymerase4 confer a translational advantage. Our findings uncover ribosome customization through a novel trans-kingdom mimicry and the mechanics of species-specific leader activity that underlie the enigmatic poxvirus polyA-leaders4.
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14
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Vaccinia Virus B1 Kinase Is Required for Postreplicative Stages of the Viral Life Cycle in a BAF-Independent Manner in U2OS Cells. J Virol 2015. [PMID: 26223647 DOI: 10.1128/jvi.01252-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED The vaccinia virus B1R gene encodes a highly conserved protein kinase that is essential for the poxviral life cycle. As demonstrated in many cell types, B1 plays a critical role during viral DNA replication when it inactivates the cellular host defense effector barrier to autointegration factor (BAF or BANF1). To better understand the role of B1 during infection, we have characterized the growth of a B1-deficient temperature-sensitive mutant virus (Cts2 virus) in U2OS osteosarcoma cells. In contrast to all other cell lines tested to date, we found that in U2OS cells, Cts2 viral DNA replication is unimpaired at the nonpermissive temperature. However, the Cts2 viral yield in these cells was reduced more than 10-fold, thus indicating that B1 is required at another stage of the vaccinia virus life cycle. Our results further suggest that the host defense function of endogenous BAF may be absent in U2OS cells but can be recovered through either overexpression of BAF or fusion of U2OS cells with mouse cells in which the antiviral function of BAF is active. Interestingly, examination of late viral proteins during Cts2 virus infection demonstrated that B1 is required for optimal processing of the L4 protein. Finally, execution point analyses as well as electron microscopy studies uncovered a role for B1 during maturation of poxviral virions. Overall, this work demonstrates that U2OS cells are a novel model system for studying the cell type-specific regulation of BAF and reveals a role for B1 beyond DNA replication during the late stages of the viral life cycle. IMPORTANCE The most well characterized role for the vaccinia virus B1 kinase is to facilitate viral DNA replication by phosphorylating and inactivating BAF, a cellular host defense responsive to foreign DNA. Additional roles for B1 later in the viral life cycle have been postulated for decades but are difficult to examine directly due to the importance of B1 during DNA replication. Here, we demonstrate that in U2OS cells, a B1 mutant virus escapes the block in DNA replication observed in other cell types and, instead, this mutant virus exhibits impaired late protein accumulation and incomplete maturation of new virions. These data provide the clearest evidence to date that B1 is needed for multiple critical junctures in the poxviral life cycle in a manner that is both dependent on and independent of BAF.
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15
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Abstract
Poxviruses are large, enveloped viruses that replicate in the cytoplasm and encode proteins for DNA replication and gene expression. Hairpin ends link the two strands of the linear, double-stranded DNA genome. Viral proteins involved in DNA synthesis include a 117-kDa polymerase, a helicase-primase, a uracil DNA glycosylase, a processivity factor, a single-stranded DNA-binding protein, a protein kinase, and a DNA ligase. A viral FEN1 family protein participates in double-strand break repair. The DNA is replicated as long concatemers that are resolved by a viral Holliday junction endonuclease.
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Affiliation(s)
- Bernard Moss
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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16
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Ibrahim N, Wicklund A, Jamin A, Wiebe MS. Barrier to autointegration factor (BAF) inhibits vaccinia virus intermediate transcription in the absence of the viral B1 kinase. Virology 2013; 444:363-73. [PMID: 23891157 DOI: 10.1016/j.virol.2013.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/01/2013] [Accepted: 07/02/2013] [Indexed: 11/16/2022]
Abstract
Barrier to autointegration factor (BAF/BANF1) is a cellular DNA-binding protein found in the nucleus and cytoplasm. Cytoplasmic BAF binds to foreign DNA and can act as a defense against vaccinia DNA replication. To evade BAF, vaccinia expresses the B1 kinase, which phosphorylates BAF and blocks its ability to bind DNA. Interestingly, B1 is also needed for viral intermediate gene expression via an unknown mechanism. Therefore, we evaluated the impact of B1-BAF signaling on vaccinia transcription. Strikingly, the decrease in vaccinia transcription caused by loss of B1 can be rescued by depletion of BAF. The repressive action of BAF is greatest on a viral promoter, and is more modest when non-vaccinia promoters are employed, which suggests BAF acts in a gene specific manner. These studies expand our understanding of the role of the B1 kinase during infection and provide the first evidence that BAF is a defense against viral gene expression.
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Affiliation(s)
- Nouhou Ibrahim
- Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA
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17
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Suzuki Y, Chew ML, Suzuki Y. Role of host-encoded proteins in restriction of retroviral integration. Front Microbiol 2012; 3:227. [PMID: 22737148 PMCID: PMC3381236 DOI: 10.3389/fmicb.2012.00227] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 06/02/2012] [Indexed: 11/13/2022] Open
Abstract
In retroviral infections, a copy of the viral DNA is first synthesized from genomic RNA by reverse transcription and subsequently integrated into host chromatin. This integration step, executed by the viral enzyme integrase (IN), is one of the hallmarks of retroviral infection. Although an obligate role for IN in retroviral integration has been clearly defined by numerous biochemical analysis of its recombinant protein and genetic analysis of the viral IN gene, several host cellular proteins have also been implicated as key factors involved in the integration step during viral replication. Although studies on integration cofactors have mostly emphasized factors that aid the integration process either through direct or indirect association with IN, it has become apparent that host cells may also harbor proteins that act as inhibitors of retroviral integration. Intriguingly, some of these inhibitory proteins appear to hamper the integration process via posttranslational modifications of the components of the preintegration complex including IN. A better understanding of the molecular mechanisms leading to the inhibition of integration will provide us with clues for the development of new strategies for treating retroviral infections. In this review, we draw attention to recent insights regarding potential host cellular factors that restrict integration, and illustrate how these inhibitory effects are achieved.
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Affiliation(s)
- Yasutsugu Suzuki
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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18
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Molecular characterization of the host defense activity of the barrier to autointegration factor against vaccinia virus. J Virol 2011; 85:11588-600. [PMID: 21880762 DOI: 10.1128/jvi.00641-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The barrier to autointegration factor (BAF) is an essential cellular protein with functions in mitotic nuclear reassembly, retroviral preintegration complex stability, and transcriptional regulation. Molecular properties of BAF include the ability to bind double-stranded DNA in a sequence-independent manner, homodimerize, and bind proteins containing a LEM domain. These capabilities allow BAF to compact DNA and assemble higher-order nucleoprotein complexes, the nature of which is poorly understood. Recently, it was revealed that BAF also acts as a potent host defense against poxviral DNA replication in the cytoplasm. Here, we extend these observations by examining the molecular mechanism through which BAF acts as a host defense against vaccinia virus replication and cytoplasmic DNA in general. Interestingly, BAF rapidly relocalizes to transfected DNA from a variety of sources, demonstrating that BAF's activity as a host defense factor is not limited to poxviral infection. BAF's relocalization to cytoplasmic foreign DNA is highly dependent upon its DNA binding and dimerization properties but does not appear to require its LEM domain binding activity. However, the LEM domain protein emerin is recruited to cytoplasmic DNA in a BAF-dependent manner during both transfection and vaccinia virus infection. Finally, we demonstrate that the DNA binding and dimerization capabilities of BAF are essential for its function as an antipoxviral effector, while the presence of emerin is not required. Together, these data provide further mechanistic insight into which of BAF's molecular properties are employed by cells to impair the replication of poxviruses or respond to foreign DNA in general.
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19
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Park CH, Choi BH, Jeong MW, Kim S, Kim W, Song YS, Kim KT. Protein kinase Cδ regulates vaccinia-related kinase 1 in DNA damage-induced apoptosis. Mol Biol Cell 2011; 22:1398-408. [PMID: 21346188 PMCID: PMC3078082 DOI: 10.1091/mbc.e10-08-0717] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 01/03/2011] [Accepted: 02/11/2011] [Indexed: 01/06/2023] Open
Abstract
Vaccinia-related kinase 1 (VRK1) is a novel serine/threonine kinase that plays an important role in cell proliferation. However, little is known about the upstream regulators of VRK1 activity. Here we provide evidence for a role of protein kinase Cδ (PKCδ) in the regulation of murine VRK1. We show that PKCδ interacts with VRK1, phosphorylates the Ser-355 residue in the putative regulatory region, and negatively regulates its kinase activity in vitro. Intriguingly, PKCδ-induced cell death was facilitated by phosphorylation of VRK1 when cells were exposed to a DNA-damaging agent. In addition, p53 played a critical role in the regulation of DNA damage-induced cell death accompanied by PKCδ-mediated modulation of VRK1. In p53-deficient cells, PKCδ-mediated phosphorylation of VRK1 had no effect on cell viability. However, cells overexpressing p53 exhibited significant reduction of cell viability when cotransfected with both VRK1 and PKCδ. Taken together, these results indicate that PKCδ regulates phosphorylation and down-regulation of VRK1, thereby contributing to cell cycle arrest and apoptotic cell death in a p53-dependent manner.
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Affiliation(s)
- Choon-Ho Park
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790–784, Korea
| | - Bo-Hwa Choi
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790–784, Korea
| | - Min-Woo Jeong
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790–784, Korea
| | - Sangjune Kim
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790–784, Korea
| | - Wanil Kim
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790–784, Korea
| | - Yun Seon Song
- College of Pharmacy, Sookmyung Women’s University, Seoul, 140–742, Korea
| | - Kyong-Tai Kim
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790–784, Korea
- Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology, Pohang, 790-784, Korea
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20
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Valbuena A, Sanz-García M, López-Sánchez I, Vega FM, Lazo PA. Roles of VRK1 as a new player in the control of biological processes required for cell division. Cell Signal 2011; 23:1267-72. [PMID: 21514377 DOI: 10.1016/j.cellsig.2011.04.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 04/04/2011] [Indexed: 11/28/2022]
Abstract
Cell division, in addition to an accurate transmission of genetic information to daughter cells, also requires the temporal and spatial coordination of several biological processes without which cell division would not be feasible. These processes include the temporal coordination of DNA replication and chromosome segregation, regulation of nuclear envelope disassembly and assembly, chromatin condensation and Golgi fragmentation for its redistribution into daughter cells, among others. However, little is known regarding regulatory proteins and signalling pathways that might participate in the coordination of all these different biological functions. Such regulatory players should directly have a role in the processes leading to cell division. VRK1 (Vaccinia-related kinase 1) is an early response gene required for cyclin D1 expression, regulates p53 by a specific Thr18 phosphorylation, controls chromatin condensation by histone phosphorylation, nuclear envelope assembly by phosphorylation of BANF1, and participates in signalling required for Golgi fragmentation late in the G2 phase. We propose that VRK1, a Ser-Thr kinase, might be a candidate to play an important coordinator role in these cell division processes as part of a novel signalling pathway.
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Affiliation(s)
- Alberto Valbuena
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
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21
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Abstract
Phosphorylation represents one the most abundant and important posttranslational modifications of proteins, including viral proteins. Virus-encoded serine/threonine protein kinases appear to be a feature that is unique to large DNA viruses. Although the importance of these kinases for virus replication in cell culture is variable, they invariably play important roles in virus virulence. The current review provides an overview of the different viral serine/threonine protein kinases of several large DNA viruses and discusses their function, importance, and potential as antiviral drug targets.
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22
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Mammalian casein kinase 1alpha and its leishmanial ortholog regulate stability of IFNAR1 and type I interferon signaling. Mol Cell Biol 2009; 29:6401-12. [PMID: 19805514 DOI: 10.1128/mcb.00478-09] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Phosphorylation of the degron of the IFNAR1 chain of the type I interferon (IFN) receptor triggers ubiquitination and degradation of this receptor and, therefore, plays a crucial role in negative regulation of IFN-alpha/beta signaling. Besides the IFN-stimulated and Jak activity-dependent pathways, a basal ligand-independent phosphorylation of IFNAR1 has been described and implicated in downregulating IFNAR1 in response to virus-induced endoplasmic reticulum (ER) stress. Here we report purification and characterization of casein kinase 1alpha (CK1alpha) as a bona fide major IFNAR1 kinase that confers basal turnover of IFNAR1 and cooperates with ER stress stimuli to mediate phosphorylation-dependent degradation of IFNAR1. Activity of CK1alpha was required for phosphorylation and downregulation of IFNAR1 in response to ER stress and viral infection. While many forms of CK1 were capable of phosphorylating IFNAR1 in vitro, human CK1alpha and L-CK1 produced by the protozoan Leishmania major were also capable of increasing IFNAR1 degron phosphorylation in cells. Expression of leishmania CK1 in mammalian cells stimulated the phosphorylation-dependent downregulation of IFNAR1 and attenuated its signaling. Infection of mammalian cells with L. major modestly decreased IFNAR1 levels and attenuated cellular responses to IFN-alpha in vitro. We propose a role for mammalian and parasite CK1 enzymes in regulating IFNAR1 stability and type I IFN signaling.
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23
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Inhibition of vaccinia virus replication by two small interfering RNAs targeting B1R and G7L genes and their synergistic combination with cidofovir. Antimicrob Agents Chemother 2009; 53:2579-88. [PMID: 19307376 DOI: 10.1128/aac.01626-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In view of the threat of the potential use of variola virus in a terrorist attack, considerable efforts have been performed to develop new antiviral strategies against orthopoxviruses. Here we report on the use of RNA interference, either alone or in combination with cidofovir, as an approach to inhibit orthopoxvirus replication. Two selected small interfering RNAs (siRNAs), named siB1R-2 and siG7L-1, and a previously reported siRNA, i.e., siD5R-2 (which targets the viral D5R mRNA), were evaluated for antiviral activity against vaccinia virus (VACV) by plaque reduction and virus yield assays. siB1R-2 and siG7L-1, administered before or after viral infection, reduced VACV replication by more than 90%. Also, these two siRNAs decreased monkeypox virus replication by 95% at a concentration of 1 nM. siB1R-2 and siG7L-1 were demonstrated to specifically silence their corresponding transcripts, i.e., B1R and G7L mRNAs, without induction of a beta interferon response. Strong synergistic effects were observed when siB1R-2, siG7L-1, or siD5R-2 was combined with cidofovir. In addition, the antiviral activities of these three siRNAs were evaluated against VACV resistant to cidofovir and other acyclic nucleoside phosphonates. siG7L-1 and siD5R-2 remained active against four of five VACV mutants, while siB1R-2 showed activity against only one of the mutants. Our results showed that siRNAs are potent inhibitory agents in vitro, not only against wild-type VACV but also against several cidofovir-resistant VACV. Furthermore, we showed that a combined therapy using siRNA and cidofovir may be useful in the treatment of poxvirus infections.
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24
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Scheeff ED, Eswaran J, Bunkoczi G, Knapp S, Manning G. Structure of the pseudokinase VRK3 reveals a degraded catalytic site, a highly conserved kinase fold, and a putative regulatory binding site. Structure 2009; 17:128-38. [PMID: 19141289 PMCID: PMC2639636 DOI: 10.1016/j.str.2008.10.018] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/15/2008] [Accepted: 10/21/2008] [Indexed: 01/19/2023]
Abstract
About 10% of all protein kinases are predicted to be enzymatically inactive pseudokinases, but the structural details of kinase inactivation have remained unclear. We present the first structure of a pseudokinase, VRK3, and that of its closest active relative, VRK2. Profound changes to the active site region underlie the loss of catalytic activity, and VRK3 cannot bind ATP because of residue substitutions in the binding pocket. However, VRK3 still shares striking structural similarity with VRK2, and appears to be locked in a pseudoactive conformation. VRK3 also conserves residue interactions that are surprising in the absence of enzymatic function; these appear to play important architectural roles required for the residual functions of VRK3. Remarkably, VRK3 has an "inverted" pattern of sequence conservation: although the active site is poorly conserved, portions of the molecular surface show very high conservation, suggesting that they form key interactions that explain the evolutionary retention of VRK3.
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Affiliation(s)
- Eric D Scheeff
- Razavi Newman Center for Bioinformatics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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25
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Kang TH, Park DY, Kim W, Kim KT. VRK1 phosphorylates CREB and mediates CCND1 expression. J Cell Sci 2008; 121:3035-41. [PMID: 18713830 DOI: 10.1242/jcs.026757] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Vaccinia virus B1 kinase plays a key role in viral DNA replication. The homologous mammalian vaccinia-related kinases (VRKs) are also implicated in the regulation of DNA replication, although direct evidence remains elusive. Here we show that VRK1 regulates cell cycle progression in the DNA replication period by inducing cyclin D1 (CCND1) expression. Furthermore, depletion of VRK1 in human cancer cells reduces the fraction of cells in S phase at a given time. VRK1 specifically enhances activity of the cAMP-response element (CRE) in the CCND1 promoter by facilitating the recruitment of phospho-CREB to this locus. VRK1 phosphorylates CREB at Ser133 in vitro and the expression of a kinase-dead mutant of VRK1 or knockdown of VRK1 using siRNA fails to activate CREB and subsequently activate CRE. Finally, we show that VRK1 is a critical link in the CCND1 gene expression pathway stimulated by Myc overexpression. Our results indicate that VRK1 is a novel regulator of CCND1 expression.
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Affiliation(s)
- Tae-Hong Kang
- Department of Life Science, Pohang University of Science and Technology , Pohang 790-784, Republic of Korea
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Wiebe MS, Traktman P. Poxviral B1 kinase overcomes barrier to autointegration factor, a host defense against virus replication. Cell Host Microbe 2007; 1:187-97. [PMID: 18005698 DOI: 10.1016/j.chom.2007.03.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 02/12/2007] [Accepted: 03/25/2007] [Indexed: 11/19/2022]
Abstract
Barrier to autointegration factor (BAF) is a DNA-binding protein found in the nucleus and cytoplasm of eukaryotic cells that functions to establish nuclear architecture during mitosis. Herein, we demonstrate a cytoplasmic role for BAF in host defense during poxviral infections. Vaccinia is the prototypic poxvirus, a family of DNA viruses that replicate exclusively in the cytoplasm of infected cells. Mutations in the vaccinia B1 kinase (B1) compromise viral DNA replication, but the mechanism by which B1 achieves this has remained elusive. We now show that BAF acts as a potent inhibitor of poxvirus replication unless its DNA-binding activity is blocked by B1-mediated phosphorylation. These data position BAF as the effector of an innate immune response that prevents replication of exogenous viral DNA in the cytoplasm. To enable the virus to evade this defense, the poxviral B1 has evolved to usurp a signaling pathway employed by the host cell.
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Affiliation(s)
- Matthew S Wiebe
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Cresawn SG, Condit RC. A targeted approach to identification of vaccinia virus postreplicative transcription elongation factors: genetic evidence for a role of the H5R gene in vaccinia transcription. Virology 2007; 363:333-41. [PMID: 17376501 PMCID: PMC1950266 DOI: 10.1016/j.virol.2007.02.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 11/18/2006] [Accepted: 02/05/2007] [Indexed: 11/17/2022]
Abstract
Treatment of wild-type vaccinia virus infected cells with the anti-poxviral drug isatin-beta-thiosemicarbazone (IBT) induces the viral postreplicative transcription apparatus to synthesize longer-than-normal mRNAs through an unknown mechanism. Prior studies have shown that virus mutants resistant to or dependent on IBT affect proteins involved in control of viral postreplicative transcription elongation, including G2, J3, and the viral RNA polymerase. Prior studies also suggest that there exist additional unidentified vaccinia genes that influence transcription elongation. The present study was undertaken to target candidate transcription elongation factor genes in an error-prone mutagenesis protocol to determine whether IBT-resistant or -dependent alleles could be isolated in those candidate genes. Mutagenesis of genes in which IBT resistance alleles have previously been isolated, namely A24R (encoding the second largest RNA polymerase subunit, rpo132) and G2R (encoding a positive transcription elongation factor), resulted in isolation of novel IBT resistance and dependence alleles therefore providing proof of principle of the targeted mutagenesis technique. The vaccinia H5 protein has been implicated previously in transcription elongation by virtue of its association with the positive elongation factor G2. Mutagenesis of the vaccinia H5R gene resulted in a novel H5R IBT resistance allele, strongly suggesting that H5 is a positive transcription elongation factor.
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Affiliation(s)
| | - Richard C. Condit
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610
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28
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Santos CR, Blanco S, Sevilla A, Lazo PA. Vaccinia virus B1R kinase interacts with JIP1 and modulates c-Jun-dependent signaling. J Virol 2006; 80:7667-75. [PMID: 16840345 PMCID: PMC1563719 DOI: 10.1128/jvi.00967-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Viruses have to adjust to the host cell to guarantee their life cycle and survival. This aspect of the virus-host cell interaction is probably performed by viral proteins, such as serine-threonine kinases, that are present early during infection. Vaccinia virus has an early Ser-Thr kinase, B1R, which, although required for successful viral infection, is poorly characterized regarding its effects on cellular proteins, and thus, its potential contribution to pathogenesis is not known. Signaling by mitogen-activated protein kinase (MAPK) is mediated by the assembly of complexes between these kinases and the JIP scaffold proteins. To understand how vaccinia virus B1R can affect the host, its roles in the cellular signaling by MAPK complexes and c-Jun activation have been studied. Independently of its kinase activity, B1R can interact with the central region of the JIP1 scaffold protein. The B1R-JIP1 complex increases the amount of MAPK bound to JIP1; thus, MKK7 and TAK1 either bind with higher affinity or bind more stably to JIP1, while there is an increase in the phosphorylation state of JNK bound to JIP1. The functional consequence of these more stable interactions is an increase in the activity of transcription factors, such as c-Jun, that respond to these complexes. Furthermore, B1R is also able to directly phosphorylate c-Jun in residues different from those targeted by JNK and, thus, B1R can also cooperate by an independent route in c-Jun activation. Vaccinia virus B1R can thus modulate the signaling of pathways that respond to cellular stress.
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Affiliation(s)
- Claudio R Santos
- IBMCC-Centro de Investigación del Cáncer, CSIC-Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
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29
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Nichols RJ, Wiebe MS, Traktman P. The vaccinia-related kinases phosphorylate the N' terminus of BAF, regulating its interaction with DNA and its retention in the nucleus. Mol Biol Cell 2006; 17:2451-64. [PMID: 16495336 PMCID: PMC1446082 DOI: 10.1091/mbc.e05-12-1179] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The vaccinia-related kinases (VRKs) comprise a branch of the casein kinase family whose members are characterized by homology to the vaccinia virus B1 kinase. The VRK orthologues encoded by Caenorhabditis elegans and Drosophila melanogaster play an essential role in cell division; however, substrates that mediate this role have yet to be elucidated. VRK1 can complement the temperature sensitivity of a vaccinia B1 mutant, implying that VRK1 and B1 have overlapping substrate specificity. Herein, we demonstrate that B1, VRK1, and VRK2 efficiently phosphorylate the extreme N' terminus of the BAF protein (Barrier to Autointegration Factor). BAF binds to both DNA and LEM domain-containing proteins of the inner nuclear membrane; in lower eukaryotes, BAF has been shown to play an important role during the reassembly of the nuclear envelope at the end of mitosis. We demonstrate that phosphorylation of ser4 and/or thr2/thr3 abrogates the interaction of BAF with DNA and reduces its interaction with the LEM domain. Coexpression of VRK1 and GFP-BAF greatly diminishes the association of BAF with the nuclear chromatin/matrix and leads to its dispersal throughout the cell. Cumulatively, our data suggest that the VRKs may modulate the association of BAF with nuclear components and hence play a role in maintaining appropriate nuclear architecture.
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Affiliation(s)
- R Jeremy Nichols
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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30
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Santos CR, Vega FM, Blanco S, Barcia R, Lazo PA. The vaccinia virus B1R kinase induces p53 downregulation by an Mdm2-dependent mechanism. Virology 2004; 328:254-65. [PMID: 15464845 DOI: 10.1016/j.virol.2004.08.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Revised: 07/10/2004] [Accepted: 08/13/2004] [Indexed: 12/20/2022]
Abstract
Poxvirus infection has a strong effect on cellular functions. To understand viral pathogenesis, it is necessary to know how viral proteins interact with host proteins. The B1R kinase is an early viral gene required for vaccinia virus DNA synthesis and replication, but no cellular substrate is known for this viral kinase. B1R is able to hyperphosphorylate p53 in several residues in the N-terminal transactivation domain, including Ser15 and Thr18. B1R does not phosphorylate Mdm2. B1R promotes an increase in p53 ubiquitination and a reduction of p53 acetylation by p300. The over-expressed B1R protein induces the degradation of p53 in a concentration-dependent manner and is lost when Ser15 and Th18 are changed to alanine or when the B1R kinase is inactivated by introducing the K149Q substitution. The B1R-induced downregulation of p53 requires Mdm2. The hyperphosphorylated p53 is transcriptionally active, and this activity also falls as B1R increases. The BAX gene promoter is more sensitive to this reduction of transcription than p21 or 14-3-3 gene promoters. This effect of B1R on p53 can be one of the mechanisms by which vaccinia virus exerts its role in infected cells.
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Affiliation(s)
- Cláudio R Santos
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, E-37007 Salamanca, Spain
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31
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Nichols RJ, Traktman P. Characterization of three paralogous members of the Mammalian vaccinia related kinase family. J Biol Chem 2003; 279:7934-46. [PMID: 14645249 DOI: 10.1074/jbc.m310813200] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the novel vaccinia related kinase (VRK) protein family are characterized by notable sequence homology to the vaccinia virus-encoded B1 kinase (vvB1). vvB1 plays an essential role in viral DNA replication, and Boyle and Traktman have demonstrated that VRK1 enzymes complement the replication defect of a temperature-sensitive viral mutant defective in vvB1 (Boyle, K., and Traktman, P. (2004) J. Virol. 78, 1992-2005). This mammalian kinase family comprises three members, VRK1, VRK2, and VRK3. We have annotated the gene structure for the members of this family and have characterized the enzyme activity and subcellular localization for the human and mouse proteins. VRK1 enzymes show robust autophosphorylation activity and will phosphorylate casein; VRK2 enzymes show modest autophosphorylation activity and will also phosphorylate casein. The VRK3 proteins have key amino acid substitutions that disrupt invariant motifs required for catalytic activity, rendering them enzymatically inert. The VRK1 and VRK2 proteins contain COOH-terminal extracatalytic sequences that mediate intracellular localization. VRK1 proteins possess a basic nuclear localization signal and are indeed nuclear; the extreme C termini of the VRK2 proteins are highly hydrophobic, and the proteins are membrane-associated and colocalize with markers of the endoplasmic reticulum. The NH(2)-terminal region of the VRK3s contains a bipartite nuclear localization signal, which directs these proteins to the nucleus. Our findings provide the basis for further studies of the structure and function of this newly discovered family of protein kinases.
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Affiliation(s)
- R Jeremy Nichols
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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