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Townsend JA, Fapohunda O, Wang Z, Pham H, Taylor MT, Kloss B, Ho Park S, Opella S, Aspinwall CA, Marty MT. Differences in Oligomerization of the SARS-CoV-2 Envelope Protein, Poliovirus VP4, and HIV Vpu. Biochemistry 2024; 63:241-250. [PMID: 38216552 PMCID: PMC10872257 DOI: 10.1021/acs.biochem.3c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2024]
Abstract
Viroporins constitute a class of viral membrane proteins with diverse roles in the viral life cycle. They can self-assemble and form pores within the bilayer that transport substrates, such as ions and genetic material, that are critical to the viral infection cycle. However, there is little known about the oligomeric state of most viroporins. Here, we use native mass spectrometry in detergent micelles to uncover the patterns of oligomerization of the full-length SARS-CoV-2 envelope (E) protein, poliovirus VP4, and HIV Vpu. Our data suggest that the E protein is a specific dimer, VP4 is exclusively monomeric, and Vpu assembles into a polydisperse mixture of oligomers under these conditions. Overall, these results revealed the diversity in the oligomerization of viroporins, which has implications for the mechanisms of their biological functions as well as their potential as therapeutic targets.
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Affiliation(s)
- Julia A. Townsend
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Oluwaseun Fapohunda
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Zhihan Wang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Hieu Pham
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Michael T. Taylor
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, NY 10027, USA
| | - Sang Ho Park
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stanley Opella
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Craig A. Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
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2
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Townsend JA, Fapohunda O, Wang Z, Pham H, Taylor MT, Kloss B, Park SH, Opella S, Aspinwall CA, Marty MT. Differences in Oligomerization of the SARS-CoV-2 Envelope Protein, Poliovirus VP4, and HIV Vpu. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.18.553902. [PMID: 37645758 PMCID: PMC10462163 DOI: 10.1101/2023.08.18.553902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Viroporins constitute a class of viral membrane proteins with diverse roles in the viral life cycle. They can self-assemble and form pores within the bilayer that transport substrates, such as ions and genetic material, that are critical to the viral infection cycle. However, there is little known about the oligomeric state of most viroporins. Here, we use native mass spectrometry (MS) in detergent micelles to uncover the patterns of oligomerization of the full-length SARS-CoV-2 envelope (E) protein, poliovirus VP4, and HIV Vpu. Our data suggest that the E protein is a specific dimer, VP4 is exclusively monomeric, and Vpu assembles into a polydisperse mixture of oligomers under these conditions. Overall, these results revealed the diversity in the oligomerization of viroporins, which has implications for mechanisms of their biological functions as well as their potential as therapeutic targets.
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Affiliation(s)
- Julia A. Townsend
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Oluwaseun Fapohunda
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Zhihan Wang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Hieu Pham
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Michael T. Taylor
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, NY 10027, USA
| | - Sang Ho Park
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stanley Opella
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Craig A. Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
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3
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Gargan S, Stevenson NJ. Unravelling the Immunomodulatory Effects of Viral Ion Channels, towards the Treatment of Disease. Viruses 2021; 13:2165. [PMID: 34834972 PMCID: PMC8618147 DOI: 10.3390/v13112165] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/07/2021] [Accepted: 10/10/2021] [Indexed: 02/07/2023] Open
Abstract
The current COVID-19 pandemic has highlighted the need for the research community to develop a better understanding of viruses, in particular their modes of infection and replicative lifecycles, to aid in the development of novel vaccines and much needed anti-viral therapeutics. Several viruses express proteins capable of forming pores in host cellular membranes, termed "Viroporins". They are a family of small hydrophobic proteins, with at least one amphipathic domain, which characteristically form oligomeric structures with central hydrophilic domains. Consequently, they can facilitate the transport of ions through the hydrophilic core. Viroporins localise to host membranes such as the endoplasmic reticulum and regulate ion homeostasis creating a favourable environment for viral infection. Viroporins also contribute to viral immune evasion via several mechanisms. Given that viroporins are often essential for virion assembly and egress, and as their structural features tend to be evolutionarily conserved, they are attractive targets for anti-viral therapeutics. This review discusses the current knowledge of several viroporins, namely Influenza A virus (IAV) M2, Human Immunodeficiency Virus (HIV)-1 Viral protein U (Vpu), Hepatitis C Virus (HCV) p7, Human Papillomavirus (HPV)-16 E5, Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) Open Reading Frame (ORF)3a and Polyomavirus agnoprotein. We highlight the intricate but broad immunomodulatory effects of these viroporins and discuss the current antiviral therapies that target them; continually highlighting the need for future investigations to focus on novel therapeutics in the treatment of existing and future emergent viruses.
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Affiliation(s)
- Siobhan Gargan
- Viral Immunology Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 R590 Dublin, Ireland;
| | - Nigel J. Stevenson
- Viral Immunology Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 R590 Dublin, Ireland;
- Viral Immunology Group, Royal College of Surgeons in Ireland-Medical University of Bahrain, Manama 15503, Bahrain
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4
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Li F, Egea PF, Vecchio AJ, Asial I, Gupta M, Paulino J, Bajaj R, Dickinson MS, Ferguson-Miller S, Monk BC, Stroud RM. Highlighting membrane protein structure and function: A celebration of the Protein Data Bank. J Biol Chem 2021; 296:100557. [PMID: 33744283 PMCID: PMC8102919 DOI: 10.1016/j.jbc.2021.100557] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/10/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
Biological membranes define the boundaries of cells and compartmentalize the chemical and physical processes required for life. Many biological processes are carried out by proteins embedded in or associated with such membranes. Determination of membrane protein (MP) structures at atomic or near-atomic resolution plays a vital role in elucidating their structural and functional impact in biology. This endeavor has determined 1198 unique MP structures as of early 2021. The value of these structures is expanded greatly by deposition of their three-dimensional (3D) coordinates into the Protein Data Bank (PDB) after the first atomic MP structure was elucidated in 1985. Since then, free access to MP structures facilitates broader and deeper understanding of MPs, which provides crucial new insights into their biological functions. Here we highlight the structural and functional biology of representative MPs and landmarks in the evolution of new technologies, with insights into key developments influenced by the PDB in magnifying their impact.
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Affiliation(s)
- Fei Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA; Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Pascal F Egea
- Department of Biological Chemistry, School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Alex J Vecchio
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | | | - Meghna Gupta
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Joana Paulino
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Ruchika Bajaj
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA
| | - Miles Sasha Dickinson
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Brian C Monk
- Sir John Walsh Research Institute and Department of Oral Sciences, University of Otago, North Dunedin, Dunedin, New Zealand
| | - Robert M Stroud
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA.
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5
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Mackie TD, Brodsky JL. Investigating Potassium Channels in Budding Yeast: A Genetic Sandbox. Genetics 2018; 209:637-650. [PMID: 29967058 PMCID: PMC6028241 DOI: 10.1534/genetics.118.301026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/15/2018] [Indexed: 12/26/2022] Open
Abstract
Like all species, the model eukaryote Saccharomyces cerevisiae, or Bakers' yeast, concentrates potassium in the cytosol as an electrogenic osmolyte and enzyme cofactor. Yeast are capable of robust growth on a wide variety of potassium concentrations, ranging from 10 µM to 2.5 M, due to the presence of a high-affinity potassium uptake system and a battery of cation exchange transporters. Genetic perturbation of either of these systems retards yeast growth on low or high potassium, respectively. However, these potassium-sensitized yeast are a powerful genetic tool, which has been leveraged for diverse studies. Notably, the potassium-sensitive cells can be transformed with plasmids encoding potassium channels from bacteria, plants, or mammals, and subsequent changes in growth rate have been found to correlate with the activity of the introduced potassium channel. Discoveries arising from the use of this assay over the past three decades have increased our understanding of the structure-function relationships of various potassium channels, the mechanisms underlying the regulation of potassium channel function and trafficking, and the chemical basis of potassium channel modulation. In this article, we provide an overview of the major genetic tools used to study potassium channels in S. cerevisiae, a survey of seminal studies utilizing these tools, and a prospective for the future use of this elegant genetic approach.
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Affiliation(s)
- Timothy D Mackie
- Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260
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6
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Deb A, Johnson WA, Kline AP, Scott BJ, Meador LR, Srinivas D, Martin-Garcia JM, Dörner K, Borges CR, Misra R, Hogue BG, Fromme P, Mor TS. Bacterial expression, correct membrane targeting and functional folding of the HIV-1 membrane protein Vpu using a periplasmic signal peptide. PLoS One 2017; 12:e0172529. [PMID: 28225803 PMCID: PMC5321405 DOI: 10.1371/journal.pone.0172529] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/06/2017] [Indexed: 12/04/2022] Open
Abstract
Viral protein U (Vpu) is a type-III integral membrane protein encoded by Human Immunodeficiency Virus-1 (HIV- 1). It is expressed in infected host cells and plays several roles in viral progeny escape from infected cells, including down-regulation of CD4 receptors. But key structure/function questions remain regarding the mechanisms by which the Vpu protein contributes to HIV-1 pathogenesis. Here we describe expression of Vpu in bacteria, its purification and characterization. We report the successful expression of PelB-Vpu in Escherichia coli using the leader peptide pectate lyase B (PelB) from Erwinia carotovora. The protein was detergent extractable and could be isolated in a very pure form. We demonstrate that the PelB signal peptide successfully targets Vpu to the cell membranes and inserts it as a type I membrane protein. PelB-Vpu was biophysically characterized by circular dichroism and dynamic light scattering experiments and was shown to be an excellent candidate for elucidating structural models.
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Affiliation(s)
- Arpan Deb
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - William A. Johnson
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Alexander P. Kline
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Boston J. Scott
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Lydia R. Meador
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Dustin Srinivas
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jose M. Martin-Garcia
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Katerina Dörner
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Chad R. Borges
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Personal Diagnostics, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Rajeev Misra
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Brenda G. Hogue
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Petra Fromme
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Tsafrir S. Mor
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- The Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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7
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Soper A, Juarez-Fernandez G, Aso H, Moriwaki M, Yamada E, Nakano Y, Koyanagi Y, Sato K. Various plus unique: Viral protein U as a plurifunctional protein for HIV-1 replication. Exp Biol Med (Maywood) 2017; 242:850-858. [PMID: 28346011 DOI: 10.1177/1535370217697384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome, encodes four accessory genes, one of which is viral protein U (Vpu). Recently, the study of Vpu has been of great interest. For instance, various cellular proteins are degraded (e.g. CD4) and down-modulated (e.g. tetherin) by Vpu. Vpu also antagonizes the function of tetherin and inhibits NF-κB. Moreover, Vpu is a viroporin forming ion channels and may represent a promising target for anti-HIV-1 drugs. In this review, we summarize the domains/residues that are responsible for Vpu's functions, describe the current understanding of the role of Vpu in HIV-1-infected cells, and review the effect of Vpu on HIV-1 in replication and pathogenesis. Future investigations that simultaneously assess a combination of Vpu functions are required to clearly delineate the most important functions for viral replication. Impact statement Viral protein U (Vpu) is a unique protein encoded by human immunodeficiency virus type 1 (HIV-1) and related lentiviruses, playing multiple roles in viral replication and pathogenesis. In this review, we briefly summarize the most up-to-date knowledge of HIV-1 Vpu.
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Affiliation(s)
- Andrew Soper
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Guillermo Juarez-Fernandez
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Hirofumi Aso
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan.,2 Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto 6068501, Japan
| | - Miyu Moriwaki
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan.,3 Graduate School of Biostudies, Kyoto University, Kyoto 6068315, Japan
| | - Eri Yamada
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Yusuke Nakano
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Yoshio Koyanagi
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Kei Sato
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan.,4 CREST, Japan Science and Technology Agency, Saitama 3220012, Japan
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8
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Monroy N, Herrero L, Carrasco L, González ME. Influence of glutathione availability on cell damage induced by human immunodeficiency virus type 1 viral protein R. Virus Res 2015; 213:116-123. [PMID: 26597719 DOI: 10.1016/j.virusres.2015.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/11/2015] [Accepted: 11/12/2015] [Indexed: 01/23/2023]
Abstract
The human immunodeficiency virus type 1 (HIV-1) encodes for accessory viral protein R (Vpr), which arrests the cell cycle of host cells at G2 and causes mitochondrial dysfunction and alterations in glycolysis. High-level expression of Vpr protein correlates with increased viral production and disease progression. Vpr causes structural and functional injury in many types of eukaryotic cells, whether or not they are permissive for viral replication; among them is the budding yeast Saccharomyces cerevisiae. We hypothesized that the dramatic Vpr-induced injuries in yeast could be prevented by strengthening their redox response capacity. We show that exogenous addition of glutathione (GSH) or its prodrug, N-acetylcysteine (NAC), protected budding yeasts from Vpr-induced cytopathic effects. Moreover, addition of adenosine triphosphate (ATP) to growing cultures of Vpr-producing yeast returned cellular growth to control levels, whereas the addition dehydroascorbic acid (DHA) had only a minor protective effect. The diminished protein levels of Cox2p and Cox4p in wild typeVpr-producing yeasts together with the acute sensitivity of petite yeasts to Vpr activity may have been caused by low intracellular ATP levels. As a consequence of this energy deficit, eukaryotic cells would be unable to synthetize adequate supplies of GSH or to signal the mitochondrial retrograde response. Our findings strongly suggest that the cytopathogenic effect of Vpr protein in eukaryotic cells can be prevented by increasing intracellular antioxidant stores or, alternatively, supplying external ATP. Furthermore, these results support a potentially promising future for S. cerevisiae expression as a modality to search for Vpr-targeted inhibitors.
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Affiliation(s)
- Noemí Monroy
- Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain
| | - Laura Herrero
- Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain
| | - Luis Carrasco
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | - María Eugenia González
- Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain.
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9
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Nkeze J, Li L, Benko Z, Li G, Zhao RY. Molecular characterization of HIV-1 genome in fission yeast Schizosaccharomyces pombe. Cell Biosci 2015; 5:47. [PMID: 26309721 PMCID: PMC4549081 DOI: 10.1186/s13578-015-0037-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/27/2015] [Indexed: 11/25/2022] Open
Abstract
Background The human immunodeficiency virus type 1 (HIV-1) genome (~9 kb RNA) is flanked by two long terminal repeats (LTR) promoter regions with nine open reading frames, which encode Gag, Pol and Env polyproteins, four accessory proteins (Vpu, Vif, Vpr, Nef) and two regulatory proteins (Rev, Tat). In this study, we carried out a genome-wide and functional analysis of the HIV-1 genome in fission yeast (Schizosaccharomyces pombe). Results Each one of the HIV-1 genes was cloned and expressed individually in fission yeast. Subcellular localization of each viral protein was first examined. The effect of protein expression on cellular proliferation and colony formations, an indication of cytotoxicity, were observed. Overall, there is a general correlation of subcellular localization of each viral protein between fission yeast and mammalian cells. Three viral proteins, viral protein R (Vpr), protease (PR) and regulator of expression of viral protein (Rev), were found to inhibit cellular proliferation. Rev was chosen for further analysis in fission yeast and mammalian cells. Consistent with the observation in fission yeast, expression of HIV-1 rev gene also caused growth retardation in mammalian cells. However, the observed growth delay was neither due to the cytotoxic effect nor due to alterations in cell cycling. Mechanistic testing of the Rev effect suggests it triggers transient induction of cellular oxidative stress. Conclusions Some of the behavioral and functional similarities of Rev between fission yeast and mammalian cells suggest fission yeast might be a useful model system for further studies of molecular functions of Rev and other HIV-1 viral proteins.
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Affiliation(s)
- Joseph Nkeze
- Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA
| | - Lin Li
- Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA.,AIDS Research Department, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China
| | - Zsigmond Benko
- Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA.,Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Ge Li
- Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA
| | - Richard Y Zhao
- Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA.,Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201-1192 USA
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10
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Vpu Protein: The Viroporin Encoded by HIV-1. Viruses 2015; 7:4352-68. [PMID: 26247957 PMCID: PMC4576185 DOI: 10.3390/v7082824] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 06/29/2015] [Accepted: 07/28/2015] [Indexed: 02/06/2023] Open
Abstract
Viral protein U (Vpu) is a lentiviral viroporin encoded by human immunodeficiency virus type 1 (HIV-1) and some simian immunodeficiency virus (SIV) strains. This small protein of 81 amino acids contains a single transmembrane domain that allows for supramolecular organization via homoligomerization or interaction with other proteins. The topology and trafficking of Vpu through subcellular compartments result in pleiotropic effects in host cells. Notwithstanding the high variability of its amino acid sequence, the functionality of Vpu is well conserved in pandemic virus isolates. This review outlines our current knowledge on the interactions of Vpu with the host cell. The regulation of cellular physiology by Vpu and the validity of this viroporin as a therapeutic target are also discussed.
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11
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Taube R, Alhadeff R, Assa D, Krugliak M, Arkin IT. Bacteria-based analysis of HIV-1 Vpu channel activity. PLoS One 2014; 9:e105387. [PMID: 25272035 PMCID: PMC4182682 DOI: 10.1371/journal.pone.0105387] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 07/21/2014] [Indexed: 02/04/2023] Open
Abstract
HIV-1 Vpu is a small, single-span membrane protein with two attributed functions that increase the virus' pathogenicity: degradation of CD4 and inactivation of BST-2. Vpu has also been shown to posses ion channel activity, yet no correlation has been found between this attribute and Vpu's role in viral release. In order to gain further insight into the channel activity of Vpu we devised two bacteria-based assays that can examine this function in detail. In the first assay Vpu was over-expressed, such that it was deleterious to bacterial growth due to membrane permeabilization. In the second and more sensitive assay, the channel was expressed at low levels in K+ transport deficient bacteria. Consequently, Vpu expression enabled the bacteria to grow at otherwise non permissive low K+ concentrations. Hence, Vpu had the opposite impact on bacterial growth in the two assays: detrimental in the former and beneficial in the latter. Furthermore, we show that channel blockers also behave reciprocally in the two assays, promoting growth in the first assay and hindering it in the second assay. Taken together, we investigated Vpu's channel activity in a rapid and quantitative approach that is amenable to high-throughput screening, in search of novel blockers.
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Affiliation(s)
- Robert Taube
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem, Israel
- Institue of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Raphael Alhadeff
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem, Israel
| | - Dror Assa
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem, Israel
| | - Miriam Krugliak
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem, Israel
| | - Isaiah T. Arkin
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem, Israel
- * E-mail:
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Viral channel proteins in intracellular protein-protein communication: Vpu of HIV-1, E5 of HPV16 and p7 of HCV. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:1113-21. [PMID: 24035804 DOI: 10.1016/j.bbamem.2013.08.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/06/2013] [Accepted: 08/09/2013] [Indexed: 01/20/2023]
Abstract
Viral channel forming proteins are known for their capability to make the lipid membrane of the host cell and its subcellular compartments permeable to ions and small compounds. There is increasing evidence that some of the representatives of this class of proteins are also strongly interacting with host proteins and the effectiveness of this interaction seems to be high. Interaction of viral channel proteins with host factors has been proposed by bioinformatics approaches and has also been identified experimentally. An overview of the interactions with host proteins is given for Vpu from HIV-1, E5 from HPV-16 and p7 from HCV. This article is part of a Special Issue entitled: Viral Membrane Proteins - Channels for Cellular Networking.
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Strebel K. HIV-1 Vpu - an ion channel in search of a job. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:1074-81. [PMID: 23831603 DOI: 10.1016/j.bbamem.2013.06.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/18/2013] [Accepted: 06/22/2013] [Indexed: 12/22/2022]
Abstract
Vpu is a small membrane protein encoded by HIV-1 and some SIV isolates. The protein is best known for its ability to degrade CD4 and to enhance the release of progeny virions from infected cells. However, Vpu also promotes host-cell apoptosis by deregulating the NFκB signaling pathway and it assembles into cation-conducting membrane pores. This review summarizes our current understanding of these various functions of Vpu with particular emphasis on recent progress in the Vpu field. This article is part of a Special Issue entitled: Viral Membrane Proteins - Channels for Cellular Networking.
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Affiliation(s)
- Klaus Strebel
- Viral Biochemistry Section, Laboratory of Molecular Microbiology, NIAID, NIH Bldg. 4, Room 310, 4 Center Drive MSC 0460, Bethesda, MD 20892-0460, USA.
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