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Sučec I, Pankratova Y, Parasar M, Hong M. Transmembrane conformation of the envelope protein of an alpha coronavirus, NL63. Protein Sci 2024; 33:e4923. [PMID: 38501465 PMCID: PMC10949323 DOI: 10.1002/pro.4923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 03/20/2024]
Abstract
The envelope (E) proteins of coronaviruses (CoVs) form cation-conducting channels that are associated with the pathogenicity of these viruses. To date, high-resolution structural information about these viroporins is limited to the SARS-CoV E protein. To broaden our structural knowledge of other members of this family of viroporins, we now investigate the conformation of the E protein of the human coronavirus (hCoV), NL63. Using two- and three-dimensional magic-angle-spinning NMR, we have measured 13 C and 15 N chemical shifts of the transmembrane domain of E (ETM), which yielded backbone (ϕ, ψ) torsion angles. We further measured the water accessibility of NL63 ETM at neutral pH versus acidic pH in the presence of Ca2+ ions. These data show that NL63 ETM adopts a regular α-helical conformation that is unaffected by pH and the N-terminal ectodomain. Interestingly, the water accessibility of NL63 ETM increases only modestly at acidic pH in the presence of Ca2+ compared to neutral pH, in contrast to SARS ETM, which becomes much more hydrated at acidic pH. This difference suggests a structural basis for the weaker channel conductance of α-CoV compared to β-CoV E proteins. The weaker E channel activity may in turn contribute to the reduced virulence of hCoV-NL63 compared to SARS-CoV viruses.
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Affiliation(s)
- Iva Sučec
- Department of ChemistryMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Yanina Pankratova
- Department of ChemistryMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Mriganka Parasar
- Department of ChemistryMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Mei Hong
- Department of ChemistryMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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2
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Paschke RR, Mohr S, Lange S, Lange A, Kozuch J. In Situ Spectroscopic Detection of Large-Scale Reorientations of Transmembrane Helices During Influenza A M2 Channel Opening. Angew Chem Int Ed Engl 2023; 62:e202309069. [PMID: 37733579 DOI: 10.1002/anie.202309069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 09/23/2023]
Abstract
Viroporins are small ion channels in membranes of enveloped viruses that play key roles during viral life cycles. To use viroporins as drug targets against viral infection requires in-depth mechanistic understanding and, with that, methods that enable investigations under in situ conditions. Here, we apply surface-enhanced infrared absorption (SEIRA) spectroscopy to Influenza A M2 reconstituted within a solid-supported membrane, to shed light on the mechanics of its viroporin function. M2 is a paradigm of pH-activated proton channels and controls the proton flux into the viral interior during viral infection. We use SEIRA to track the large-scale reorientation of M2's transmembrane α-helices in situ during pH-activated channel opening. We quantify this event as a helical tilt from 26° to 40° by correlating the experimental results with solid-state nuclear magnetic resonance-informed computational spectroscopy. This mechanical motion is impeded upon addition of the inhibitor rimantadine, giving a direct spectroscopic marker to test antiviral activity. The presented approach provides a spectroscopic tool to quantify large-scale structural changes and to track the function and inhibition of the growing number of viroporins from pathogenic viruses in future studies.
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Affiliation(s)
- Ronja Rabea Paschke
- Physics Department, Freie Universität Berlin, Experimental Molecular Biophysics, Arnimallee 14, 14195, Berlin, Germany
- Research Building SupraFAB, Freie Universität Berlin, Altensteinstr. 23a, 14195, Berlin, Germany
| | - Swantje Mohr
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Sascha Lange
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Adam Lange
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Jacek Kozuch
- Physics Department, Freie Universität Berlin, Experimental Molecular Biophysics, Arnimallee 14, 14195, Berlin, Germany
- Research Building SupraFAB, Freie Universität Berlin, Altensteinstr. 23a, 14195, Berlin, Germany
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4
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Medeiros-Silva J, Dregni AJ, Somberg NH, Duan P, Hong M. Atomic structure of the open SARS-CoV-2 E viroporin. Sci Adv 2023; 9:eadi9007. [PMID: 37831764 PMCID: PMC10575589 DOI: 10.1126/sciadv.adi9007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/08/2023] [Indexed: 10/15/2023]
Abstract
The envelope (E) protein of the SARS-CoV-2 virus forms cation-conducting channels in the endoplasmic reticulum Golgi intermediate compartment (ERGIC) of infected cells. The calcium channel activity of E is associated with the inflammatory responses of COVID-19. Using solid-state NMR (ssNMR) spectroscopy, we have determined the open-state structure of E's transmembrane domain (ETM) in lipid bilayers. Compared to the closed state, open ETM has an expansive water-filled amino-terminal chamber capped by key glutamate and threonine residues, a loose phenylalanine aromatic belt in the middle, and a constricted polar carboxyl-terminal pore filled with an arginine and a threonine residue. This structure gives insights into how protons and calcium ions are selected by ETM and how they permeate across the hydrophobic gate of this viroporin.
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Affiliation(s)
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Pu Duan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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5
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Ewart G, Bobardt M, Bentzen BH, Yan Y, Thomson A, Klumpp K, Becker S, Rosenkilde MM, Miller M, Gallay P. Post-infection treatment with the E protein inhibitor BIT225 reduces disease severity and increases survival of K18-hACE2 transgenic mice infected with a lethal dose of SARS-CoV-2. PLoS Pathog 2023; 19:e1011328. [PMID: 37549173 PMCID: PMC10434922 DOI: 10.1371/journal.ppat.1011328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 08/17/2023] [Accepted: 07/06/2023] [Indexed: 08/09/2023] Open
Abstract
The Coronavirus envelope (E) protein is a small structural protein with ion channel activity that plays an important role in virus assembly, budding, immunopathogenesis and disease severity. The viroporin E is also located in Golgi and ER membranes of infected cells and is associated with inflammasome activation and immune dysregulation. Here we evaluated in vitro antiviral activity, mechanism of action and in vivo efficacy of BIT225 for the treatment of SARS-CoV-2 infection. BIT225 showed broad-spectrum direct-acting antiviral activity against SARS-CoV-2 in Calu3 and Vero cells with similar potency across 6 different virus strains. BIT225 inhibited ion channel activity of E protein but did not inhibit endogenous currents or calcium-induced ion channel activity of TMEM16A in Xenopus oocytes. BIT225 administered by oral gavage for 12 days starting 12 hours before infection completely prevented body weight loss and mortality in SARS-CoV-2 infected K18 mice (100% survival, n = 12), while all vehicle-dosed animals reached a mortality endpoint by Day 9 across two studies (n = 12). When treatment started at 24 hours after infection, body weight loss, and mortality were also prevented (100% survival, n = 5), while 4 of 5 mice maintained and increased body weight and survived when treatment started 48 hours after infection. Treatment efficacy was dependent on BIT225 dose and was associated with significant reductions in lung viral load (3.5 log10), virus titer (4000 pfu/ml) and lung and serum cytokine levels. These results validate viroporin E as a viable antiviral target and support the clinical study of BIT225 for treatment and prophylaxis of SARS-CoV-2 infection.
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Affiliation(s)
- Gary Ewart
- Biotron Limited, North Ryde, New South Wales, Australia
| | - Michael Bobardt
- The Scripps Institute, Immunology and Microbiology, La Jolla, California, United States of America
| | - Bo Hjorth Bentzen
- University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark
| | - Yannan Yan
- University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark
| | | | - Klaus Klumpp
- Biotron Limited, North Ryde, New South Wales, Australia
| | | | - Mette M. Rosenkilde
- University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark
| | | | - Philippe Gallay
- The Scripps Institute, Immunology and Microbiology, La Jolla, California, United States of America
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6
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Somberg NH, Wu WW, Medeiros-Silva J, Dregni AJ, Jo H, DeGrado WF, Hong M. SARS-CoV-2 Envelope Protein Forms Clustered Pentamers in Lipid Bilayers. Biochemistry 2022; 61:2280-2294. [PMID: 36219675 PMCID: PMC9583936 DOI: 10.1021/acs.biochem.2c00464] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/26/2022] [Indexed: 11/30/2022]
Abstract
The SARS-CoV-2 envelope (E) protein is a viroporin associated with the acute respiratory symptoms of COVID-19. E forms cation-selective ion channels that assemble in the lipid membrane of the endoplasmic reticulum Golgi intermediate compartment. The channel activity of E is linked to the inflammatory response of the host cell to the virus. Like many viroporins, E is thought to oligomerize with a well-defined stoichiometry. However, attempts to determine the E stoichiometry have led to inconclusive results and suggested mixtures of oligomers whose exact nature might vary with the detergent used. Here, we employ 19F solid-state nuclear magnetic resonance and the centerband-only detection of exchange (CODEX) technique to determine the oligomeric number of E's transmembrane domain (ETM) in lipid bilayers. The CODEX equilibrium value, which corresponds to the inverse of the oligomeric number, indicates that ETM assembles into pentamers in lipid bilayers, without any detectable fraction of low-molecular-weight oligomers. Unexpectedly, at high peptide concentrations and in the presence of the lipid phosphatidylinositol, the CODEX data indicate that more than five 19F spins are within a detectable distance of about 2 nm, suggesting that the ETM pentamers cluster in the lipid bilayer. Monte Carlo simulations that take into account peptide-peptide and peptide-lipid interactions yielded pentamer clusters that reproduced the CODEX data. This supramolecular organization is likely important for E-mediated virus assembly and budding and for the channel function of the protein.
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Affiliation(s)
- Noah H. Somberg
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Westley W. Wu
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - João Medeiros-Silva
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, University of California, San Francisco, San Francisco, CA 94158
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, University of California, San Francisco, San Francisco, CA 94158
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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7
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Xia S, Fang P, Pan T, Xiao W, Zhang H, Zhu X, Xiao S, Fang L. Porcine deltacoronavirus accessory protein NS7a possesses the functional characteristics of a viroporin. Vet Microbiol 2022; 274:109551. [PMID: 36067658 DOI: 10.1016/j.vetmic.2022.109551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 10/31/2022]
Abstract
Viroporins are virus-encoded proteins that mediate ion channel (IC) activity, playing critical roles in virus entry, replication, pathogenesis, and immune evasion. Previous studies have shown that some coronavirus accessory proteins have viroporin-like activity. Porcine deltacoronavirus (PDCoV) is an emerging enteropathogenic coronavirus that encodes three accessory proteins, NS6, NS7, and NS7a. However, whether any of the PDCoV accessory proteins possess viroporin-like activity, and if so which, remains unknown. In this study, we analyzed the biochemical properties of the three PDCoV-encoded accessory proteins and found that NS7a could enhance the membrane permeability of both mammalian cells and Escherichia coli cells. Indirect immunofluorescence assay and co-immunoprecipitation assay results further indicated that NS7a is an integral membrane protein and can form homo-oligomers. A bioinformation analysis revealed that a putative viroporin domain (VPD) is located within amino acids 69-88 (aa69-88) of NS7a. Experiments with truncated mutants and alanine scanning mutagenesis additionally demonstrated that the amino acid residues 69FLR71 of NS7a are essential for its viroporin-like activity. Together, our findings are the first to demonstrate that PDCoV NS7a possesses viroporin-like activity and identify its key amino acid residues associated with viroporin-like activity.
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Affiliation(s)
- Sijin Xia
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Puxian Fang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Ting Pan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Wenwen Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Huichang Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Xuerui Zhu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Shaobo Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Liurong Fang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
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8
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Asrani P, Seebohm G, Stoll R. Potassium viroporins as model systems for understanding eukaryotic ion channel behaviour. Virus Res 2022; 320:198903. [PMID: 36037849 DOI: 10.1016/j.virusres.2022.198903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022]
Abstract
Ion channels are membrane proteins essential for a plethora of cellular functions including maintaining cell shape, ion homeostasis, cardiac rhythm and action potential in neurons. The complexity and often extensive structure of eukaryotic membrane proteins makes it difficult to understand their basic biological regulation. Therefore, this article suggests, viroporins - the miniature versions of eukaryotic protein homologs from viruses - might serve as model systems to provide insights into behaviour of eukaryotic ion channels in general. The structural requirements for correct assembly of the channel along with the basic functional properties of a K+ channel exist in the minimal design of the viral K+ channels from two viruses, Chlorella virus (Kcv) and Ectocarpus siliculosus virus (Kesv). These small viral proteins readily assemble into tetramers and they sort in cells to distinct target membranes. When these viruses-encoded channels are expressed into the mammalian cells, they utilise their protein machinery and hence can serve as excellent tools to study the cells protein sorting machinery. This combination of small size and robust function makes viral K+ channels a valuable model system for detection of basic structure-function correlations. It is believed that molecular and physiochemical analyses of these viroporins may serve as basis for the development of inhibitors or modulators to ion channel activity for targeting ion channel diseases - so called channelopathies. Therefore, it may provide a potential different scope for molecular pharmacology studies aiming at novel and innovative therapeutics associated with channel related diseases. This article reviews the structural and functional properties of Kcv and Kesv upon expression in mammalian cells and Xenopus oocytes. The mechanisms behind differential protein sorting in Kcv and Kesv are also thoroughly discussed.
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Affiliation(s)
- Purva Asrani
- Biomolecular Spectroscopy and RUBiospec|NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster D-48149, Germany
| | - Raphael Stoll
- Biomolecular Spectroscopy and RUBiospec|NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany.
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9
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Weerawardhana A, Uddin MB, Choi JH, Pathinayake P, Shin SH, Chathuranga K, Park JH, Lee JS. Foot-and-mouth disease virus non-structural protein 2B downregulates the RLR signaling pathway via degradation of RIG-I and MDA5. Front Immunol 2022; 13:1020262. [PMID: 36248821 PMCID: PMC9556895 DOI: 10.3389/fimmu.2022.1020262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) is a single-stranded, positive-sense RNA virus containing at least 13 proteins. Many of these proteins show immune modulation capabilities. As a non-structural protein of the FMDV, 2B is involved in the rearrangement of the host cell membranes and the disruption of the host secretory pathway as a viroporin. Previous studies have also shown that FMDV 2B plays a role in the modulation of host type-I interferon (IFN) responses through the inhibition of expression of RIG-I and MDA5, key cytosolic sensors of the type-I IFN signaling. However, the exact molecular mechanism is poorly understood. Here, we demonstrated that FMDV 2B modulates host IFN signal pathway by the degradation of RIG-I and MDA5. FMDV 2B targeted the RIG-I for ubiquitination and proteasomal degradation by recruiting E3 ubiquitin ligase ring finger protein 125 (RNF125) and also targeted MDA5 for apoptosis-induced caspase-3- and caspase-8-dependent degradation. Ultimately, FMDV 2B significantly inhibited RNA virus-induced IFN-β production. Importantly, we identified that the C-terminal amino acids 126-154 of FMDV 2B are essential for 2B-mediated degradation of the RIG-I and MDA5. Collectively, these results provide a clearer understanding of the specific molecular mechanisms used by FMDV 2B to inhibit the IFN responses and a rational approach to virus attenuation for future vaccine development.
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Affiliation(s)
- Asela Weerawardhana
- College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea
| | - Md Bashir Uddin
- College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medicine, Sylhet Agricultural University, Sylhet, Bangladesh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Joo-Hyung Choi
- Foot and Mouth Disease Division, Animal Quarantine and Inspection Agency, Anyang, South Korea
- Wildlife Disease Response Team, National Institute of Wildlife Disease Control and Prevention (NIWDC), Gwangju, South Korea
| | - Prabuddha Pathinayake
- College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea
- Immune Health Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Sung Ho Shin
- Foot and Mouth Disease Division, Animal Quarantine and Inspection Agency, Anyang, South Korea
| | - Kiramage Chathuranga
- College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea
| | - Jong-Hyeon Park
- Foot and Mouth Disease Division, Animal Quarantine and Inspection Agency, Anyang, South Korea
- *Correspondence: Jong-Hyeon Park, ; Jong-Soo Lee,
| | - Jong-Soo Lee
- College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea
- *Correspondence: Jong-Hyeon Park, ; Jong-Soo Lee,
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10
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Vollmers S, Lobermeyer A, Niehrs A, Fittje P, Indenbirken D, Nakel J, Virdi S, Brias S, Trenkner T, Sauer G, Peine S, Behrens GM, Lehmann C, Meurer A, Pauli R, Postel N, Roider J, Scholten S, Spinner CD, Stephan C, Wolf E, Wyen C, Richert L, Norman PJ, Sauter J, Schmidt AH, Hoelzemer A, Altfeld M, Körner C. Host KIR/HLA-C Genotypes Determine HIV-Mediated Changes of the NK Cell Repertoire and Are Associated With Vpu Sequence Variations Impacting Downmodulation of HLA-C. Front Immunol 2022; 13:922252. [PMID: 35911762 PMCID: PMC9334850 DOI: 10.3389/fimmu.2022.922252] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 06/13/2022] [Indexed: 12/29/2022] Open
Abstract
NK cells play a pivotal role in viral immunity, utilizing a large array of activating and inhibitory receptors to identify and eliminate virus-infected cells. Killer-cell immunoglobulin-like receptors (KIRs) represent a highly polymorphic receptor family, regulating NK cell activity and determining the ability to recognize target cells. Human leukocyte antigen (HLA) class I molecules serve as the primary ligand for KIRs. Herein, HLA-C stands out as being the dominant ligand for the majority of KIRs. Accumulating evidence indicated that interactions between HLA-C and its inhibitory KIR2DL receptors (KIR2DL1/L2/L3) can drive HIV-1-mediated immune evasion and thus may contribute to the intrinsic control of HIV-1 infection. Of particular interest in this context is the recent observation that HIV-1 is able to adapt to host HLA-C genotypes through Vpu-mediated downmodulation of HLA-C. However, our understanding of the complex interplay between KIR/HLA immunogenetics, NK cell-mediated immune pressure and HIV-1 immune escape is still limited. Therefore, we investigated the impact of specific KIR/HLA-C combinations on the NK cell receptor repertoire and HIV-1 Vpu protein sequence variations of 122 viremic, untreated HIV-1+ individuals. Compared to 60 HIV-1- controls, HIV-1 infection was associated with significant changes within the NK cell receptor repertoire, including reduced percentages of NK cells expressing NKG2A, CD8, and KIR2DS4. In contrast, the NKG2C+ and KIR3DL2+ NK cell sub-populations from HIV-1+ individuals was enlarged compared to HIV-1- controls. Stratification along KIR/HLA-C genotypes revealed a genotype-dependent expansion of KIR2DL1+ NK cells that was ultimately associated with increased binding affinities between KIR2DL1 and HLA-C allotypes. Lastly, our data hinted to a preferential selection of Vpu sequence variants that were associated with HLA-C downmodulation in individuals with high KIR2DL/HLA-C binding affinities. Altogether, our study provides evidence that HIV-1-associated changes in the KIR repertoire of NK cells are to some extent predetermined by host KIR2DL/HLA-C genotypes. Furthermore, analysis of Vpu sequence polymorphisms indicates that differential KIR2DL/HLA-C binding affinities may serve as an additional mechanism how host genetics impact immune evasion by HIV-1.
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Affiliation(s)
| | | | | | - Pia Fittje
- Leibniz Institute of Virology, Hamburg, Germany
| | | | | | | | - Sebastien Brias
- Leibniz Institute of Virology, Hamburg, Germany
- First Department of Medicine, Division of Infectious Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Gabriel Sauer
- Department I for Internal Medicine, University Hospital of Cologne, Cologne, Germany
| | - Sven Peine
- Institute for Transfusion Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Georg M.N. Behrens
- Department for Rheumatology and Clinical Immunology, Hannover Medical School, Hannover, Germany
| | - Clara Lehmann
- Department I for Internal Medicine, Division of Infectious Diseases, University Hospital Cologne, Cologne, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Anja Meurer
- Center for Internal Medicine and Infectiology, Munich, Germany
| | - Ramona Pauli
- Medizinisches Versorgungszentrum (MVZ) am Isartor, Munich, Germany
| | - Nils Postel
- Prinzmed, Practice for Infectious Diseases, Munich, Germany
| | - Julia Roider
- Department of Internal Medicine IV, Department of Infectious Diseases, Ludwig-Maximilians University Munich, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | | | - Christoph D. Spinner
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
- Technical University of Munich, School of Medicine, University Hospital rechts der Isar, Department of Internal Medicine II, Munich, Germany
| | - Christoph Stephan
- Infectious Diseases Unit, Goethe-University Hospital Frankfurt, Frankfurt, Germany
| | | | - Christoph Wyen
- Department I for Internal Medicine, Division of Infectious Diseases, University Hospital Cologne, Cologne, Germany
- Praxis am Ebertplatz, Cologne, Germany
| | - Laura Richert
- University of Bordeaux, Inserm U1219 Bordeaux Population Health, Inria Sistm, Bordeaux, France
| | - Paul J. Norman
- Division of Biomedical Informatics and Personalized Medicine, University of Colorado, Aurora, CO, United States
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States
| | | | | | - Angelique Hoelzemer
- Leibniz Institute of Virology, Hamburg, Germany
- First Department of Medicine, Division of Infectious Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Marcus Altfeld
- Leibniz Institute of Virology, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Christian Körner
- Leibniz Institute of Virology, Hamburg, Germany
- *Correspondence: Christian Körner,
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11
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Sund JD, Bollerup S, Glamann JB, Vinten CA, Jensen LR, Toft-Bethelsen TL, Bentzen BH, Kledal TN, Weis N, Rosenkilde M. [The antiviral targeting potential of viroporins]. Ugeskr Laeger 2022; 184:V02220103. [PMID: 35703076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Viroporins are ion channels found in many viruses, where they contribute to virus life cycle and thereby pathogenesis. Viroporin targeting is a known, yet largely unexplored, therapeutic strategy so far only used in Influenza A with the drugs amantadine and rimantadine. In this review, we seek to utilize the inhibition by amantadine of the viroporin Protein E in SARS-CoV-2 in an attempt to treat COVID-19 in its early stages. We are executing a double-blinded placebo-controlled trial based on promising in vivo and in vitro work as a stepping-stone for establishing a therapeutic antiviral regime: blocking of viroporins.
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Affiliation(s)
- John D Sund
- Infektionsmedicinsk Afdeling, Københavns Universitetshospital - Hvidovre Hospital
- Biomedicinsk Institut, Det Sundhedsvidenskabelige Fakultet, Københavns Universitet
| | - Signe Bollerup
- Infektionsmedicinsk Afdeling, Københavns Universitetshospital - Hvidovre Hospital
| | - Jekob B Glamann
- Infektionsmedicinsk Afdeling, Københavns Universitetshospital - Hvidovre Hospital
| | - Caroline An Vinten
- Infektionsmedicinsk Afdeling, Københavns Universitetshospital - Hvidovre Hospital
| | - Louise R Jensen
- Infektionsmedicinsk Afdeling, Københavns Universitetshospital - Hvidovre Hospital
| | - Trine L Toft-Bethelsen
- Institut for Neurovidenskab, Det Sundhedsvidenskabelige Fakultet, Københavns Universitet
| | - Bo H Bentzen
- Biomedicinsk Institut, Det Sundhedsvidenskabelige Fakultet, Københavns Universitet
| | | | - Nina Weis
- Infektionsmedicinsk Afdeling, Københavns Universitetshospital - Hvidovre Hospital
- Institut for Klinisk Medicin, Det Sundhedsvidenskabelige Fakultet, Københavns Universitet
| | - Mette Rosenkilde
- Biomedicinsk Institut, Det Sundhedsvidenskabelige Fakultet, Københavns Universitet
- Synklino
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12
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Bignon E, Marazzi M, Monari A. Hijacking of Cellular Functions by Severe Acute Respiratory Syndrome Coronavirus-2. Permeabilization and Polarization of the Host Lipid Membrane by Viroporins. J Phys Chem Lett 2022; 13:4642-4649. [PMID: 35593652 PMCID: PMC9159072 DOI: 10.1021/acs.jpclett.2c01102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Like all viral infections, SARS-CoV-2 acts at multiple levels, hijacking fundamental cellular functions and assuring its replication and immune system evasion. In particular, the viral 3' Open Reading Frame (ORF3a) codes for a hydrophobic protein, which embeds in the cellular membrane, where it acts as an ion viroporin and is related to strong inflammatory response. Here we report equilibrium and enhanced sampling molecular dynamic simulation of the SARS-CoV-2 ORF3a in a model lipid bilayer, showing how the protein permeabilizes the lipid membrane, via the formation of a water channel, which in turn assures ion transport. We report the free energy profile for both K+ and Cl- transfer from the cytosol to the extracellular domain. The important role of ORF3a in the viral cycle and its high conservation among coronaviruses may also make it a target of choice for future antiviral development, further justifying the elucidation of its mechanism at the atomistic level.
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Affiliation(s)
- Emmanuelle Bignon
- Université
de Lorraine and CNRS, UMR 7019 LPCT, F-54000 Nancy, France
| | - Marco Marazzi
- Departamento
de Química Analítica, Química Física e
Ingeniería Química, Grupo de Reactividad y Estructura
Molecular (RESMOL), Universidad de Alcalá, 28806 Alcalá
de Henares, Madrid, Spain
- Instituto
de Investigación Química ‘‘Andrés
M. del Río’’ (IQAR), Universidad de Alcalá, 28806 Alcalá de Henares, Madrid, Spain
| | - Antonio Monari
- Université
Paris Cité and CNRS, ITODYS, F-75006 Paris, France
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13
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Sun Y, Gong L, Yin Y, Zhang L, Sun Q, Feng K, Cui Y, Zhang Q, Zhang X, Deng X, You F, Lu D, Lin Z. A Gradient pH-Sensitive Polymer-Based Antiviral Strategy via Viroporin-Induced Membrane Acidification. Adv Mater 2022; 34:e2109580. [PMID: 35229371 DOI: 10.1002/adma.202109580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/19/2022] [Indexed: 06/14/2023]
Abstract
Lipid-membrane-targeting strategies hold great promise to develop broad-spectrum antivirals. However, it remains a big challenge to identify novel membrane-based targets of viruses and virus-infected cells for development of precision targeted approaches. Here, it is discovered that viroporins, viral-encoded ion channels, which have been reported to mediate release of hydrogen ions, trigger membrane acidification of virus-infected cells. Through development of a fine-scale library of gradient pH-sensitive (GPS) polymeric nanoprobes, the cellular membrane pH transitions are measured from pH 6.8-7.1 (uninfection) to pH 6.5-6.8 (virus-infection). In response to the subtle pH alterations, the GPS polymer with sharp response at pH 6.8 (GPS6.8 ) selectively binds to virus-infected cell membranes or the viral envelope, and even completely disrupts the viral envelope. Accordingly, GPS6.8 treatment exerts suppressive effects on a wide variety of viruses including SARS-CoV-2 through triggering viral-envelope lysis rather than affecting immune pathway or viability of host cells. Murine viral-infection models exhibit that supplementation of GPS6.8 decreases viral titers and ameliorates inflammatory damage. Thus, the gradient pH-sensitive nanotechnology offers a promising strategy for accurate detection of biological pH environments and robust interference with viruses.
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Affiliation(s)
- Yizhe Sun
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Lidong Gong
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Yue Yin
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Lei Zhang
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Qiangming Sun
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, 65018, P. R. China
| | - Kai Feng
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, 65018, P. R. China
| | - Yimin Cui
- Department of Pharmacy Administration and Clinical Pharmacy, Department of Pharmaceutics, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Qiang Zhang
- Department of Pharmacy Administration and Clinical Pharmacy, Department of Pharmaceutics, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Xuehui Zhang
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Peking University School and Hospital of Stomatology, Beijing, 100081, P. R. China
| | - Xuliang Deng
- National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Peking University School and Hospital of Stomatology, Beijing, 100081, P. R. China
| | - Fuping You
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Dan Lu
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Zhiqiang Lin
- Institute of Systems Biomedicine, Department of Pathology, Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
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14
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Peñaflor-Téllez Y, Chávez-Munguía B, Lagunes-Guillén A, Salazar-Villatoro L, Gutiérrez-Escolano AL. The Feline Calicivirus Leader of the Capsid Protein Has the Functional Characteristics of a Viroporin. Viruses 2022; 14:v14030635. [PMID: 35337042 PMCID: PMC8955107 DOI: 10.3390/v14030635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
The leader of the capsid (LC) protein is exclusive to the Vesivirus genus, and it is needed for successful feline calicivirus (FCV) replication, as well as an efficient apoptosis induction through the mitochondrial pathway. In this work, we aimed to determine if the LC protein from the FCV is a viroporin. Although lacking in a transmembrane domain or an amphipathic helix, the LC protein from the FCV is toxic when expressed in bacteria and it oligomerizes through disulfide bonds, which are both key characteristics of viroporins. An electron microscopy analysis of LC-expressing E. coli cells suggest that the protein induces osmotic stress. Moreover, we found that the previously studied C40A LC mutant, that fails to induce apoptosis and that hinders the replication cycle, also oligomerizes but it has a reduced toxicity and fails to induce osmotic stress in bacteria. We propose that the LC protein is a viroporin that acts as a disulfide bond-dependent antimicrobial peptide, similar to the Ebola virus delta peptide.
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15
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Cavezzi A, Menicagli R, Troiani E, Corrao S. COVID-19, Cation Dysmetabolism, Sialic Acid, CD147, ACE2, Viroporins, Hepcidin and Ferroptosis: A Possible Unifying Hypothesis. F1000Res 2022; 11:102. [PMID: 35340277 PMCID: PMC8921693 DOI: 10.12688/f1000research.108667.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/17/2022] [Indexed: 12/15/2022] Open
Abstract
Background: iron and calcium dysmetabolism, with hyperferritinemia, hypoferremia, hypocalcemia and anemia have been documented in the majority of COVID-19 patients at later/worse stages. Furthermore, complementary to ACE2, both sialic acid (SA) molecules and CD147 proved relevant host receptors for SARS-CoV-2 entry, which explains the viral attack to multiple types of cells, including erythrocytes, endothelium and neural tissue. Several authors advocated that cell ferroptosis may be the core and final cell degenerative mechanism. Methods: a literature research was performed in several scientific search engines, such as PubMed Central, Cochrane Library, Chemical Abstract Service. More than 500 articles were retrieved until mid-December 2021, to highlight the available evidence about the investigated issues. Results: based on COVID-19 literature data, we have highlighted a few pathophysiological mechanisms, associated with virus-based cation dysmetabolism, multi-organ attack, mitochondria degeneration and ferroptosis. Our suggested elucidated pathological sequence is: a) spike protein subunit S1 docking with sialylated membrane glycoproteins/receptors (ACE2, CD147), and S2 subunit fusion with the lipid layer; b) cell membrane morpho-functional changes due to the consequent electro-chemical variations and viroporin action, which induce an altered ion channel function and intracellular cation accumulation; c) additional intracellular iron concentration due to a deregulated hepcidin-ferroportin axis, with higher hepcidin levels. Viral invasion may also affect erythrocytes/erythroid precursors, endothelial cells and macrophages, through SA and CD147 receptors, with relative hemoglobin and iron/calcium dysmetabolism. AB0 blood group, hemochromatosis, or environmental elements may represent possible factors which affect individual susceptibility to COVID-19. Conclusions: our literature analysis confirms the combined role of SA molecules, ACE2, CD147, viroporins and hepcidin in determining the cation dysmetabolism and final ferroptosis in the cells infected by SARS-CoV-2. The altered ion channels and electrochemical gradients of the cell membrane have a pivotal role in the virus entry and cell dysmetabolism, with subsequent multi-organ immune-inflammatory degeneration and erythrocyte/hemoglobin alterations.
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Affiliation(s)
- Attilio Cavezzi
- Eurocenter Venalinfa, San Benedetto del Tronto, AP, 63074, Italy
| | | | - Emidio Troiani
- Cardiology Unit, Social Security Institute, State Hospital, Cailungo, 47893, San Marino
| | - Salvatore Corrao
- Department of Clinical Medicine, Internal Medicine Division,, ARNAS Civico Di Cristina Benfratelli Hospital Trust, Palermo, Italy
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16
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Shin J, Jin YS, Park YC, Park JB, Lee YO, Kim SK, Kweon DH. Enhancing acid tolerance of Escherichia coli via viroporin-mediated export of protons and its application for efficient whole-cell biotransformation. Metab Eng 2021; 67:277-284. [PMID: 34280569 DOI: 10.1016/j.ymben.2021.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/09/2021] [Accepted: 07/14/2021] [Indexed: 11/15/2022]
Abstract
Escherichia coli-based whole-cell biocatalysts are widely used for the sustainable production of value-added chemicals. However, weak acids present as substrates and/or products obstruct the growth and fermentation capability of E. coli. Here, we show that a viroporin consisting of the influenza A matrix-2 (M2) protein, is activated by low pH and has proton channel activity in E. coli. The heterologous expression of the M2 protein in E. coli resulted in a significant increase in the intracellular pH and cell viability in the presence of various weak acids with different lengths of carbon chains. In addition, the feasibility of developing a robust and efficient E. coli-based whole-cell biocatalyst via introduction of the proton-selective viroporin was explored by employing (Z)-11-(heptanolyoxy)undec-9-enoic acid (ester) and 2-fucosyllactose (2'-FL) as model products, whose production is hampered by cytosolic acidification. The engineered E. coli strains containing the proton-selective viroporin exhibited approximately 80% and 230% higher concentrations of the ester and 2'-FL, respectively, than the control strains without the M2 protein. The simple and powerful strategy developed in this study can be applied to produce other valuable chemicals whose production involves substrates and/or products that cause cytosolic acidification.
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Affiliation(s)
- Jonghyeok Shin
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, Gyeonggi, 16419, Republic of Korea; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yong-Cheol Park
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, 02707, Republic of Korea
| | - Jin-Byung Park
- Department of Food Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Young-Oh Lee
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi, 17546, Republic of Korea
| | - Sun-Ki Kim
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi, 17546, Republic of Korea.
| | - Dae-Hyuk Kweon
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, Gyeonggi, 16419, Republic of Korea.
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17
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Yu S, Nimse SB, Kim J, Song KS, Kim T. Development of a Lateral Flow Strip Membrane Assay for Rapid and Sensitive Detection of the SARS-CoV-2. Anal Chem 2020; 92:14139-14144. [PMID: 32967427 PMCID: PMC7539551 DOI: 10.1021/acs.analchem.0c03202] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/23/2020] [Indexed: 01/12/2023]
Abstract
The infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has threatened public health worldwide. The easy human-to-human transmission of this virus has rapidly evolved into a global pandemic. Therefore, to control the community spread of the virus, it is crucial to identify the infected individuals, including asymptomatic people. Hence, a specific and rapid assay is crucial for the early diagnosis and active monitoring of individuals potentially exposed to SARS-CoV-2 for controlling the COVID-19 outbreak. In this study, we have developed the novel lateral flow strip membrane (LFSM) assay that allows the simultaneous detection of RdRp, ORF3a, and N genes using the PCR product obtained by using the single-tube reverse transcription polymerase chain reaction (RT-PCR). The LFSM assay allows detection of SARS-CoV-2 in 30 min at 25 °C after the RT-PCR with the detection limit of 10 copies/test for each gene. The clinical performance of the LFSM assay for the detection of SARS-Cov-2 was evaluated using 162 clinical samples previously detected by using the commercial assay. The percent positive agreement, percent negative agreement, and overall percent agreement of the LFSM assay with the commercial assay were 100% (94.2-100%), 99.0% (94.6-100%), and 99.4% (96.6-100%), respectively. Therefore, the results of the LFSM assay showed significantly high concordance with the commercial assay for the detection of SARS-CoV-2 in clinical specimens. Therefore, we conclude that the developed LFSM assay can be used alone or complementary to the RT-PCR or other methods for the diagnosis and monitoring of the patients to curb community transmission and the pandemic.
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Affiliation(s)
- Sangheon Yu
- Biometrix Technology, Inc.,
2-2 Bio Venture Plaza 56, Chuncheon 24232, Korea
| | - Satish Balasaheb Nimse
- Institute of Applied Chemistry and Department of
Chemistry, Hallym University, Chuncheon 24252,
Korea
| | - Junghoon Kim
- Institute of Applied Chemistry and Department of
Chemistry, Hallym University, Chuncheon 24252,
Korea
| | - Keum-Soo Song
- Biometrix Technology, Inc.,
2-2 Bio Venture Plaza 56, Chuncheon 24232, Korea
| | - Taisun Kim
- Institute of Applied Chemistry and Department of
Chemistry, Hallym University, Chuncheon 24252,
Korea
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18
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Abstract
Identification of the full complement of genes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a crucial step towards gaining a fuller understanding of its molecular biology. However, short and/or overlapping genes can be difficult to detect using conventional computational approaches, whereas high-throughput experimental approaches - such as ribosome profiling - cannot distinguish translation of functional peptides from regulatory translation or translational noise. By studying regions showing enhanced conservation at synonymous sites in alignments of SARS-CoV-2 and related viruses (subgenus Sarbecovirus) and correlating the results with the conserved presence of an open reading frame (ORF) and a plausible translation mechanism, a putative new gene - ORF3c - was identified. ORF3c overlaps ORF3a in an alternative reading frame. A recently published ribosome profiling study confirmed that ORF3c is indeed translated during infection. ORF3c is conserved across the subgenus Sarbecovirus, and encodes a 40-41 amino acid predicted transmembrane protein.
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Affiliation(s)
- Andrew E. Firth
- Division of Virology, Department of Pathology, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
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19
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Batra N, De Souza C, Batra J, Raetz AG, Yu AM. The HMOX1 Pathway as a Promising Target for the Treatment and Prevention of SARS-CoV-2 of 2019 (COVID-19). Int J Mol Sci 2020; 21:E6412. [PMID: 32899231 PMCID: PMC7503392 DOI: 10.3390/ijms21176412] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 08/26/2020] [Accepted: 09/01/2020] [Indexed: 02/07/2023] Open
Abstract
The coronavirus disease of 2019 (COVID-19) or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a global pandemic with increasing incidence and mortality rates. Recent evidence based on the cytokine profiles of severe COVID-19 cases suggests an overstimulation of macrophages and monocytes associated with reduced T-cell abundance (lymphopenia) in patients infected with SARS-CoV-2. The SARS-CoV-2 open reading frame 3 a (ORF3a) protein was found to bind to the human HMOX1 protein at a high confidence through high-throughput screening experiments. The HMOX1 pathway can inhibit platelet aggregation, and can have anti-thrombotic and anti-inflammatory properties, amongst others, all of which are critical medical conditions observed in COVID-19 patients. Here, we review the potential of modulating the HMOX1-ORF3a nexus to regulate the innate immune response for therapeutic benefits in COVID-19 patients. We also review other potential treatment strategies and suggest novel synthetic and natural compounds that may have the potential for future development in clinic.
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Affiliation(s)
- Neelu Batra
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA; (N.B.); (C.D.S.); (A.G.R.)
| | - Cristabelle De Souza
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA; (N.B.); (C.D.S.); (A.G.R.)
- Department of Internal Medicine, University of New Mexico Cancer Center, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Jyoti Batra
- Gladstone Institute, San Francisco, CA 94158, USA;
| | - Alan G. Raetz
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA; (N.B.); (C.D.S.); (A.G.R.)
| | - Ai-Ming Yu
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA; (N.B.); (C.D.S.); (A.G.R.)
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20
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Hassan SS, Choudhury PP, Basu P, Jana SS. Molecular conservation and differential mutation on ORF3a gene in Indian SARS-CoV2 genomes. Genomics 2020; 112:3226-3237. [PMID: 32540495 PMCID: PMC7291963 DOI: 10.1016/j.ygeno.2020.06.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/06/2020] [Accepted: 06/08/2020] [Indexed: 01/28/2023]
Abstract
A global emergency due to the COVID-19 pandemic demands various studies related to genes and genomes of the SARS-CoV2. Among other important proteins, the role of accessory proteins are of immense importance in replication, regulation of infections of the coronavirus in the hosts. The largest accessory protein in the SARS-CoV2 genome is ORF3a which modulates the host response to the virus infection and consequently it plays an important role in pathogenesis. In this study, an attempt is made to decipher the conservation of nucleotides, dimers, codons and amino acids in the ORF3a genes across thirty-two genomes of Indian patients. ORF3a gene possesses single and double point mutations in Indian SARS-CoV2 genomes suggesting the change of SARS-CoV2's virulence property in Indian patients. We find that the parental origin of the ORF3a gene over the genomes of SARS-CoV2 and Pangolin-CoV is same from the phylogenetic analysis based on conservation of nucleotides and so on. This study highlights the accumulation of mutation on ORF3a in Indian SARS-CoV2 genomes which may provide the designing therapeutic approach against SARS-CoV2.
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Affiliation(s)
- Sk Sarif Hassan
- Department of Mathematics, Pingla Thana Mahavidyalaya, Maligram 721140, India.
| | - Pabitra Pal Choudhury
- Applied Statistics Unit, Indian Statistical Institute, Kolkata 700108, West Bengal, India.
| | - Pallab Basu
- Mandelstem Institute, School of Physics, University of the Witwatersrand, Johannesburg, South Africa.
| | - Siddhartha Sankar Jana
- School of Biological Sciences, Indian Association for the Cultivation of Science, West Bengal 700032, India.
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21
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Alam I, Kamau AA, Kulmanov M, Jaremko Ł, Arold ST, Pain A, Gojobori T, Duarte CM. Functional Pangenome Analysis Shows Key Features of E Protein Are Preserved in SARS and SARS-CoV-2. Front Cell Infect Microbiol 2020; 10:405. [PMID: 32850499 PMCID: PMC7396417 DOI: 10.3389/fcimb.2020.00405] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 06/30/2020] [Indexed: 11/13/2022] Open
Abstract
The spread of the novel coronavirus (SARS-CoV-2) has triggered a global emergency, that demands urgent solutions for detection and therapy to prevent escalating health, social, and economic impacts. The spike protein (S) of this virus enables binding to the human receptor ACE2, and hence presents a prime target for vaccines preventing viral entry into host cells. The S proteins from SARS and SARS-CoV-2 are similar, but structural differences in the receptor binding domain (RBD) preclude the use of SARS-specific neutralizing antibodies to inhibit SARS-CoV-2. Here we used comparative pangenomic analysis of all sequenced reference Betacoronaviruses, complemented with functional and structural analyses. This analysis reveals that, among all core gene clusters present in these viruses, the envelope protein E shows a variant cluster shared by SARS and SARS-CoV-2 with two completely-conserved key functional features, namely an ion-channel, and a PDZ-binding motif (PBM). These features play a key role in the activation of the inflammasome causing the acute respiratory distress syndrome, the leading cause of death in SARS and SARS-CoV-2 infections. Together with functional pangenomic analysis, mutation tracking, and previous evidence, on E protein as a determinant of pathogenicity in SARS, we suggest E protein as an alternative therapeutic target to be considered for further studies to reduce complications of SARS-CoV-2 infections in COVID-19.
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Affiliation(s)
- Intikhab Alam
- Biological and Environmental Science and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Allan A. Kamau
- Biological and Environmental Science and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Maxat Kulmanov
- Biological and Environmental Science and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Łukasz Jaremko
- Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Stefan T. Arold
- Biological and Environmental Science and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Arnab Pain
- Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Takashi Gojobori
- Biological and Environmental Science and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Carlos M. Duarte
- Biological and Environmental Science and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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22
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Abstract
The devastating effects of the recent global pandemic (termed COVID-19 for "coronavirus disease 2019") caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) are paramount with new cases and deaths growing at an exponential rate. In order to provide a better understanding of SARS CoV-2, this article will review the proteins found in the SARS CoV-2 that caused this global pandemic.
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Affiliation(s)
- Francis K Yoshimoto
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, TX, 78249-0698, USA.
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23
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Abstract
The SARS-CoV-2 virus has spread around the world. At this time, there is no vaccine that can help people prevent the spread of coronavirus. We are proposing amantadine as a drug that can be used to mitigate the effects of the virus. It is demonstrated by docking models how amantadine can exert its action on Coronavirus viroporin E.
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Affiliation(s)
- Gonzalo Emiliano Aranda Abreu
- Centro de Investigaciones Cerebrales/Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, carr. Xalapa-Veracruz, km 3.5, C.P. 91190 Xalapa, Veracruz, Mexico
| | - María Elena Hernández Aguilar
- Centro de Investigaciones Cerebrales/Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, carr. Xalapa-Veracruz, km 3.5, C.P. 91190 Xalapa, Veracruz, Mexico
| | - Deissy Herrera Covarrubias
- Centro de Investigaciones Cerebrales/Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, carr. Xalapa-Veracruz, km 3.5, C.P. 91190 Xalapa, Veracruz, Mexico
| | - Fausto Rojas Durán
- Centro de Investigaciones Cerebrales/Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, carr. Xalapa-Veracruz, km 3.5, C.P. 91190 Xalapa, Veracruz, Mexico
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24
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Tomar PPS, Oren R, Krugliak M, Arkin IT. Potential Viroporin Candidates From Pathogenic Viruses Using Bacteria-Based Bioassays. Viruses 2019; 11:v11070632. [PMID: 31324045 PMCID: PMC6669592 DOI: 10.3390/v11070632] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/23/2019] [Accepted: 07/05/2019] [Indexed: 12/13/2022] Open
Abstract
Viroporins are a family of small hydrophobic proteins found in many enveloped viruses that are capable of ion transport. Building upon the ability to inhibit influenza by blocking its archetypical M2 H+ channel, as a family, viroporins may represent a viable target to curb viral infectivity. To this end, using three bacterial assays we analyzed six small hydrophobic proteins from biomedically important viruses as potential viroporin candidates. Our results indicate that Eastern equine encephalitis virus 6k, West Nile virus MgM, Dengue virus 2k, Dengue virus P1, Variola virus gp170, and Variola virus gp151 proteins all exhibit channel activity in the bacterial assays, and as such may be considered viroporin candidates. It is clear that more studies, such as patch clamping, will be needed to characterize the ionic conductivities of these proteins. However, our approach presents a rapid procedure to analyze open reading frames in other viruses, yielding new viroporin candidates for future detailed investigation. Finally, if conductivity is proven vital to their cognate viruses, the bio-assays presented herein afford a simple approach to screen for new channel blockers.
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Affiliation(s)
- Prabhat Pratap Singh Tomar
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, Jerusalem 91904, Israel
| | - Rivka Oren
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, Jerusalem 91904, Israel
| | - Miriam Krugliak
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, Jerusalem 91904, Israel
| | - Isaiah T Arkin
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, Jerusalem 91904, Israel.
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25
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Li Z, Zou Z, Jiang Z, Huang X, Liu Q. Biological Function and Application of Picornaviral 2B Protein: A New Target for Antiviral Drug Development. Viruses 2019; 11:v11060510. [PMID: 31167361 PMCID: PMC6630369 DOI: 10.3390/v11060510] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 05/31/2019] [Accepted: 06/02/2019] [Indexed: 12/22/2022] Open
Abstract
Picornaviruses are associated with acute and chronic diseases. The clinical manifestations of infections are often mild, but infections may also lead to respiratory symptoms, gastroenteritis, myocarditis, meningitis, hepatitis, and poliomyelitis, with serious impacts on human health and economic losses in animal husbandry. Thus far, research on picornaviruses has mainly focused on structural proteins such as VP1, whereas the non-structural protein 2B, which plays vital roles in the life cycle of the viruses and exhibits a viroporin or viroporin-like activity, has been overlooked. Viroporins are viral proteins containing at least one amphipathic α-helical structure, which oligomerizes to form transmembrane hydrophilic pores. In this review, we mainly summarize recent research data on the viroporin or viroporin-like activity of 2B proteins, which affects the biological function of the membrane, regulates cell death, and affects the host immune response. Considering these mechanisms, the potential application of the 2B protein as a candidate target for antiviral drug development is discussed, along with research challenges and prospects toward realizing a novel treatment strategy for picornavirus infections.
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Affiliation(s)
- Zengbin Li
- School of Public Health, Nanchang University, Nanchang 330006, China.
| | - Zixiao Zou
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang 330006, China.
| | - Zeju Jiang
- Jiangxi Medical College, Nanchang University, Nanchang 330006, China.
| | - Xiaotian Huang
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang 330006, China.
| | - Qiong Liu
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang 330006, China.
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26
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Nieto-Torres JL, Verdiá-Báguena C, Jimenez-Guardeño JM, Regla-Nava JA, Castaño-Rodriguez C, Fernandez-Delgado R, Torres J, Aguilella VM, Enjuanes L. Severe acute respiratory syndrome coronavirus E protein transports calcium ions and activates the NLRP3 inflammasome. Virology 2015; 485:330-9. [PMID: 26331680 PMCID: PMC4619128 DOI: 10.1016/j.virol.2015.08.010] [Citation(s) in RCA: 360] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/30/2015] [Accepted: 08/12/2015] [Indexed: 11/18/2022]
Abstract
Severe acute respiratory syndrome coronavirus (SARS-CoV) envelope (E) protein is a viroporin involved in virulence. E protein ion channel (IC) activity is specifically correlated with enhanced pulmonary damage, edema accumulation and death. IL-1β driven proinflammation is associated with those pathological signatures, however its link to IC activity remains unknown. In this report, we demonstrate that SARS-CoV E protein forms protein–lipid channels in ERGIC/Golgi membranes that are permeable to calcium ions, a highly relevant feature never reported before. Calcium ions together with pH modulated E protein pore charge and selectivity. Interestingly, E protein IC activity boosted the activation of the NLRP3 inflammasome, leading to IL-1β overproduction. Calcium transport through the E protein IC was the main trigger of this process. These findings strikingly link SARS-CoV E protein IC induced ionic disturbances at the cell level to immunopathological consequences and disease worsening in the infected organism. SARS-CoV E protein forms calcium ion channels, a novel highly relevant function. Transport of calcium ions through E protein channel stimulates the inflammasome. Inflammasome derived exacerbated proinflammation causes SARS worsening. E protein ion channel and its driven proinflammation may be targets to treat SARS.
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Affiliation(s)
- Jose L Nieto-Torres
- Department of Molecular and Cell Biology, National Center of Biotechnology (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Carmina Verdiá-Báguena
- Department of Physics, Laboratory of Molecular Biophysics. Universitat Jaume I, 12071 Castellón, Spain
| | - Jose M Jimenez-Guardeño
- Department of Molecular and Cell Biology, National Center of Biotechnology (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Jose A Regla-Nava
- Department of Molecular and Cell Biology, National Center of Biotechnology (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Carlos Castaño-Rodriguez
- Department of Molecular and Cell Biology, National Center of Biotechnology (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Raul Fernandez-Delgado
- Department of Molecular and Cell Biology, National Center of Biotechnology (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Jaume Torres
- School of Biological Sciences, Division of Structural and Computational Biology, Nanyang Technological University, Singapore 637551, Singapore
| | - Vicente M Aguilella
- Department of Physics, Laboratory of Molecular Biophysics. Universitat Jaume I, 12071 Castellón, Spain.
| | - Luis Enjuanes
- Department of Molecular and Cell Biology, National Center of Biotechnology (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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27
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Jimenez-Guardeño JM, Nieto-Torres JL, DeDiego ML, Regla-Nava JA, Fernandez-Delgado R, Castaño-Rodriguez C, Enjuanes L. The PDZ-binding motif of severe acute respiratory syndrome coronavirus envelope protein is a determinant of viral pathogenesis. PLoS Pathog 2014; 10:e1004320. [PMID: 25122212 PMCID: PMC4133396 DOI: 10.1371/journal.ppat.1004320] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/08/2014] [Indexed: 01/24/2023] Open
Abstract
A recombinant severe acute respiratory syndrome coronavirus (SARS-CoV) lacking the envelope (E) protein is attenuated in vivo. Here we report that E protein PDZ-binding motif (PBM), a domain involved in protein-protein interactions, is a major determinant of virulence. Elimination of SARS-CoV E protein PBM by using reverse genetics caused a reduction in the deleterious exacerbation of the immune response triggered during infection with the parental virus and virus attenuation. Cellular protein syntenin was identified to bind the E protein PBM during SARS-CoV infection by using three complementary strategies, yeast two-hybrid, reciprocal coimmunoprecipitation and confocal microscopy assays. Syntenin redistributed from the nucleus to the cell cytoplasm during infection with viruses containing the E protein PBM, activating p38 MAPK and leading to the overexpression of inflammatory cytokines. Silencing of syntenin using siRNAs led to a decrease in p38 MAPK activation in SARS-CoV infected cells, further reinforcing their functional relationship. Active p38 MAPK was reduced in lungs of mice infected with SARS-CoVs lacking E protein PBM as compared with the parental virus, leading to a decreased expression of inflammatory cytokines and to virus attenuation. Interestingly, administration of a p38 MAPK inhibitor led to an increase in mice survival after infection with SARS-CoV, confirming the relevance of this pathway in SARS-CoV virulence. Therefore, the E protein PBM is a virulence domain that activates immunopathology most likely by using syntenin as a mediator of p38 MAPK induced inflammation. SARS-CoV caused a worldwide epidemic infecting 8000 people with a mortality of about 10%. A recombinant SARS-CoV lacking the E protein was attenuated in vivo. The E protein contains a PDZ-binding motif (PBM), a domain potentially involved in the interaction with more than 400 cellular proteins, which highlights its relevance in modulating host-cell behavior. To analyze the contributions of this motif to virulence, recombinant viruses with or without E protein PBM were generated. Recombinant SARS-CoVs lacking E protein PBM caused minimal lung damage and were attenuated, in contrast to viruses containing this motif, indicating that E protein PBM is a virulence determinant. E protein PBM induces the deleterious exacerbated immune response triggered during SARS-CoV infection, and interacts with the cellular protein syntenin, as demonstrated using proteomic analyses. Interestingly, syntenin redistributed from nucleus to cytoplasm during SARS-CoV infection, activating p38 MAPK and triggering the overexpression of inflammatory cytokines. Furthermore, silencing of syntenin using siRNAs led to a decrease in p38 MAPK activation. In addition, administration of a p38 MAPK inhibitor led to an increase in mice survival after SARS-CoV infection. These results indicate that syntenin and p38 MAPK are potential therapeutic targets to reduce the exacerbated immune response during SARS-CoV infection.
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Affiliation(s)
- Jose M. Jimenez-Guardeño
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Jose L. Nieto-Torres
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta L. DeDiego
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Jose A. Regla-Nava
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Raul Fernandez-Delgado
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Carlos Castaño-Rodriguez
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Luis Enjuanes
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
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28
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Minakshi R, Padhan K, Rehman S, Hassan MI, Ahmad F. The SARS Coronavirus 3a protein binds calcium in its cytoplasmic domain. Virus Res 2014; 191:180-3. [PMID: 25116391 PMCID: PMC7114474 DOI: 10.1016/j.virusres.2014.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 01/17/2023]
Abstract
We expressed and purified the cytoplasmic domain of the 3a protein. Cyto3a domain binds calcium. Calcium binding causes a conformational change. 3a protein in vivo to have significant role in viral pathogenesis.
The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) is a positive stranded RNA virus with ∼30 kb genome. Among all open reading frames (orfs) of this virus, the orf3a is the largest, and encodes a protein of 274 amino acids, named as 3a protein. Sequence analysis suggests that the orf3a aligned to one calcium pump present in Plasmodium falciparum and the enzyme glutamine synthetase found in Leptospira interrogans. This sequence similarity was found to be limited only to amino acid residues 209–264 which form the cytoplasmic domain of the orf3a. Furthermore, this region was predicted to be involved in the calcium binding. Owing to this hypothesis, we were driven to establish its calcium binding property in vitro. Here, we expressed and purified the cytoplasmic domain of the 3a protein, called Cyto3a, as a recombinant His-tagged protein in the E. coli. The calcium binding nature was established by performing various staining methods such as ruthenium red and stains-all. 45Ca overlay method was also done to further support the data. Since the 3a protein forms ion channels, we were interested to see any conformational changes occurring in the Cyot3a upon calcium binding, using fluorescence spectroscopy and circular dichroism. These studies clearly indicate a significant change in the conformation of the Cyto3a protein after binding with calcium. Our results strongly suggest that the cytoplasmic domain of the 3a protein of SARS-CoV binds calcium in vitro, causing a change in protein conformation.
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Affiliation(s)
- Rinki Minakshi
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India; Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India.
| | - Kartika Padhan
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Safikur Rehman
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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29
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Schwarz S, Sauter D, Wang K, Zhang R, Sun B, Karioti A, Bilia AR, Efferth T, Schwarz W. Kaempferol derivatives as antiviral drugs against the 3a channel protein of coronavirus. Planta Med 2014; 80:177-82. [PMID: 24458263 PMCID: PMC7171712 DOI: 10.1055/s-0033-1360277] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The protein coded by the open-reading-frame 3a of SARS coronavirus has been demonstrated to form a cation-selective channel that may become expressed in the infected cell. The activity of the channel is involved in the mechanism of virus release. Drugs that inhibit the ion channel can, therefore, inhibit virus release, and they could be a source for development of novel therapeutic antiviral agents. Various drugs found in Chinese herbs that are well known as anticancer agents also have an antiviral potency. Here we tested the flavonols kaempferol, kaempferol glycosides, and acylated kaempferol glucoside derivatives with respect to their potency to block the 3a channel. We used the Xenopus oocyte with a heterologously expressed 3a protein as a model system to test the efficacy of the flavonols. Some of these drugs turned out to be potent inhibitors of the 3a channel. The most effective one was the glycoside juglanin (carrying an arabinose residue) with an IC50 value of 2.3 µM for inhibition of the 3a-mediated current. Kaempferol derivatives with rhamnose residue also seem to be quite effective. We suggest that viral ion channels, in general, may be a good target for the development of antiviral agents, and that, in particular, kaempferol glycosides are good candidates for 3a channel proteins of coronaviruses.
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Affiliation(s)
- Silvia Schwarz
- Shanghai Research Center for Acupuncture & Meridians, Shanghai,
China
| | - Daniel Sauter
- Shanghai Research Center for Acupuncture & Meridians, Shanghai,
China
- Institute for Biophysics, JW-Goethe-University, Frankfurt a. M.,
Germany
| | - Kai Wang
- Key Laboratory of Molecular Virology & Immunology, Institut Pasteur
of Shanghai, Shanghai Chinese Academy of Sciences, Shanghai, China
| | - Ronghua Zhang
- Key Laboratory of Molecular Virology & Immunology, Institut Pasteur
of Shanghai, Shanghai Chinese Academy of Sciences, Shanghai, China
| | - Bing Sun
- Key Laboratory of Molecular Virology & Immunology, Institut Pasteur
of Shanghai, Shanghai Chinese Academy of Sciences, Shanghai, China
| | - Anastasia Karioti
- Department of Chemistry, Building of Pharmaceutical Sciences,
University of Florence, Sesto Fiorentino (FI), Italy
| | - Anna Rita Bilia
- Department of Chemistry, Building of Pharmaceutical Sciences,
University of Florence, Sesto Fiorentino (FI), Italy
| | - Thomas Efferth
- Institute for Pharmacology and Biochemistry, J-Gutenberg University,
Mainz, Germany
| | - Wolfgang Schwarz
- Shanghai Research Center for Acupuncture & Meridians, Shanghai,
China
- Institute for Biophysics, JW-Goethe-University, Frankfurt a. M.,
Germany
- Correspondence Wolfgang Schwarz Institute for Biophysics, JW-Goethe UniversityMax-von-Laue Str. 160438 Frankfurt a. M.Germany+49 69 79 84 64 01
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30
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Nieto-Torres JL, Dediego ML, Alvarez E, Jiménez-Guardeño JM, Regla-Nava JA, Llorente M, Kremer L, Shuo S, Enjuanes L. Subcellular location and topology of severe acute respiratory syndrome coronavirus envelope protein. Virology 2011; 415:69-82. [PMID: 21524776 PMCID: PMC4726981 DOI: 10.1016/j.virol.2011.03.029] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 03/10/2011] [Accepted: 03/31/2011] [Indexed: 11/28/2022]
Abstract
Severe acute respiratory syndrome (SARS) coronavirus (CoV) envelope (E) protein is a transmembrane protein. Several subcellular locations and topological conformations of E protein have been proposed. To identify the correct ones, polyclonal and monoclonal antibodies specific for the amino or the carboxy terminus of E protein, respectively, were generated. E protein was mainly found in the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) of cells transfected with a plasmid encoding E protein or infected with SARS-CoV. No evidence of E protein presence in the plasma membrane was found by using immunofluorescence, immunoelectron microscopy and cell surface protein labeling. In addition, measurement of plasma membrane voltage gated ion channel activity by whole-cell patch clamp suggested that E protein was not present in the plasma membrane. A topological conformation in which SARS-CoV E protein amino terminus is oriented towards the lumen of intracellular membranes and carboxy terminus faces cell cytoplasm is proposed.
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Affiliation(s)
- Jose L Nieto-Torres
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
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31
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Schwarz S, Wang K, Yu W, Sun B, Schwarz W. Emodin inhibits current through SARS-associated coronavirus 3a protein. Antiviral Res 2011; 90:64-9. [PMID: 21356245 PMCID: PMC7114100 DOI: 10.1016/j.antiviral.2011.02.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 02/15/2011] [Accepted: 02/21/2011] [Indexed: 12/17/2022]
Abstract
The open-reading-frame 3a of SARS coronavirus (SARS-CoV) had been demonstrated previously to form a cation-selective channel that may become expressed in the infected cell and is then involved in virus release. Drugs that inhibit the ion channel formed by the 3a protein can be expected to inhibit virus release, and would be a source for the development of novel therapeutic agents. Here we demonstrate that emodin can inhibit the 3a ion channel of coronavirus SARS-CoV and HCoV-OC43 as well as virus release from HCoV-OC43 with a K1/2 value of about 20 μM. We suggest that viral ion channels, in general, may be a good target for the development of antiviral agents.
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Affiliation(s)
- Silvia Schwarz
- Shanghai Research Center for Acupuncture & Meridians, 199 Guoshoujing Rd., Shanghai 201203, China
| | - Kai Wang
- Molecular Virus Unit, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai Institutes of Biological Sciences, 225 South Chongqing Road, Shanghai, 200025, China
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Wenjing Yu
- Molecular Virus Unit, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai Institutes of Biological Sciences, 225 South Chongqing Road, Shanghai, 200025, China
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Bing Sun
- Molecular Virus Unit, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai Institutes of Biological Sciences, 225 South Chongqing Road, Shanghai, 200025, China
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Wolfgang Schwarz
- Shanghai Research Center for Acupuncture & Meridians, 199 Guoshoujing Rd., Shanghai 201203, China
- Max-Planck-Institute for Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
- Institute for Biophysics, Goethe-University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany
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32
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Tsui SKW. Functional roles of 3a protein in the pathogenesis of SARS. Hong Kong Med J 2009; 15 Suppl 8:19-20. [PMID: 20393207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Affiliation(s)
- S K W Tsui
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
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33
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Torres J, Maheswari U, Parthasarathy K, Ng L, Liu DX, Gong X. Conductance and amantadine binding of a pore formed by a lysine-flanked transmembrane domain of SARS coronavirus envelope protein. Protein Sci 2007; 16:2065-71. [PMID: 17766393 PMCID: PMC2206980 DOI: 10.1110/ps.062730007] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The coronavirus responsible for the severe acute respiratory syndrome (SARS-CoV) contains a small envelope protein, E, with putative involvement in host cell apoptosis and virus morphogenesis. It has been suggested that E protein can form a membrane destabilizing transmembrane (TM) hairpin, or homooligomerize to form a regular TM α-helical bundle. We have shown previously that the topology of the α-helical putative TM domain of E protein (ETM), flanked by two lysine residues at C and N termini to improve solubility, is consistent with a regular TM α-helix, with orientational parameters in lipid bilayers that are consistent with a homopentameric model. Herein, we show that this peptide, reconstituted in lipid bilayers, shows sodium conductance. Channel activity is inhibited by the anti-influenza drug amantadine, which was found to bind our preparation with moderate affinity. Results obtained from single or double mutants indicate that the organization of the transmembrane pore is consistent with our previously reported pentameric α-helical bundle model.
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Affiliation(s)
- Jaume Torres
- School of Biological Sciences, Nanyang Technological University, Singapore.
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34
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Yuan X, Yao Z, Wu J, Zhou Y, Shan Y, Dong B, Zhao Z, Hua P, Chen J, Cong Y. G1 phase cell cycle arrest induced by SARS-CoV 3a protein via the cyclin D3/pRb pathway. Am J Respir Cell Mol Biol 2007; 37:9-19. [PMID: 17413032 DOI: 10.1165/rcmb.2005-0345rc] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
SARS-CoV 3a is a structural protein, mainly localizing to Golgi apparatus and co-localizing with SARS-CoV M in co-transfected cells. Here we observed that transient expression of 3a inhibited cell growth and prevented 5-bromodeoxyuridine incorporation, suggesting that 3a deregulated cell cycle progression. Cell cycle analysis demonstrated that 3a expression was associated with blockage of cell cycle progression at G1 phase in HEK 293, COS-7, and Vero cells 24-60 h after transfection. Mutation analysis of 3a revealed that C-terminal region (176 aa approximately 274 aa), including a potential calcium ATPase motif, was essential for induction of cell cycle arrest. Topological analysis showed that 3a predominantly located in Golgi apparatus, with its N-terminus residing in the lumen (Nlum) and C-terminus in the cytosol (Ccyt). Analyzing the cellular proteins involving in regulation of cell cycle progression, we demonstrated that 3a expression was correlated with a significant reduction of cyclin D3 level and phosphorylation of retinoblastoma (Rb) protein at Ser-795 and Ser-809/811, not with the expression of cyclin D1, D2, cdk4, and cdk6 in 293 cells. Increases in p53 phosphorylation on Ser-15 were observed in both SARS-CoV M and 3a transfected cells, suggesting that it might not correlate with the 3a-induced G0/G1 phase arrest. The reduction of cyclin D3 level and phosphorylation of Rb were further confirmed in SARS-CoV infected Vero cells. These results indicate that SARS-CoV 3a protein, through limiting the expression of cyclin D3, may inhibit Rb phosphorylation, which in turn leads to a block in the G1 phase of the cell cycle and an inhibition of cell proliferation.
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Affiliation(s)
- Xiaoling Yuan
- Department of Pathophysiology, Beijing Institute of Radiation Medicine, No. 27 Taiping Road, Beijing 100850, China
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35
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Huang C, Narayanan K, Ito N, Peters CJ, Makino S. Severe acute respiratory syndrome coronavirus 3a protein is released in membranous structures from 3a protein-expressing cells and infected cells. J Virol 2007; 80:210-7. [PMID: 16352545 PMCID: PMC1317539 DOI: 10.1128/jvi.80.1.210-217.2006] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus (SCoV) accessory protein 3a is a virus structural protein. We demonstrate here that 3a protein was released efficiently in membranous structures from various cell lines expressing 3a protein. A subpopulation of the released 3a protein is associated with detergent-resistant membranes. The presence of the YxxPhi and diacidic motifs, located within the cytoplasmic tail of the 3a protein, was not required for its efficient release. Analysis of supernatant from SCoV-infected cells with sucrose gradient sedimentation and virus capture assay indicated that the 3a protein was released from infected cells in two distinct populations, as a component of SCoV particles, and in membrane structures with a lower buoyant density. These data provide new insights into the biological properties of SCoV 3a protein.
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Affiliation(s)
- Cheng Huang
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1019, USA
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36
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Chen S, Luo H, Chen L, Chen J, Shen J, Zhu W, Chen K, Shen X, Jiang H. An overall picture of SARS coronavirus (SARS-CoV) genome-encoded major proteins: structures, functions and drug development. Curr Pharm Des 2007; 12:4539-53. [PMID: 17168760 DOI: 10.2174/138161206779010459] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A severe atypical pneumonia designated as severe acute respiratory syndrome (SARS) by The World Health Organization broke out in China and menaced to more than other 30 countries between the end of the year 2002 and June of the year 2003. A novel coronavirus called severe acute respiratory syndrome coronavirus (SARS-CoV) has been recently identified as the etiological agent responsible for the infectious SARS disease. Based on extensively scientific cooperation and almost two-year's studies, remarkable achievements have been made in the understanding of the phylogenetic property and the genome organization of SARS-CoV, as well as the detailed characters of the major proteins involved in SARS-CoV life cycle. In this review, we would like to summarize the substantial scientific progress that has been made towards the structural and functional aspects of SARS-CoV associated key proteins. The progress focused on the corresponding key proteins' structure-based drug and vaccine developments has been also highlighted. The concerted and cooperative response for the treatment of the SARS disease has been proved to be a triumph of global public health and provides a new paradigm for the detection and control of future emerging infectious disease threats.
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Affiliation(s)
- Shuai Chen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
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37
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Khan S, Ng ML, Tan YJ. Expression of the severe acute respiratory syndrome coronavirus 3a protein and the assembly of coronavirus-like particles in the baculovirus expression system. Methods Mol Biol 2007; 379:35-50. [PMID: 17502669 PMCID: PMC7120620 DOI: 10.1007/978-1-59745-393-6_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Bac-to-Bac Baculovirus expression system was used to generate a recombinant baculovirus capable of expressing the severe acute respiratory syndrome (SARS)-coronavirus (CoV) 3a protein. Using the same expression system, two structural proteins, membrane (M) and envelope (E), were co-expressed to form SARS-CoV virus-like particles (VLPs) within an insect cell. Expression of viral proteins was confirmed by Western blot analysis and the formation of VLPs was studied by transmission electron microscopy.
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Affiliation(s)
- Sehaam Khan
- Collaborative Antiviral Research Group, Institute of Molecular and Cell Biology, Proteos, Singapore
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38
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Affiliation(s)
- Stanley Perlman
- Department of Pediatrics, University of Iowa, 52242 Iowa City, IA USA
| | - Kathryn V. Holmes
- Department of Microbiology, University of Colorado Health Sciences Center at Fitzsimons, 80045-8333 Aurora, CO USA
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39
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Zhang X, Wu K, Yue X, Zhu Y, Wu J. Inhibition of SARS-CoV gene expression by adenovirus-delivered small hairpin RNA. Intervirology 2006; 50:63-70. [PMID: 17139181 PMCID: PMC7179548 DOI: 10.1159/000097391] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 02/14/2006] [Indexed: 02/04/2023] Open
Abstract
Objective Severe acute respiratory syndrome (SARS) is a highly contagious and lethal disease caused by a new type of coronavirus, SARS-associated coronavirus (SARS-CoV). Currently, there is no efficient treatment and prevention for this disease. We constructed recombinant adenoviral vectors that can express shRNAs, which inhibited the expression of SARS-CoV genes effectively in mammalian cells. Methods In this study, we designed several plasmids that express small hairpin RNA molecules (shRNA) specifically targeting to the genes encoding for the SARS-CoV nucleocapsid (N) protein and envelope (E) protein, respectively. Effective shRNA molecules to the viral genes were screened and identified, and then constructed into adenovirus vectors. The effects of adenovirus-delivered small hairpin RNA on SARS-CoV gene expression were determined by RT-PCR, Western blot, and luciferase activity assays. Results The levels of viral mRNAs and viral proteins of the targets were significantly decreased or completely inhibited in cell lines after being infected with the recombinant adenoviruses that expressed specific shRNA molecules. Conclusions Since many cell types can be efficiently infected by adenovirus, recombinant adenoviruses could serve as an alternative powerful tool for shRNA delivery and for gene suppression, especially when the targeted cells are resistant to transfection by DNA or RNA. With availability of high titers of adenoviruses and uniform and rapid infection, this approach would have foreseeable wide applications both in experimental biology and molecular medicine.
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Affiliation(s)
- Xue Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, PR China
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40
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Lu W, Zheng BJ, Xu K, Schwarz W, Du L, Wong CKL, Chen J, Duan S, Deubel V, Sun B. Severe acute respiratory syndrome-associated coronavirus 3a protein forms an ion channel and modulates virus release. Proc Natl Acad Sci U S A 2006; 103:12540-5. [PMID: 16894145 PMCID: PMC1567914 DOI: 10.1073/pnas.0605402103] [Citation(s) in RCA: 221] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Fourteen ORFs have been identified in the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) genome. ORF 3a of SARS-CoV codes for a recently identified transmembrane protein, but its function remains unknown. In this study we confirmed the 3a protein expression and investigated its localization at the surface of SARS-CoV-infected or 3a-cDNA-transfected cells. Our experiments showed that recombinant 3a protein can form a homotetramer complex through interprotein disulfide bridges in 3a-cDNA-transfected cells, providing a clue to ion channel function. The putative ion channel activity of this protein was assessed in 3a-complement RNA-injected Xenopus oocytes by two-electrode voltage clamp. The results suggest that 3a protein forms a potassium sensitive channel, which can be efficiently inhibited by barium. After FRhK-4 cells were transfected with an siRNA, which is known to suppress 3a expression, followed by infection with SARS-CoV, the released virus was significantly decreased, whereas the replication of the virus in the infected cells was not changed. Our observation suggests that SARS-CoV ORF 3a functions as an ion channel that may promote virus release. This finding will help to explain the highly pathogenic nature of SARS-CoV and to develop new strategies for treatment of SARS infection.
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Affiliation(s)
- Wei Lu
- *Laboratory of Molecular Virology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology
- Max Planck Guest Laboratory, and
| | - Bo-Jian Zheng
- Department of Microbiology, University of Hong Kong and Queen Mary Hospital, Hong Kong, China; and
| | - Ke Xu
- *Laboratory of Molecular Virology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology
| | - Wolfgang Schwarz
- Max Planck Guest Laboratory, and
- Max Planck Institute for Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt/M, Germany
| | - Lanying Du
- Department of Microbiology, University of Hong Kong and Queen Mary Hospital, Hong Kong, China; and
| | - Charlotte K. L. Wong
- Department of Microbiology, University of Hong Kong and Queen Mary Hospital, Hong Kong, China; and
| | - Jiadong Chen
- **Shanghai Institute of Neuroscience, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Shuming Duan
- **Shanghai Institute of Neuroscience, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Vincent Deubel
- *Laboratory of Molecular Virology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China
| | - Bing Sun
- *Laboratory of Molecular Virology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology
- To whom correspondence should be sent at the ∗ address. E-mail:
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Peng H, Yang LT, Li J, Lu ZQ, Wang LY, Koup RA, Bailer RT, Wu CY. Human memory T cell responses to SARS-CoV E protein. Microbes Infect 2006; 8:2424-31. [PMID: 16844400 PMCID: PMC7110890 DOI: 10.1016/j.micinf.2006.05.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Revised: 05/12/2006] [Accepted: 05/15/2006] [Indexed: 11/02/2022]
Abstract
E protein is a membrane component of severe acute respiratory syndrome coronavirus (SARS-CoV). Disruption of E protein may reduce viral infectivity. Thus, the SARS-CoV E protein is considered a potential target for the development of antiviral drugs. However, the cellular immune responses to E protein remain unclear in humans. In this study, we found that peripheral blood mononuclear cells (PBMCs) from fully recovered SARS individuals rapidly produced IFN-gamma and IL-2 following stimulation with a pool of 9 peptides overlapping the entire E protein sequence. Analysis of the immune responses by flow cytometry showed that both CD4+ and CD8+T cells were involved in the SARS-CoV E-specific immune responses after stimulation with SARS-CoV E peptides. Moreover, the majority of IFN-gamma+CD4+T cells were central memory cells expressing CD45RO+CCR7+CD62L-; whereas IFN-gamma+CD8+ memory T cells were mostly effector memory cells expressing CD45RO-CCR7-CD62L-. The results of T-cell responses to 9 individual peptides indicated that the E protein contained at least two major T cell epitopes (E2 amino acid [aa] 9-26 and E5-6: aa 33-57) which were important in eliciting cellular immune response to SARS-CoV E protein in humans.
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Affiliation(s)
- Hui Peng
- Department of Immunology, Zhongshan Medical School, Sun Yat-sen University, No. 74 Zhongshan Road II, Guangzhou 510089, China
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Keng CT, Choi YW, Welkers MRA, Chan DZL, Shen S, Gee Lim S, Hong W, Tan YJ. The human severe acute respiratory syndrome coronavirus (SARS-CoV) 8b protein is distinct from its counterpart in animal SARS-CoV and down-regulates the expression of the envelope protein in infected cells. Virology 2006; 354:132-42. [PMID: 16876844 PMCID: PMC7111915 DOI: 10.1016/j.virol.2006.06.026] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 06/15/2006] [Accepted: 06/17/2006] [Indexed: 12/14/2022]
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV), isolated from humans infected during the peak of epidemic, encodes two accessory proteins termed as 8a and 8b. Interestingly, the SARS-CoV isolated from animals contains an extra 29-nucleotide in this region such that these proteins are fused to become a single protein, 8ab. Here, we compared the cellular properties of the 8a, 8b and 8ab proteins by examining their cellular localizations and their abilities to interact with other SARS-CoV proteins. These results may suggest that the conformations of 8a and 8b are different from 8ab although nearly all the amino acids in 8a and 8b are found in 8ab. In addition, the expression of the structural protein, envelope (E), was down-regulated by 8b but not 8a or 8ab. Consequently, E was not detectable in SARS-CoV-infected cells that were expressing high levels of 8b. These findings suggest that 8b may modulate viral replication and/or pathogenesis.
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Affiliation(s)
- Choong-Tat Keng
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore, 138673
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Åkerström S, Tan YJ, Mirazimi A. Amino acids 15-28 in the ectodomain of SARS coronavirus 3a protein induces neutralizing antibodies. FEBS Lett 2006; 580:3799-803. [PMID: 16781713 PMCID: PMC7094653 DOI: 10.1016/j.febslet.2006.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 05/29/2006] [Accepted: 06/01/2006] [Indexed: 12/13/2022]
Abstract
A synthetic peptide corresponding to amino acids (aa) 15–28 of the severe acute respiratory syndrome coronavirus (SARS‐CoV) 3a protein was used to raise polyclonal antibodies in rabbits. This anti‐3a N‐terminal antibody could detect 3a protein in infected cells, as did an anti‐3a C‐terminal antibody previously described. The latter targeted the C‐terminal cytoplasmic domain of 3a (aa 134–274). The anti‐3a N‐terminal antibody could detect intracellular 3a as well as 3a expressed on the cell surface. Interestingly, only the anti‐3a N‐terminal antibody can inhibit SARS‐CoV propagation in Vero E6 culture although the binding affinity of the anti‐3a N‐terminal antibody was lower than the anti‐3a C‐terminal antibody.
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Affiliation(s)
- Sara Åkerström
- Center for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
| | - Yee-Joo Tan
- Institute of Molecular and Cell Biology, CAVR, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Ali Mirazimi
- Center for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
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Meng B, Lui YW, Meng S, Cao C, Hu Y. Identification of effective siRNA blocking the expression of SARS viral envelope E and RDRP genes. Mol Biotechnol 2006; 33:141-8. [PMID: 16757801 PMCID: PMC7090727 DOI: 10.1385/mb:33:2:141] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 12/04/2022]
Abstract
A cell-based assay was developed to screen small interference RNA (siRNA) to block the expression of two genes of the severe acute respiratory syndrome (SARS) virus. These two genes encode RNA-dependent RNA polymerase (RDRP) and envelope E protein. The RDRP plays an essential role in viral RNA replication where envelope E protein is involved in envelope formation and virus assembly. The RDRP and envelope E genes, based on published sequences, have been synthesized and cloned into mammalian expression vectors. In addition, four siRNA sites for the RDRP gene and two siRNA sites for envelope E gene were designed and tested. The siRNA or short hairpin RNA (shRNA) expression cassettes were co-transfected with the SARS viral RDRP or envelope E expression vectors into NIH 3T3 cells. The expression levels of RDRP and envelope E genes were examined by reverse transcription followed by quantitative real-time polymerase chain reaction (PCR). Two of the siRNA expression cassettes for RDRP successfully inhibited the expression of the gene, whereas both of the siRNA expression cassettes for envelope E decreased approx 90% of the envelope E gene expression. The siRNA and shRNA for one of the siRNA sites of the RDRP gene were also tested, and it was found that both inhibited exogenous RDRP expression in a dose-dependent manner. These siRNA molecules could be used to examine the function of these genes in SARS virus replication and assembly. Furthermore, these molecules could potentially be developed into therapeutic agents for the treatment of patients with SARS.
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Affiliation(s)
- Bo Meng
- Key Lab of Brain Functional Genomics, MOE & STCSM, Shanghai Institute of Brain Functional Genomics, East China Normal University, 200062 Shanghai, China
| | - Yue-woon Lui
- College of Automation, Chongqing University, 400044 China, Chongqing
| | - Shi Meng
- Key Lab of Brain Functional Genomics, MOE & STCSM, Shanghai Institute of Brain Functional Genomics, East China Normal University, 200062 Shanghai, China
| | - Changxiu Cao
- College of Automation, Chongqing University, 400044 China, Chongqing
| | - Yinghe Hu
- Key Lab of Brain Functional Genomics, MOE & STCSM, Shanghai Institute of Brain Functional Genomics, East China Normal University, 200062 Shanghai, China
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Torres J, Parthasarathy K, Lin X, Saravanan R, Kukol A, Liu DX. Model of a putative pore: the pentameric alpha-helical bundle of SARS coronavirus E protein in lipid bilayers. Biophys J 2006; 91:938-47. [PMID: 16698774 PMCID: PMC1563757 DOI: 10.1529/biophysj.105.080119] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The coronavirus responsible for the severe acute respiratory syndrome contains a small envelope protein, E, with putative involvement in host apoptosis and virus morphogenesis. To perform these functions, it has been suggested that protein E can form a membrane destabilizing transmembrane (TM) hairpin, or homooligomerize to form a TM pore. Indeed, in a recent study we reported that the α-helical putative transmembrane domain of E protein (ETM) forms several SDS-resistant TM interactions: a dimer, a trimer, and two pentameric forms. Further, these interactions were found to be evolutionarily conserved. Herein, we have studied multiple isotopically labeled ETM peptides reconstituted in model lipid bilayers, using the orientational parameters derived from infrared dichroic data. We show that the topology of ETM is consistent with a regular TM α-helix. Further, the orientational parameters obtained unequivocally correspond to a homopentameric model, by comparison with previous predictions. We have independently confirmed that the full polypeptide of E protein can also aggregate as pentamers after expression in Escherichia coli. This interaction must be stabilized, at least partially, at the TM domain. The model we report for this pentameric α-helical bundle may explain some of the permabilizing properties of protein E, and should be the basis of mutagenesis efforts in future functional studies.
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Affiliation(s)
- Jaume Torres
- School of Biological Sciences, Nanyang Technological University, Singapore.
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Zhong X, Guo Z, Yang H, Peng L, Xie Y, Wong TY, Lai ST, Guo Z. Amino terminus of the SARS coronavirus protein 3a elicits strong, potentially protective humoral responses in infected patients. J Gen Virol 2006; 87:369-373. [PMID: 16432024 DOI: 10.1099/vir.0.81078-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The 3a protein of severe acute respiratory syndrome (SARS)-associated coronavirus is expressed and transported to the plasma membrane in tissue cells of infected patients. Its short N-terminal ectodomain was found to elicit strong humoral responses in half of the patients who had recovered from SARS. The ectodomain-specific antibodies from the convalescent-phase plasma readily recognized and induced destruction of 3a-expressing cells in the presence of the human complement system, demonstrating their potential ability to provide immune protection by recognizing and eliminating SARS coronavirus-infected cells that express the target protein. In addition, when coupled to a carrier protein, the ectodomain peptide elicited 3a-specific antibodies in mice and rabbit at high titres. These results showed that the N terminus of the 3a protein is highly immunogenic and elicits potentially protective humoral responses in infected patients. Therefore, the short extracellular domain may be a valuable immunogen in the development of a vaccine for infectious SARS.
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Affiliation(s)
- Xiaofen Zhong
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Zufeng Guo
- Biotechnology Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Huanghao Yang
- Biotechnology Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Lisheng Peng
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Yong Xie
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Tin-Yau Wong
- Princess Margaret Hospital, Hong Kong SAR, China
| | - Sik-To Lai
- Princess Margaret Hospital, Hong Kong SAR, China
| | - Zhihong Guo
- Biotechnology Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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47
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Oostra M, de Haan CAM, de Groot RJ, Rottier PJM. Glycosylation of the severe acute respiratory syndrome coronavirus triple-spanning membrane proteins 3a and M. J Virol 2006; 80:2326-36. [PMID: 16474139 PMCID: PMC1395384 DOI: 10.1128/jvi.80.5.2326-2336.2006] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) open reading frame 3a protein has recently been shown to be a structural protein. The protein is encoded by one of the so-called group-specific genes and has no sequence homology with any of the known structural or group-specific proteins of coronaviruses. It does, however, have several similarities to the coronavirus M proteins; (i) they are triple membrane spanning with the same topology, (ii) they have similar intracellular localizations (predominantly Golgi), (iii) both are viral structural proteins, and (iv) they appear to interact with the E and S proteins, as well as with each other. The M protein plays a crucial role in coronavirus assembly and is glycosylated in all coronaviruses, either by N-linked or by O-linked oligosaccharides. The conserved glycosylation of the coronavirus M proteins and the resemblance of the 3a protein to them led us to investigate the glycosylation of these two SARS-CoV membrane proteins. The proteins were expressed separately using the vaccinia virus T7 expression system, followed by metabolic labeling. Pulse-chase analysis showed that both proteins were modified, although in different ways. While the M protein acquired cotranslationally oligosaccharides that could be removed by PNGaseF, the 3a protein acquired its modifications posttranslationally, and they were not sensitive to the N-glycosidase enzyme. The SARS-CoV 3a protein, however, was demonstrated to contain sialic acids, indicating the presence of oligosaccharides. O-glycosylation of the 3a protein was indeed confirmed using an in situ O-glycosylation assay of endoplasmic reticulum-retained mutants. In addition, we showed that substitution of serine and threonine residues in the ectodomain of the 3a protein abolished the addition of the O-linked sugars. Thus, the SARS-CoV 3a protein is an O-glycosylated glycoprotein, like the group 2 coronavirus M proteins but unlike the SARS-CoV M protein, which is N glycosylated.
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Affiliation(s)
- M Oostra
- Virology Division, Department of Infectious Diseases and Immunology, Utrecht University, The Netherlands
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Khattari Z, Brotons G, Akkawi M, Arbely E, Arkin IT, Salditt T. SARS coronavirus E protein in phospholipid bilayers: an x-ray study. Biophys J 2006; 90:2038-50. [PMID: 16361349 PMCID: PMC1386782 DOI: 10.1529/biophysj.105.072892] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Accepted: 11/21/2005] [Indexed: 11/18/2022] Open
Abstract
We investigated the structure of the hydrophobic domain of the severe acute respiratory syndrome E protein in model lipid membranes by x-ray reflectivity and x-ray scattering. In particular, we used x-ray reflectivity to study the location of an iodine-labeled residue within the lipid bilayer. The label imposes spatial constraints on the protein topology. Experimental data taken as a function of protein/lipid ratio P/L and different swelling states support the hairpin conformation of severe acute respiratory syndrome E protein reported previously. Changes in the bilayer thickness and acyl-chain ordering are presented as a function of P/L, and discussed in view of different structural models.
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Affiliation(s)
- Z Khattari
- Institute for X-ray Physics, University of Göttingen, Göttingen, Germany
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Liao Y, Yuan Q, Torres J, Tam J, Liu D. Biochemical and functional characterization of the membrane association and membrane permeabilizing activity of the severe acute respiratory syndrome coronavirus envelope protein. Virology 2006; 349:264-75. [PMID: 16507314 PMCID: PMC7111751 DOI: 10.1016/j.virol.2006.01.028] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 12/07/2005] [Accepted: 01/21/2006] [Indexed: 12/02/2022]
Abstract
A diverse group of cytolytic animal viruses encodes small, hydrophobic proteins to modify host cell membrane permeability to ions and small molecules during their infection cycles. In this study, we show that expression of the SARS-CoV E protein in mammalian cells alters the membrane permeability of these cells. Immunofluorescent staining and cell fractionation studies demonstrate that this protein is an integral membrane protein. It is mainly localized to the ER and the Golgi apparatus. The protein can be translocated to the cell surface and is partially associated with lipid rafts. Further biochemical characterization of the protein reveals that it is posttranslationally modified by palmitoylation on all three cysteine residues. Systematic mutagenesis studies confirm that the membrane permeabilizing activity of the SARS-CoV E protein is associated with its transmembrane domain.
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Affiliation(s)
- Y. Liao
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Q. Yuan
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - J. Torres
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - J.P. Tam
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - D.X. Liu
- School of Biological Science, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
- Corresponding author. Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore.
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Yang Y, Xiong Z, Zhang S, Yan Y, Nguyen J, Ng B, Lu H, Brendese J, Yang F, Wang H, Yang XF. Bcl-xL inhibits T-cell apoptosis induced by expression of SARS coronavirus E protein in the absence of growth factors. Biochem J 2006; 392:135-43. [PMID: 16048439 PMCID: PMC1317672 DOI: 10.1042/bj20050698] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
One of the hallmark findings in patients suffering from SARS (severe acute respiratory syndrome) is lymphopenia, which is the result of massive lymphocyte death. SARS-CoV (SARS coronavirus), a novel coronavirus that has been etiologically associated with SARS cases, is homologous with MHV (murine hepatitis coronavirus), and MHV small envelope E protein is capable of inducing apoptosis. We hypothesized that SARS-CoV encodes a small envelope E protein that is homologous with MHV E protein, thus inducing T-cell apoptosis. To test this hypothesis, a cDNA encoding SARS-CoV E protein was created using whole gene synthesis. Our results showed that SARS-CoV E protein induced apoptosis in the transfected Jurkat T-cells, which was amplified to higher apoptosis rates in the absence of growth factors. However, apoptosis was inhibited by overexpressed antiapoptotic protein Bcl-xL. Moreover, we found that SARS-CoV E protein interacted with Bcl-xL in vitro and endogenous Bcl-xL in vivo and that Bcl-xL interaction with SARS-CoV E protein was mediated by BH3 (Bcl-2 homology domain 3) of Bcl-xL. Finally, we identified a novel BH3-like region located in the C-terminal cytosolic domain of SARS-CoV E protein, which mediates its binding to Bcl-xL. These results demonstrate, for the first time, a novel molecular mechanism of T-cell apoptosis that contributes to the SARS-CoV-induced lymphopenia observed in most SARS patients.
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Affiliation(s)
- Yu Yang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Zeyu Xiong
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Sheng Zhang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Yan Yan
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Justin Nguyen
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Bernard Ng
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Huifang Lu
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - John Brendese
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Fan Yang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Hong Wang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
- †Section of Atherosclerosis and Lipoprotein Research, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Xiao-Feng Yang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
- ‡Department of Immunology, Baylor College of Medicine, Houston, TX 77030, U.S.A
- To whom correspondence should be addressed, at Department of Medicine, Biology of Inflammation Center, Baylor College of Medicine (email )
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