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Escalera A, Laporte M, Turner S, Karakus U, Gonzalez-Reiche AS, van de Guchte A, Farrugia K, Khalil Z, van Bakel H, Smith D, García-Sastre A, Aydillo T. The impact of S2 mutations on Omicron SARS-CoV-2 cell surface expression and fusogenicity. Emerg Microbes Infect 2024; 13:2297553. [PMID: 38112266 PMCID: PMC10866063 DOI: 10.1080/22221751.2023.2297553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 12/17/2023] [Indexed: 12/21/2023]
Abstract
SARS-CoV-2 Omicron subvariants are still emerging and spreading worldwide. These variants contain a high number of polymorphisms in the spike (S) glycoprotein that could potentially impact their pathogenicity and transmission. We have previously shown that the S:655Y and P681H mutations enhance S protein cleavage and syncytia formation. Interestingly, these polymorphisms are present in Omicron S protein. Here, we characterized the cleavage efficiency and fusogenicity of the S protein of different Omicron sublineages. Our results showed that Omicron BA.1 subvariant is efficiently cleaved but it is poorly fusogenic compared to previous SARS-CoV-2 strains. To understand the basis of this phenotype, we generated chimeric S protein using combinations of the S1 and S2 domains from WA1, Delta and Omicron BA.1 variants. We found that the S2 domain of Omicron BA.1 hindered efficient cell-cell fusion. Interestingly, this domain only contains six unique polymorphisms never detected before in ancestral SARS-CoV-2 variants. WA1614G S proteins containing the six individuals S2 Omicron mutations were assessed for their fusogenicity and S surface expression after transfection in cells. Results showed that the S:N856K and N969K substitutions decreased syncytia formation and impacted S protein cell surface levels. However, we observed that "first-generation" Omicron sublineages that emerged subsequently, had convergently evolved to an enhanced fusogenic activity and S expression on the surface of infected cells while "second-generation" Omicron variants have highly diverged and showed lineage-specific fusogenic properties. Importantly, our findings could have potential implications in the improvement and redesign of COVID-19 vaccines.
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Affiliation(s)
- Alba Escalera
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Manon Laporte
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sam Turner
- Center for Pathogen Evolution, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Umut Karakus
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ana S. Gonzalez-Reiche
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Adriana van de Guchte
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Keith Farrugia
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Zain Khalil
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Harm van Bakel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Icahn Genomics Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Derek Smith
- Center for Pathogen Evolution, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Teresa Aydillo
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Sadeghloo Z, Nabavi-Rad A, Zali MR, Klionsky DJ, Yadegar A. The interplay between probiotics and host autophagy: mechanisms of action and emerging insights. Autophagy 2024:1-23. [PMID: 39291740 DOI: 10.1080/15548627.2024.2403277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 07/09/2024] [Accepted: 07/10/2024] [Indexed: 09/19/2024] Open
Abstract
Autophagy, a lysosome-dependent protein degradation mechanism, is a highly conserved catabolic process seen in all eukaryotes. This cell protection system, which is present in all tissues and functions at a basic level, can be up- or downregulated in response to various stresses. A disruption in the natural route of the autophagy process is frequently followed by an interruption in the inherent operation of the body's cells and organs. Probiotics are live bacteria that protect the host through various mechanisms. One of the processes through which probiotics exert their beneficial effects on various cells and tissues is autophagy. Autophagy can assist in maintaining host homeostasis by stimulating the immune system and affecting numerous physiological and pathological responses. In this review, we particularly focus on autophagy impairments occurring in several human illnesses and investigate how probiotics affect the autophagy process under various circumstances.Abbreviation: AD: Alzheimer disease; AKT: AKT serine/threonine kinase; AMPK: 5'AMP-activated protein kinase; ATG: autophagy related; CCl4: carbon tetrachloride; CFS: cell-free supernatant; CMA: chaperone-mediated autophagy; CRC: colorectal cancer; EPS: L. plantarum H31 exopolysaccharide; HD: Huntington disease; HFD: high-fat diet; HPV: human papillomavirus; IFNG/IFN-γ: interferon gamma; IL6: interleukin 6; LGG: L. rhamnosus GG; LPS: lipopolysaccharide; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; PD: Parkinson disease; Pg3G: pelargonidin-3-O-glucoside; PI3K: phosphoinositide 3-kinase; PolyQ: polyglutamine; ROS: reactive oxygen species; SCFAs: short-chain fatty acids; SLAB51: a novel formulation of lactic acid bacteria and bifidobacteria; Slp: surface layer protein (of acidophilus NCFM); SNCA: synuclein alpha; ULK1: unc-51 like autophagy-activating kinase 1; YB: B. longum subsp. infantis YB0411; YFP: yeast fermentate prebiotic.
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Affiliation(s)
- Zahra Sadeghloo
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Nabavi-Rad
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Daniel J Klionsky
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Ferreira da Silva L, Valle Garay A, Queiroz PF, Garcia de Resende S, Gomide M, Moreira de Oliveira IC, Souza Bernasol A, Arce A, Canet Santos L, Torres F, Silva-Pereira I, de Freitas SM, Marques Coelho C. A novel viral RNA detection method based on the combined use of trans-acting ribozymes and HCR-FRET analyses. PLoS One 2024; 19:e0310171. [PMID: 39325749 PMCID: PMC11426510 DOI: 10.1371/journal.pone.0310171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Accepted: 08/26/2024] [Indexed: 09/28/2024] Open
Abstract
The diagnoses of retroviruses are essential for controlling the rapid spread of pandemics. However, the real-time Reverse Transcriptase quantitative Polymerase Chain Reaction (RT-qPCR), which has been the gold standard for identifying viruses such as SARS-CoV-2 in the early stages of infection, is associated with high costs and logistical challenges. To innovate in viral RNA detection a novel molecular approach for detecting SARS-CoV-2 viral RNA, as a proof of concept, was developed. This method combines specific viral gene analysis, trans-acting ribozymes, and Fluorescence Resonance Energy Transfer (FRET)-based hybridization of fluorescent DNA hairpins. In this molecular mechanism, SARS-CoV-2 RNA is specifically recognized and cleaved by ribozymes, releasing an initiator fragment that triggers a hybridization chain reaction (HCR) with DNA hairpins containing fluorophores, leading to a FRET process. A consensus SARS-CoV-2 RNA target sequence was identified, and specific ribozymes were designed and transcribed in vitro to cleave the viral RNA into fragments. DNA hairpins labeled with Cy3/Cy5 fluorophores were then designed and synthesized for HCR-FRET assays targeting the RNA fragment sequences resulting from ribozyme cleavage. The results demonstrated that two of the three designed ribozymes effectively cleaved the target RNA within 10 minutes. Additionally, DNA hairpins labeled with Cy3/Cy5 pairs efficiently detected target RNA specifically and triggered detectable HCR-FRET reactions. This method is versatile and can be adapted for use with other viruses. Furthermore, the design and construction of a DIY photo-fluorometer prototype enabled us to explore the development of a simple and cost-effective point-of-care detection method based on digital image analysis.
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Affiliation(s)
- Leonardo Ferreira da Silva
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Aisel Valle Garay
- Laboratory of Molecular Biophysics, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Pedro Felipe Queiroz
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Sophia Garcia de Resende
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Mayna Gomide
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Izadora Cristina Moreira de Oliveira
- Laboratory of Molecular Biophysics, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Amanda Souza Bernasol
- Laboratory of Molecular Biophysics, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Anibal Arce
- Institute for biological and medical engineering, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
| | - Liem Canet Santos
- Laboratory of Molecular Biophysics, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Fernando Torres
- Laboratory of Molecular Biology, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Ildinete Silva-Pereira
- Laboratory of Molecular Biology of Pathogenic Fungi, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Sonia Maria de Freitas
- Laboratory of Molecular Biophysics, Department of Cell Biology, Institute of Biological Sciences, University of Brasília (UnB), Brasília, Federal District, Brazil
| | - Cíntia Marques Coelho
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Federal District, Brazil
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Han Y, Yuan Z, Yi Z. Identification of a membrane-associated element (MAE) in the C-terminal region of SARS-CoV-2 nsp6 that is essential for viral replication. J Virol 2024; 98:e0034924. [PMID: 38639488 PMCID: PMC11092323 DOI: 10.1128/jvi.00349-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 03/29/2024] [Indexed: 04/20/2024] Open
Abstract
The coronavirus disease 2019 (COVID-19) pandemic, caused by the novel coronavirus severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), has rapidly spread worldwide since its emergence in late 2019. Its ongoing evolution poses challenges for antiviral drug development. Coronavirus nsp6, a multiple-spanning transmembrane protein, participates in the biogenesis of the viral replication complex, which accommodates the viral replication-transcription complex. The roles of its structural domains in viral replication are not well studied. Herein, we predicted the structure of the SARS-CoV-2 nsp6 protein using AlphaFold2 and identified a highly folded C-terminal region (nsp6C) downstream of the transmembrane helices. The enhanced green fluorescent protein (EGFP)-fused nsp6C was found to cluster in the cytoplasm and associate with membranes. Functional mapping identified a minimal membrane-associated element (MAE) as the region from amino acids 237 to 276 (LGV-KLL), which is mainly composed of the α-helix H1 and the α-helix H2; the latter exhibits characteristics of an amphipathic helix (AH). Mutagenesis studies and membrane flotation experiments demonstrate that AH-like H2 is required for MAE-mediated membrane association. This MAE was functionally conserved across MERS-CoV, HCoV-OC43, HCoV-229E, HCoV-HKU1, and HCoV-NL63, all capable of mediating membrane association. In a SARS-CoV-2 replicon system, mutagenesis studies of H2 and replacements of H1 and H2 with their homologous counterparts demonstrated requirements of residues on both sides of the H2 and properly paired H1-H2 for MAE-mediated membrane association and viral replication. Notably, mutations I266A and K274A significantly attenuated viral replication without dramatically affecting membrane association, suggesting a dual role of the MAE in viral replication: mediating membrane association as well as participating in protein-protein interactions.IMPORTANCESevere acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) assembles a double-membrane vesicle (DMV) by the viral non-structural proteins for viral replication. Understanding the mechanisms of the DMV assembly is of paramount importance for antiviral development. Nsp6, a multiple-spanning transmembrane protein, plays an important role in the DMV biogenesis. Herein, we predicted the nsp6 structure of SARS-CoV-2 and other human coronaviruses using AlphaFold2 and identified a putative membrane-associated element (MAE) in the highly conserved C-terminal regions of nsp6. Experimentally, we verified a functionally conserved minimal MAE composed of two α-helices, the H1, and the amphipathic helix-like H2. Mutagenesis studies confirmed the requirement of H2 for MAE-mediated membrane association and viral replication and demonstrated a dual role of the MAE in viral replication, by mediating membrane association and participating in residue-specific interactions. This functionally conserved MAE may serve as a novel anti-viral target.
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Affiliation(s)
- Yuying Han
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, and Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, and Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China
| | - Zhigang Yi
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, and Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
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5
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Lv X, Chen R, Liang T, Peng H, Fang Q, Xiao S, Liu S, Hu M, Yu F, Cao L, Zhang Y, Pan T, Xi Z, Ding Y, Feng L, Zeng T, Huang W, Zhang H, Ma X. NSP6 inhibits the production of ACE2-containing exosomes to promote SARS-CoV-2 infectivity. mBio 2024; 15:e0335823. [PMID: 38303107 PMCID: PMC10936183 DOI: 10.1128/mbio.03358-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/04/2024] [Indexed: 02/03/2024] Open
Abstract
The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a global pandemic, which severely endangers public health. Our and others' works have shown that the angiotensin-converting enzyme 2 (ACE2)-containing exosomes (ACE2-exos) have superior antiviral efficacies, especially in response to emerging variants. However, the mechanisms of how the virus counteracts the host and regulates ACE2-exos remain unclear. Here, we identified that SARS-CoV-2 nonstructural protein 6 (NSP6) inhibits the production of ACE2-exos by affecting the protein level of ACE2 as well as tetraspanin-CD63 which is a key factor for exosome biogenesis. We further found that the protein stability of CD63 and ACE2 is maintained by the deubiquitination of proteasome 26S subunit, non-ATPase 12 (PSMD12). NSP6 interacts with PSMD12 and counteracts its function, consequently promoting the degradation of CD63 and ACE2. As a result, NSP6 diminishes the antiviral efficacy of ACE2-exos and facilitates the virus to infect healthy bystander cells. Overall, our study provides a valuable target for the discovery of promising drugs for the treatment of coronavirus disease 2019. IMPORTANCE The outbreak of coronavirus disease 2019 (COVID-19) severely endangers global public health. The efficacy of vaccines and antibodies declined with the rapid emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants. Angiotensin-converting enzyme 2-containing exosomes (ACE2-exos) therapy exhibits a broad neutralizing activity, which could be used against various viral mutations. Our study here revealed that SARS-CoV-2 nonstructural protein 6 inhibited the production of ACE2-exos, thereby promoting viral infection to the adjacent bystander cells. The identification of a new target for blocking SARS-CoV-2 depends on fully understanding the virus-host interaction networks. Our study sheds light on the mechanism by which the virus resists the host exosome defenses, which would facilitate the study and design of ACE2-exos-based therapeutics for COVID-19.
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Affiliation(s)
- Xi Lv
- School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Ran Chen
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Taizhen Liang
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, Guangdong, China
| | - Haojie Peng
- Department of Breast Surgery, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Qiannan Fang
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Shiqi Xiao
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, Guangdong, China
| | - Sen Liu
- School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, Guangdong, China
| | - Meilin Hu
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, Guangdong, China
- Department of Breast Surgery, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Fei Yu
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Lixue Cao
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Yiwen Zhang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ting Pan
- Center for Infection and Immunity Studies, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Zhihui Xi
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Yao Ding
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Linyuan Feng
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Tao Zeng
- Department of Breast Surgery, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Wenjing Huang
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Hui Zhang
- School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry Education, Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiancai Ma
- School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
- Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, Guangdong, China
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6
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Denker L, Dixon AM. The cell edit: Looking at and beyond non-structural proteins to understand membrane rearrangement in coronaviruses. Arch Biochem Biophys 2024; 752:109856. [PMID: 38104958 DOI: 10.1016/j.abb.2023.109856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/24/2023] [Accepted: 12/08/2023] [Indexed: 12/19/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-stranded RNA virus that sits at the centre of the recent global pandemic. As a member of the coronaviridae family of viruses, it shares features such as a very large genome (>30 kb) that is replicated in a purpose-built replication organelle. Biogenesis of the replication organelle requires significant and concerted rearrangement of the endoplasmic reticulum membrane, a job that is carried out by a group of integral membrane non-structural proteins (NSP3, 4 and 6) expressed by the virus along with a host of viral replication enzymes and other factors that support transcription and replication. The primary sites for RNA replication within the replication organelle are double membrane vesicles (DMVs). The small size of DMVs requires generation of high membrane curvature, as well as stabilization of a double-membrane arrangement, but the mechanisms that underlie DMV formation remain elusive. In this review, we discuss recent breakthroughs in our understanding of the molecular basis for membrane rearrangements by coronaviruses. We incorporate established models of NSP3-4 protein-protein interactions to drive double membrane formation, and recent data highlighting the roles of lipid composition and host factor proteins (e.g. reticulons) that influence membrane curvature, to propose a revised model for DMV formation in SARS-CoV-2.
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Affiliation(s)
- Lea Denker
- Warwick Medical School, Biomedical Sciences, University of Warwick, Coventry, CV4 7AL, UK.
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry, CV4 7SH, UK.
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Bills CJ, Xia H, Chen JYC, Yeung J, Kalveram B, Walker D, Xie X, Shi PY. Mutations in SARS-CoV-2 variant nsp6 enhance type-I interferon antagonism. Emerg Microbes Infect 2023; 12:2209208. [PMID: 37114433 PMCID: PMC10184609 DOI: 10.1080/22221751.2023.2209208] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve after its emergence. Given its importance in viral infection and vaccine development, mutations in the viral Spike gene have been studied extensively; however, the impact of mutations outside the Spike gene are poorly understood. Here, we report that a triple deletion (ΔSGF or ΔLSG) in nonstructural protein 6 (nsp6) independently acquired in Alpha and Omicron sublineages of SARS-CoV-2 augments nsp6-mediated antagonism of type-I interferon (IFN-I) signaling. Specifically, these triple deletions enhance the ability of mutant nsp6 to suppress phosphorylation of STAT1 and STAT2. A parental SARS-CoV-2 USA-WA1/2020 strain containing the nsp6 ΔSGF deletion (ΔSGF-WA1) shows reduced susceptibility to IFN-I treatment in vitro, outcompetes the parental strain in human primary airway cultures, and increases virulence in mice; however, the ΔSGF-WA1 virus is less virulent than the Alpha variant (which has the nsp6 ΔSGF deletion and additional mutations in other genes). Analyses of host responses from ΔSGF-WA1-infected mice and primary airway cultures reveal activation of pathways indicative of a cytokine storm. These results provide evidence that mutations outside the Spike protein affect virus-host interactions and may alter pathogenesis of SARS-CoV-2 variants in humans.
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Affiliation(s)
- Cody J Bills
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Hongjie Xia
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - John Yun-Chung Chen
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Jason Yeung
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Birte Kalveram
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - David Walker
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA
| | - Xuping Xie
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Institute for Drug Discovery, University of Texas Medical Branch, Galveston, TX, USA
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
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