1
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Zhu J, Liu G, Sayyad Z, Goins CM, Stauffer SR, Gack MU. ISGylation of the SARS-CoV-2 N protein by HERC5 impedes N oligomerization and thereby viral RNA synthesis. J Virol 2024:e0086924. [PMID: 39194248 DOI: 10.1128/jvi.00869-24] [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: 05/17/2024] [Accepted: 07/20/2024] [Indexed: 08/29/2024] Open
Abstract
Interferon (IFN)-stimulated gene 15 (ISG15), a ubiquitin-like protein, is covalently conjugated to host immune proteins such as MDA5 and IRF3 in a process called ISGylation, thereby promoting type I IFN induction to limit the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, whether SARS-CoV-2 proteins can be directly targeted for ISGylation remains elusive. In this study, we identified the nucleocapsid (N) protein of SARS-CoV-2 as a major substrate of ISGylation catalyzed by the host E3 ligase HERC5; however, N ISGylation is readily removed through deISGylation by the papain-like protease (PLpro) activity of NSP3. Mass spectrometry analysis identified that the N protein undergoes ISGylation at four lysine residues (K266, K355, K387, and K388), and mutational analysis of these sites in the context of a SARS-CoV-2 replicon (N-4KR) abolished N ISGylation and alleviated ISGylation-mediated inhibition of viral RNA synthesis. Furthermore, our results indicated that HERC5 targets preferentially phosphorylated N protein for ISGylation to regulate its oligomeric assembly. These findings reveal a novel mechanism by which the host ISGylation machinery directly targets SARS-CoV-2 proteins to restrict viral replication and illuminate how an intricate interplay of host (HERC5) and viral (PLpro) enzymes coordinates viral protein ISGylation and thereby regulates virus replication.IMPORTANCEThe role of protein ISGylation in regulating host cellular processes has been studied extensively; however, how ISG15 conjugation influences the activity of viral proteins, particularly coronaviral proteins, is largely unknown. Our study uncovered that the nucleocapsid (N) protein of SARS-CoV-2 is ISGylated by the HERC5 ISGylation machinery and that this modification impedes the functional assembly of N into oligomers ultimately inhibiting viral RNA synthesis. This antiviral restriction mechanism is antagonized by the PLpro deISGylation activity of SARS-CoV-2 NSP3. This study deepens our understanding of SARS-CoV-2 protein regulation by posttranslational modifications and may open new avenues for designing antiviral strategies for COVID-19.
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Affiliation(s)
- Junji Zhu
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, Florida, USA
| | - GuanQun Liu
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, Florida, USA
- Department of Microbiology & Immunology, McGill University, Montreal, Quebec, Canada
| | - Zuberwasim Sayyad
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, Florida, USA
| | - Christopher M Goins
- Center for Therapeutics Discovery, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Shaun R Stauffer
- Center for Therapeutics Discovery, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Michaela U Gack
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, Florida, USA
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2
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Young VL, McSweeney AM, Edwards MJ, Ward VK. The Disorderly Nature of Caliciviruses. Viruses 2024; 16:1324. [PMID: 39205298 PMCID: PMC11360831 DOI: 10.3390/v16081324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 08/07/2024] [Accepted: 08/17/2024] [Indexed: 09/04/2024] Open
Abstract
An intrinsically disordered protein (IDP) or region (IDR) lacks or has little protein structure but still maintains function. This lack of structure creates flexibility and fluidity, allowing multiple protein conformations and potentially transient interactions with more than one partner. Caliciviruses are positive-sense ssRNA viruses, containing a relatively small genome of 7.6-8.6 kb and have a broad host range. Many viral proteins are known to contain IDRs, which benefit smaller viral genomes by expanding the functional proteome through the multifunctional nature of the IDR. The percentage of intrinsically disordered residues within the total proteome for each calicivirus type species can range between 8 and 23%, and IDRs have been experimentally identified in NS1-2, VPg and RdRP proteins. The IDRs within a protein are not well conserved across the genera, and whether this correlates to different activities or increased tolerance to mutations, driving virus adaptation to new selection pressures, is unknown. The function of norovirus NS1-2 has not yet been fully elucidated but includes involvement in host cell tropism, the promotion of viral spread and the suppression of host interferon-λ responses. These functions and the presence of host cell-like linear motifs that interact with host cell caspases and VAPA/B are all found or affected by the disordered region of norovirus NS1-2. The IDRs of calicivirus VPg are involved in viral transcription and translation, RNA binding, nucleotidylylation and cell cycle arrest, and the N-terminal IDR within the human norovirus RdRP could potentially drive liquid-liquid phase separation. This review identifies and summarises the IDRs of proteins within the Caliciviridae family and their importance during viral replication and subsequent host interactions.
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Affiliation(s)
| | | | | | - Vernon K. Ward
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
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3
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Botova M, Camacho-Zarco AR, Tognetti J, Bessa LM, Guseva S, Mikkola E, Salvi N, Maurin D, Herrmann T, Blackledge M. A specific phosphorylation-dependent conformational switch in SARS-CoV-2 nucleocapsid protein inhibits RNA binding. SCIENCE ADVANCES 2024; 10:eaax2323. [PMID: 39093972 PMCID: PMC11296341 DOI: 10.1126/sciadv.aax2323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/27/2024] [Indexed: 08/04/2024]
Abstract
The nucleocapsid protein of severe acute respiratory syndrome coronavirus 2 encapsidates the viral genome and is essential for viral function. The central disordered domain comprises a serine-arginine-rich (SR) region that is hyperphosphorylated in infected cells. This modification regulates function, although mechanistic details remain unknown. We use nuclear magnetic resonance to follow structural changes occurring during hyperphosphorylation by serine arginine protein kinase 1, glycogen synthase kinase 3, and casein kinase 1, that abolishes interaction with RNA. When eight approximately uniformly distributed sites have been phosphorylated, the SR domain binds the same interface as single-stranded RNA, resulting in complete inhibition of RNA binding. Phosphorylation by protein kinase A does not prevent RNA binding, indicating that the pattern resulting from physiologically relevant kinases is specific for inhibition. Long-range contacts between the RNA binding, linker, and dimerization domains are abrogated, phenomena possibly related to genome packaging and unpackaging. This study provides insight into the recruitment of specific host kinases to regulate viral function.
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Affiliation(s)
| | | | | | | | | | - Emmi Mikkola
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | | | - Damien Maurin
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | - Torsten Herrmann
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
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4
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Nguyen A, Zhao H, Myagmarsuren D, Srinivasan S, Wu D, Chen J, Piszczek G, Schuck P. Modulation of biophysical properties of nucleocapsid protein in the mutant spectrum of SARS-CoV-2. eLife 2024; 13:RP94836. [PMID: 38941236 PMCID: PMC11213569 DOI: 10.7554/elife.94836] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024] Open
Abstract
Genetic diversity is a hallmark of RNA viruses and the basis for their evolutionary success. Taking advantage of the uniquely large genomic database of SARS-CoV-2, we examine the impact of mutations across the spectrum of viable amino acid sequences on the biophysical phenotypes of the highly expressed and multifunctional nucleocapsid protein. We find variation in the physicochemical parameters of its extended intrinsically disordered regions (IDRs) sufficient to allow local plasticity, but also observe functional constraints that similarly occur in related coronaviruses. In biophysical experiments with several N-protein species carrying mutations associated with major variants, we find that point mutations in the IDRs can have nonlocal impact and modulate thermodynamic stability, secondary structure, protein oligomeric state, particle formation, and liquid-liquid phase separation. In the Omicron variant, distant mutations in different IDRs have compensatory effects in shifting a delicate balance of interactions controlling protein assembly properties, and include the creation of a new protein-protein interaction interface in the N-terminal IDR through the defining P13L mutation. A picture emerges where genetic diversity is accompanied by significant variation in biophysical characteristics of functional N-protein species, in particular in the IDRs.
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Affiliation(s)
- Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Dulguun Myagmarsuren
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Sanjana Srinivasan
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Jiji Chen
- Advanced Imaging and Microscopy Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
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5
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Zhao H, Syed AM, Khalid MM, Nguyen A, Ciling A, Wu D, Yau WM, Srinivasan S, Esposito D, Doudna J, Piszczek G, Ott M, Schuck P. Assembly of SARS-CoV-2 nucleocapsid protein with nucleic acid. Nucleic Acids Res 2024; 52:6647-6661. [PMID: 38587193 PMCID: PMC11194069 DOI: 10.1093/nar/gkae256] [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: 11/22/2023] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024] Open
Abstract
The viral genome of SARS-CoV-2 is packaged by the nucleocapsid (N-)protein into ribonucleoprotein particles (RNPs), 38 ± 10 of which are contained in each virion. Their architecture has remained unclear due to the pleomorphism of RNPs, the high flexibility of N-protein intrinsically disordered regions, and highly multivalent interactions between viral RNA and N-protein binding sites in both N-terminal (NTD) and C-terminal domain (CTD). Here we explore critical interaction motifs of RNPs by applying a combination of biophysical techniques to ancestral and mutant proteins binding different nucleic acids in an in vitro assay for RNP formation, and by examining nucleocapsid protein variants in a viral assembly assay. We find that nucleic acid-bound N-protein dimers oligomerize via a recently described protein-protein interface presented by a transient helix in its long disordered linker region between NTD and CTD. The resulting hexameric complexes are stabilized by multivalent protein-nucleic acid interactions that establish crosslinks between dimeric subunits. Assemblies are stabilized by the dimeric CTD of N-protein offering more than one binding site for stem-loop RNA. Our study suggests a model for RNP assembly where N-protein scaffolding at high density on viral RNA is followed by cooperative multimerization through protein-protein interactions in the disordered linker.
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Affiliation(s)
- Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Abdullah M Syed
- Gladstone Institutes, San Francisco, CA 94158, USA
- Innovative Genomics Institute, University of California, Berkeley, CA 94720, USA
| | - Mir M Khalid
- Gladstone Institutes, San Francisco, CA 94158, USA
| | - Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alison Ciling
- Gladstone Institutes, San Francisco, CA 94158, USA
- Innovative Genomics Institute, University of California, Berkeley, CA 94720, USA
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sanjana Srinivasan
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dominic Esposito
- Protein Expression Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Jennifer A Doudna
- Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- HHMI, University of California, Berkeley, CA 94720, USA
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720, USA
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Melanie Ott
- Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, CA 94143, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
- Center for Biomedical Engineering Technology Acceleration, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
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6
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Stuwe H, Reardon PN, Yu Z, Shah S, Hughes K, Barbar EJ. Phosphorylation in the Ser/Arg-rich region of the nucleocapsid of SARS-CoV-2 regulates phase separation by inhibiting self-association of a distant helix. J Biol Chem 2024; 300:107354. [PMID: 38718862 PMCID: PMC11180338 DOI: 10.1016/j.jbc.2024.107354] [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: 04/01/2024] [Revised: 04/24/2024] [Accepted: 04/30/2024] [Indexed: 06/06/2024] Open
Abstract
The nucleocapsid protein (N) of SARS-CoV-2 is essential for virus replication, genome packaging, evading host immunity, and virus maturation. N is a multidomain protein composed of an independently folded monomeric N-terminal domain that is the primary site for RNA binding and a dimeric C-terminal domain that is essential for efficient phase separation and condensate formation with RNA. The domains are separated by a disordered Ser/Arg-rich region preceding a self-associating Leu-rich helix. Phosphorylation in the Ser/Arg region in infected cells decreases the viscosity of N:RNA condensates promoting viral replication and host immune evasion. The molecular level effect of phosphorylation, however, is missing from our current understanding. Using NMR spectroscopy and analytical ultracentrifugation, we show that phosphorylation destabilizes the self-associating Leu-rich helix 30 amino-acids distant from the phosphorylation site. NMR and gel shift assays demonstrate that RNA binding by the linker is dampened by phosphorylation, whereas RNA binding to the full-length protein is not significantly affected presumably due to retained strong interactions with the primary RNA-binding domain. Introducing a switchable self-associating domain to replace the Leu-rich helix confirms the importance of linker self-association to droplet formation and suggests that phosphorylation not only increases solubility of the positively charged elongated Ser/Arg region as observed in other RNA-binding proteins but can also inhibit self-association of the Leu-rich helix. These data highlight the effect of phosphorylation both at local sites and at a distant self-associating hydrophobic helix in regulating liquid-liquid phase separation of the entire protein.
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Affiliation(s)
- Hannah Stuwe
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | | | - Zhen Yu
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Sahana Shah
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Kaitlyn Hughes
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Elisar J Barbar
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA.
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7
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Zhu J, Liu G, Goins CM, Stauffer SR, Gack MU. ISGylation of the SARS-CoV-2 N protein by HERC5 impedes N oligomerization and thereby viral RNA synthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.15.594393. [PMID: 39149229 PMCID: PMC11326284 DOI: 10.1101/2024.05.15.594393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Interferon (IFN)-stimulated gene 15 (ISG15), a ubiquitin-like protein, is covalently conjugated to host (immune) proteins such as MDA5 and IRF3 in a process called ISGylation, thereby limiting the replication of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, whether SARS-CoV-2 proteins can be directly targeted for ISGylation remains elusive. In this study, we identified the nucleocapsid (N) protein of SARS-CoV-2 as a major substrate of ISGylation catalyzed by the host E3 ligase HERC5; however, N ISGylation is readily removed through de-ISGylation by the papain-like protease (PLpro) activity of NSP3. Mass spectrometry analysis identified that the N protein undergoes ISGylation at four lysine residues (K266, K355, K387 and K388), and mutational analysis of these sites in the context of a SARS-CoV-2 replicon (N-4KR) abolished N ISGylation and alleviated ISGylation-mediated inhibition of viral RNA synthesis. Furthermore, our results indicated that HERC5 targets preferentially phosphorylated N protein for ISGylation to regulate its oligomeric assembly. These findings reveal a novel mechanism by which the host ISGylation machinery directly targets SARS-CoV-2 proteins to restrict viral replication and illuminate how an intricate interplay of host (HERC5) and viral (PLpro) enzymes coordinates viral protein ISGylation and thereby regulates virus replication.
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Affiliation(s)
- Junji Zhu
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, FL 34987, USA
| | - GuanQun Liu
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, FL 34987, USA
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Christopher M. Goins
- Center for Therapeutics Discovery, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Shaun R. Stauffer
- Center for Therapeutics Discovery, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Michaela U. Gack
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, FL 34987, USA
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8
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Nguyen A, Zhao H, Myagmarsuren D, Srinivasan S, Wu D, Chen J, Piszczek G, Schuck P. Modulation of Biophysical Properties of Nucleocapsid Protein in the Mutant Spectrum of SARS-CoV-2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.21.568093. [PMID: 38045241 PMCID: PMC10690151 DOI: 10.1101/2023.11.21.568093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Genetic diversity is a hallmark of RNA viruses and the basis for their evolutionary success. Taking advantage of the uniquely large genomic database of SARS-CoV-2, we examine the impact of mutations across the spectrum of viable amino acid sequences on the biophysical phenotypes of the highly expressed and multifunctional nucleocapsid protein. We find variation in the physicochemical parameters of its extended intrinsically disordered regions (IDRs) sufficient to allow local plasticity, but also exhibiting functional constraints that similarly occur in related coronaviruses. In biophysical experiments with several N-protein species carrying mutations associated with major variants, we find that point mutations in the IDRs can have nonlocal impact and modulate thermodynamic stability, secondary structure, protein oligomeric state, particle formation, and liquid-liquid phase separation. In the Omicron variant, distant mutations in different IDRs have compensatory effects in shifting a delicate balance of interactions controlling protein assembly properties, and include the creation of a new protein-protein interaction interface in the N-terminal IDR through the defining P13L mutation. A picture emerges where genetic diversity is accompanied by significant variation in biophysical characteristics of functional N-protein species, in particular in the IDRs.
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Affiliation(s)
- Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dulguun Myagmarsuren
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sanjana Srinivasan
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jiji Chen
- Advanced Imaging and Microscopy Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
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9
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Schuck P, Zhao H. Diversity of short linear interaction motifs in SARS-CoV-2 nucleocapsid protein. mBio 2023; 14:e0238823. [PMID: 38018991 PMCID: PMC10746173 DOI: 10.1128/mbio.02388-23] [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: 09/01/2023] [Accepted: 10/16/2023] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE Short linear motifs (SLiMs) are 3-10 amino acid long binding motifs in intrinsically disordered protein regions (IDRs) that serve as ubiquitous protein-protein interaction modules in eukaryotic cells. Through molecular mimicry, viruses hijack these sequence motifs to control host cellular processes. It is thought that the small size of SLiMs and the high mutation frequencies of viral IDRs allow rapid host adaptation. However, a salient characteristic of RNA viruses, due to high replication errors, is their obligate existence as mutant swarms. Taking advantage of the uniquely large genomic database of SARS-CoV-2, here, we analyze the role of sequence diversity in the presentation of SLiMs, focusing on the highly abundant, multi-functional nucleocapsid protein. We find that motif mimicry is a highly dynamic process that produces an abundance of motifs transiently present in subsets of mutant species. This diversity allows the virus to efficiently explore eukaryotic motifs and evolve the host-virus interface.
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Affiliation(s)
- Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
| | - Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
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10
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Adly AN, Bi M, Carlson CR, Syed AM, Ciling A, Doudna JA, Cheng Y, Morgan DO. Assembly of SARS-CoV-2 ribonucleosomes by truncated N ∗ variant of the nucleocapsid protein. J Biol Chem 2023; 299:105362. [PMID: 37863261 PMCID: PMC10665939 DOI: 10.1016/j.jbc.2023.105362] [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: 08/18/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/22/2023] Open
Abstract
The nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compacts the RNA genome into viral ribonucleoprotein (vRNP) complexes within virions. Assembly of vRNPs is inhibited by phosphorylation of the N protein serine/arginine (SR) region. Several SARS-CoV-2 variants of concern carry N protein mutations that reduce phosphorylation and enhance the efficiency of viral packaging. Variants of the dominant B.1.1 viral lineage also encode a truncated N protein, termed N∗ or Δ(1-209), that mediates genome packaging despite lacking the N-terminal RNA-binding domain and SR region. Here, we use mass photometry and negative stain electron microscopy to show that purified Δ(1-209) and viral RNA assemble into vRNPs that are remarkably similar in size and shape to those formed with full-length N protein. We show that assembly of Δ(1-209) vRNPs requires the leucine-rich helix of the central disordered region and that this helix promotes N protein oligomerization. We also find that fusion of a phosphomimetic SR region to Δ(1-209) inhibits RNA binding and vRNP assembly. Our results provide new insights into the mechanisms by which RNA binding promotes N protein self-association and vRNP assembly, and how this process is modulated by phosphorylation.
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Affiliation(s)
- Armin N Adly
- Department of Physiology, University of California, San Francisco, California, USA
| | - Maxine Bi
- Department of Biochemistry & Biophysics, University of California, San Francisco, California, USA
| | | | - Abdullah M Syed
- J. David Gladstone Institutes, San Francisco, California, USA
| | - Alison Ciling
- J. David Gladstone Institutes, San Francisco, California, USA
| | - Jennifer A Doudna
- J. David Gladstone Institutes, San Francisco, California, USA; Department of Molecular and Cell Biology, University of California, Berkeley, California, USA; Howard Hughes Medical Institute, University of California, Berkeley, California, USA; Innovative Genomics Institute, University of California, Berkeley, California, USA; California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Yifan Cheng
- Department of Biochemistry & Biophysics, University of California, San Francisco, California, USA; Howard Hughes Medical Institute, University of California, San Francisco, California, USA
| | - David O Morgan
- Department of Physiology, University of California, San Francisco, California, USA.
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11
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Zhao H, Syed AM, Khalid MM, Nguyen A, Ciling A, Wu D, Yau WM, Srinivasan S, Esposito D, Doudna JA, Piszczek G, Ott M, Schuck P. Assembly reactions of SARS-CoV-2 nucleocapsid protein with nucleic acid. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568361. [PMID: 38045338 PMCID: PMC10690241 DOI: 10.1101/2023.11.22.568361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The viral genome of SARS-CoV-2 is packaged by the nucleocapsid (N-) protein into ribonucleoprotein particles (RNPs), 38±10 of which are contained in each virion. Their architecture has remained unclear due to the pleomorphism of RNPs, the high flexibility of N-protein intrinsically disordered regions, and highly multivalent interactions between viral RNA and N-protein binding sites in both N-terminal (NTD) and C-terminal domain (CTD). Here we explore critical interaction motifs of RNPs by applying a combination of biophysical techniques to mutant proteins binding different nucleic acids in an in vitro assay for RNP formation, and by examining mutant proteins in a viral assembly assay. We find that nucleic acid-bound N-protein dimers oligomerize via a recently described protein-protein interface presented by a transient helix in its long disordered linker region between NTD and CTD. The resulting hexameric complexes are stabilized by multi-valent protein-nucleic acid interactions that establish crosslinks between dimeric subunits. Assemblies are stabilized by the dimeric CTD of N-protein offering more than one binding site for stem-loop RNA. Our study suggests a model for RNP assembly where N-protein scaffolding at high density on viral RNA is followed by cooperative multimerization through protein-protein interactions in the disordered linker.
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Affiliation(s)
- Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Abdullah M. Syed
- Gladstone Institutes, San Francisco, CA 94158
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | | | - Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Alison Ciling
- Gladstone Institutes, San Francisco, CA 94158
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sanjana Srinivasan
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Dominic Esposito
- Protein Expression Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Jennifer A. Doudna
- Gladstone Institutes, San Francisco, CA 94158
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- HHMI, University of California, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Melanie Ott
- Gladstone Institutes, San Francisco, CA 94158
- Department of Medicine, University of California, San Francisco, CA 94143
- Chan Zuckerberg Biohub, San Francisco, CA 94158
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
- Center for Biomedical Engineering Technology Acceleration, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
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12
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Boniardi I, Corona A, Basquin J, Basquin C, Milia J, Nagy I, Tramontano E, Zinzula L. Suramin inhibits SARS-CoV-2 nucleocapsid phosphoprotein genome packaging function. Virus Res 2023; 336:199221. [PMID: 37704176 PMCID: PMC10514558 DOI: 10.1016/j.virusres.2023.199221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/27/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic is fading, however its etiologic agent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues posing - despite the availability of licensed vaccines - a global health threat, due to the potential emergence of vaccine-resistant SARS-CoV-2 variants. This makes the development of new drugs against COVID-19 a persistent urgency and sets as research priority the validation of novel therapeutic targets within the SARS-CoV-2 proteome. Among these, a promising one is the SARS-CoV-2 nucleocapsid (N) phosphoprotein, a major structural component of the virion with indispensable role in packaging the viral genome into a ribonucleoprotein (RNP) complex, which also contributes to SARS-CoV-2 innate immune evasion by inhibiting the host cell type-I interferon (IFN-I) response. By combining miniaturized differential scanning fluorimetry with microscale thermophoresis, we found that the 100-year-old drug Suramin interacts with SARS-CoV-2 N-terminal domain (NTD) and C-terminal domain (CTD), thereby inhibiting their single-stranded RNA (ssRNA) binding function with low-micromolar Kd and IC50 values. Molecular docking suggests that Suramin interacts with basic NTD cleft and CTD dimer interface groove, highlighting three potentially druggable ssRNA binding sites. Electron microscopy shows that Suramin inhibits the formation in vitro of RNP complex-like condensates by SARS-CoV-2 N with a synthetic ssRNA. In a dose-dependent manner, Suramin also reduced SARS-CoV-2-induced cytopathic effect on Vero E6 and Calu-3 cells, partially reverting the SARS-CoV-2 N-inhibited IFN-I production in 293T cells. Our findings indicate that Suramin inhibits SARS-CoV-2 replication by hampering viral genome packaging, thereby representing a starting model for design of new COVID-19 antivirals.
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Affiliation(s)
- Irene Boniardi
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Monserrato 09042, Italy
| | - Jerome Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Claire Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Jessica Milia
- Department of Life and Environmental Sciences, University of Cagliari, Monserrato 09042, Italy
| | - István Nagy
- Center of Research and Development, Eszterházy Károly Catholic University, Eger 3300, Hungary
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Monserrato 09042, Italy.
| | - Luca Zinzula
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany.
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13
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Schuck P, Zhao H. Diversity of Short Linear Interaction Motifs in SARS-CoV-2 Nucleocapsid Protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.01.551467. [PMID: 37790474 PMCID: PMC10542142 DOI: 10.1101/2023.08.01.551467] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Molecular mimicry of short linear interaction motifs has emerged as a key mechanism for viral proteins binding host domains and hijacking host cell processes. Here, we examine the role of RNA-virus sequence diversity in the dynamics of the virus-host interface, by analyzing the uniquely vast sequence record of viable SARS-CoV-2 species with focus on the multi-functional nucleocapsid protein. We observe the abundant presentation of motifs encoding several essential host protein interactions, alongside a majority of possibly non-functional and randomly occurring motif sequences absent in subsets of viable virus species. A large number of motifs emerge ex nihilo through transient mutations relative to the ancestral consensus sequence. The observed mutational landscape implies an accessible motif space that spans at least 25% of known eukaryotic motifs. This reveals motif mimicry as a highly dynamic process with the capacity to broadly explore host motifs, allowing the virus to rapidly evolve the virus-host interface.
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Affiliation(s)
- Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
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14
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Wang Y, Ling X, Zhang C, Zou J, Luo B, Luo Y, Jia X, Jia G, Zhang M, Hu J, Liu T, Wang Y, Lu K, Li D, Ma J, Liu C, Su Z. Modular characterization of SARS-CoV-2 nucleocapsid protein domain functions in nucleocapsid-like assembly. MOLECULAR BIOMEDICINE 2023; 4:16. [PMID: 37211575 DOI: 10.1186/s43556-023-00129-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/09/2023] [Indexed: 05/23/2023] Open
Abstract
SARS-CoV-2 and its variants, with the Omicron subvariant XBB currently prevailing the global infections, continue to pose threats on public health worldwide. This non-segmented positive-stranded RNA virus encodes the multi-functional nucleocapsid protein (N) that plays key roles in viral infection, replication, genome packaging and budding. N protein consists of two structural domains, NTD and CTD, and three intrinsically disordered regions (IDRs) including the NIDR, the serine/arginine rich motif (SRIDR), and the CIDR. Previous studies revealed functions of N protein in RNA binding, oligomerization, and liquid-liquid phase separation (LLPS), however, characterizations of individual domains and their dissected contributions to N protein functions remain incomplete. In particular, little is known about N protein assembly that may play essential roles in viral replication and genome packing. Here, we present a modular approach to dissect functional roles of individual domains in SARS-CoV-2 N protein that reveals inhibitory or augmented modulations of protein assembly and LLPS in the presence of viral RNAs. Intriguingly, full-length N protein (NFL) assembles into ring-like architecture whereas the truncated SRIDR-CTD-CIDR (N182-419) promotes filamentous assembly. Moreover, LLPS droplets of NFL and N182-419 are significantly enlarged in the presence of viral RNAs, and we observed filamentous structures in the N182-419 droplets using correlative light and electron microscopy (CLEM), suggesting that the formation of LLPS droplets may promote higher-order assembly of N protein for transcription, replication and packaging. Together this study expands our understanding of the multiple functions of N protein in SARS-CoV-2.
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Affiliation(s)
- Yan Wang
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Xiaobin Ling
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Chong Zhang
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Jian Zou
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Bingnan Luo
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Yongbo Luo
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Xinyu Jia
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Guowen Jia
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Minghua Zhang
- College of Polymer Science and Engineering, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Junchao Hu
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Ting Liu
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Yuanfeiyi Wang
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Kefeng Lu
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China
| | - Dan Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai, 200438, China.
| | - Cong Liu
- Interdisciplinary Research Center On Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 201210, China.
- State Key Laboratory of Bio-Organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Zhaoming Su
- The State Key Laboratory of Biotherapy, Frontiers Medical Center of Tianfu Jincheng Laboratory, National Clinical Research Center for Geriatrics and Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, 610044, Sichuan, China.
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15
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Zhao H, Wu D, Hassan SA, Nguyen A, Chen J, Piszczek G, Schuck P. A conserved oligomerization domain in the disordered linker of coronavirus nucleocapsid proteins. SCIENCE ADVANCES 2023; 9:eadg6473. [PMID: 37018390 PMCID: PMC10075959 DOI: 10.1126/sciadv.adg6473] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/07/2023] [Indexed: 06/01/2023]
Abstract
The nucleocapsid (N-)protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a key role in viral assembly and scaffolding of the viral RNA. It promotes liquid-liquid phase separation (LLPS), forming dense droplets that support the assembly of ribonucleoprotein particles with as-of-yet unknown macromolecular architecture. Combining biophysical experiments, molecular dynamics simulations, and analysis of the mutational landscape, we describe a heretofore unknown oligomerization site that contributes to LLPS, is required for the assembly of higher-order protein-nucleic acid complexes, and is coupled to large-scale conformational changes of N-protein upon nucleic acid binding. The self-association interface is located in a leucine-rich sequence of the intrinsically disordered linker between N-protein folded domains and formed by transient helices assembling into trimeric coiled-coils. Critical residues stabilizing hydrophobic and electrostatic interactions between adjacent helices are highly protected against mutations in viable SARS-CoV-2 genomes, and the oligomerization motif is conserved across related coronaviruses, thus presenting a target for antiviral therapeutics.
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Affiliation(s)
- Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sergio A. Hassan
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jiji Chen
- Advanced Imaging and Microscopy Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
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16
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Lee E, Redzic JS, Saviola AJ, Li X, Ebmeier CC, Kutateladze T, Hansen KC, Zhao R, Ahn N, Sluchanko NN, Eisenmesser E. Molecular insight into the specific interactions of the SARS-Coronavirus-2 nucleocapsid with RNA and host protein. Protein Sci 2023; 32:e4603. [PMID: 36807437 PMCID: PMC10019451 DOI: 10.1002/pro.4603] [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: 12/20/2022] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 02/23/2023]
Abstract
The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) nucleocapsid protein is the most abundantly expressed viral protein during infection where it targets both RNA and host proteins. However, identifying how a single viral protein interacts with so many different targets remains a challenge, providing the impetus here for identifying the interaction sites through multiple methods. Through a combination of nuclear magnetic resonance (NMR), electron microscopy, and biochemical methods, we have characterized nucleocapsid interactions with RNA and with three host proteins, which include human cyclophilin-A, Pin1, and 14-3-3τ. Regarding RNA interactions, the nucleocapsid protein N-terminal folded domain preferentially interacts with smaller RNA fragments relative to the C-terminal region, suggesting an initial RNA engagement is largely dictated by this N-terminal region followed by weaker interactions to the C-terminal region. The nucleocapsid protein forms 10 nm ribonuclear complexes with larger RNA fragments that include 200 and 354 nucleic acids, revealing its potential diversity in sequestering different viral genomic regions during viral packaging. Regarding host protein interactions, while the nucleocapsid targets all three host proteins through its serine-arginine-rich region, unstructured termini of the nucleocapsid protein also engage host cyclophilin-A and host 14-3-3τ. Considering these host proteins play roles in innate immunity, the SARS-CoV-2 nucleocapsid protein may block the host response by competing interactions. Finally, phosphorylation of the nucleocapsid protein quenches an inherent dynamic exchange process within its serine-arginine-rich region. Our studies identify many of the diverse interactions that may be important for SARS-CoV-2 pathology during infection.
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Affiliation(s)
- Eunjeong Lee
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
| | - Jasmina S. Redzic
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
| | - Anthony J. Saviola
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
| | - Xueni Li
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
| | | | - Tatiana Kutateladze
- Department of PharmacologySchool of Medicine, University of Colorado DenverAuroraColoradoUSA
| | - Kirk Charles Hansen
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
| | - Rui Zhao
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
| | - Natalie Ahn
- Department of BiochemistryUniversity of Colorado BoulderBoulderColoradoUSA
| | - Nikolai N. Sluchanko
- A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of SciencesMoscowRussia
| | - Elan Eisenmesser
- Department of Biochemistry and Molecular Genetics, School of MedicineUniversity of Colorado DenverAuroraColoradoUSA
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17
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Zheng Y, Gao C. Phase Separation: The Robust Modulator of Innate Antiviral Signaling and SARS-CoV-2 Infection. Pathogens 2023; 12:pathogens12020243. [PMID: 36839515 PMCID: PMC9962166 DOI: 10.3390/pathogens12020243] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/28/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023] Open
Abstract
SARS-CoV-2 has been a pandemic threat to human health and the worldwide economy, but efficient treatments are still lacking. Type I and III interferons are essential for controlling viral infection, indicating that antiviral innate immune signaling is critical for defense against viral infection. Phase separation, one of the basic molecular processes, governs multiple cellular activities, such as cancer progression, microbial infection, and signaling transduction. Notably, recent studies suggest that phase separation regulates antiviral signaling such as the RLR and cGAS-STING pathways. Moreover, proper phase separation of viral proteins is essential for viral replication and pathogenesis. These observations indicate that phase separation is a critical checkpoint for virus and host interaction. In this study, we summarize the recent advances concerning the regulation of antiviral innate immune signaling and SARS-CoV-2 infection by phase separation. Our review highlights the emerging notion that phase separation is the robust modulator of innate antiviral signaling and viral infection.
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18
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Tugaeva KV, Sysoev AA, Kapitonova AA, Smith JLR, Zhu P, Cooley RB, Antson AA, Sluchanko NN. Human 14-3-3 Proteins Site-selectively Bind the Mutational Hotspot Region of SARS-CoV-2 Nucleoprotein Modulating its Phosphoregulation. J Mol Biol 2023; 435:167891. [PMID: 36427566 PMCID: PMC9683861 DOI: 10.1016/j.jmb.2022.167891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/06/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022]
Abstract
Phosphorylation of SARS-CoV-2 nucleoprotein recruits human cytosolic 14-3-3 proteins playing a well-recognized role in replication of many viruses. Here we use genetic code expansion to demonstrate that 14-3-3 binding is triggered by phosphorylation of SARS-CoV-2 nucleoprotein at either of two pseudo-repeats centered at Ser197 and Thr205. According to fluorescence anisotropy measurements, the pT205-motif,presentin SARS-CoV-2 but not in SARS-CoV, is preferred over the pS197-motif by all seven human 14-3-3 isoforms, which collectively display an unforeseen pT205/pS197 peptide binding selectivity hierarchy. Crystal structures demonstrate that pS197 and pT205 are mutually exclusive 14-3-3-binding sites, whereas SAXS and biochemical data obtained on the full protein-protein complex indicate that 14-3-3 binding occludes the Ser/Arg-rich region of the nucleoprotein, inhibiting its dephosphorylation. This Ser/Arg-rich region is highly prone to mutations, as exemplified by the Omicron and Delta variants, with our data suggesting that the strength of 14-3-3/nucleoprotein interaction can be linked with the replicative fitness of the virus.
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Affiliation(s)
- Kristina V Tugaeva
- A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Andrey A Sysoev
- A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Anna A Kapitonova
- A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Jake L R Smith
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Phillip Zhu
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Richard B Cooley
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Alfred A Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Nikolai N Sluchanko
- A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia.
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