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Wang H, Liao S, Yu X, Zhang J, Zhou ZH. TomoNet: A streamlined cryogenic electron tomography software pipeline with automatic particle picking on flexible lattices. BIOLOGICAL IMAGING 2024; 4:e7. [PMID: 38828212 PMCID: PMC11140495 DOI: 10.1017/s2633903x24000060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/04/2024] [Accepted: 03/25/2024] [Indexed: 06/05/2024]
Abstract
Cryogenic electron tomography (cryoET) is capable of determining in situ biological structures of molecular complexes at near-atomic resolution by averaging half a million subtomograms. While abundant complexes/particles are often clustered in arrays, precisely locating and seamlessly averaging such particles across many tomograms present major challenges. Here, we developed TomoNet, a software package with a modern graphical user interface to carry out the entire pipeline of cryoET and subtomogram averaging to achieve high resolution. TomoNet features built-in automatic particle picking and three-dimensional (3D) classification functions and integrates commonly used packages to streamline high-resolution subtomogram averaging for structures in 1D, 2D, or 3D arrays. Automatic particle picking is accomplished in two complementary ways: one based on template matching and the other using deep learning. TomoNet's hierarchical file organization and visual display facilitate efficient data management as required for large cryoET datasets. Applications of TomoNet to three types of datasets demonstrate its capability of efficient and accurate particle picking on flexible and imperfect lattices to obtain high-resolution 3D biological structures: virus-like particles, bacterial surface layers within cellular lamellae, and membranes decorated with nuclear egress protein complexes. These results demonstrate TomoNet's potential for broad applications to various cryoET projects targeting high-resolution in situ structures.
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Affiliation(s)
- Hui Wang
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Shiqing Liao
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Xinye Yu
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Jiayan Zhang
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Z. Hong Zhou
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
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2
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Jih J, Liu YT, Liu W, Zhou ZH. The incredible bulk: Human cytomegalovirus tegument architectures uncovered by AI-empowered cryo-EM. SCIENCE ADVANCES 2024; 10:eadj1640. [PMID: 38394211 PMCID: PMC10889378 DOI: 10.1126/sciadv.adj1640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
The compartmentalization of eukaryotic cells presents considerable challenges to the herpesvirus life cycle. The herpesvirus tegument, a bulky proteinaceous aggregate sandwiched between herpesviruses' capsid and envelope, is uniquely evolved to address these challenges, yet tegument structure and organization remain poorly characterized. We use deep-learning-enhanced cryogenic electron microscopy to investigate the tegument of human cytomegalovirus virions and noninfectious enveloped particles (NIEPs; a genome packaging-aborted state), revealing a portal-biased tegumentation scheme. We resolve atomic structures of portal vertex-associated tegument (PVAT) and identify multiple configurations of PVAT arising from layered reorganization of pUL77, pUL48 (large tegument protein), and pUL47 (inner tegument protein) assemblies. Analyses show that pUL77 seals the last-packaged viral genome end through electrostatic interactions, pUL77 and pUL48 harbor a head-linker-capsid-binding motif conducive to PVAT reconfiguration, and pUL47/48 dimers form 45-nm-long filaments extending from the portal vertex. These results provide a structural framework for understanding how herpesvirus tegument facilitates and evolves during processes spanning viral genome packaging to delivery.
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Affiliation(s)
- Jonathan Jih
- Molecular Biology Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Yun-Tao Liu
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Wei Liu
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Z. Hong Zhou
- Molecular Biology Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
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3
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Zhang M, Wang X, Li J, Peng F, Liu Z, Chen ZS. Ligands and receptors in human cytomegalovirus entry: Current therapies and new directions. Drug Discov Today 2024; 29:103833. [PMID: 37992888 DOI: 10.1016/j.drudis.2023.103833] [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: 08/20/2023] [Revised: 11/11/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023]
Abstract
The demand for human cytomegalovirus (HCMV) vaccines was first raised by a committee convened during the 1990s. A comprehensive investigation into the mechanism of viral infection supports the prioritization of developing drugs or vaccines that specifically target receptors and ligands involved in the infection process. As primary targets for neutralizing antibodies to combat HCMV, viral ligands (trimer, pentamer, and glycoprotein B) have crucial roles and exhibit substantial antiviral potential, which could be exploited for breakthroughs in antiviral research.
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Affiliation(s)
- Min Zhang
- School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Xiaochen Wang
- Department of Medical Microbiology, Basic Medical College, Weifang Medical University, Weifang 261053, China
| | - Jianshe Li
- School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Fujun Peng
- School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China.
| | - Zhijun Liu
- Department of Medical Microbiology, Basic Medical College, Weifang Medical University, Weifang 261053, China.
| | - Zhe-Sheng Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St John's University, Queens, NY 11439, USA.
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4
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Zhou M, Vollmer B, Machala E, Chen M, Grünewald K, Arvin AM, Chiu W, Oliver SL. Targeted mutagenesis of the herpesvirus fusogen central helix captures transition states. Nat Commun 2023; 14:7958. [PMID: 38042814 PMCID: PMC10693595 DOI: 10.1038/s41467-023-43011-w] [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: 12/12/2022] [Accepted: 10/27/2023] [Indexed: 12/04/2023] Open
Abstract
Herpesviruses remain a burden for animal and human health, including the medically important varicella-zoster virus (VZV). Membrane fusion mediated by conserved core glycoproteins, the fusogen gB and the heterodimer gH-gL, enables herpesvirus cell entry. The ectodomain of gB orthologs has five domains and is proposed to transition from a prefusion to postfusion conformation but the functional relevance of the domains for this transition remains poorly defined. Here we describe structure-function studies of the VZV gB DIII central helix targeting residues 526EHV528. Critically, a H527P mutation captures gB in a prefusion conformation as determined by cryo-EM, a loss of membrane fusion in a virus free assay, and failure of recombinant VZV to spread in cell monolayers. Importantly, two predominant cryo-EM structures of gB[H527P] are identified by 3D classification and focused refinement, suggesting they represented gB conformations in transition. These studies reveal gB DIII as a critical element for herpesvirus gB fusion function.
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Affiliation(s)
- Momei Zhou
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA.
| | - Benjamin Vollmer
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Department of Chemistry, University of Hamburg, Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Emily Machala
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Department of Chemistry, University of Hamburg, Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Muyuan Chen
- Division of Cryo-EM and Bioimaging SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Kay Grünewald
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Department of Chemistry, University of Hamburg, Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Ann M Arvin
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
- Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Vir Biotechnology Inc, San Francisco, CA, USA
| | - Wah Chiu
- Division of Cryo-EM and Bioimaging SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Bioengineering, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Stefan L Oliver
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
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5
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Sun C, Kang YF, Fang XY, Liu YN, Bu GL, Wang AJ, Li Y, Zhu QY, Zhang H, Xie C, Kong XW, Peng YJ, Lin WJ, Zhou L, Chen XC, Lu ZZ, Xu HQ, Hong DC, Zhang X, Zhong L, Feng GK, Zeng YX, Xu M, Zhong Q, Liu Z, Zeng MS. A gB nanoparticle vaccine elicits a protective neutralizing antibody response against EBV. Cell Host Microbe 2023; 31:1882-1897.e10. [PMID: 37848029 DOI: 10.1016/j.chom.2023.09.011] [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: 01/02/2023] [Revised: 08/17/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023]
Abstract
Epstein-Barr virus (EBV) is a global public health concern, as it is known to cause multiple diseases while also being etiologically associated with a wide range of epithelial and lymphoid malignancies. Currently, there is no available prophylactic vaccine against EBV. gB is the EBV fusion protein that mediates viral membrane fusion and participates in host recognition, making it critical for EBV infection in both B cells and epithelial cells. Here, we present a gB nanoparticle, gB-I53-50 NP, that displays multiple copies of gB. Compared with the gB trimer, gB-I53-50 NP shows improved structural integrity and stability, as well as enhanced immunogenicity in mice and non-human primate (NHP) preclinical models. Immunization and passive transfer demonstrate a robust and durable protective antibody response that protects humanized mice against lethal EBV challenge. This vaccine candidate demonstrates significant potential in preventing EBV infection, providing a possible platform for developing prophylactic vaccines for EBV.
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Affiliation(s)
- Cong Sun
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Yin-Feng Kang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Xin-Yan Fang
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yi-Na Liu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Guo-Long Bu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Ao-Jie Wang
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yan Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Qian-Ying Zhu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Hua Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China; MOE Key Laboratory of Tropical Disease Control, Centre for Infection and Immunity Studies (CIIS), School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Chu Xie
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Xiang-Wei Kong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Yong-Jian Peng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Wen-Jie Lin
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Ling Zhou
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Xin-Chun Chen
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Zheng-Zhou Lu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Hui-Qin Xu
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Dong-Chun Hong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Xiao Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Ling Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Guo-Kai Feng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Yi-Xin Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Miao Xu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China
| | - Qian Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China.
| | - Zheng Liu
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
| | - Mu-Sheng Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China.
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6
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Zhu D, Cao D, Zhang X. Virus structures revealed by advanced cryoelectron microscopy methods. Structure 2023; 31:1348-1359. [PMID: 37797619 DOI: 10.1016/j.str.2023.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/25/2023] [Accepted: 09/11/2023] [Indexed: 10/07/2023]
Abstract
Before the resolution revolution, cryoelectron microscopy (cryo-EM) single-particle analysis (SPA) already achieved resolutions beyond 4 Å for certain icosahedral viruses, enabling ab initio atomic model building of these viruses. As the only samples that achieved such high resolution at that time, cryo-EM method development was closely intertwined with the improvement of reconstructions of symmetrical viruses. Viral morphology exhibits significant diversity, ranging from small to large, uniform to non-uniform, and from containing single symmetry to multiple symmetries. Furthermore, viruses undergo conformational changes during their life cycle. Several methods, such as asymmetric reconstruction, Ewald sphere correction, cryoelectron tomography (cryo-ET), and sub-tomogram averaging (STA), have been developed and applied to determine virus structures in vivo and in vitro. This review outlines current advanced cryo-EM methods for high-resolution structure determination of viruses and summarizes accomplishments obtained with these approaches. Moreover, persisting challenges in comprehending virus structures are discussed and we propose potential solutions.
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Affiliation(s)
- Dongjie Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Duanfang Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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7
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Abstract
There are at least 21 families of enveloped viruses that infect mammals, and many contain members of high concern for global human health. All enveloped viruses have a dedicated fusion protein or fusion complex that enacts the critical genome-releasing membrane fusion event that is essential before viral replication within the host cell interior can begin. Because all enveloped viruses enter cells by fusion, it behooves us to know how viral fusion proteins function. Viral fusion proteins are also major targets of neutralizing antibodies, and hence they serve as key vaccine immunogens. Here we review current concepts about viral membrane fusion proteins focusing on how they are triggered, structural intermediates between pre- and postfusion forms, and their interplay with the lipid bilayers they engage. We also discuss cellular and therapeutic interventions that thwart virus-cell membrane fusion.
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Affiliation(s)
- Judith M White
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, USA;
| | - Amanda E Ward
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Laura Odongo
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
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8
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Bogdanow B, Gruska I, Mühlberg L, Protze J, Hohensee S, Vetter B, Bosse JB, Lehmann M, Sadeghi M, Wiebusch L, Liu F. Spatially resolved protein map of intact human cytomegalovirus virions. Nat Microbiol 2023; 8:1732-1747. [PMID: 37550507 PMCID: PMC10465357 DOI: 10.1038/s41564-023-01433-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/20/2023] [Indexed: 08/09/2023]
Abstract
Herpesviruses assemble large enveloped particles that are difficult to characterize structurally due to their size, fragility and complex multilayered proteome with partially amorphous nature. Here we used crosslinking mass spectrometry and quantitative proteomics to derive a spatially resolved interactome map of intact human cytomegalovirus virions. This enabled the de novo allocation of 32 viral proteins into four spatially resolved virion layers, each organized by a dominant viral scaffold protein. The viral protein UL32 engages with all layers in an N-to-C-terminal radial orientation, bridging nucleocapsid to viral envelope. We observed the layer-specific incorporation of 82 host proteins, of which 39 are selectively recruited. We uncovered how UL32, by recruitment of PP-1 phosphatase, antagonizes binding to 14-3-3 proteins. This mechanism assures effective viral biogenesis, suggesting a perturbing role of UL32-14-3-3 interaction. Finally, we integrated these data into a coarse-grained model to provide global insights into the native configuration of virus and host protein interactions inside herpesvirions.
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Affiliation(s)
- Boris Bogdanow
- Research group 'Structural Interactomics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
| | - Iris Gruska
- Labor für Pädiatrische Molekularbiologie, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lars Mühlberg
- Research group 'Structural Interactomics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Jonas Protze
- Research group 'Structural Bioinformatics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Svea Hohensee
- Cellular Imaging core facility, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Barbara Vetter
- Labor für Pädiatrische Molekularbiologie, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jens B Bosse
- Centre for Structural Systems Biology, Hamburg, Germany
- Hannover Medical School, Institute of Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
| | - Martin Lehmann
- Cellular Imaging core facility, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Mohsen Sadeghi
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany.
| | - Lüder Wiebusch
- Labor für Pädiatrische Molekularbiologie, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
| | - Fan Liu
- Research group 'Structural Interactomics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
- Charité Universitätsmedizin Berlin, Berlin, Germany.
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9
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Yamaguchi K, Shimizu H, Takahashi K, Nagatomo T, Nishimura T, Matsumoto M, Koshizuka T, Mori H, Inoue N, Torikai M. Characterization of epitopes of human monoclonal antibodies against cytomegalovirus glycoprotein B for neutralization and antibody-dependent phagocytosis. Vaccine 2023; 41:4497-4507. [PMID: 37321896 DOI: 10.1016/j.vaccine.2023.06.003] [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: 02/25/2023] [Revised: 05/29/2023] [Accepted: 06/01/2023] [Indexed: 06/17/2023]
Abstract
As congenital cytomegalovirus (CMV) infections are the leading non-genetic cause of sensorineural hearing loss and significant neurological disabilities in children, the development of CMV vaccines should be given the highest public health priority. Although MF59-adjuvanted glycoprotein B (gB) vaccine (gB/MF59) is safe and immunogenic, its efficacy in terms of protection from natural infection was around 50 % in clinical trials. Although gB/MF59 induced high antibody titers, anti-gB antibodies contributed little to the neutralization of infection. Recent studies have found that non-neutralizing functions, including antibody-dependent phagocytosis of virions and virus-infected cells, are likely to play important roles in pathogenesis and vaccine design. Previously, we isolated human monoclonal antibodies (MAbs) that reacted with the trimeric form of gB ectodomain and found that preferential epitopes for neutralization were present on Domains (Doms) I and II of gB, while there were abundant non-neutralizing antibodies targeting Dom IV. In this study, we analyzed the phagocytosis activities of these MAbs and found the following: 1) MAbs effective for phagocytosis of the virions targeted Doms I and II, 2) the MAbs effective for phagocytosis of the virions and those of virus-infected cells were generally distinct, and 3) the antibody-dependent phagocytosis showed little correlation with neutralizing activities. Taking account of the frequency and levels of neutralization and phagocytosis, incorporation of the epitopes on Doms I and II into developing vaccines is considered desirable for the prevention of viremia.
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Affiliation(s)
| | | | - Keita Takahashi
- Microbiology & Immunology, Gifu Pharmaceutical University, Japan
| | | | | | | | - Tetsuo Koshizuka
- Microbiology & Immunology, Gifu Pharmaceutical University, Japan
| | - Hiroaki Mori
- Kikuchi Research Center, KM Biologics Co., Ltd, Japan
| | - Naoki Inoue
- Microbiology & Immunology, Gifu Pharmaceutical University, Japan.
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10
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Zhong L, Zhang W, Krummenacher C, Chen Y, Zheng Q, Zhao Q, Zeng MS, Xia N, Zeng YX, Xu M, Zhang X. Targeting herpesvirus entry complex and fusogen glycoproteins with prophylactic and therapeutic agents. Trends Microbiol 2023:S0966-842X(23)00077-X. [DOI: 10.1016/j.tim.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 04/03/2023]
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11
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Gomes AC, Baraniak IA, Lankina A, Moulder Z, Holenya P, Atkinson C, Tang G, Mahungu T, Kern F, Griffiths PD, Reeves MB. The cytomegalovirus gB/MF59 vaccine candidate induces antibodies against an antigenic domain controlling cell-to-cell spread. Nat Commun 2023; 14:1041. [PMID: 36823200 PMCID: PMC9950427 DOI: 10.1038/s41467-023-36683-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 02/13/2023] [Indexed: 02/25/2023] Open
Abstract
Vaccination against human cytomegalovirus (CMV) infection remains high priority. A recombinant form of a protein essential for CMV entry, glycoprotein B (gB), demonstrated partial protection in a clinical trial (NCT00299260) when delivered with the MF59 adjuvant. Although the antibody titre against gB correlated with protection poor neutralising responses against the 5 known antigenic domains (AD) of gB were evident. Here, we show that vaccination of CMV seronegative patients induces an antibody response against a region of gB we term AD-6. Responses to the polypeptide AD-6 are detected in >70% of vaccine recipients yet in <5% of naturally infected people. An AD-6 antibody binds to gB and to infected cells but not the virion directly. Consistent with this, the AD-6 antibody is non-neutralising but, instead, prevents cell-cell spread of CMV in vitro. The discovery of AD-6 responses has the potential to explain part of the protection mediated by gB vaccines against CMV following transplantation.
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Affiliation(s)
- A C Gomes
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - I A Baraniak
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - A Lankina
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - Z Moulder
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - P Holenya
- JPT Peptide Technologies GmbH, Berlin, Germany
| | - C Atkinson
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - G Tang
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - T Mahungu
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - F Kern
- JPT Peptide Technologies GmbH, Berlin, Germany
- Experimental Medicine, Brighton and Sussex Medical School, Brighton, United Kingdom
| | - P D Griffiths
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom
| | - M B Reeves
- Institute of Immunity & Transplantation, UCL, London, NW3 2PP, United Kingdom.
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12
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Sakuma M, Honda S, Ueno H, Tabata KV, Miyazaki K, Tokuriki N, Noji H. Genetic Perturbation Alters Functional Substates in Alkaline Phosphatase. J Am Chem Soc 2023; 145:2806-2814. [PMID: 36706363 PMCID: PMC9912328 DOI: 10.1021/jacs.2c06693] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Enzymes inherently exhibit molecule-to-molecule heterogeneity in their conformational and functional states, which is considered to be a key to the evolution of new functions. Single-molecule enzyme assays enable us to directly observe such multiple functional states or functional substates. Here, we quantitatively analyzed functional substates in the wild-type and 69 single-point mutants of Escherichia coli alkaline phosphatase by employing a high-throughput single-molecule assay with a femtoliter reactor array device. Interestingly, many mutant enzymes exhibited significantly heterogeneous functional substates with various types, while the wild-type enzyme showed a highly homogeneous substate. We identified a correlation between the degree of functional substates and the level of improvement in promiscuous activities. Our work provides much comprehensive evidence that the functional substates can be easily altered by mutations, and the evolution toward a new catalytic activity may involve the modulation of the functional substates.
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Affiliation(s)
- Morito Sakuma
- Department
of Applied Chemistry, The University of
Tokyo, Tokyo113-8656, Japan,Michael
Smith Laboratories, The University of British
Columbia, British
ColumbiaV6T1Z4, Canada
| | - Shingo Honda
- Department
of Applied Chemistry, The University of
Tokyo, Tokyo113-8656, Japan
| | - Hiroshi Ueno
- Department
of Applied Chemistry, The University of
Tokyo, Tokyo113-8656, Japan
| | - Kazuhito V. Tabata
- Department
of Applied Chemistry, The University of
Tokyo, Tokyo113-8656, Japan
| | - Kentaro Miyazaki
- International
Center for Biotechnology, Osaka University, Suita565-0871, Japan
| | - Nobuhiko Tokuriki
- Michael
Smith Laboratories, The University of British
Columbia, British
ColumbiaV6T1Z4, Canada,
| | - Hiroyuki Noji
- Department
of Applied Chemistry, The University of
Tokyo, Tokyo113-8656, Japan,
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13
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Okamoto M, Kurino R, Miura R, Takada K. A fully human neutralizing monoclonal antibody targeting a highly conserved epitope of the human cytomegalovirus glycoprotein B. PLoS One 2023; 18:e0285672. [PMID: 37192198 DOI: 10.1371/journal.pone.0285672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 04/27/2023] [Indexed: 05/18/2023] Open
Abstract
Human cytomegalovirus causes severe diseases in children (by congenital infection) and immunocompromised patients. Treatment with antiviral agents, such as ganciclovir, is limited by their toxicity. In this study, we investigated the effectiveness of a fully human neutralizing monoclonal antibody to inhibit human cytomegalovirus infection and viral cell-to-cell spread. We isolated a potent neutralizing antibody, EV2038 (IgG1 lambda), targeting human cytomegalovirus glycoprotein B using Epstein-Barr virus transformation. This antibody inhibited human cytomegalovirus infection by all four laboratory strains and 42 Japanese clinical isolates, including ganciclovir-resistant isolates, with a 50% inhibitory concentration (IC50) ranging from 0.013 to 0.105 μg/mL, and 90% inhibitory concentration (IC90) ranging from 0.208 to 1.026 μg/mL, in both human embryonic lung fibroblasts (MRC-5) and human retinal pigment epithelial (ARPE-19) cells. Additionally, EV2038 prevented cell-to-cell spread of eight clinical viral isolates, with IC50 values ranging from 1.0 to 3.1 μg/mL, and IC90 values ranging from 13 to 19 μg/mL, in ARPE-19 cells. EV2038 recognized three discontinuous sequences on antigenic domain 1 of glycoprotein B (amino acids 549-560, 569-576, and 625-632), which were highly conserved among 71 clinical isolates from Japan and the United States. Pharmacokinetics study in cynomolgus monkeys suggested the potential efficacy of EV2038 in vivo, the concentration of which in serum remained higher than the IC90 values of cell-to-cell spread until 28 days after intravenous injection of 10 mg/kg EV2038. Our data strongly support EV2038 as a promising candidate and novel alternative for the treatment of human cytomegalovirus infection.
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Affiliation(s)
- Miwa Okamoto
- Sapporo Laboratory, EVEC, Inc., Sapporo, Hokkaido, Japan
| | - Rika Kurino
- Sapporo Laboratory, EVEC, Inc., Sapporo, Hokkaido, Japan
| | - Ryu Miura
- Sapporo Laboratory, EVEC, Inc., Sapporo, Hokkaido, Japan
| | - Kenzo Takada
- Sapporo Laboratory, EVEC, Inc., Sapporo, Hokkaido, Japan
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14
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Zhou K, Si Z, Ge P, Tsao J, Luo M, Zhou ZH. Atomic model of vesicular stomatitis virus and mechanism of assembly. Nat Commun 2022; 13:5980. [PMID: 36216930 PMCID: PMC9549855 DOI: 10.1038/s41467-022-33664-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/27/2022] [Indexed: 11/22/2022] Open
Abstract
Like other negative-strand RNA viruses (NSVs) such as influenza and rabies, vesicular stomatitis virus (VSV) has a three-layered organization: a layer of matrix protein (M) resides between the glycoprotein (G)-studded membrane envelope and the nucleocapsid, which is composed of the nucleocapsid protein (N) and the encapsidated genomic RNA. Lack of in situ atomic structures of these viral components has limited mechanistic understanding of assembling the bullet-shaped virion. Here, by cryoEM and sub-particle reconstruction, we have determined the in situ structures of M and N inside VSV at 3.47 Å resolution. In the virion, N and M sites have a stoichiometry of 1:2. The in situ structures of both N and M differ from their crystal structures in their N-terminal segments and oligomerization loops. N-RNA, N-N, and N-M-M interactions govern the formation of the capsid. A double layer of M contributes to packaging of the helical nucleocapsid: the inner M (IM) joins neighboring turns of the N helix, while the outer M (OM) contacts G and the membrane envelope. The pseudo-crystalline organization of G is further mapped by cryoET. The mechanism of VSV assembly is delineated by the network interactions of these viral components. Zhou and Si et al. used cryogenic electron microscopy and tomography to delineate the molecular interactions among genomic RNA, nucleocapsid protein, matrix protein and glycoprotein in vesicular stomatitis virus and suggest a model of assembly.
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Affiliation(s)
- Kang Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA.,California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA.,School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Zhu Si
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA.,California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Peng Ge
- California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA.,Departments of Chemistry and Biochemistry and Biological Chemistry, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Jun Tsao
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Al, 35294, USA
| | - Ming Luo
- The Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA. .,California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA.
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15
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Hu X, Wang HY, Otero CE, Jenks JA, Permar SR. Lessons from Acquired Natural Immunity and Clinical Trials to Inform Next-Generation Human Cytomegalovirus Vaccine Development. Annu Rev Virol 2022; 9:491-520. [PMID: 35704747 PMCID: PMC10154983 DOI: 10.1146/annurev-virology-100220-010653] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human cytomegalovirus (HCMV) infection, the most common cause of congenital disease globally, affecting an estimated 1 million newborns annually, can result in lifelong sequelae in infants, such as sensorineural hearing loss and brain damage. HCMV infection also leads to a significant disease burden in immunocompromised individuals. Hence, an effective HCMV vaccine is urgently needed to prevent infection and HCMV-associated diseases. Unfortunately, despite more than five decades of vaccine development, no successful HCMV vaccine is available. This review summarizes what we have learned from acquired natural immunity, including innate and adaptive immunity; the successes and failures of HCMV vaccine human clinical trials; the progress in related animal models; and the analysis of protective immune responses during natural infection and vaccination settings. Finally, we propose novel vaccine strategies that will harness the knowledge of protective immunity and employ new technology and vaccine concepts to inform next-generation HCMV vaccine development.
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Affiliation(s)
- Xintao Hu
- Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA;
| | - Hsuan-Yuan Wang
- Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA;
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Claire E Otero
- Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA;
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Jennifer A Jenks
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Sallie R Permar
- Department of Pediatrics, Weill Cornell Medicine, New York, New York, USA;
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16
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Ng WM, Fedosyuk S, English S, Augusto G, Berg A, Thorley L, Haselon AS, Segireddy RR, Bowden TA, Douglas AD. Structure of trimeric pre-fusion rabies virus glycoprotein in complex with two protective antibodies. Cell Host Microbe 2022; 30:1219-1230.e7. [PMID: 35985336 PMCID: PMC9605875 DOI: 10.1016/j.chom.2022.07.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/07/2022] [Accepted: 07/19/2022] [Indexed: 11/03/2022]
Abstract
Rabies virus (RABV) causes lethal encephalitis and is responsible for approximately 60,000 deaths per year. As the sole virion-surface protein, the rabies virus glycoprotein (RABV-G) mediates host-cell entry. RABV-G's pre-fusion trimeric conformation displays epitopes bound by protective neutralizing antibodies that can be induced by vaccination or passively administered for post-exposure prophylaxis. We report a 2.8-Å structure of a RABV-G trimer in the pre-fusion conformation, in complex with two neutralizing and protective monoclonal antibodies, 17C7 and 1112-1, that recognize distinct epitopes. One of these antibodies is a licensed prophylactic (17C7, Rabishield), which we show locks the protein in pre-fusion conformation. Targeted mutations can similarly stabilize RABV-G in the pre-fusion conformation, a key step toward structure-guided vaccine design. These data reveal the higher-order architecture of a key therapeutic target and the structural basis of neutralization by antibodies binding two key antigenic sites, and this will facilitate the development of improved vaccines and prophylactic antibodies.
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Affiliation(s)
- Weng M Ng
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Sofiya Fedosyuk
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Solomon English
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Gilles Augusto
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Adam Berg
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Luke Thorley
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Anna-Sophie Haselon
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Rameswara R Segireddy
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Alexander D Douglas
- Jenner Institute, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
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17
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Ebel H, Benecke T, Vollmer B. Stabilisation of Viral Membrane Fusion Proteins in Prefusion Conformation by Structure-Based Design for Structure Determination and Vaccine Development. Viruses 2022; 14:1816. [PMID: 36016438 PMCID: PMC9415420 DOI: 10.3390/v14081816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/08/2022] [Accepted: 08/15/2022] [Indexed: 11/20/2022] Open
Abstract
The membrane surface of enveloped viruses contains dedicated proteins enabling the fusion of the viral with the host cell membrane. Working with these proteins is almost always challenging because they are membrane-embedded and naturally metastable. Fortunately, based on a range of different examples, researchers now have several possibilities to tame membrane fusion proteins, making them amenable for structure determination and immunogen generation. This review describes the structural and functional similarities of the different membrane fusion proteins and ways to exploit these features to stabilise them by targeted mutational approaches. The recent determination of two herpesvirus membrane fusion proteins in prefusion conformation holds the potential to apply similar methods to this group of viral fusogens. In addition to a better understanding of the herpesviral fusion mechanism, the structural insights gained will help to find ways to further stabilise these proteins using the methods described to obtain stable immunogens that will form the basis for the development of the next generation of vaccines and antiviral drugs.
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Affiliation(s)
- Henriette Ebel
- Centre for Structural Systems Biology (CSSB), 22607 Hamburg, Germany
- Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
- Leibniz Institute of Virology (LIV), 20251 Hamburg, Germany
| | - Tim Benecke
- Centre for Structural Systems Biology (CSSB), 22607 Hamburg, Germany
- Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
- Leibniz Institute of Virology (LIV), 20251 Hamburg, Germany
| | - Benjamin Vollmer
- Centre for Structural Systems Biology (CSSB), 22607 Hamburg, Germany
- Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
- Leibniz Institute of Virology (LIV), 20251 Hamburg, Germany
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18
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Abstract
Herpesviruses—ubiquitous pathogens that cause persistent infections—have some of the most complex cell entry mechanisms. Entry of the prototypical herpes simplex virus 1 (HSV-1) requires coordinated efforts of 4 glycoproteins, gB, gD, gH, and gL. The current model posits that the glycoproteins do not interact before receptor engagement and that binding of gD to its receptor causes a “cascade” of sequential pairwise interactions, first activating the gH/gL complex and subsequently activating gB, the viral fusogen. But how these glycoproteins interact remains unresolved. Here, using a quantitative split-luciferase approach, we show that pairwise HSV-1 glycoprotein complexes form before fusion, interact at a steady level throughout fusion, and do not depend on the presence of the cellular receptor. Based on our findings, we propose a revised “conformational cascade” model of HSV-1 entry. We hypothesize that all 4 glycoproteins assemble into a complex before fusion, with gH/gL positioned between gD and gB. Once gD binds to a cognate receptor, the proximity of the glycoproteins within this complex allows for efficient transmission of the activating signal from the receptor-activated gD to gH/gL to gB through sequential conformational changes, ultimately triggering the fusogenic refolding of gB. Our results also highlight previously unappreciated contributions of the transmembrane and cytoplasmic domains to glycoprotein interactions and fusion. Similar principles could be at play in other multicomponent viral entry systems, and the split-luciferase approach used here is a powerful tool for investigating protein-protein interactions in these and a variety of other systems.
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19
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He L, Taylor S, Costa C, Görzer I, Kalser J, Fu TM, Freed D, Wang D, Cui X, Hertel L, McVoy MA. Polymorphic Forms of Human Cytomegalovirus Glycoprotein O Protect against Neutralization of Fibroblast Entry by Antibodies Targeting Epitopes Defined by Glycoproteins H and L. Viruses 2022; 14:1508. [PMID: 35891489 PMCID: PMC9323020 DOI: 10.3390/v14071508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Human cytomegalovirus (CMV) utilizes different glycoproteins to enter into fibroblast and epithelial cells. A trimer of glycoproteins H, L, and O (gH/gL/gO) is required for entry into all cells, whereas a pentamer of gH/gL/UL128/UL130/UL131A is selectively required for infection of epithelial, endothelial, and some myeloid-lineage cells, but not of fibroblasts. Both complexes are of considerable interest for vaccine and immunotherapeutic development but present a conundrum: gH/gL-specific antibodies have moderate potency yet neutralize CMV entry into all cell types, whereas pentamer-specific antibodies are more potent but do not block fibroblast infection. Which cell types and neutralizing activities are important for protective efficacy in vivo remain unclear. Here, we present evidence that certain CMV strains have evolved polymorphisms in gO to evade trimer-specific neutralizing antibodies. Using luciferase-tagged variants of strain TB40/E in which the native gO is replaced by gOs from other strains, we tested the effects of gO polymorphisms on neutralization by monoclonal antibodies (mAbs) targeting four independent epitopes in gH/gL that are common to both trimer and pentamer. Neutralization of fibroblast entry by three mAbs displayed a range of potencies that depended on the gO type, a fourth mAb failed to neutralize fibroblast entry regardless of the gO type, while neutralization of epithelial cell entry by all four mAbs was potent and independent of the gO type. Thus, specific polymorphisms in gO protect the virus from mAb neutralization in the context of fibroblast but not epithelial cell entry. No influence of gO type was observed for protection against CMV hyperimmune globulin or CMV-seropositive human sera, suggesting that antibodies targeting protected gH/gL epitopes represent a minority of the polyclonal neutralizing repertoire induced by natural infection.
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Affiliation(s)
- Li He
- Department of Microbiology & Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA;
| | - Scott Taylor
- School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (S.T.); (C.C.)
| | - Catherine Costa
- School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (S.T.); (C.C.)
| | - Irene Görzer
- Center for Virology, Medical University of Vienna, 1090 Vienna, Austria; (I.G.); (J.K.)
| | - Julia Kalser
- Center for Virology, Medical University of Vienna, 1090 Vienna, Austria; (I.G.); (J.K.)
| | - Tong-Ming Fu
- Texas Therapeutic Institute, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
| | - Daniel Freed
- Merck & Co., Inc., Rahway, NJ 07065, USA; (D.F.); (D.W.)
| | - Dai Wang
- Merck & Co., Inc., Rahway, NJ 07065, USA; (D.F.); (D.W.)
| | - Xiaohong Cui
- Department of Anatomy, Virginia Commonwealth University, Richmond, VA 23298, USA;
| | - Laura Hertel
- Department of Pediatrics, University of California San Francisco, Oakland, CA 94609, USA;
| | - Michael A. McVoy
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA
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20
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Dasari V, Beckett K, Horsefield S, Ambalathingal G, Khanna R. A bivalent CMV vaccine formulated with human compatible TLR9 agonist CpG1018 elicits potent cellular and humoral immunity in HLA expressing mice. PLoS Pathog 2022; 18:e1010403. [PMID: 35737741 PMCID: PMC9223316 DOI: 10.1371/journal.ppat.1010403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/26/2022] [Indexed: 11/30/2022] Open
Abstract
There is now convincing evidence that the successful development of an effective CMV vaccine will require improved formulation and adjuvant selection that is capable of inducing both humoral and cellular immune responses. Here, we have designed a novel bivalent subunit vaccine formulation based on CMV-encoded oligomeric glycoprotein B (gB) and polyepitope protein in combination with human compatible TLR9 agonist CpG1018. The polyepitope protein includes multiple minimal HLA class I-restricted CD8+ T cell epitopes from different antigens of CMV. This subunit vaccine generated durable anti-viral antibodies, CMV-specific CD4+ and CD8+ T cell responses in multiple HLA expressing mice. Antibody responses included broad TH1 isotypes (IgG2a, IgG2b and IgG3) and potently neutralized CMV infection in fibroblasts and epithelial cells. Furthermore, polyfunctional antigen-specific T cell immunity and antiviral antibody responses showed long-term memory maintenance. These observations argue that this novel vaccine strategy, if applied to humans, could facilitate the generation of robust humoral and cellular immune responses which may be more effective in preventing CMV-associated complications in various clinical settings. Human Cytomegalovirus (CMV) is a significant human pathogen. Generally, in healthy people CMV causes mild symptomatic disease, but during pregnancy CMV can transmit from mother to foetus (1 out of every 200 live births worldwide) and lead to sensorineural hearing loss, vision impairment and central nervous system damage. In transplant patients, CMV can cause serious complications leading to organ rejection and even death. Currently, there is no licensed vaccine available to prevent CMV-associated complications in pregnant women and transplant patients. Here, we have developed a novel bivalent CMV vaccine formulation consisting of recombinant CMVpoly and gB proteins in combination with human compatible adjuvant CpG1018. Preclinical immunogenicity evaluation in multiple HLA expressing mice demonstrated that bivalent CMV vaccine formulation consistently generated robust CMV-specific neutralising antibodies, CD4+ and CD8+ T cell responses. More importantly, long-term follow-up analysis showed that the CMV vaccine can induce durable CMV-specific humoral and cellular immune responses. Our results support further development of this bivalent subunit CMV vaccine to test safety, immunogenicity and efficacy in humans.
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Affiliation(s)
- Vijayendra Dasari
- QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Tumour Immunology Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- * E-mail: (VD); (RK)
| | - Kirrilee Beckett
- QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Tumour Immunology Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Shane Horsefield
- QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Tumour Immunology Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - George Ambalathingal
- QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Tumour Immunology Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Rajiv Khanna
- QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Tumour Immunology Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- * E-mail: (VD); (RK)
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21
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Hong J, Wei D, Zhong L, Wu Q, Chen K, Zhang W, Yang Y, Chen J, Xia N, Zhang X, Chen Y. Glycoprotein B Antibodies Completely Neutralize EBV Infection of B Cells. Front Immunol 2022; 13:920467. [PMID: 35711430 PMCID: PMC9197244 DOI: 10.3389/fimmu.2022.920467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 04/29/2022] [Indexed: 11/26/2022] Open
Abstract
The Epstein–Barr virus (EBV) is the first reported oncogenic herpesvirus that establishes persistent infection in B lymphocytes in 95% of adults worldwide. Glycoprotein B (gB) plays a predominant role in the fusion of the viral envelope with the host cell membrane. Hence, it is of great significance to isolate gB-specific fusion-inhibiting neutralizing antibodies (NAbs). AMMO5 is the only gB NAb but fails to antagonize B-cell infection. It is essential to isolate potent NAbs that can completely block EBV infection of B cells. Using hybridoma technology and neutralization assay, we isolate two gB NAbs 8A9 and 8C12 that are capable of completely neutralizing B-cell infection in vitro. In addition, 8A9 shows cross-reactivity with rhesus lymphocryptovirus (rhLCV) gB. Competitive binding experiments demonstrate that 8A9 and 8C12 recognize novel epitopes that are different from the AMMO5 epitope. The epitopes of 8A9 and 8C12 are mapped to gB D-II, and the AMMO5 epitope is located precisely at gB aa 410–419. We find that 8A9 and 8C12 significantly inhibit gB-derived membrane fusion using a virus-free fusion assay. In summary, this study identifies two gB-specific NAbs that potently block EBV infection of B cells. Our work highlights the importance of gB D-II as a predominant neutralizing epitope, and aids in the rational design of therapeutics or vaccines based on gB.
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Affiliation(s)
- Junping Hong
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Dongmei Wei
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Ling Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Qian Wu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Kaiyun Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Wanlin Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yanbo Yang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Junyu Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
| | - Xiao Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yixin Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China
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22
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Chin A, Liu J, Jardetzky T, Johnson DC, Vanarsdall A. Identification of functionally important domains of human cytomegalovirus gO that act after trimer binding to receptors. PLoS Pathog 2022; 18:e1010452. [PMID: 35452493 PMCID: PMC9032346 DOI: 10.1371/journal.ppat.1010452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 03/17/2022] [Indexed: 11/18/2022] Open
Abstract
Human cytomegalovirus (HCMV) entry involves trimer (gH/gL/gO) that interacts with PDGFRα in fibroblasts. Entry into epithelial and endothelial cells requires trimer, which binds unidentified receptors, and pentamer (gH/gL/UL128-131), which binds neuropilin-2. To identify functionally important domains in trimer, we screened an overlapping 20-mer gO peptide library and identified two sets of peptides: 19/20 (a.a. 235–267) and 32/33 (a.a. 404–436) that could block virus entry. Soluble trimer containing wild type gO blocked HCMV entry, whereas soluble trimers with the 19/20 or 32/33 sequences mutated did not block entry. Interestingly, the mutant trimers retained the capacity to bind to cellular receptors including PDGFRα. Peptide 19/20 and 32/33 sequences formed a lobe extending from the surface of gO and an adjacent concave structure, respectively. Neither of these sets of sequences contacted PDGFRα. Instead, our data support a model in which the 19/20 and 32/33 trimer sequences function downstream of receptor binding, e.g. trafficking of HCMV into endosomes or binding to gB for entry fusion. We also screened for peptides that bound antibodies (Abs) in human sera, observing that peptides 20 and 26 bound Abs. These peptides engendered neutralizing Abs (NAbs) after immunization of rabbits and could pull out NAbs from human sera. Peptides 20 and 26 sequences represent the first NAb epitopes identified in trimer. These studies describe two important surfaces on gO defined by: i) peptides 19/20 and 32/33, which apparently act downstream of receptor binding and ii) peptide 26 that interacts with PDGFRα. Both these surfaces are targets of NAbs. Human cytomegalovirus (HCMV) infects 80% of the world population, causing severe morbidity and mortality in transplant patients and can be transmitted to the developing fetus leading to severe neurological defects. The current anti-viral agents used to treat HCMV are not very effective as viruses can develop resistance and there is no licensed HCMV vaccine available. Recently, there has been intense interest in the HCMV envelope glycoproteins involved in entry as a component of vaccines. One glycoprotein complex, the gH/gL/gO trimer is especially intriguing as it is required for infection of extracellular virus in all cell types. Here, we identify domains in the trimer that have an essential function in entry downstream of receptor binding and are also epitopes recognized by naturally induced neutralizing antibodies. These results will have implications for advancing the efforts to develop novel HCMV therapeutics.
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Affiliation(s)
- Andrea Chin
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jing Liu
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Theodore Jardetzky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - David C. Johnson
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Adam Vanarsdall
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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23
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Wrapp D, Ye X, Ku Z, Su H, Jones HG, Wang N, Mishra AK, Freed DC, Li F, Tang A, Li L, Jaijyan DK, Zhu H, Wang D, Fu TM, Zhang N, An Z, McLellan JS. Structural basis for HCMV Pentamer recognition by neuropilin 2 and neutralizing antibodies. SCIENCE ADVANCES 2022; 8:eabm2546. [PMID: 35275718 PMCID: PMC8916728 DOI: 10.1126/sciadv.abm2546] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Human cytomegalovirus (HCMV) encodes multiple surface glycoprotein complexes to infect a variety of cell types. The HCMV Pentamer, composed of gH, gL, UL128, UL130, and UL131A, enhances entry into epithelial, endothelial, and myeloid cells by interacting with the cell surface receptor neuropilin 2 (NRP2). Despite the critical nature of this interaction, the molecular determinants that govern NRP2 recognition remain unclear. Here, we describe the cryo-EM structure of NRP2 bound to Pentamer. The high-affinity interaction between these proteins is calcium dependent and differs from the canonical carboxyl-terminal arginine (CendR) binding that NRP2 typically uses. We also determine the structures of four neutralizing human antibodies bound to the HCMV Pentamer to define susceptible epitopes. Two of these antibodies compete with NRP2 binding, but the two most potent antibodies recognize a previously unidentified epitope that does not overlap the NRP2-binding site. Collectively, these findings provide a structural basis for HCMV tropism and antibody-mediated neutralization.
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Affiliation(s)
- Daniel Wrapp
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Xiaohua Ye
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Zhiqiang Ku
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Hang Su
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Harrison G. Jones
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Nianshuang Wang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Akaash K. Mishra
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Daniel C. Freed
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ 07033, USA
| | - Fengsheng Li
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ 07033, USA
| | - Aimin Tang
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ 07033, USA
| | - Leike Li
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Dabbu Kumar Jaijyan
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Hua Zhu
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Dai Wang
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ 07033, USA
| | - Tong-Ming Fu
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ningyan Zhang
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Zhiqiang An
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Corresponding author. (Z.A.); (J.S.M.)
| | - Jason S. McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
- Corresponding author. (Z.A.); (J.S.M.)
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24
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Gonzalez-Del Pino GL, Heldwein EE. Well Put Together—A Guide to Accessorizing with the Herpesvirus gH/gL Complexes. Viruses 2022; 14:v14020296. [PMID: 35215889 PMCID: PMC8874593 DOI: 10.3390/v14020296] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/20/2022] [Accepted: 01/22/2022] [Indexed: 02/06/2023] Open
Abstract
Herpesviruses are enveloped, double-stranded DNA viruses that infect a variety of hosts across the animal kingdom. Nine of these establish lifelong infections in humans, for which there are no cures and few vaccine or treatment options. Like all enveloped viruses, herpesviruses enter cells by fusing their lipid envelopes with a host cell membrane. Uniquely, herpesviruses distribute the functions of receptor engagement and membrane fusion across a diverse cast of glycoproteins. Two glycoprotein complexes are conserved throughout the three herpesvirus subfamilies: the trimeric gB that functions as a membrane fusogen and the heterodimeric gH/gL, the role of which is less clearly defined. Here, we highlight the conserved and divergent functions of gH/gL across the three subfamilies of human herpesviruses by comparing its interactions with a broad range of accessory viral proteins, host cell receptors, and neutralizing or inhibitory antibodies. We propose that the intrinsic structural plasticity of gH/gL enables it to function as a signal integration machine that can accept diverse regulatory inputs and convert them into a “trigger” signal that activates the fusogenic ability of gB.
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25
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Lees JA, Dias JM, Han S. Applications of Cryo-EM in small molecule and biologics drug design. Biochem Soc Trans 2021; 49:2627-2638. [PMID: 34812853 PMCID: PMC8786282 DOI: 10.1042/bst20210444] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/22/2021] [Accepted: 10/27/2021] [Indexed: 02/03/2023]
Abstract
Electron cryo-microscopy (cryo-EM) is a powerful technique for the structural characterization of biological macromolecules, enabling high-resolution analysis of targets once inaccessible to structural interrogation. In recent years, pharmaceutical companies have begun to utilize cryo-EM for structure-based drug design. Structural analysis of integral membrane proteins, which comprise a large proportion of druggable targets and pose particular challenges for X-ray crystallography, by cryo-EM has enabled insights into important drug target families such as G protein-coupled receptors (GPCRs), ion channels, and solute carrier (SLCs) proteins. Structural characterization of biologics, such as vaccines, viral vectors, and gene therapy agents, has also become significantly more tractable. As a result, cryo-EM has begun to make major impacts in bringing critical therapeutics to market. In this review, we discuss recent instructive examples of impacts from cryo-EM in therapeutics design, focusing largely on its implementation at Pfizer. We also discuss the opportunities afforded by emerging technological advances in cryo-EM, and the prospects for future development of the technique.
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Affiliation(s)
- Joshua A. Lees
- Discovery Sciences, Medicine Design, Pfizer Worldwide Research and Development, Groton, CT 06340, U.S.A
| | - Joao M. Dias
- Discovery Sciences, Medicine Design, Pfizer Worldwide Research and Development, Groton, CT 06340, U.S.A
| | - Seungil Han
- Discovery Sciences, Medicine Design, Pfizer Worldwide Research and Development, Groton, CT 06340, U.S.A
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26
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The Structures and Functions of VZV Glycoproteins. Curr Top Microbiol Immunol 2021; 438:25-58. [PMID: 34731265 DOI: 10.1007/82_2021_243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The virions of all enveloped viruses, including those of the Herpesviridae, must bind to the cell surface then undergo a process of membrane fusion between the cell plasma membrane and the virus particle envelope. As for all herpesviruses, glycoproteins in the virion envelope are the modus operandi of these events.
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27
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Xia X, Wu W, Cui Y, Roy P, Zhou ZH. Bluetongue virus capsid protein VP5 perforates membranes at low endosomal pH during viral entry. Nat Microbiol 2021; 6:1424-1432. [PMID: 34702979 PMCID: PMC9015746 DOI: 10.1038/s41564-021-00988-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/22/2021] [Indexed: 01/25/2023]
Abstract
Bluetongue virus (BTV) is a non-enveloped virus and causes substantial morbidity and mortality in ruminants such as sheep. Fashioning a receptor-binding protein (VP2) and a membrane penetration protein (VP5) on the surface, BTV releases its genome-containing core (VP3 and VP7) into the host cell cytosol after perforation of the endosomal membrane. Unlike enveloped ones, the entry mechanisms of non-enveloped viruses into host cells remain poorly understood. Here we applied single-particle cryo-electron microscopy, cryo-electron tomography and structure-guided functional assays to characterize intermediate states of BTV cell entry in endosomes. Four structures of BTV at the resolution range of 3.4-3.9 Å show the different stages of structural rearrangement of capsid proteins on exposure to low pH, including conformational changes of VP5, stepwise detachment of VP2 and a small shift of VP7. In detail, sensing of the low-pH condition by the VP5 anchor domain triggers three major VP5 actions: projecting the hidden dagger domain, converting a surface loop to a protonated β-hairpin that anchors VP5 to the core and stepwise refolding of the unfurling domains into a six-helix stalk. Cryo-electron tomography structures of BTV interacting with liposomes show a length decrease of the VP5 stalk from 19.5 to 15.5 nm after its insertion into the membrane. Our structures, functional assays and structure-guided mutagenesis experiments combined indicate that this stalk, along with dagger domain and the WHXL motif, creates a single pore through the endosomal membrane that enables the viral core to enter the cytosol. Our study unveils the detailed mechanisms of BTV membrane penetration and showcases general methods to study cell entry of other non-enveloped viruses.
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Affiliation(s)
- Xian Xia
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Weining Wu
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Polly Roy
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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28
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Herpes Simplex Virus Glycoprotein B Mutations Define Structural Sites in Domain I, the Membrane Proximal Region, and the Cytodomain That Regulate Entry. J Virol 2021; 95:e0105021. [PMID: 34431697 DOI: 10.1128/jvi.01050-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The viral fusion protein glycoprotein B (gB) is conserved in all herpesviruses and is essential for virus entry. During entry, gB fuses viral and host cell membranes by refolding from a prefusion to a postfusion form. We previously introduced three structure-based mutations (gB-I671A/H681A/F683A) into the domain V arm of the gB ectodomain that resulted in reduced cell-cell fusion. A virus carrying these three mutations (called gB3A) displayed a small-plaque phenotype and remarkably delayed entry into cells. To identify mutations that could counteract this phenotype, we serially passaged the gB3A virus and selected for revertant viruses with increased plaque sizes. Genomic sequencing revealed that the revertant viruses had second-site mutations in gB, including E187A, M742T, and S383F/G645R/V705I/V880G. Using expression constructs encoding these mutations, only gB-V880G was shown to enhance cell-cell fusion. In contrast, all of the revertant viruses showed enhanced entry kinetics, underscoring the fact that cell-cell fusion and virus-cell fusion are different. The results indicate that mutations in three different regions of gB (domain I, the membrane proximal region, and the cytoplasmic tail domain) can counteract the slow-entry phenotype of gB3A virus. Mapping these compensatory mutations to prefusion and postfusion structural models suggests sites of intramolecular functional interactions with the gB domain V arm that may contribute to the gB fusion function. IMPORTANCE The nine human herpesviruses are ubiquitous and cause a range of diseases in humans. Glycoprotein B (gB) is an essential viral fusion protein that is conserved in all herpesviruses. During host cell entry, gB mediates virus-cell membrane fusion by undergoing a conformational change. Structural models for the prefusion and postfusion forms of gB exist, but the details of how the protein converts from one to the other are unclear. We previously introduced structure-based mutations into gB that inhibited virus entry and fusion. By passaging this entry-deficient virus over time, we selected second-site mutations that partially restore virus entry. The locations of these mutations suggest regulatory sites that contribute to fusion and gB refolding during entry. gB is a target of neutralizing antibodies, and defining how gB refolds during entry could provide a basis for the development of fusion inhibitors for future research or clinical use.
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29
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Cryo-Electron Microscopy Structure and Interactions of the Human Cytomegalovirus gHgLgO Trimer with Platelet-Derived Growth Factor Receptor Alpha. mBio 2021; 12:e0262521. [PMID: 34700375 PMCID: PMC8546573 DOI: 10.1128/mbio.02625-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus that produces disease in transplant patients and newborn children. Entry of HCMV into cells relies on gH/gL trimer (gHgLgO) and pentamer (gHgLUL128–131) complexes that bind cellular receptors. Here, we studied the structure and interactions of the HCMV trimer, formed by AD169 strain gH and gL and TR strain gO proteins, with the human platelet-derived growth factor receptor alpha (PDGFRα). Three trimer surfaces make extensive contacts with three PDGFRα N-terminal domains, causing PDGFRα to wrap around gO in a structure similar to a human hand, explaining the high-affinity interaction. gO is among the least conserved HCMV proteins, with 8 distinct genotypes. We observed high conservation of residues mediating gO-gL interactions but more extensive gO variability in the PDGFRα interface. Comparisons between our trimer structure and a previously determined structure composed of different subunit genotypes indicate that gO variability is accommodated by adjustments in the gO-PDGFRα interface. We identified two loops within gO that were disordered and apparently glycosylated, which could be deleted without disrupting PDGFRα binding. We also identified four gO residues that contact PDGFRα, which when mutated produced markedly reduced receptor binding. These residues fall within conserved contact sites of gO with PDGFRα and may represent key targets for anti-trimer neutralizing antibodies and HCMV vaccines. Finally, we observe that gO mutations distant from the gL interaction site impact trimer expression, suggesting that the intrinsic folding or stability of gO can impact the efficiency of trimer assembly.
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30
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Tang J, Frascaroli G, Zhou X, Knickmann J, Brune W. Cell Fusion and Syncytium Formation in Betaherpesvirus Infection. Viruses 2021; 13:v13101973. [PMID: 34696402 PMCID: PMC8537622 DOI: 10.3390/v13101973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/22/2021] [Accepted: 09/28/2021] [Indexed: 12/14/2022] Open
Abstract
Cell–cell fusion is a fundamental and complex process that occurs during reproduction, organ and tissue growth, cancer metastasis, immune response, and infection. All enveloped viruses express one or more proteins that drive the fusion of the viral envelope with cellular membranes. The same proteins can mediate the fusion of the plasma membranes of adjacent cells, leading to the formation of multinucleated syncytia. While cell–cell fusion triggered by alpha- and gammaherpesviruses is well-studied, much less is known about the fusogenic potential of betaherpesviruses such as human cytomegalovirus (HCMV) and human herpesviruses 6 and 7 (HHV-6 and HHV-7). These are slow-growing viruses that are highly prevalent in the human population and associated with several diseases, particularly in individuals with an immature or impaired immune system such as fetuses and transplant recipients. While HHV-6 and HHV-7 are strictly lymphotropic, HCMV infects a very broad range of cell types including epithelial, endothelial, mesenchymal, and myeloid cells. Syncytia have been observed occasionally for all three betaherpesviruses, both during in vitro and in vivo infection. Since cell–cell fusion may allow efficient spread to neighboring cells without exposure to neutralizing antibodies and other host immune factors, viral-induced syncytia may be important for viral dissemination, long-term persistence, and pathogenicity. In this review, we provide an overview of the viral and cellular factors and mechanisms identified so far in the process of cell–cell fusion induced by betaherpesviruses and discuss the possible consequences for cellular dysfunction and pathogenesis.
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Affiliation(s)
- Jiajia Tang
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (J.T.); (G.F.); (X.Z.); (J.K.)
- Center for Single-Cell Omics, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Giada Frascaroli
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (J.T.); (G.F.); (X.Z.); (J.K.)
| | - Xuan Zhou
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (J.T.); (G.F.); (X.Z.); (J.K.)
| | - Jan Knickmann
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (J.T.); (G.F.); (X.Z.); (J.K.)
| | - Wolfram Brune
- Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany; (J.T.); (G.F.); (X.Z.); (J.K.)
- Correspondence:
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31
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Li S. Cryo-electron tomography of enveloped viruses. Trends Biochem Sci 2021; 47:173-186. [PMID: 34511334 DOI: 10.1016/j.tibs.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/12/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
Viruses are macromolecular machineries that hijack cellular metabolism for replication. Enveloped viruses comprise a large variety of RNA and DNA viruses, many of which are notorious human or animal pathogens. Despite their importance, the presence of lipid bilayers in their assembly has made most enveloped viruses too pleomorphic to be reconstructed as a whole by traditional structural biology methods. Furthermore, structural biology of the viral lifecycle was hindered by the sample thickness. Here, I review the recent advances in the applications of cryo-electron tomography (cryo-ET) on enveloped viral structures and intracellular viral activities.
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Affiliation(s)
- Sai Li
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Beijing Advanced Innovation Center for Structural Biology and Frontier Research Center for Biological Structure, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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32
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Jenks JA, Nelson CS, Roark HK, Goodwin ML, Pass RF, Bernstein DI, Walter EB, Edwards KM, Wang D, Fu TM, An Z, Chan C, Permar SR. Antibody binding to native cytomegalovirus glycoprotein B predicts efficacy of the gB/MF59 vaccine in humans. Sci Transl Med 2021; 12:12/568/eabb3611. [PMID: 33148624 DOI: 10.1126/scitranslmed.abb3611] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/02/2020] [Indexed: 12/21/2022]
Abstract
Human cytomegalovirus (CMV) is the most common infectious cause of infant brain damage and posttransplant complications worldwide. Despite the high global burden of disease, vaccine development to prevent infection remains hampered by challenges in generating protective immunity. The most efficacious CMV vaccine candidate tested to date is a soluble glycoprotein B (gB) subunit vaccine with MF59 adjuvant (gB/MF59), which achieved 50% protection in multiple historical phase 2 clinical trials. The vaccine-elicited immune responses that conferred this protection have remained unclear. We investigated the humoral immune correlates of protection from CMV acquisition in populations of CMV-seronegative adolescent and postpartum women who received the gB/MF59 vaccine. We found that gB/MF59 immunization elicited distinct CMV-specific immunoglobulin G (IgG)-binding profiles and IgG-mediated functional responses in adolescent and postpartum vaccinees, with heterologous CMV strain neutralization observed primarily in adolescent vaccinees. Using penalized multiple logistic regression analysis, we determined that protection against primary CMV infection in both cohorts was associated with serum IgG binding to gB present on a cell surface but not binding to the soluble vaccine antigen, suggesting that IgG binding to cell-associated gB is an immune correlate of vaccine efficacy. Supporting this, we identified gB-specific monoclonal antibodies that differentially recognized soluble or cell-associated gB, revealing that there are structural differences in cell-associated and soluble gB are relevant to the generation of protective immunity. Our results highlight the importance of the native, cell-associated gB conformation in future CMV vaccine design.
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Affiliation(s)
- Jennifer A Jenks
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27705, USA
| | - Cody S Nelson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27705, USA.,Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hunter K Roark
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27705, USA
| | - Matthew L Goodwin
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27705, USA
| | - Robert F Pass
- Department of Pediatrics, University of Alabama of Birmingham, Birmingham, AL 35233, USA
| | - David I Bernstein
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Emmanuel B Walter
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27705, USA
| | - Kathryn M Edwards
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Dai Wang
- Merck & Co. Inc., Kenilworth, NJ 07033, USA
| | - Tong-Ming Fu
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhiqiang An
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Cliburn Chan
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27705, USA
| | - Sallie R Permar
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27705, USA. .,Department of Pediatrics, Duke University Medical Center, Durham, NC 27705, USA
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33
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Sun C, Chen XC, Kang YF, Zeng MS. The Status and Prospects of Epstein-Barr Virus Prophylactic Vaccine Development. Front Immunol 2021; 12:677027. [PMID: 34168649 PMCID: PMC8218244 DOI: 10.3389/fimmu.2021.677027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 05/20/2021] [Indexed: 12/30/2022] Open
Abstract
Epstein–Barr virus (EBV) is a human herpesvirus that is common among the global population, causing an enormous disease burden. EBV can directly cause infectious mononucleosis and is also associated with various malignancies and autoimmune diseases. In order to prevent primary infection and subsequent chronic disease, efforts have been made to develop a prophylactic vaccine against EBV in recent years, but there is still no vaccine in clinical use. The outbreak of the COVID-19 pandemic and the global cooperation in vaccine development against SARS-CoV-2 provide insights for next-generation antiviral vaccine design and opportunities for developing an effective prophylactic EBV vaccine. With improvements in antigen selection, vaccine platforms, formulation and evaluation systems, novel vaccines against EBV are expected to elicit dual protection against infection of both B lymphocytes and epithelial cells. This would provide sustainable immunity against EBV-associated malignancies, finally enabling the control of worldwide EBV infection and management of EBV-associated diseases.
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Affiliation(s)
- Cong Sun
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Xin-Chun Chen
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Yin-Feng Kang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Mu-Sheng Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, China
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Beilstein F, Abou Hamdan A, Raux H, Belot L, Ouldali M, Albertini AA, Gaudin Y. Identification of a pH-Sensitive Switch in VSV-G and a Crystal Structure of the G Pre-fusion State Highlight the VSV-G Structural Transition Pathway. Cell Rep 2021; 32:108042. [PMID: 32814045 DOI: 10.1016/j.celrep.2020.108042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 07/12/2020] [Accepted: 07/24/2020] [Indexed: 10/23/2022] Open
Abstract
VSV fusion machinery, like that of many other enveloped viruses, is triggered at low pH in endosomes after virion endocytosis. It was suggested that some histidines could play the role of pH-sensitive switches. By mutating histidine residues H22, H60, H132, H162, H389, H397, H407, and H409, we demonstrate that residues H389 and D280, facing each other in the six-helix bundle of the post-fusion state, and more prominently H407, located at the interface between the C-terminal part of the ectodomain and the fusion domain, are crucial for fusion. Passages of recombinant viruses bearing mutant G resulted in the selection of compensatory mutations. Thus, the H407A mutation in G resulted in two independent compensatory mutants, L396I and S422I. Together with a crystal structure of G, presented here, which extends our knowledge of G pre-fusion structure, this indicates that the conformational transition is initiated by refolding of the C-terminal part of the G ectodomain.
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Affiliation(s)
- Frauke Beilstein
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Abbas Abou Hamdan
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Hélène Raux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Laura Belot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Malika Ouldali
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Aurélie A Albertini
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Yves Gaudin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
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35
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Winter SL, Chlanda P. Dual-axis Volta phase plate cryo-electron tomography of Ebola virus-like particles reveals actin-VP40 interactions. J Struct Biol 2021; 213:107742. [PMID: 33971285 DOI: 10.1016/j.jsb.2021.107742] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/17/2021] [Accepted: 05/03/2021] [Indexed: 12/20/2022]
Abstract
Cryo-electron tomography (cryo-ET) is a pivotal imaging technique for studying the structure of pleomorphic enveloped viruses and their interactions with the host at native conditions. Owing to the limited tilting range of samples with a slab geometry, electron tomograms suffer from so-called missing wedge information in Fourier space. In dual-axis cryo-ET, two tomograms reconstructed from orthogonally oriented tilt series are combined into a tomogram with improved resolution as the missing wedge information is reduced to a pyramid. Volta phase plate (VPP) allows to perform in-focus cryo-ET with high contrast transfer at low-resolution frequencies and thus its application may improve the quality of dual-axis tomograms. Here, we compare dual-axis cryo-ET with and without VPP on Ebola virus-like particles to visualize and segment viral and host cell proteins within the membrane-enveloped filamentous particles. Dual-axis VPP cryo-ET reduces the missing wedge information and ray artifacts arising from the weighted back-projection during tomogram reconstruction, thereby minimizing ambiguity in the analysis of crowded environments and facilitating 3D segmentation. We show that dual-axis VPP tomograms provide a comprehensive description of macromolecular organizations such as nucleocapsid assembly states, the distribution of glycoproteins on the viral envelope and asymmetric arrangements of the VP40 layer in non-filamentous regions of virus-like particles. Our data reveal actin filaments within virus-like particles in close proximity to the viral VP40 scaffold, suggesting a direct interaction between VP40 and actin filaments. Dual-axis VPP cryo-ET provides more complete 3D information at high contrast and allows for better interpretation of macromolecule interactions and pleomorphic organizations.
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Affiliation(s)
- Sophie L Winter
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany; Research Group "Membrane Biology of Viral Infection", Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Petr Chlanda
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany; Research Group "Membrane Biology of Viral Infection", Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany.
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36
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In Vitro Viral Evolution Identifies a Critical Residue in the Alphaherpesvirus Fusion Glycoprotein B Ectodomain That Controls gH/gL-Independent Entry. mBio 2021; 12:mBio.00557-21. [PMID: 33947756 PMCID: PMC8262866 DOI: 10.1128/mbio.00557-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Herpesvirus entry and spread requires fusion of viral and host cell membranes, which is mediated by the conserved surface glycoprotein B (gB). Upon activation, gB undergoes a major conformational change and transits from a metastable prefusion to a stable postfusion conformation. Although gB is a structural homolog of low-pH-triggered class III fusogens, its fusion activity depends strictly on the presence of the conserved regulatory gH/gL complex and nonconserved receptor binding proteins, which ensure that fusion occurs at the right time and space. How gB maintains its prefusion conformation and how gB fusogenicity is controlled remain poorly understood. Here, we report the isolation and characterization of a naturally selected pseudorabies virus (PrV) gB able to mediate efficient gH/gL-independent virus-cell and cell-cell fusion. We found that the control exerted on gB by the accompanying viral proteins is mediated via its cytosolic domain (CTD). Whereas gB variants lacking the CTD are inactive, a single mutation of a conserved asparagine residue in an alpha-helical motif of the ectodomain recently shown to be at the core of the gB prefusion trimer compensated for CTD absence and uncoupled gB from regulatory viral proteins, resulting in a hyperfusion phenotype. This phenotype was transferred to gB homologs from different alphaherpesvirus genera. Overall, our data propose a model in which the central helix acts as a molecular switch for the gB pre-to-postfusion transition by conveying the structural status of the endo- to the ectodomain, thereby governing their cross talk for fusion activation, providing a new paradigm for herpesvirus fusion regulation.
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37
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Choi KY, El-Hamdi NS, McGregor A. A trimeric capable gB CMV vaccine provides limited protection against a highly cell associated and epithelial tropic strain of cytomegalovirus in guinea pigs. J Gen Virol 2021; 102. [PMID: 33729125 DOI: 10.1099/jgv.0.001579] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multiple strains of human cytomegalovirus (HCMV) can cause congenital cytomegalovirus (cCMV) by primary or secondary infection. The viral gB glycoprotein is a leading vaccine candidate, essential for infection of all cell-types, and immunodominant antibody target. Guinea pig cytomegalovirus (GPCMV) is the only small animal model for cCMV. Various gB vaccines have shown efficacy but studies have utilized truncated gB and protection against prototype strain 22122 with preferential tropism to fibroblasts despite encoding a gH-based pentamer complex for non-fibroblast infection. A highly cell-associated novel strain of GPCMV (TAMYC) with 99 % identity in gB sequence to 22122 exhibited preferred tropism to epithelial cells. An adenovirus vaccine encoding full-length gB (AdgB) was highly immunogenic and partially protected against 22122 strain challenge in vaccinated animals but not when challenged with TAMYC strain. GPCMV studies with AdgB vaccine sera on numerous cell-types demonstrated impaired neutralization (NA50) compared to fibroblasts. GPCMV-convalescent sera including pentamer complex antibodies increased virus neutralization on non-fibroblasts and anti-gB depletion from GPCMV-convalescent sera had minimal impact on epithelial cell neutralization. GPCMV(PC+) 22122-convalescent animals challenged with TAMYC exhibited higher protection compared to AdgB vaccine. Overall, results suggest that antibody response to both gB and PC are important components of a GPCMV vaccine.
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Affiliation(s)
- K Yeon Choi
- Dept. Microbial Pathogenesis & Immunology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Nadia S El-Hamdi
- Dept. Microbial Pathogenesis & Immunology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Alistair McGregor
- Dept. Microbial Pathogenesis & Immunology, College of Medicine, Texas A&M University, Bryan, TX, USA
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38
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Liu Y, Heim KP, Che Y, Chi X, Qiu X, Han S, Dormitzer PR, Yang X. Prefusion structure of human cytomegalovirus glycoprotein B and structural basis for membrane fusion. SCIENCE ADVANCES 2021; 7:7/10/eabf3178. [PMID: 33674318 PMCID: PMC7935361 DOI: 10.1126/sciadv.abf3178] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/21/2021] [Indexed: 05/12/2023]
Abstract
Human cytomegalovirus (HCMV) causes congenital disease with long-term morbidity. HCMV glycoprotein B (gB) transitions irreversibly from a metastable prefusion to a stable postfusion conformation to fuse the viral envelope with a host cell membrane during entry. We stabilized prefusion gB on the virion with a fusion inhibitor and a chemical cross-linker, extracted and purified it, and then determined its structure to 3.6-Å resolution by electron cryomicroscopy. Our results revealed the structural rearrangements that mediate membrane fusion and details of the interactions among the fusion loops, the membrane-proximal region, transmembrane domain, and bound fusion inhibitor that stabilized gB in the prefusion state. The structure rationalizes known gB antigenic sites. By analogy to successful vaccine antigen engineering approaches for other viral pathogens, the high-resolution prefusion gB structure provides a basis to develop stabilized prefusion gB HCMV vaccine antigens.
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Affiliation(s)
- Yuhang Liu
- Discovery Sciences, Pfizer Inc., Groton, CT 06340, USA.
| | - Kyle P Heim
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY 10965, USA
| | - Ye Che
- Discovery Sciences, Pfizer Inc., Groton, CT 06340, USA
| | - Xiaoyuan Chi
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY 10965, USA
| | - Xiayang Qiu
- Discovery Sciences, Pfizer Inc., Groton, CT 06340, USA
| | - Seungil Han
- Discovery Sciences, Pfizer Inc., Groton, CT 06340, USA
| | - Philip R Dormitzer
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY 10965, USA.
| | - Xinzhen Yang
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY 10965, USA
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39
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Kschonsak M, Rougé L, Arthur CP, Hoangdung H, Patel N, Kim I, Johnson MC, Kraft E, Rohou AL, Gill A, Martinez-Martin N, Payandeh J, Ciferri C. Structures of HCMV Trimer reveal the basis for receptor recognition and cell entry. Cell 2021; 184:1232-1244.e16. [PMID: 33626330 DOI: 10.1016/j.cell.2021.01.036] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/10/2021] [Accepted: 01/21/2021] [Indexed: 01/19/2023]
Abstract
Human cytomegalovirus (HCMV) infects the majority of the human population and represents the leading viral cause of congenital birth defects. HCMV utilizes the glycoproteins gHgLgO (Trimer) to bind to platelet-derived growth factor receptor alpha (PDGFRα) and transforming growth factor beta receptor 3 (TGFβR3) to gain entry into multiple cell types. This complex is targeted by potent neutralizing antibodies and represents an important candidate for therapeutics against HCMV. Here, we determine three cryogenic electron microscopy (cryo-EM) structures of the trimer and the details of its interactions with four binding partners: the receptor proteins PDGFRα and TGFβR3 as well as two broadly neutralizing antibodies. Trimer binding to PDGFRα and TGFβR3 is mutually exclusive, suggesting that they function as independent entry receptors. In addition, Trimer-PDGFRα interaction has an inhibitory effect on PDGFRα signaling. Our results provide a framework for understanding HCMV receptor engagement, neutralization, and the development of anti-viral strategies against HCMV.
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Affiliation(s)
- Marc Kschonsak
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
| | - Lionel Rougé
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | | | - Ho Hoangdung
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Nidhi Patel
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Ingrid Kim
- Department of Antibody Engineering, Genentech, South San Francisco, CA 94080, USA
| | - Matthew C Johnson
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Edward Kraft
- Department of BioMolecular Resources, Genentech, South San Francisco, CA 94080, USA
| | - Alexis L Rohou
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Avinash Gill
- Department of Antibody Engineering, Genentech, South San Francisco, CA 94080, USA
| | - Nadia Martinez-Martin
- Department of Microchemistry, Proteomics and Lipidomics Department, Genentech, South San Francisco, CA 94080, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA; Department of Antibody Engineering, Genentech, South San Francisco, CA 94080, USA.
| | - Claudio Ciferri
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
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40
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Vallbracht M, Klupp BG, Mettenleiter TC. Influence of N-glycosylation on Expression and Function of Pseudorabies Virus Glycoprotein gB. Pathogens 2021; 10:61. [PMID: 33445487 PMCID: PMC7827564 DOI: 10.3390/pathogens10010061] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 01/13/2023] Open
Abstract
Envelope glycoprotein (g)B is conserved throughout the Herpesviridae and mediates fusion of the viral envelope with cellular membranes for infectious entry and spread. Like all viral envelope fusion proteins, gB is modified by asparagine (N)-linked glycosylation. Glycans can contribute to protein function, intracellular transport, trafficking, structure and immune evasion. gB of the alphaherpesvirus pseudorabies virus (PrV) contains six consensus sites for N-linked glycosylation, but their functional relevance is unknown. Here, we investigated the occupancy and functional relevance of N-glycosylation sites in PrV gB. To this end, all predicted N-glycosylation sites were inactivated either singly or in combination by the introduction of conservative mutations (N➔Q). The resulting proteins were tested for expression, fusion activity in cell-cell fusion assays and complementation of a gB-deficient PrV mutant. Our results indicate that all six sites are indeed modified. However, while glycosylation at most sites was dispensable for gB expression and fusogenicity, inactivation of N154 and N700 affected gB processing by furin cleavage and surface localization. Although all single mutants were functional in cell-cell fusion and viral entry, simultaneous inactivation of all six N-glycosylation sites severely impaired fusion activity and viral entry, suggesting a critical role of N-glycans for maintaining gB structure and function.
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Affiliation(s)
| | | | - Thomas C. Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany; (M.V.); (B.G.K.)
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41
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Oliver SL, Xing Y, Chen DH, Roh SH, Pintilie GD, Bushnell DA, Sommer MH, Yang E, Carfi A, Chiu W, Arvin AM. The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. PLoS Pathog 2021; 17:e1008961. [PMID: 33411789 PMCID: PMC7817050 DOI: 10.1371/journal.ppat.1008961] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/20/2021] [Accepted: 12/01/2020] [Indexed: 12/13/2022] Open
Abstract
Varicella-zoster virus (VZV) is a medically important alphaherpesvirus that induces fusion of the virion envelope and the cell membrane during entry, and between cells to form polykaryocytes within infected tissues during pathogenesis. All members of the Herpesviridae, including VZV, have a conserved core fusion complex composed of glycoproteins, gB, gH and gL. The ectodomain of the primary fusogen, gB, has five domains, DI-V, of which DI contains the fusion loops needed for fusion function. We recently demonstrated that DIV is critical for fusion initiation, which was revealed by a 2.8Å structure of a VZV neutralizing mAb, 93k, bound to gB and mutagenesis of the gB-93k interface. To further assess the mechanism of mAb 93k neutralization, the binding site of a non-neutralizing mAb to gB, SG2, was compared to mAb 93k using single particle cryogenic electron microscopy (cryo-EM). The gB-SG2 interface partially overlapped with that of gB-93k but, unlike mAb 93k, mAb SG2 did not interact with the gB N-terminus, suggesting a potential role for the gB N-terminus in membrane fusion. The gB ectodomain structure in the absence of antibody was defined at near atomic resolution by single particle cryo-EM (3.9Å) of native, full-length gB purified from infected cells and by X-ray crystallography (2.4Å) of the transiently expressed ectodomain. Both structures revealed that the VZV gB N-terminus (aa72-114) was flexible based on the absence of visible structures in the cryo-EM or X-ray crystallography data but the presence of gB N-terminal peptides were confirmed by mass spectrometry. Notably, N-terminal residues 109KSQD112 were predicted to form a small α-helix and alanine substitution of these residues abolished cell-cell fusion in a virus-free assay. Importantly, transferring the 109AAAA112 mutation into the VZV genome significantly impaired viral propagation. These data establish a functional role for the gB N-terminus in membrane fusion broadly relevant to the Herpesviridae.
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Affiliation(s)
- Stefan L. Oliver
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
| | - Yi Xing
- GSK Vaccines, Cambridge, Massachusetts, United States of America
| | - Dong-Hua Chen
- Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Soung Hun Roh
- Department of Biological Sciences, Institute of Molecular Biology & Genetics, Seoul National University, Seoul, Korea
| | - Grigore D. Pintilie
- Bioengineering, Stanford University School of Medicine, Stanford, California, United States of America
| | - David A. Bushnell
- Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Marvin H. Sommer
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Edward Yang
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Andrea Carfi
- GSK Vaccines, Cambridge, Massachusetts, United States of America
| | - Wah Chiu
- Bioengineering, Stanford University School of Medicine, Stanford, California, United States of America
- Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Division of Cryo-EM and Bioimaging SSRL, SLAC National Accelerator Laboratory, Menlo Park, California, United States of America
| | - Ann M. Arvin
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
- Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
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42
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Perotti M, Marcandalli J, Demurtas D, Sallusto F, Perez L. Rationally designed Human Cytomegalovirus gB nanoparticle vaccine with improved immunogenicity. PLoS Pathog 2020; 16:e1009169. [PMID: 33370407 PMCID: PMC7794029 DOI: 10.1371/journal.ppat.1009169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/08/2021] [Accepted: 11/16/2020] [Indexed: 12/15/2022] Open
Abstract
Human cytomegalovirus (HCMV) is the primary viral cause of congenital birth defects and causes significant morbidity and mortality in immune-suppressed transplant recipients. Despite considerable efforts in vaccine development, HCMV infection still represents an unmet clinical need. In recent phase II trials, a MF59-adjuvanted gB vaccine showed only modest efficacy in preventing infection. These findings might be attributed to low level of antibodies (Abs) with a neutralizing activity induced by this vaccine. Here, we analyzed the immunogenicity of each gB antigenic domain (AD) and demonstrated that domain I of gB (AD5) is the main target of HCMV neutralizing antibodies. Furthermore, we designed, characterized and evaluated immunogenic responses to two different nanoparticles displaying a trimeric AD5 antigen. We showed that mice immunization with nanoparticles induces sera neutralization titers up to 100-fold higher compared to those obtained with the gB extracellular domain (gBECD). Collectively, these results illustrate with a medically relevant example the advantages of using a general approach combining antigen discovery, protein engineering and scaffold presentation for modern development of subunit vaccines against complex pathogens.
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Affiliation(s)
- Michela Perotti
- Institute for Research in Biomedicine, Università della Svizzera italiana, faculty of Biomedical Sciences, Bellinzona, Switzerland.,Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Jessica Marcandalli
- Institute for Research in Biomedicine, Università della Svizzera italiana, faculty of Biomedical Sciences, Bellinzona, Switzerland
| | - Davide Demurtas
- BioEM Facility, School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Federica Sallusto
- Institute for Research in Biomedicine, Università della Svizzera italiana, faculty of Biomedical Sciences, Bellinzona, Switzerland.,Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Laurent Perez
- Institute for Research in Biomedicine, Università della Svizzera italiana, faculty of Biomedical Sciences, Bellinzona, Switzerland.,University of Lausanne (UNIL), Lausanne University Hospital (CHUV), Department of Medicine, Division of Immunology and Allergy, Center for Human Immunology (CHIL), Lausanne, Switzerland
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43
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Abstract
Herpesviruses are ubiquitous, double-stranded DNA, enveloped viruses that establish lifelong infections and cause a range of diseases. Entry into host cells requires binding of the virus to specific receptors, followed by the coordinated action of multiple viral entry glycoproteins to trigger membrane fusion. Although the core fusion machinery is conserved for all herpesviruses, each species uses distinct receptors and receptor-binding glycoproteins. Structural studies of the prototypical herpesviruses herpes simplex virus 1 (HSV-1), HSV-2, human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) entry glycoproteins have defined the interaction sites for glycoprotein complexes and receptors, and have revealed conformational changes that occur on receptor binding. Recent crystallography and electron microscopy studies have refined our model of herpesvirus entry into cells, clarifying both the conserved features and the unique features. In this Review, we discuss recent insights into herpesvirus entry by analysing the structures of entry glycoproteins, including the diverse receptor-binding glycoproteins (HSV-1 glycoprotein D (gD), EBV glycoprotein 42 (gp42) and HCMV gH-gL-gO trimer and gH-gL-UL128-UL130-UL131A pentamer), as well gH-gL and the fusion protein gB, which are conserved in all herpesviruses.
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44
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Quemin ERJ, Machala EA, Vollmer B, Pražák V, Vasishtan D, Rosch R, Grange M, Franken LE, Baker LA, Grünewald K. Cellular Electron Cryo-Tomography to Study Virus-Host Interactions. Annu Rev Virol 2020; 7:239-262. [PMID: 32631159 DOI: 10.1146/annurev-virology-021920-115935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Viruses are obligatory intracellular parasites that reprogram host cells upon infection to produce viral progeny. Here, we review recent structural insights into virus-host interactions in bacteria, archaea, and eukaryotes unveiled by cellular electron cryo-tomography (cryoET). This advanced three-dimensional imaging technique of vitreous samples in near-native state has matured over the past two decades and proven powerful in revealing molecular mechanisms underlying viral replication. Initial studies were restricted to cell peripheries and typically focused on early infection steps, analyzing surface proteins and viral entry. Recent developments including cryo-thinning techniques, phase-plate imaging, and correlative approaches have been instrumental in also targeting rare events inside infected cells. When combined with advances in dedicated image analyses and processing methods, details of virus assembly and egress at (sub)nanometer resolution were uncovered. Altogether, we provide a historical and technical perspective and discuss future directions and impacts of cryoET for integrative structural cell biology analyses of viruses.
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Affiliation(s)
- Emmanuelle R J Quemin
- Centre for Structural Systems Biology, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, University of Hamburg, D-22607 Hamburg, Germany;
| | - Emily A Machala
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Benjamin Vollmer
- Centre for Structural Systems Biology, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, University of Hamburg, D-22607 Hamburg, Germany;
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Vojtěch Pražák
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Daven Vasishtan
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Rene Rosch
- Centre for Structural Systems Biology, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, University of Hamburg, D-22607 Hamburg, Germany;
| | - Michael Grange
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Linda E Franken
- Centre for Structural Systems Biology, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, University of Hamburg, D-22607 Hamburg, Germany;
| | - Lindsay A Baker
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Kay Grünewald
- Centre for Structural Systems Biology, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, University of Hamburg, D-22607 Hamburg, Germany;
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
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Critical Residues and Contacts within Domain IV of Autographa californica Multiple Nucleopolyhedrovirus GP64 Contribute to Its Refolding during Membrane Fusion. J Virol 2020; 94:JVI.01105-20. [PMID: 32699096 DOI: 10.1128/jvi.01105-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/19/2020] [Indexed: 01/14/2023] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) GP64 is a class III viral fusion protein that mediates low-pH-triggered membrane fusion during virus entry. Although the structure of GP64 in a postfusion conformation has been solved, its prefusion structure and the mechanism of how the protein refolds to execute fusion are unknown. In its postfusion structure, GP64 is composed of five domains (domains I to V). Domain IV (amino acids [aa] 374 to 407) contains two loops (loop 1 and loop 2) that form a hydrophobic pocket at the membrane-distal end of the molecule. To determine the roles of domain IV, we used alanine-scanning mutagenesis to replace each of the individual residues and the contact-forming residues within domain IV and evaluate their contributions to GP64-mediated membrane fusion and virus infection. In many cases, replacement of a single amino acid had no significant impact on GP64. However, replacement of R392 or disruption of the N381-N385, N384-Y388, N385-W393, or K389-W393 contact resulted in poor cell surface expression and fusion loss of the modified GP64, whereas replacement of E390 or G391 or disruption of the N381-K389, N381-Q401, or N381-I403 contact reduced the cell surface expression level of the constructs and the ability of GP64 to mediate fusion pore expansion. In contrast, replacement of N407 or disruption of contact D404-S406 appeared to restrict fusion pore expansion without affecting expression. Combined with the finding that these constructs remain in the prefusion conformation or have a dramatically less efficient transition from the prefusion to the postfusion state under acidic conditions, we proposed that domain IV is necessary for refolding of GP64 during membrane fusion.IMPORTANCE Baculovirus GP64 is grouped with rhabdovirus G, herpesvirus gB, and thogotovirus glycoproteins as a class III viral fusion protein. In their postfusion structures, these proteins contain five domains (domains I to V). Distinct from domain IV of rhabdovirus G and herpesvirus gB proteins, which is composed of β-sheets, domain IV of GP64 is a loop region; the same domain in thogotovirus glycoproteins has not been solved. In addition, domain IV is proximal to domain I (fusion domain) in prefusion structures of vesicular stomatitis virus (VSV) G and human cytomegalovirus (HCMV) gB but resides at the domain I-distal end of the molecule in a postfusion conformation. In this study, we identified that highly conserved residues and contacts within domain IV of AcMNPV GP64 are necessary for low-pH-triggered conformational change and fusion pore expansion. Our results highlight the roles of domain IV of class III viral fusion proteins in refolding during membrane fusion.
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Goodwin ML, Webster HS, Wang HY, Jenks JA, Nelson CS, Tu JJ, Mangold JF, Valencia S, Pollara J, Edwards W, McLellan JS, Wrapp D, Fu TM, Zhang N, Freed DC, Wang D, An Z, Permar SR. Specificity and effector functions of non-neutralizing gB-specific monoclonal antibodies isolated from healthy individuals with human cytomegalovirus infection. Virology 2020; 548:182-191. [PMID: 32838941 PMCID: PMC7447913 DOI: 10.1016/j.virol.2020.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/07/2020] [Accepted: 07/10/2020] [Indexed: 01/23/2023]
Abstract
Human cytomegalovirus (HCMV) is the most common congenital infection. A glycoprotein B (gB) subunit vaccine (gB/MF59) is the most efficacious clinically tested to date, having achieved 50% protection against primary infection of HCMV-seronegative women. We previously identified that gB/MF59 vaccination primarily elicits non-neutralizing antibody responses, with variable binding to gB genotypes, and protection associated with binding to membrane-associated gB. We hypothesized that gB-specific non-neutralizing antibody binding breadth and function are dependent on epitope and genotype specificity, and ability to interact with membrane-associated gB. We mapped twenty-four gB-specific monoclonal antibodies (mAbs) from naturally HCMV-infected individuals for gB domain specificity, genotype preference, and ability to mediate phagocytosis or NK cell activation. gB-specific mAbs were primarily specific for Domain II and demonstrated variable binding to gB genotypes. Two mAbs facilitated phagocytosis with binding specificities of Domain II and AD2. This investigation provides novel understanding on the relationship between gB domain specificity and antigenic variability on gB-specific antibody effector functions.
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Affiliation(s)
- Matthew L Goodwin
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Helen S Webster
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Hsuan-Yuan Wang
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Jennifer A Jenks
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Cody S Nelson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Joshua J Tu
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Jesse F Mangold
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Sarah Valencia
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Justin Pollara
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Whitney Edwards
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Jason S McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Daniel Wrapp
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Tong-Ming Fu
- Merck & Co., Inc., Kenilworth, NJ, USA; Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, USA
| | - Ningyan Zhang
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, USA
| | | | - Dai Wang
- Merck & Co., Inc., Kenilworth, NJ, USA
| | - Zhiqiang An
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, USA
| | - Sallie R Permar
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA.
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Vollmer B, Pražák V, Vasishtan D, Jefferys EE, Hernandez-Duran A, Vallbracht M, Klupp BG, Mettenleiter TC, Backovic M, Rey FA, Topf M, Grünewald K. The prefusion structure of herpes simplex virus glycoprotein B. SCIENCE ADVANCES 2020; 6:eabc1726. [PMID: 32978151 PMCID: PMC7518877 DOI: 10.1126/sciadv.abc1726] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 08/12/2020] [Indexed: 05/03/2023]
Abstract
Cell entry of enveloped viruses requires specialized viral proteins that mediate fusion with the host membrane by substantial structural rearrangements from a metastable pre- to a stable postfusion conformation. This metastability renders the herpes simplex virus 1 (HSV-1) fusion glycoprotein B (gB) highly unstable such that it readily converts into the postfusion form, thereby precluding structural elucidation of the pharmacologically relevant prefusion conformation. By identification of conserved sequence signatures and molecular dynamics simulations, we devised a mutation that stabilized this form. Functionally locking gB allowed the structural determination of its membrane-embedded prefusion conformation at sub-nanometer resolution and enabled the unambiguous fit of all ectodomains. The resulting pseudo-atomic model reveals a notable conservation of conformational domain rearrangements during fusion between HSV-1 gB and the vesicular stomatitis virus glycoprotein G, despite their very distant phylogeny. In combination with our comparative sequence-structure analysis, these findings suggest common fusogenic domain rearrangements in all class III viral fusion proteins.
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Affiliation(s)
- B Vollmer
- Oxford Particle Imaging Centre, Department of Structural Biology, Wellcome Centre Human Genetics, University of Oxford, Oxford, UK
- Centre for Structural Systems Biology, Heinrich-Pette-Institut, Leibniz-Institut für Experimentelle Virologie, Hamburg, Germany
| | - V Pražák
- Oxford Particle Imaging Centre, Department of Structural Biology, Wellcome Centre Human Genetics, University of Oxford, Oxford, UK
| | - D Vasishtan
- Oxford Particle Imaging Centre, Department of Structural Biology, Wellcome Centre Human Genetics, University of Oxford, Oxford, UK
| | - E E Jefferys
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - M Vallbracht
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Insel Riems, Germany
| | - B G Klupp
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Insel Riems, Germany
| | - T C Mettenleiter
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Insel Riems, Germany
| | - M Backovic
- Institut Pasteur, Structural Virology Unit, Department of Virology, Paris, France
| | - F A Rey
- Institut Pasteur, Structural Virology Unit, Department of Virology, Paris, France
| | - M Topf
- Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - K Grünewald
- Oxford Particle Imaging Centre, Department of Structural Biology, Wellcome Centre Human Genetics, University of Oxford, Oxford, UK.
- Centre for Structural Systems Biology, Heinrich-Pette-Institut, Leibniz-Institut für Experimentelle Virologie, Hamburg, Germany
- Department of Chemistry, MIN Faculty, Universität Hamburg, Hamburg, Germany
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48
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A glycoprotein B-neutralizing antibody structure at 2.8 Å uncovers a critical domain for herpesvirus fusion initiation. Nat Commun 2020; 11:4141. [PMID: 32811830 PMCID: PMC7435202 DOI: 10.1038/s41467-020-17911-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/21/2020] [Indexed: 11/24/2022] Open
Abstract
Members of the Herpesviridae, including the medically important alphaherpesvirus varicella-zoster virus (VZV), induce fusion of the virion envelope with cell membranes during entry, and between cells to form polykaryocytes in infected tissues. The conserved glycoproteins, gB, gH and gL, are the core functional proteins of the herpesvirus fusion complex. gB serves as the primary fusogen via its fusion loops, but functions for the remaining gB domains remain unexplained. As a pathway for biological discovery of domain function, our approach used structure-based analysis of the viral fusogen together with a neutralizing antibody. We report here a 2.8 Å cryogenic-electron microscopy structure of native gB recovered from VZV-infected cells, in complex with a human monoclonal antibody, 93k. This high-resolution structure guided targeted mutagenesis at the gB-93k interface, providing compelling evidence that a domain spatially distant from the gB fusion loops is critical for herpesvirus fusion, revealing a potential new target for antiviral therapies. Herpesvirus virions have an outer lipid membrane dotted with glycoproteins that enable fusion with cell membranes to initiate entry and establish infection. Here the authors elucidate the structural mechanism of a neutralizing antibody derived from a patient infected by the herpesvirus varicella-zoster virus and targeted to its fusogen, glycoprotein-B.
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49
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Draganova EB, Zhang J, Zhou ZH, Heldwein EE. Structural basis for capsid recruitment and coat formation during HSV-1 nuclear egress. eLife 2020; 9:56627. [PMID: 32579107 PMCID: PMC7340501 DOI: 10.7554/elife.56627] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/22/2020] [Indexed: 12/19/2022] Open
Abstract
During herpesvirus infection, egress of nascent viral capsids from the nucleus is mediated by the viral nuclear egress complex (NEC). NEC deforms the inner nuclear membrane (INM) around the capsid by forming a hexagonal array. However, how the NEC coat interacts with the capsid and how curved coats are generated to enable budding is yet unclear. Here, by structure-guided truncations, confocal microscopy, and cryoelectron tomography, we show that binding of the capsid protein UL25 promotes the formation of NEC pentagons rather than hexagons. We hypothesize that during nuclear budding, binding of UL25 situated at the pentagonal capsid vertices to the NEC at the INM promotes formation of NEC pentagons that would anchor the NEC coat to the capsid. Incorporation of NEC pentagons at the points of contact with the vertices would also promote assembly of the curved hexagonal NEC coat around the capsid, leading to productive egress of UL25-decorated capsids.
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Affiliation(s)
- Elizabeth B Draganova
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, United States
| | - Jiayan Zhang
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, United States.,Molecular Biology Institute, UCLA, Los Angeles, United States.,California NanoSystems Institute, UCLA, Los Angeles, United States
| | - Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, United States.,Molecular Biology Institute, UCLA, Los Angeles, United States.,California NanoSystems Institute, UCLA, Los Angeles, United States
| | - Ekaterina E Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, United States
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50
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Guinea pig cytomegalovirus trimer complex gH/gL/gO uses PDGFRA as universal receptor for cell fusion and entry. Virology 2020; 548:236-249. [PMID: 32791352 DOI: 10.1016/j.virol.2020.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022]
Abstract
Species-specific guinea pig cytomegalovirus (GPCMV) causes congenital CMV and the virus encodes homolog glycoprotein complexes to human CMV, including gH-based trimer (gH/gL/gO) and pentamer-complex (PC). Platelet-derived growth factor receptor alpha (gpPDGFRA), only present on fibroblast cells, was identified via CRISPR as the putative receptor for PC-independent GPCMV infection. Immunoprecipitation assays demonstrated direct interaction of gH/gL/gO with gpPDGFRA but not in absence of gO. Expression of viral gB also resulted in precipitation of gB/gH/gL/gO/gpPDGFRA complex. Cell-cell fusion assays determined that expression of gpPDGFRA and gH/gL/gO in adjacent cells enabled cell fusion, which was not enhanced by gB. N-linked gpPDGFRA glycosylation inhibition had limited effect and blocking tyrosine kinase (TK) transduction had no impact on infection. Ectopically expressed gpPDGFRA or TK-domain mutant in trophoblast or epithelial cells previously non-susceptible to GPCMV(PC-) enabled viral infection. In contrast, transient human PDGFRA expression did not complement GPCMV(PC-) infection, a potential basis for viral species specificity.
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