1
|
Fukuhara H, Yumoto K, Sako M, Kajikawa M, Ose T, Kawamura M, Yoda M, Chen S, Ito Y, Takeda S, Mwaba M, Wang J, Hashiguchi T, Kamishikiryo J, Maita N, Kitatsuji C, Takeda M, Kuroki K, Maenaka K. Glycan-shielded homodimer structure and dynamical features of the canine distemper virus hemagglutinin relevant for viral entry and efficient vaccination. eLife 2024; 12:RP88929. [PMID: 39046448 PMCID: PMC11268888 DOI: 10.7554/elife.88929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024] Open
Abstract
Canine distemper virus (CDV) belongs to morbillivirus, including measles virus (MeV) and rinderpest virus, which causes serious immunological and neurological disorders in carnivores, including dogs and rhesus monkeys, as recently reported, but their vaccines are highly effective. The attachment glycoprotein hemagglutinin (CDV-H) at the CDV surface utilizes signaling lymphocyte activation molecule (SLAM) and Nectin-4 (also called poliovirus-receptor-like-4; PVRL4) as entry receptors. Although fusion models have been proposed, the molecular mechanism of morbillivirus fusion entry is poorly understood. Here, we determined the crystal structure of the globular head domain of CDV-H vaccine strain at 3.2 Å resolution, revealing that CDV-H exhibits a highly tilted homodimeric form with a six-bladed β-propeller fold. While the predicted Nectin-4-binding site is well conserved with that of MeV-H, that of SLAM is similar but partially different, which is expected to contribute to host specificity. Five N-linked sugars covered a broad area of the CDV-H surface to expose receptor-binding sites only, supporting the effective production of neutralizing antibodies. These features are common to MeV-H, although the glycosylation sites are completely different. Furthermore, real-time observation using high-speed atomic force microscopy revealed highly mobile features of the CDV-H dimeric head via the connector region. These results suggest that sugar-shielded tilted homodimeric structure and dynamic conformational changes are common characteristics of morbilliviruses and ensure effective fusion entry and vaccination.
Collapse
Affiliation(s)
- Hideo Fukuhara
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
- Division of Pathogen Structure, Research Center for Zoonosis Control, Hokkaido UniversitySapporoJapan
| | - Kohei Yumoto
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Miyuki Sako
- Medical Institute of Bioregulation, Kyushu UniversityFukuokaJapan
| | - Mizuho Kajikawa
- Medical Institute of Bioregulation, Kyushu UniversityFukuokaJapan
| | - Toyoyuki Ose
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Mihiro Kawamura
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Mei Yoda
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Surui Chen
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Yuri Ito
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Shin Takeda
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Mwila Mwaba
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Jiaqi Wang
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Takao Hashiguchi
- Department of Virology, Faculty of Medicine, Kyushu UniversityFukuokaJapan
| | - Jun Kamishikiryo
- Medical Institute of Bioregulation, Kyushu UniversityFukuokaJapan
| | - Nobuo Maita
- Institute for Enzyme Research, University of TokushimaTokushimaJapan
| | - Chihiro Kitatsuji
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Makoto Takeda
- Department of Microbiology, Graduate School of Medicine and Faculty of Medicine, The University of TokyoTokyoJapan
| | - Kimiko Kuroki
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
| | - Katsumi Maenaka
- Laboratory of Biomolecular Science and Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido UniversitySapporoJapan
- Division of Pathogen Structure, Research Center for Zoonosis Control, Hokkaido UniversitySapporoJapan
- Global Station for Biosurfaces and Drug Discovery, Hokkaido UniversitySapporoJapan
- Institute for Vaccine Research and Development (HU-IVReD), Hokkaido UniversitySapporoJapan
- Core Research for Evolutional Science and Technology, Japan Science and Technology AgencySaitamaJapan
| |
Collapse
|
2
|
Guo Y, Wu S, Li W, Yang H, Shi T, Ju B, Zhang Z, Yan R. The cryo-EM structure of homotetrameric attachment glycoprotein from langya henipavirus. Nat Commun 2024; 15:812. [PMID: 38280880 PMCID: PMC10821904 DOI: 10.1038/s41467-024-45202-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 01/18/2024] [Indexed: 01/29/2024] Open
Abstract
Langya Henipavirus (LayV) infection is an emerging zoonotic disease that has been causing respiratory symptoms in China since 2019. For virus entry, LayV's genome encodes the fusion protein F and the attachment glycoprotein G. However, the structural and functional information regarding LayV-G remains unclear. In this study, we revealed that LayV-G cannot bind to the receptors found in other HNVs, such as ephrin B2/B3, and it shows different antigenicity from HeV-G and NiV-G. Furthermore, we determined the near full-length structure of LayV-G, which displays a distinct mushroom-shaped configuration, distinguishing it from other attachment glycoproteins of HNV. The stalk and transmembrane regions resemble the stem and root of mushroom and four downward-tilted head domains as mushroom cap potentially interact with the F protein and influence membrane fusion process. Our findings enhance the understanding of emerging HNVs that cause human diseases through zoonotic transmission and provide implication for LayV related vaccine development.
Collapse
Affiliation(s)
- Yingying Guo
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China.
| | - Songyue Wu
- Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China
- The Second Affiliated Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Wenting Li
- Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China
- The Second Affiliated Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Haonan Yang
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Tianhao Shi
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Bin Ju
- Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China.
- The Second Affiliated Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, China.
| | - Zheng Zhang
- Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China.
- The Second Affiliated Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, China.
| | - Renhong Yan
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China.
| |
Collapse
|
3
|
Zinzula L, Scholz J, Nagy I, Di Guardo G, Orsini M. Biophysical characterization of the cetacean morbillivirus haemagglutinin glycoprotein. Virus Res 2023; 336:199231. [PMID: 37769814 PMCID: PMC10550842 DOI: 10.1016/j.virusres.2023.199231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/24/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023]
Abstract
Cetacean morbillivirus (CeMV) is an enveloped, non-segmented, negative-stranded RNA virus that infects marine mammals, spreading across species and causing lethal disease outbreaks worldwide. Among the eight proteins encoded by the CeMV genome, the haemagglutinin (H) glycoprotein is responsible for the virus attachment to host cell receptors. CeMV H represents an attractive target for antiviral and diagnostic research, yet the elucidation of the molecular mechanisms underlying its role in infection and inter-species transmission was hampered thus far due to the unavailability of recombinant versions of the protein. Here we present the cloning, expression and purification of a recombinant CeMV H ectodomain (rH-ecto), providing an initial characterization of its biophysical and structural properties. Sodium dodecyl sulphate - polyacrylamide gel electrophoresis (PAGE) combined to Western blot analysis and periodic acid Schiff assay showed that CeMV rH-ecto is purifiable at homogeneity from insect cells as a secreted, soluble and glycosylated protein. Miniaturized differential scanning fluorimetry, Blue Native PAGE and size exclusion chromatography coupled to multiangle light scattering revealed that CeMV rH-ecto is globularly folded, thermally stable and exists in solution in the oligomeric states of dimer and multiple of dimers. Furthermore, negative stain electron microscopy single particle analysis allowed us to delineate a low-resolution molecular architecture of the CeMV rH-ecto dimer, which recapitulates native assemblies from other morbilliviral H proteins, such as those from measles virus and canine distemper virus. This set of experiments by orthogonal techniques validates the CeMV rH-ecto as an experimental model for future biochemical studies on its structure and functions.
Collapse
Affiliation(s)
- Luca Zinzula
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany; Centro di Educazione Ambientale e alla Sostenibilità (CEAS) Laguna di Nora, Pula, Italy.
| | - Judith Scholz
- Core Facility, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - István Nagy
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany; Center of Research and Development, Eszterházy Károly Catholic University, Eger, Hungary
| | - Giovanni Di Guardo
- Retired Professor of General Pathology and Veterinary Pathophysiology, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - Massimiliano Orsini
- Laboratory of Microbial Ecology and Genomics, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| |
Collapse
|
4
|
Bi Z, Wang W, Xia X. Structure and function of a novel lineage-specific neutralizing epitope on H protein of canine distemper virus. Front Microbiol 2023; 13:1088243. [PMID: 36713169 PMCID: PMC9875009 DOI: 10.3389/fmicb.2022.1088243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/28/2022] [Indexed: 01/13/2023] Open
Abstract
Canine distemper virus (CDV) infects many sensitive species worldwide and its host range is expanding. The hemagglutinin (H) protein, the major neutralizing target, binds to cellular receptors and subsequently triggers fusion for initial viral infection. So it's necessary to clarify the precise neutralizing epitopes of H protein and extend the knowledge of mechanisms of virus neutralization. In this study, a neutralizing monoclonal antibody (mAb) 2D12 against CDV H protein, which had different reactivity with different CDV strains, was generated and characterized. A series of truncated H proteins were screened to define the minimal linear epitope 238DIEREFD244 recognized by 2D12. Further investigation revealed that the epitope was highly conserved in America-1 vaccine lineage of CDV strains, but different substitutions in the epitope appeared in CDV strains of the other lineages and two substitutions (D238Y and R241G) caused the change of antigenicity. Thus, the epitope represents a novel lineage-specific neutralizing target on H protein of CDV for differentiation of America-1 vaccine lineage and the other lineages of CDV strains. The epitope was identified to localize at the surface of H protein in two different positions in a three-dimensional (3D) structure, but not at the position of the receptor-binding site (RBS), so the mAb 2D12 that recognized the epitope did not inhibit binding of H protein to the receptor. But mAb 2D12 interfered with the H-F interaction for inhibiting membrane fusion, suggesting that the mAb plays key roles for formation of H-F protein oligomeric structure. Our data will contribute to the understanding of the structure, function, and antigenicity of CDV H protein and mechanisms of virus neutralization.
Collapse
Affiliation(s)
- Zhenwei Bi
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-products, Nanjing, China,Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China,*Correspondence: Zhenwei Bi,
| | - Wenjie Wang
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-products, Nanjing, China,Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xingxia Xia
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, National Center for Engineering Research of Veterinary Bio-products, Nanjing, China,Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| |
Collapse
|
5
|
Mittal A, Chauhan A. Aspects of Biological Replication and Evolution Independent of the Central Dogma: Insights from Protein-Free Vesicular Transformations and Protein-Mediated Membrane Remodeling. J Membr Biol 2022; 255:185-209. [PMID: 35333977 PMCID: PMC8951669 DOI: 10.1007/s00232-022-00230-4] [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: 01/22/2022] [Accepted: 03/06/2022] [Indexed: 11/21/2022]
Abstract
Biological membrane remodeling is central to living systems. In spite of serving as “containers” of whole-living systems and functioning as dynamic compartments within living systems, biological membranes still find a “blue collar” treatment compared to the “white collar” nucleic acids and proteins in biology. This may be attributable to the fact that scientific literature on biological membrane remodeling is only 50 years old compared to ~ 150 years of literature on proteins and a little less than 100 years on nucleic acids. However, recently, evidence for symbiotic origins of eukaryotic cells from data only on biological membranes was reported. This, coupled with appreciation of reproducible amphiphilic self-assemblies in aqueous environments (mimicking replication), has already initiated discussions on origins of life beyond nucleic acids and proteins. This work presents a comprehensive compilation and meta-analyses of data on self-assembly and vesicular transformations in biological membranes—starting from model membranes to establishment of Influenza Hemagglutinin-mediated membrane fusion as a prototypical remodeling system to a thorough comparison between enveloped mammalian viruses and cellular vesicles. We show that viral membrane fusion proteins, in addition to obeying “stoichiometry-driven protein folding”, have tighter compositional constraints on their amino acid occurrences than general-structured proteins, regardless of type/class. From the perspective of vesicular assemblies and biological membrane remodeling (with and without proteins) we find that cellular vesicles are quite different from viruses. Finally, we propose that in addition to pre-existing thermodynamic frameworks, kinetic considerations in de novo formation of metastable membrane structures with available “third-party” constituents (including proteins) were not only crucial for origins of life but also continue to offer morphological replication and/or functional mechanisms in modern life forms, independent of the central dogma.
Collapse
Affiliation(s)
- Aditya Mittal
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi (IIT Delhi), Hauz Khas, New Delhi, 110016, India. .,Supercomputing Facility for Bioinformatics and Computational Biology (SCFBio), IIT Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Akanksha Chauhan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi (IIT Delhi), Hauz Khas, New Delhi, 110016, India
| |
Collapse
|
6
|
Sendai Virus-Vectored Vaccines That Express Envelope Glycoproteins of Respiratory Viruses. Viruses 2021; 13:v13061023. [PMID: 34072332 PMCID: PMC8230104 DOI: 10.3390/v13061023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/10/2021] [Accepted: 05/21/2021] [Indexed: 01/01/2023] Open
Abstract
Human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), and human parainfluenza viruses (HPIVs) are leading causes of respiratory disease in young children, the elderly, and individuals of all ages with immunosuppression. Vaccination strategies against these pneumoviruses and paramyxoviruses are vast in number, yet no licensed vaccines are available. Here, we review development of Sendai virus (SeV), a versatile pediatric vaccine that can (a) serve as a Jennerian vaccine against HPIV1, (b) serve as a recombinant vaccine against HRSV, HPIV2, HPIV3, and HMPV, (c) accommodate foreign genes for viral glycoproteins in multiple intergenic positions, (d) induce durable, mucosal, B-cell, and T-cell immune responses without enhanced immunopathology, (e) protect cotton rats, African green monkeys, and chimpanzees from infection, and (f) be formulated into a vaccine cocktail. Clinical phase I safety trials of SeV have been completed in adults and 3–6-year-old children. Clinical testing of SeVRSV, an HRSV fusion (F) glycoprotein gene recombinant, has also been completed in adults. Positive results from these studies, and collaborative efforts with the National Institutes of Health and the Serum Institute of India assist advanced development of SeV-based vaccines. Prospects are now good for vaccine successes in infants and consequent protection against serious viral disease.
Collapse
|
7
|
Yan F, Li E, Li L, Schiffman Z, Huang P, Zhang S, Li G, Jin H, Wang H, Zhang X, Gao Y, Feng N, Zhao Y, Wang C, Xia X. Virus-Like Particles Derived From a Virulent Strain of Pest des Petits Ruminants Virus Elicit a More Vigorous Immune Response in Mice and Small Ruminants Than Those From a Vaccine Strain. Front Microbiol 2020; 11:609. [PMID: 32390966 PMCID: PMC7190788 DOI: 10.3389/fmicb.2020.00609] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/19/2020] [Indexed: 11/13/2022] Open
Abstract
Peste des petits ruminants (PPRs) is highly contagious, acute or subacute disease of small ruminants caused by peste des petits ruminants virus (PPRV). To date, several studies have designed and evaluated PPRV-like particles (VLPs) as a vaccine candidate for the prevention and control of PPR, with the majority of these VLPs constructed using sequences derived from a PPRV vaccine strain due to its high immunogenicity. However, because of the lack of available genetic material and certain structural proteins and/or the alteration of posttranslational glycosylation modifications, the immunogenicity of VLPs derived from a vaccine strain is not always optimal. In this study, two PPRV VLP candidates, derived from either the lineage IV Tibet/30 virulent strain or the lineage II Nigeria 75/1 vaccine strain, were generated using a baculovirus system through the coexpression of the PPRV matrix (M), hemagglutinin (H), and fusion (F) proteins in the high expression level cell line High Five. These VLPs were then used to immunize mice, goats, and sheep followed by two boosts after primary immunization. Both VLPs were found to induce a potent humoral immune response as demonstrated by the high ratio of immunoglobulin G1 (IgG1) to IgG2a. In all animals, both VLPs induced high titers of virus-neutralizing antibodies (VNAs), as well as H- and F-specific antibodies, with the Tibet/30 VLPs yielding higher antibody titers by comparison to the Nigeria 75/1 VLPs. Studies in mice also demonstrated that the Tibet/30 VLPs induced a more robust interleukin 4 and interferon γ response than the Nigeria 75/1 VLPs. Goats and sheep immunized with both VLPs exhibited a robust humoral and cell-mediated immune response. Furthermore, our results demonstrated that the VLPs derived from the virulent lineage IV Tibet/30 strain were more immunogenic, inducing a more potent and robust humoral and cell-mediated immune response in vaccinated animals by comparison to the lineage II Nigeria 75/1 vaccine strain VLPs. In addition, VNA titers were significantly higher among animals vaccinated with the Tibet/30 VLPs by comparison to the Nigeria 75/1 VLPs. Taken together, these findings suggest that VLPs derived from the virulent lineage IV Tibet/30 strain are more immunogenic by comparison to those derived from the lineage II Nigeria 75/1 vaccine strain and thus represent a promising vaccine candidate for the control and eradication of PPR.
Collapse
Affiliation(s)
- Feihu Yan
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Entao Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Ling Li
- National Research Center for Exotic Animal Diseases, China Animal Health and Epidemiology Center, Qingdao, China
| | - Zachary Schiffman
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada.,National Microbiology Laboratory, Special Pathogens Program, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Pei Huang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, Jilin Agricultural University, Changchun, China
| | - Shengnan Zhang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Wildlife Resources, Northeast Forestry University, Harbin, China
| | - Guohua Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Hongli Jin
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - Hualei Wang
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xinghai Zhang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yuwei Gao
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Na Feng
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Yongkun Zhao
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Chengyu Wang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Xianzhu Xia
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,College of Veterinary Medicine, Jilin Agricultural University, Changchun, China
| |
Collapse
|
8
|
meng X, Zhu X, Alfred N, Zhang Z. Identification of amino acid residues involved in the interaction between peste-des-petits-ruminants virus haemagglutinin protein and cellular receptors. J Gen Virol 2020; 101:242-251. [PMID: 31859612 PMCID: PMC7416607 DOI: 10.1099/jgv.0.001368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/19/2019] [Indexed: 02/04/2023] Open
Abstract
Peste-des-petits-ruminants virus (PPRV) haemagglutinin (H) protein mediates binding to cellular receptors and then initiates virus entry. To identify the key residues of PPRV H (Hv) protein of the Nigeria 75/1 strain involved in binding to receptors, interaction of the Hv and mutated Hv (mHv) proteins with receptors (SLAM and Nectin 4) and their mutants (mSLAM1, mSLAM2, mSLAM3 and mNectin 4) was investigated using surface plasmon resonance imaging (SPRi) and coimmunoprecipitation (co-IP) assays. The results showed that the Hv protein failed to interact with mSLAM3, but interacted at a strong or medium intensity with SLAM, mSLAM2, Nectin 4 and mNectin 4, and at a low level with mSLAM1. The mHv protein was unable to interact with SLAM and its mutants, but bound to Nectin 4 and mNectin 4 with medium and weak intensity, respectively. Further analysis showed that the Hv protein could precipitate mSLAM1, mSLAM2 and mNectin 4, but not mSLAM3. The mHv protein failed to coprecipitate with SLAM and its mutants. The binding activities of mNectin 4 and Nectin 4 to mHv were less than 30.36 and 51.94 % of the wild-type levels, respectively. Based on the results obtained, amino acids at positions R389, L464, I498, R503, R533, Y541, Y543, F552 and Y553 of H protein and I61, H62, L64, K76, K78, E123, H130, I210, A211, S226 and R227 in SLAM were identified to be essential for the specificity of H-SLAM interaction, while the critical residues of H-Nectin 4 interaction require further study. These findings would improve our understanding of the invasive mechanisms of PPRV.
Collapse
Affiliation(s)
- Xuelian meng
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Yanchangpu, Chengguan District, Lanzhou 730046, PR China
| | - Xueliang Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Yanchangpu, Chengguan District, Lanzhou 730046, PR China
| | - Niyokwishimira Alfred
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Yanchangpu, Chengguan District, Lanzhou 730046, PR China
| | - Zhidong Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Yanchangpu, Chengguan District, Lanzhou 730046, PR China
| |
Collapse
|
9
|
Azarm KD, Lee B. Differential Features of Fusion Activation within the Paramyxoviridae. Viruses 2020; 12:v12020161. [PMID: 32019182 PMCID: PMC7077268 DOI: 10.3390/v12020161] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/13/2022] Open
Abstract
Paramyxovirus (PMV) entry requires the coordinated action of two envelope glycoproteins, the receptor binding protein (RBP) and fusion protein (F). The sequence of events that occurs during the PMV entry process is tightly regulated. This regulation ensures entry will only initiate when the virion is in the vicinity of a target cell membrane. Here, we review recent structural and mechanistic studies to delineate the entry features that are shared and distinct amongst the Paramyxoviridae. In general, we observe overarching distinctions between the protein-using RBPs and the sialic acid- (SA-) using RBPs, including how their stalk domains differentially trigger F. Moreover, through sequence comparisons, we identify greater structural and functional conservation amongst the PMV fusion proteins, as compared to the RBPs. When examining the relative contributions to sequence conservation of the globular head versus stalk domains of the RBP, we observe that, for the protein-using PMVs, the stalk domains exhibit higher conservation and find the opposite trend is true for SA-using PMVs. A better understanding of conserved and distinct features that govern the entry of protein-using versus SA-using PMVs will inform the rational design of broader spectrum therapeutics that impede this process.
Collapse
|
10
|
Abstract
Oncolytic virotherapy uses replication-competent virus as a means of treating cancer. Whereas this field has shown great promise as a viable treatment method, the limited spread of these viruses throughout the tumor microenvironment remains a major challenge. To overcome this issue, researchers have begun looking at syncytia formation as a novel method of increasing viral spread. Several naturally occurring fusogenic viruses have been shown to possess strong oncolytic potential and have since been studied to gain insight into how this process benefits oncolytic virotherapy. Whereas these naturally fusogenic viruses have been beneficial, there are still challenges associated with their regular use. Because of this, engineered/recombinant fusogenic viruses have also been created that enhance nonfusogenic oncolytic viruses with the beneficial property of syncytia formation. The purpose of this review is to examine the existing body of literature on syncytia formation in oncolytics and offer direction for potential future studies.
Collapse
Affiliation(s)
- Chase Burton
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Eric Bartee
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA
| |
Collapse
|
11
|
Molecular mechanism by which residues at position 481 and 546 of measles virus hemagglutinin protein define CD46 receptor binding using a molecular docking approach. Comput Biol Chem 2019; 80:384-389. [PMID: 31112822 DOI: 10.1016/j.compbiolchem.2019.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 05/08/2019] [Accepted: 05/10/2019] [Indexed: 11/23/2022]
Abstract
The hemagglutinin (H) protein of measles viruses (MeV) mediates binding to the cellular receptors, CD46,human signaling lymphocyte activation molecule and nectin-4. Vaccine strains primarily contain H-proteins possessing MeV-H: Y481 and can utilize CD46. Reports suggest that a single amino acid change in MeV-H at position 481 in wild type strains renders them inefficient in utilizing CD46. The in-depth molecular mechanism by which substitutions at 481 and another reported critical residue position 546 affects CD46 binding affinity however remains elusive. We used molecular docking studies of CD46 with MeV-H possessing Y481 N/D to understand the in-depth molecular mechanism involved. It was found that loss in either of the hydrogen bond (H-bond) contacts (MeV-H:481-CD46:65, MeV-H:546-CD46:63) in the central contact region prevented efficient CD46 binding. Y481 N could form the specific H-bond, while G546S H-bond could be formed only in conjunction with Y481, revealing the significance of these residues in determining CD46 receptor binding potential. Elucidating the underlying molecular mechanism of receptor usage by the MeV has implications to understanding cellular tropism, viral pathogenesis and therapy.
Collapse
|
12
|
Regulatory Role of the Morbillivirus Attachment Protein Head-to-Stalk Linker Module in Membrane Fusion Triggering. J Virol 2018; 92:JVI.00679-18. [PMID: 29997204 DOI: 10.1128/jvi.00679-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/05/2018] [Indexed: 12/12/2022] Open
Abstract
Morbillivirus (e.g., measles virus [MeV] and canine distemper virus [CDV]) host cell entry is coordinated by two interacting envelope glycoproteins, namely, an attachment (H) protein and a fusion (F) protein. The ectodomain of H proteins consists of stalk, connector, and head domains that assemble into functional noncovalent dimer-of-dimers. The role of the C-terminal module of the H-stalk domain (termed linker) and the connector, although putatively able to assume flexible structures and allow receptor-induced structural rearrangements, remains largely unexplored. Here, we carried out a nonconservative mutagenesis scan analysis of the MeV and CDV H-linker/connector domains. Our data demonstrated that replacing isoleucine 146 in H-linker (H-I146) with any charged amino acids prevented virus-mediated membrane fusion activity, despite proper trafficking of the mutants to the cell surface and preserved binding efficiency to the SLAM/CD150 receptor. Nondenaturing electrophoresis revealed that these charged amino acid changes led to the formation of irregular covalent H tetramers rather than functional dimer-of-dimers formed when isoleucine or other hydrophobic amino acids were present at residue position 146. Remarkably, we next demonstrated that covalent H tetramerization per se was not the only mechanism preventing F activation. Indeed, the neutral glycine mutant (H-I146G), which exhibited strong covalent tetramerization propensity, maintained limited fusion promotion activity. Conversely, charged H-I146 mutants, which additionally carried alanine substitution of natural cysteines (H-C139A and H-C154A) and thus were unable to form covalently linked tetramers, were fusion activation defective. Our data suggest a dual regulatory role of the hydrophobic residue at position 146 of the morbillivirus head-to-stalk H-linker module: securing the assembly of productive dimer-of-dimers and contributing to receptor-induced F-triggering activity.IMPORTANCE MeV and CDV remain important human and animal pathogens. Development of antivirals may significantly support current global vaccination campaigns. Cell entry is orchestrated by two interacting glycoproteins (H and F). The current hypothesis postulates that tetrameric H ectodomains (composed of stalk, connector, and head domains) undergo receptor-induced rearrangements to productively trigger F; these conformational changes may be regulated by the H-stalk C-terminal module (linker) and the following connector domain. Mutagenesis scan analysis of both microdomains revealed that replacing amino acid 146 in the H-linker region with nonhydrophobic residues produced covalent H tetramers which were compromised in triggering membrane fusion activity. However, these mutant proteins retained their ability to traffic to the cell surface and to bind to the virus receptor. These data suggest that the morbillivirus linker module contributes to the folding of functional pre-F-triggering H tetramers. Furthermore, such structures might be critical to convert receptor engagement into F activation.
Collapse
|
13
|
Russell CJ, Simões EAF, Hurwitz JL. Vaccines for the Paramyxoviruses and Pneumoviruses: Successes, Candidates, and Hurdles. Viral Immunol 2018; 31:133-141. [PMID: 29323621 DOI: 10.1089/vim.2017.0137] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human parainfluenza viruses (family Paramyxoviridae), human metapneumovirus, and respiratory syncytial virus (family Pneumoviridae) infect most infants and children within the first few years of life and are the etiologic agents for many serious acute respiratory illnesses. These virus infections are also associated with long-term diseases that impact quality of life, including asthma. Despite over a half-century of vaccine research, development, and clinical trials, no vaccine has been licensed to date for the paramyxoviruses or pneumoviruses for the youngest infants. In this study, we describe the recent reclassification of paramyxoviruses and pneumoviruses into distinct families by the International Committee on the Taxonomy of Viruses. We also discuss some past unsuccessful vaccine trials and some currently preferred vaccine strategies. Finally, we discuss hurdles that must be overcome to support successful respiratory virus vaccine development for the youngest children.
Collapse
Affiliation(s)
- Charles J Russell
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee.,2 Department of Molecular Biology, Immunology, and Biochemistry, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Eric A F Simões
- 3 Department of Pediatrics, University of Colorado School of Medicine, Department of Epidemiology, Colorado School of Public Health, Section of Infectious Diseases, Children's Hospital Colorado, Aurora, Colorado
| | - Julia L Hurwitz
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee.,2 Department of Molecular Biology, Immunology, and Biochemistry, University of Tennessee Health Science Center , Memphis, Tennessee
| |
Collapse
|
14
|
Rissanen I, Ahmed AA, Azarm K, Beaty S, Hong P, Nambulli S, Duprex WP, Lee B, Bowden TA. Idiosyncratic Mòjiāng virus attachment glycoprotein directs a host-cell entry pathway distinct from genetically related henipaviruses. Nat Commun 2017; 8:16060. [PMID: 28699636 PMCID: PMC5510225 DOI: 10.1038/ncomms16060] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/25/2017] [Indexed: 12/28/2022] Open
Abstract
In 2012, cases of lethal pneumonia among Chinese miners prompted the isolation of a rat-borne henipavirus (HNV), Mòjiāng virus (MojV). Although MojV is genetically related to highly pathogenic bat-borne henipaviruses, the absence of a conserved ephrin receptor-binding motif in the MojV attachment glycoprotein (MojV-G) indicates a differing host-cell recognition mechanism. Here we find that MojV-G displays a six-bladed β-propeller fold bearing limited similarity to known paramyxoviral attachment glycoproteins, in particular at host receptor-binding surfaces. We confirm the inability of MojV-G to interact with known paramyxoviral receptors in vitro, indicating an independence from well-characterized ephrinB2/B3, sialic acid and CD150-mediated entry pathways. Furthermore, we find that MojV-G is antigenically distinct, indicating that MojV would less likely be detected in existing large-scale serological screening studies focused on well-established HNVs. Altogether, these data indicate a unique host-cell entry pathway for this emerging and potentially pathogenic HNV. The attachment glycoprotein (HNV-G) of henipaviruses interacts with host receptors at the cell surface and is a major determinant of species tropism. Here the authors provide structural and functional evidence that the emergent henipavirus, Mòjiang virus, uses an entry mechanism that is independent of known paramyoxviral cellular receptors.
Collapse
Affiliation(s)
- Ilona Rissanen
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, Oxfordshire OX3 7BN, UK
| | - Asim A Ahmed
- Division of Infectious Disease, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Kristopher Azarm
- Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, #1124, New York, New York 10029, USA
| | - Shannon Beaty
- Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, #1124, New York, New York 10029, USA
| | - Patrick Hong
- Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, #1124, New York, New York 10029, USA
| | - Sham Nambulli
- Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - W Paul Duprex
- Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Benhur Lee
- Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, #1124, New York, New York 10029, USA
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, Oxfordshire OX3 7BN, UK
| |
Collapse
|
15
|
Yu R, Zhu R, Gao W, Zhang M, Dong S, Chen B, Yu L, Xie C, Jiang F, Li Z. Fine mapping and conservation analysis of linear B-cell epitopes of peste des petits ruminants virus hemagglutinin protein. Vet Microbiol 2017; 208:110-117. [PMID: 28888625 PMCID: PMC7126934 DOI: 10.1016/j.vetmic.2017.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/05/2017] [Accepted: 07/07/2017] [Indexed: 12/24/2022]
Abstract
Hemagglutinin protein (H), one of the two glycoproteins of peste des petits ruminants virus (PPRV), binds to its receptor on the host cell and acts as a major antigen that induces and confers highly protective immunity in the host. In order to delineate the epitopes on H protein, fine epitope mapping and conservation analysis of linear B-cell epitopes (BCEs) on PPRV H has been undertaken using biosynthetic peptides and rabbit anti-PPRV H sera. Thirteen linear BCEs were identified and their corresponding minimal motifs were located on the H protein of PPRV China/Tibet/Geg/07-30. Conservation analysis indicated that two of the 13 minimal motifs were conserved among 52 PPRV strains. Nine of the 13 peptides containing the minimal motifs were recognized using anti-PPRV serum from a goat immunized with PPRV vaccine strain Nigeria 75/1. Identified epitopes and their motifs improve our understanding of the antigenic characteristics of PPRV H and provide a basis for the development of epitope-based diagnostic assays and multiple epitopes vaccine.
Collapse
Affiliation(s)
- Ruisong Yu
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Rui Zhu
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China
| | - Weixiang Gao
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Ming Zhang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Shijuan Dong
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Bingqing Chen
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Li Yu
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Chunfang Xie
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Fengying Jiang
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Zhen Li
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China.
| |
Collapse
|
16
|
Jiang Y, Qin Y, Chen M. Host-Pathogen Interactions in Measles Virus Replication and Anti-Viral Immunity. Viruses 2016; 8:v8110308. [PMID: 27854326 PMCID: PMC5127022 DOI: 10.3390/v8110308] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/06/2016] [Accepted: 11/07/2016] [Indexed: 12/12/2022] Open
Abstract
The measles virus (MeV) is a contagious pathogenic RNA virus of the family Paramyxoviridae, genus Morbillivirus, that can cause serious symptoms and even fetal complications. Here, we summarize current molecular advances in MeV research, and emphasize the connection between host cells and MeV replication. Although measles has reemerged recently, the potential for its eradication is promising with significant progress in our understanding of the molecular mechanisms of its replication and host-pathogen interactions.
Collapse
Affiliation(s)
- Yanliang Jiang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Yali Qin
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Mingzhou Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| |
Collapse
|
17
|
Adu-Gyamfi E, Kim LS, Jardetzky TS, Lamb RA. Flexibility of the Head-Stalk Linker Domain of Paramyxovirus HN Glycoprotein Is Essential for Triggering Virus Fusion. J Virol 2016; 90:9172-81. [PMID: 27489276 PMCID: PMC5044854 DOI: 10.1128/jvi.01187-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 07/25/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED The Paramyxoviridae comprise a large family of enveloped, negative-sense, single-stranded RNA viruses with significant economic and public health implications. For nearly all paramyxoviruses, infection is initiated by fusion of the viral and host cell plasma membranes in a pH-independent fashion. Fusion is orchestrated by the receptor binding protein hemagglutinin-neuraminidase (HN; also called H or G depending on the virus type) protein and a fusion (F) protein, the latter undergoing a major refolding process to merge the two membranes. Mechanistic details regarding the coupling of receptor binding to F activation are not fully understood. Here, we have identified the flexible loop region connecting the bulky enzymatically active head and the four-helix bundle stalk to be essential for fusion promotion. Proline substitution in this region of HN of parainfluenza virus 5 (PIV5) and Newcastle disease virus HN abolishes cell-cell fusion, whereas HN retains receptor binding and neuraminidase activity. By using reverse genetics, we engineered recombinant PIV5-EGFP viruses with mutations in the head-stalk linker region of HN. Mutations in this region abolished virus recovery and infectivity. In sum, our data suggest that the loop region acts as a "hinge" around which the bulky head of HN swings to-and-fro to facilitate timely HN-mediate F-triggering, a notion consistent with the stalk-mediated activation model of paramyxovirus fusion. IMPORTANCE Paramyxovirus fusion with the host cell plasma membrane is essential for virus infection. Membrane fusion is orchestrated via interaction of the receptor binding protein (HN, H, or G) with the viral fusion glycoprotein (F). Two distinct models have been suggested to describe the mechanism of fusion: these include "the clamp" and the "provocateur" model of activation. By using biochemical and reverse genetics tools, we have obtained strong evidence in favor of the HN stalk-mediated activation of paramyxovirus fusion. Specifically, our data strongly support the notion that the short linker between the head and stalk plays a role in "conformational switching" of the head group to facilitate F-HN interaction and triggering.
Collapse
Affiliation(s)
- Emmanuel Adu-Gyamfi
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
| | - Lori S Kim
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
| | - Theodore S Jardetzky
- Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois, USA
| | - Robert A Lamb
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA Department of Structural Biology, Stanford University, Stanford, California, USA
| |
Collapse
|
18
|
Lin LT, Richardson CD. The Host Cell Receptors for Measles Virus and Their Interaction with the Viral Hemagglutinin (H) Protein. Viruses 2016; 8:v8090250. [PMID: 27657109 PMCID: PMC5035964 DOI: 10.3390/v8090250] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/29/2016] [Accepted: 09/02/2016] [Indexed: 12/14/2022] Open
Abstract
The hemagglutinin (H) protein of measles virus (MeV) interacts with a cellular receptor which constitutes the initial stage of infection. Binding of H to this host cell receptor subsequently triggers the F protein to activate fusion between virus and host plasma membranes. The search for MeV receptors began with vaccine/laboratory virus strains and evolved to more relevant receptors used by wild-type MeV. Vaccine or laboratory strains of measles virus have been adapted to grow in common cell lines such as Vero and HeLa cells, and were found to use membrane cofactor protein (CD46) as a receptor. CD46 is a regulator that normally prevents cells from complement-mediated self-destruction, and is found on the surface of all human cells, with the exception of erythrocytes. Mutations in the H protein, which occur during adaptation and allow the virus to use CD46 as a receptor, have been identified. Wild-type isolates of measles virus cannot use the CD46 receptor. However, both vaccine/laboratory and wild-type strains can use an immune cell receptor called signaling lymphocyte activation molecule family member 1 (SLAMF1; also called CD150) and a recently discovered epithelial receptor known as Nectin-4. SLAMF1 is found on activated B, T, dendritic, and monocyte cells, and is the initial target for infections by measles virus. Nectin-4 is an adherens junction protein found at the basal surfaces of many polarized epithelial cells, including those of the airways. It is also over-expressed on the apical and basal surfaces of many adenocarcinomas, and is a cancer marker for metastasis and tumor survival. Nectin-4 is a secondary exit receptor which allows measles virus to replicate and amplify in the airways, where the virus is expelled from the body in aerosol droplets. The amino acid residues of H protein that are involved in binding to each of the receptors have been identified through X-ray crystallography and site-specific mutagenesis. Recombinant measles “blind” to each of these receptors have been constructed, allowing the virus to selectively infect receptor specific cell lines. Finally, the observations that SLAMF1 is found on lymphomas and that Nectin-4 is expressed on the cell surfaces of many adenocarcinomas highlight the potential of measles virus for oncolytic therapy. Although CD46 is also upregulated on many tumors, it is less useful as a target for cancer therapy, since normal human cells express this protein on their surfaces.
Collapse
Affiliation(s)
- Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
| | - Christopher D Richardson
- Department of Microbiology and Immunology, Dalhousie University, 5850 College St., Halifax, NS B3H 4R2, Canada.
- Department of Pediatrics and Canadian Center for Vaccinology, Izaak Walton Killam Health Centre, Halifax, NS B3K 6R8, Canada.
| |
Collapse
|
19
|
Measles Virus Fusion Protein: Structure, Function and Inhibition. Viruses 2016; 8:112. [PMID: 27110811 PMCID: PMC4848605 DOI: 10.3390/v8040112] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 03/26/2016] [Accepted: 04/14/2016] [Indexed: 01/02/2023] Open
Abstract
Measles virus (MeV), a highly contagious member of the Paramyxoviridae family, causes measles in humans. The Paramyxoviridae family of negative single-stranded enveloped viruses includes several important human and animal pathogens, with MeV causing approximately 120,000 deaths annually. MeV and canine distemper virus (CDV)-mediated diseases can be prevented by vaccination. However, sub-optimal vaccine delivery continues to foster MeV outbreaks. Post-exposure prophylaxis with antivirals has been proposed as a novel strategy to complement vaccination programs by filling herd immunity gaps. Recent research has shown that membrane fusion induced by the morbillivirus glycoproteins is the first critical step for viral entry and infection, and determines cell pathology and disease outcome. Our molecular understanding of morbillivirus-associated membrane fusion has greatly progressed towards the feasibility to control this process by treating the fusion glycoprotein with inhibitory molecules. Current approaches to develop anti-membrane fusion drugs and our knowledge on drug resistance mechanisms strongly suggest that combined therapies will be a prerequisite. Thus, discovery of additional anti-fusion and/or anti-attachment protein small-molecule compounds may eventually translate into realistic therapeutic options.
Collapse
|
20
|
Liang Z, Yuan R, Chen L, Zhu X, Dou Y. Molecular Evolution and Characterization of Hemagglutinin (H) in Peste des Petits Ruminants Virus. PLoS One 2016; 11:e0152587. [PMID: 27035347 PMCID: PMC4818033 DOI: 10.1371/journal.pone.0152587] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 11/24/2022] Open
Abstract
Peste des Petits Ruminants (PPR) is an acute, highly contagious, and febrile viral disease that affects both domestic and wild small ruminants. The disease has become a major obstacle to the development of sustainable Agriculture. Hemagglutinin (H), the envelope glycoprotein of Peste des Petits Ruminants Virus (PPRV), plays a crucial role in regulating viral adsorption and entry, thus determining pathogenicity, and release of newly produced viral particles. In order to accurately understand the epidemic of the disease and the interactions between the virus and host, we launch the work. Here, we examined H gene from all four lineages of the PPRV to investigate evolutionary and epidemiologic dynamics of PPRV by the Bayesian method. In addition, we predicted positive selection sites due to selective pressures. Finally, we studied the interaction between H protein and SLAM receptor based on homology model of the complex. Phylogenetic analysis suggested that H gene can also be used to investigate evolutionary and epidemiologic dynamics of PPRV. Positive selection analysis identified four positive selection sites in H gene, in which only one common site (aa246) was detected by two methods, suggesting strong operation structural and/or functional constraint of changes on the H protein. This target site may be of interest for future mutagenesis studies. The results of homology modeling showed PPRVHv-shSLAM binding interface and MVH-maSLAM binding interface were consistent, wherein the groove in the B4 blade and B5 of the head domain of PPRVHv bound to the AGFCC′ β-sheets of the membrane-distal ectodomain of shSLAM. The binding regions could provide insight on the nature of the protein for epitope vaccine design, novel drug discovery, and rational drug design against PPRV.
Collapse
Affiliation(s)
- Zhongxiang Liang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Ruyi Yuan
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Lei Chen
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Xueliang Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Yongxi Dou
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
- * E-mail:
| |
Collapse
|
21
|
Sawatsky B, Bente DA, Czub M, von Messling V. Morbillivirus and henipavirus attachment protein cytoplasmic domains differently affect protein expression, fusion support and particle assembly. J Gen Virol 2016; 97:1066-1076. [PMID: 26813519 PMCID: PMC7482510 DOI: 10.1099/jgv.0.000415] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The amino-terminal cytoplasmic domains of paramyxovirus attachment glycoproteins
include trafficking signals that influence protein processing and cell surface
expression. To characterize the role of the cytoplasmic domain in protein expression,
fusion support and particle assembly in more detail, we constructed chimeric Nipah
virus (NiV) glycoprotein (G) and canine distemper virus (CDV) haemagglutinin (H)
proteins carrying the respective heterologous cytoplasmic domain, as well as a series
of mutants with progressive deletions in this domain. CDV H retained fusion function
and was normally expressed on the cell surface with a heterologous cytoplasmic
domain, while the expression and fusion support of NiV G was dramatically decreased
when its cytoplasmic domain was replaced with that of CDV H. The cell surface
expression and fusion support functions of CDV H were relatively insensitive to
cytoplasmic domain deletions, while short deletions in the corresponding region of
NiV G dramatically decreased both. In addition, the first 10 residues of the CDV H
cytoplasmic domain strongly influence its incorporation into virus-like particles
formed by the CDV matrix (M) protein, while the co-expression of NiV M with NiV G had
no significant effect on incorporation of G into particles. The cytoplasmic domains
of both the CDV H and NiV G proteins thus contribute differently to the virus life
cycle.
Collapse
Affiliation(s)
- Bevan Sawatsky
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, USA.,INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada.,Veterinary Medicine Division, Paul-Ehrlich-Institute, Langen, Germany.,Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Dennis A Bente
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, USA.,Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, USA
| | - Markus Czub
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Veronika von Messling
- INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada.,Veterinary Medicine Division, Paul-Ehrlich-Institute, Langen, Germany
| |
Collapse
|
22
|
Canine Distemper Virus Fusion Activation: Critical Role of Residue E123 of CD150/SLAM. J Virol 2015; 90:1622-37. [PMID: 26608324 DOI: 10.1128/jvi.02405-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/18/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Measles virus (MeV) and canine distemper virus (CDV) possess tetrameric attachment proteins (H) and trimeric fusion proteins, which cooperate with either SLAM or nectin 4 receptors to trigger membrane fusion for cell entry. While the MeV H-SLAM cocrystal structure revealed the binding interface, two distinct oligomeric H assemblies were also determined. In one of the conformations, two SLAM units were sandwiched between two discrete H head domains, thus spotlighting two binding interfaces ("front" and "back"). Here, we investigated the functional relevance of both interfaces in activating the CDV membrane fusion machinery. While alanine-scanning mutagenesis identified five critical regulatory residues in the front H-binding site of SLAM, the replacement of a conserved glutamate residue (E at position 123, replaced with A [E123A]) led to the most pronounced impact on fusion promotion. Intriguingly, while determination of the interaction of H with the receptor using soluble constructs revealed reduced binding for the identified SLAM mutants, no effect was recorded when physical interaction was investigated with the full-length counterparts of both molecules. Conversely, although mutagenesis of three strategically selected residues within the back H-binding site of SLAM did not substantially affect fusion triggering, nevertheless, the mutants weakened the H-SLAM interaction recorded with the membrane-anchored protein constructs. Collectively, our findings support a mode of binding between the attachment protein and the V domain of SLAM that is common to all morbilliviruses and suggest a major role of the SLAM residue E123, located at the front H-binding site, in triggering the fusion machinery. However, our data additionally support the hypothesis that other microdomain(s) of both glycoproteins (including the back H-binding site) might be required to achieve fully productive H-SLAM interactions. IMPORTANCE A complete understanding of the measles virus and canine distemper virus (CDV) cell entry molecular framework is still lacking, thus impeding the rational design of antivirals. Both viruses share many biological features that partially rely on the use of analogous Ig-like host cell receptors, namely, SLAM and nectin 4, for entering immune and epithelial cells, respectively. Here, we provide evidence that the mode of binding between the membrane-distal V domain of SLAM and the attachment protein (H) of morbilliviruses is very likely conserved. Moreover, although structural information revealed two discrete conformational states of H, one of the structures displayed two H-SLAM binding interfaces ("front" and "back"). Our data not only spotlight the front H-binding site of SLAM as the main determinant of membrane fusion promotion but suggest that the triggering efficiency of the viral entry machinery may rely on a local conformational change within the front H-SLAM interactive site rather than the binding affinity.
Collapse
|
23
|
A Structurally Unresolved Head Segment of Defined Length Favors Proper Measles Virus Hemagglutinin Tetramerization and Efficient Membrane Fusion Triggering. J Virol 2015; 90:68-75. [PMID: 26446605 DOI: 10.1128/jvi.02253-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/05/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Paramyxoviruses include several insidious and ubiquitous pathogens of humans and animals, with measles virus (MeV) being a prominent one. The MeV membrane fusion apparatus consists of a receptor binding protein (hemagglutinin [H]) tetramer and a fusion (F) protein trimer. Four globular MeV H heads are connected to a tetrameric stalk through flexible linkers. We sought here to characterize the function of a 17-residue H-head segment proximal to the stalk that was unresolved in all five MeV H-head crystal or cocrystal structures. In particular, we assessed whether its primary sequence and length are critical for proper protein oligomerization and intracellular transport or for membrane fusion triggering. Extensive alanine substitutions had no effect on fusion triggering, suggesting that sequence identity is not critical for this function. Excessive shortening of this segment reduced or completely abrogated fusion trigger function, while length compensation restored it. We then characterized the mechanism of function loss. Mutated H proteins were efficiently transported to the cell surface, but certain alterations enhancing linker flexibility resulted in accumulation of high-molecular-weight H oligomers. Some oligomers had reduced fusion trigger capacity, while others retained this function. Thus, length and rigidity of the unresolved head segment favor proper H tetramerization and counteract interactions between subunits from different tetramers. The structurally unresolved H-head segment, together with the top of the stalk, may act as a leash to provide the right degree of freedom for the heads of individual tetramers to adopt a triggering-permissive conformation while avoiding improper contacts with heads of neighboring tetramers. IMPORTANCE Understanding the molecular mechanism of membrane fusion triggering may allow development of new antiviral strategies. The fusion apparatus of paramyxoviruses consists of a receptor binding tetramer and a fusion protein trimer. Structural analyses of the receptor binding hemagglutinin-neuraminidases of certain paramyxoviruses suggest that fusion triggering is preceded by relocation of its head domains, facilitated by flexible linkers. Having noted a structurally unresolved 17-residue segment linking the globular heads to the tetrameric stalk of the measles virus hemagglutinin (H), we asked whether and how it may facilitate membrane fusion triggering. We conclude that, together with the top of the stalk, the flexible linker keeps H heads on a leash long enough to adopt a triggering-permissive conformation but short enough to limit roaming and improper contacts with heads of neighboring tetramers. All morbillivirus H-protein heads appear to be connected to their stalks through a "leash," suggesting a conserved triggering mechanism.
Collapse
|
24
|
Ader-Ebert N, Khosravi M, Herren M, Avila M, Alves L, Bringolf F, Örvell C, Langedijk JP, Zurbriggen A, Plemper RK, Plattet P. Sequential conformational changes in the morbillivirus attachment protein initiate the membrane fusion process. PLoS Pathog 2015; 11:e1004880. [PMID: 25946112 PMCID: PMC4422687 DOI: 10.1371/journal.ppat.1004880] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/14/2015] [Indexed: 11/18/2022] Open
Abstract
Despite large vaccination campaigns, measles virus (MeV) and canine distemper virus (CDV) cause major morbidity and mortality in humans and animals, respectively. The MeV and CDV cell entry system relies on two interacting envelope glycoproteins: the attachment protein (H), consisting of stalk and head domains, co-operates with the fusion protein (F) to mediate membrane fusion. However, how receptor-binding by the H-protein leads to F-triggering is not fully understood. Here, we report that an anti-CDV-H monoclonal antibody (mAb-1347), which targets the linear H-stalk segment 126-133, potently inhibits membrane fusion without interfering with H receptor-binding or F-interaction. Rather, mAb-1347 blocked the F-triggering function of H-proteins regardless of the presence or absence of the head domains. Remarkably, mAb-1347 binding to headless CDV H, as well as standard and engineered bioactive stalk-elongated CDV H-constructs treated with cells expressing the SLAM receptor, was enhanced. Despite proper cell surface expression, fusion promotion by most H-stalk mutants harboring alanine substitutions in the 126-138 "spacer" section was substantially impaired, consistent with deficient receptor-induced mAb-1347 binding enhancement. However, a previously reported F-triggering defective H-I98A variant still exhibited the receptor-induced "head-stalk" rearrangement. Collectively, our data spotlight a distinct mechanism for morbillivirus membrane fusion activation: prior to receptor contact, at least one of the morbillivirus H-head domains interacts with the membrane-distal "spacer" domain in the H-stalk, leaving the F-binding site located further membrane-proximal in the stalk fully accessible. This "head-to-spacer" interaction conformationally stabilizes H in an auto-repressed state, which enables intracellular H-stalk/F engagement while preventing the inherent H-stalk's bioactivity that may prematurely activate F. Receptor-contact disrupts the "head-to-spacer" interaction, which subsequently "unlocks" the stalk, allowing it to rearrange and trigger F. Overall, our study reveals essential mechanistic requirements governing the activation of the morbillivirus membrane fusion cascade and spotlights the H-stalk "spacer" microdomain as a possible drug target for antiviral therapy.
Collapse
Affiliation(s)
- Nadine Ader-Ebert
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Mojtaba Khosravi
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Michael Herren
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Mislay Avila
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Lisa Alves
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Fanny Bringolf
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Claes Örvell
- Division of Laboratory Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | | | - Andreas Zurbriggen
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Richard K. Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
| | - Philippe Plattet
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- * E-mail:
| |
Collapse
|
25
|
Harrison SC. Viral membrane fusion. Virology 2015; 479-480:498-507. [PMID: 25866377 DOI: 10.1016/j.virol.2015.03.043] [Citation(s) in RCA: 519] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 02/23/2015] [Accepted: 03/10/2015] [Indexed: 11/27/2022]
Abstract
Membrane fusion is an essential step when enveloped viruses enter cells. Lipid bilayer fusion requires catalysis to overcome a high kinetic barrier; viral fusion proteins are the agents that fulfill this catalytic function. Despite a variety of molecular architectures, these proteins facilitate fusion by essentially the same generic mechanism. Stimulated by a signal associated with arrival at the cell to be infected (e.g., receptor or co-receptor binding, proton binding in an endosome), they undergo a series of conformational changes. A hydrophobic segment (a "fusion loop" or "fusion peptide") engages the target-cell membrane and collapse of the bridging intermediate thus formed draws the two membranes (virus and cell) together. We know of three structural classes for viral fusion proteins. Structures for both pre- and postfusion conformations of illustrate the beginning and end points of a process that can be probed by single-virion measurements of fusion kinetics.
Collapse
Affiliation(s)
- Stephen C Harrison
- Boston Children׳s Hospital, Harvard Medical School, and Howard Hughes Medical Institute, 3 Blackfan Circle, Boston, MA 02115, United States.
| |
Collapse
|
26
|
Bose S, Jardetzky TS, Lamb RA. Timing is everything: Fine-tuned molecular machines orchestrate paramyxovirus entry. Virology 2015; 479-480:518-31. [PMID: 25771804 PMCID: PMC4424121 DOI: 10.1016/j.virol.2015.02.037] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 01/21/2015] [Accepted: 02/18/2015] [Indexed: 11/30/2022]
Abstract
The Paramyxoviridae include some of the great and ubiquitous disease-causing viruses of humans and animals. In most paramyxoviruses, two viral membrane glycoproteins, fusion protein (F) and receptor binding protein (HN, H or G) mediate a concerted process of recognition of host cell surface molecules followed by fusion of viral and cellular membranes, resulting in viral nucleocapsid entry into the cytoplasm. The interactions between the F and HN, H or G viral glycoproteins and host molecules are critical in determining host range, virulence and spread of these viruses. Recently, atomic structures, together with biochemical and biophysical studies, have provided major insights into how these two viral glycoproteins successfully interact with host receptors on cellular membranes and initiate the membrane fusion process to gain entry into cells. These studies highlight the conserved core mechanisms of paramyxovirus entry that provide the fundamental basis for rational anti-viral drug design and vaccine development. New structural and functional insights into paramyxovirus entry mechanisms. Current data on paramyxovirus glycoproteins suggest a core conserved entry mechanism. Diverse mechanisms preventing premature fusion activation exist in these viruses. Precise spacio-temporal interplay between paramyxovirus glycoproteins initiate entry.
Collapse
Affiliation(s)
- Sayantan Bose
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208-3500, United States.
| | - Theodore S Jardetzky
- Department of Structural Biology and Program in Immunology, Stanford University School of Medicine, Stanford, CA 94305, United States
| | - Robert A Lamb
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208-3500, United States; Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208-3500, United States.
| |
Collapse
|
27
|
Friedel T, Hanisch LJ, Muth A, Honegger A, Abken H, Plückthun A, Buchholz CJ, Schneider IC. Receptor-targeted lentiviral vectors are exceptionally sensitive toward the biophysical properties of the displayed single-chain Fv. Protein Eng Des Sel 2015; 28:93-106. [PMID: 25715658 DOI: 10.1093/protein/gzv005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
An increasing number of applications require the expression of single-chain variable fragments (scFv) fusion proteins in mammalian cells at the cell surface membrane. Here we assessed the CD30-specific scFv HRS3, which is used in immunotherapy, for its ability to retarget lentiviral vectors (LVs) to CD30 and to mediate selective gene transfer into CD30-positive cells. Fused to the C-terminus of the type-II transmembrane protein hemagglutinin (H) of measles virus and expressed in LV packaging cells, gene transfer mediated by the released LV particles was inefficient. A series of point mutations in the scFv framework regions addressing its biophysical properties, which substantially improved production and increased the melting temperature without impairing its kinetic binding behavior to CD30, also improved the performance of LV particles. Gene transfer into CD30-positive cells increased ∼100-fold due to improved transport of the H-scFv protein to the plasma membrane. Concomitantly, LV particle aggregation and syncytia formation in packaging cells were substantially reduced. The data suggest that syncytia formation can be triggered by trans-cellular dimerization of H-scFv proteins displayed on adjacent cells. Taken together, we show that the biophysical properties of the targeting ligand have a decisive role for the gene transfer efficiency of receptor-targeted LVs.
Collapse
Affiliation(s)
- Thorsten Friedel
- Section of Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, Langen 63225, Germany
| | - Lydia J Hanisch
- Roche Pharmaceutical Research and Early Development, Protein Engineering Group, Roche Innovation Center Zürich, Schlieren 8952, Switzerland
| | - Anke Muth
- Section of Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, Langen 63225, Germany
| | - Annemarie Honegger
- Department of Biochemistry, University of Zürich, Zürich 8057, Switzerland
| | - Hinrich Abken
- Center for Molecular Medicine Cologne, University of Cologne, Cologne 50931, Germany Department I of Internal Medicine, University Hospital Cologne, Cologne 50931, Germany
| | - Andreas Plückthun
- Department of Biochemistry, University of Zürich, Zürich 8057, Switzerland
| | - Christian J Buchholz
- Section of Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, Langen 63225, Germany
| | - Irene C Schneider
- Section of Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, Langen 63225, Germany
| |
Collapse
|
28
|
Palgen JL, Jurgens EM, Moscona A, Porotto M, Palermo LM. Unity in diversity: shared mechanism of entry among paramyxoviruses. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 129:1-32. [PMID: 25595799 DOI: 10.1016/bs.pmbts.2014.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Paramyxoviridae family includes many viruses that are pathogenic in humans, including parainfluenza viruses, measles virus, respiratory syncytial virus, and the emerging zoonotic Henipaviruses. No effective treatments are currently available for these viruses, and there is a need for efficient antiviral therapies. Paramyxoviruses enter the target cell by binding to a cell surface receptor and then fusing the viral envelope with the target cell membrane, allowing the release of the viral genome into the cytoplasm. Blockage of these crucial steps prevents infection and disease. Binding and fusion are driven by two virus-encoded glycoproteins, the receptor-binding protein and the fusion protein, that together form the viral "fusion machinery." The development of efficient antiviral drugs requires a deeper understanding of the mechanism of action of the Paramyxoviridae fusion machinery, which is still controversial. Here, we review recent structural and functional data on these proteins and the current understanding of the mechanism of the paramyxovirus cell entry process.
Collapse
Affiliation(s)
- Jean-Louis Palgen
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA; Department of Biology, Ecole Normale Supérieure, Lyon, France
| | - Eric M Jurgens
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA
| | - Anne Moscona
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA; Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, New York, USA
| | - Matteo Porotto
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA.
| | - Laura M Palermo
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA; Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, New York, USA
| |
Collapse
|
29
|
Probing the functions of the paramyxovirus glycoproteins F and HN with a panel of synthetic antibodies. J Virol 2014; 88:11713-25. [PMID: 25122782 DOI: 10.1128/jvi.01707-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paramyxoviruses are enveloped negative-strand RNA viruses that are significant human and animal pathogens. Most paramyxoviruses infect host cells via the concerted action of a tetrameric attachment protein (variously called HN, H, or G) that binds either sialic acid or protein receptors on target cells and a trimeric fusion protein (F) that merges the viral envelope with the plasma membrane at neutral pH. F initially folds to a metastable prefusion conformation that becomes activated via a cleavage event during cellular trafficking. Upon receptor binding, the attachment protein, which consists of a globular head anchored to the membrane via a helical tetrameric stalk, triggers a major conformation change in F which results in fusion of virus and host cell membranes. We recently proposed a model for F activation in which the attachment protein head domains move following receptor binding to expose HN stalk residues critical for triggering F. To test the model in the context of wild-type viral glycoproteins, we used a restricted-diversity combinatorial Fab library and phage display to rapidly generate synthetic antibodies (sAbs) against multiple domains of the paramyxovirus parainfluenza 5 (PIV5) pre- and postfusion F and HN. As predicted by the model, sAbs that bind to the critical F-triggering region of the HN stalk do not disrupt receptor binding or neuraminidase (NA) activity but are potent inhibitors of fusion. An inhibitory prefusion F-specific sAb recognized a quaternary antigenic site and may inhibit fusion by preventing F refolding or by blocking the F-HN interaction. Importance: The paramyxovirus family of negative-strand RNA viruses cause significant disease in humans and animals. The viruses bind to cells via their receptor binding protein and then enter cells by fusion of their envelope with the host cell plasma membrane, a process mediated by a metastable viral fusion (F) protein. To understand the steps in viral membrane fusion, a library of synthetic antibodies to F protein and the receptor binding protein was generated in bacteriophage. These antibodies bound to different regions of the F protein and the receptor binding protein, and the location of antibody binding affected different processes in viral entry into cells.
Collapse
|
30
|
Paramyxovirus glycoprotein incorporation, assembly and budding: a three way dance for infectious particle production. Viruses 2014; 6:3019-54. [PMID: 25105277 PMCID: PMC4147685 DOI: 10.3390/v6083019] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 12/21/2022] Open
Abstract
Paramyxoviruses are a family of negative sense RNA viruses whose members cause serious diseases in humans, such as measles virus, mumps virus and respiratory syncytial virus; and in animals, such as Newcastle disease virus and rinderpest virus. Paramyxovirus particles form by assembly of the viral matrix protein, the ribonucleoprotein complex and the surface glycoproteins at the plasma membrane of infected cells and subsequent viral budding. Two major glycoproteins expressed on the viral envelope, the attachment protein and the fusion protein, promote attachment of the virus to host cells and subsequent virus-cell membrane fusion. Incorporation of the surface glycoproteins into infectious progeny particles requires coordinated interplay between the three viral structural components, driven primarily by the matrix protein. In this review, we discuss recent progress in understanding the contributions of the matrix protein and glycoproteins in driving paramyxovirus assembly and budding while focusing on the viral protein interactions underlying this process and the intracellular trafficking pathways for targeting viral components to assembly sites. Differences in the mechanisms of particle production among the different family members will be highlighted throughout.
Collapse
|
31
|
Mateo M, Navaratnarajah CK, Cattaneo R. Structural basis of efficient contagion: measles variations on a theme by parainfluenza viruses. Curr Opin Virol 2014; 5:16-23. [PMID: 24492202 PMCID: PMC4028398 DOI: 10.1016/j.coviro.2014.01.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/26/2013] [Accepted: 01/08/2014] [Indexed: 11/19/2022]
Abstract
A quartet of attachment proteins and a trio of fusion protein subunits play the cell entry concert of parainfluenza viruses. While many of these viruses bind sialic acid to enter cells, wild type measles binds exclusively two tissue-specific proteins, the lymphatic receptor signaling lymphocytic activation molecule (SLAM), and the epithelial receptor nectin-4. SLAM binds near the stalk-head junction of the hemagglutinin. Nectin-4 binds a hydrophobic groove located between blades 4 and 5 of the hemagglutinin β-propeller head. The mutated vaccine strain hemagglutinin binds in addition the ubiquitous protein CD46, which explains attenuation. The measles virus entry concert has four movements. Andante misterioso: the virus takes over the immune system. Allegro con brio: it rapidly spreads in the upper airway's epithelia. 'Targeting' fugue: the versatile orchestra takes off. Presto furioso: the virus exits the host with thunder. Be careful: music is contagious.
Collapse
MESH Headings
- Animals
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Cell Adhesion Molecules/chemistry
- Cell Adhesion Molecules/genetics
- Cell Adhesion Molecules/metabolism
- Hemagglutinins, Viral/chemistry
- Hemagglutinins, Viral/genetics
- Hemagglutinins, Viral/metabolism
- Humans
- Measles/genetics
- Measles/metabolism
- Measles/virology
- Measles virus/chemistry
- Measles virus/genetics
- Measles virus/metabolism
- Protein Binding
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Virus/chemistry
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Signaling Lymphocytic Activation Molecule Family Member 1
Collapse
Affiliation(s)
- Mathieu Mateo
- Department of Molecular Medicine, Mayo Clinic, and Virology and Gene Therapy Track, Mayo Graduate School, 200 First Street SW, Rochester, MN 55905, USA
| | - Chanakha K Navaratnarajah
- Department of Molecular Medicine, Mayo Clinic, and Virology and Gene Therapy Track, Mayo Graduate School, 200 First Street SW, Rochester, MN 55905, USA
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, and Virology and Gene Therapy Track, Mayo Graduate School, 200 First Street SW, Rochester, MN 55905, USA.
| |
Collapse
|
32
|
Activation of paramyxovirus membrane fusion and virus entry. Curr Opin Virol 2014; 5:24-33. [PMID: 24530984 DOI: 10.1016/j.coviro.2014.01.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 12/11/2013] [Accepted: 01/08/2014] [Indexed: 12/31/2022]
Abstract
The paramyxoviruses represent a diverse virus family responsible for a wide range of human and animal diseases. In contrast to other viruses, such as HIV and influenza virus, which use a single glycoprotein to mediate host receptor binding and virus entry, the paramyxoviruses require two distinct proteins. One of these is an attachment glycoprotein that binds receptor, while the second is a fusion glycoprotein, which undergoes conformational changes that drive virus-cell membrane fusion and virus entry. The details of how receptor binding by one protein activates the second to undergo conformational changes have been poorly understood until recently. Over the past couple of years, structural and functional data have accumulated on representative members of this family, including parainfluenza virus 5, Newcastle disease virus, measles virus, Nipah virus and others, which suggest a mechanistic convergence of activation models. Here we review the data indicating that paramyxovirus attachment glycoproteins shield activating residues within their N-terminal stalk domains, which are then exposed upon receptor binding, leading to the activation of the fusion protein by a 'provocateur' mechanism.
Collapse
|
33
|
Fusion activation through attachment protein stalk domains indicates a conserved core mechanism of paramyxovirus entry into cells. J Virol 2014; 88:3925-41. [PMID: 24453369 DOI: 10.1128/jvi.03741-13] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Paramyxoviruses are a large family of membrane-enveloped negative-stranded RNA viruses causing important diseases in humans and animals. Two viral integral membrane glycoproteins (fusion [F] and attachment [HN, H, or G]) mediate a concerted process of host receptor recognition, followed by the fusion of viral and cellular membranes, resulting in viral nucleocapsid entry into the cytoplasm. However, the sequence of events that closely links the timing of receptor recognition by HN, H, or G and the "triggering" interaction of the attachment protein with F is unclear. F activation results in F undergoing a series of irreversible conformational rearrangements to bring about membrane merger and virus entry. By extensive study of properties of multiple paramyxovirus HN proteins, we show that key features of F activation, including the F-activating regions of HN proteins, flexibility within this F-activating region, and changes in globular head-stalk interactions are highly conserved. These results, together with functionally active "headless" mumps and Newcastle disease virus HN proteins, provide insights into the F-triggering process. Based on these data and very recently published data for morbillivirus H and henipavirus G proteins, we extend our recently proposed "stalk exposure model" to other paramyxoviruses and propose an "induced fit" hypothesis for F-HN/H/G interactions as conserved core mechanisms of paramyxovirus-mediated membrane fusion. IMPORTANCE Paramyxoviruses are a large family of membrane-enveloped negative-stranded RNA viruses causing important diseases in humans and animals. Two viral integral membrane glycoproteins (fusion [F] and attachment [HN, H, or G]) mediate a concerted process of host receptor recognition, followed by the fusion of viral and cellular membranes. We describe here the molecular mechanism by which HN activates the F protein such that virus-cell fusion is controlled and occurs at the right time and the right place. We extend our recently proposed "stalk exposure model" first proposed for parainfluenza virus 5 to other paramyxoviruses and propose an "induced fit" hypothesis for F-HN/H/G interactions as conserved core mechanisms of paramyxovirus-mediated membrane fusion.
Collapse
|
34
|
Molecular determinants defining the triggering range of prefusion F complexes of canine distemper virus. J Virol 2013; 88:2951-66. [PMID: 24371057 DOI: 10.1128/jvi.03123-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The morbillivirus cell entry machinery consists of a fusion (F) protein trimer that refolds to mediate membrane fusion following receptor-induced conformational changes in its binding partner, the tetrameric attachment (H) protein. To identify molecular determinants that control F refolding, we generated F chimeras between measles virus (MeV) and canine distemper virus (CDV). We located a central pocket in the globular head domain of CDV F that regulates the stability of the metastable, prefusion conformational state of the F trimer. Most mutations introduced into this "pocket'" appeared to mediate a destabilizing effect, a phenotype associated with enhanced membrane fusion activity. Strikingly, under specific triggering conditions (i.e., variation of receptor type and H protein origin), some F mutants also exhibited resistance to a potent morbillivirus entry inhibitor, which is known to block F triggering by enhancing the stability of prefusion F trimers. Our data reveal that the molecular nature of the F stimulus and the intrinsic stability of metastable prefusion F both regulate the efficiency of F refolding and escape from small-molecule refolding blockers. IMPORTANCE With the aim to better characterize the thermodynamic basis of morbillivirus membrane fusion for cell entry and spread, we report here that the activation energy barrier of prefusion F trimers together with the molecular nature of the triggering "stimulus" (attachment protein and receptor types) define a "triggering range," which governs the initiation of the membrane fusion process. A central "pocket" microdomain in the globular F head contributes substantially to the regulation of the conformational stability of the prefusion complexes. The triggering range also defines the mechanism of viral escape from entry inhibitors and describes how the cellular environment can affect membrane fusion efficiency.
Collapse
|
35
|
Mutations in the parainfluenza virus 5 fusion protein reveal domains important for fusion triggering and metastability. J Virol 2013; 87:13520-31. [PMID: 24089572 DOI: 10.1128/jvi.02123-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Paramyxovirus membrane glycoproteins F (fusion protein) and HN, H, or G (attachment protein) are critical for virus entry, which occurs through fusion of viral and cellular envelopes. The F protein folds into a homotrimeric, metastable prefusion form that can be triggered by the attachment protein to undergo a series of structural rearrangements, ultimately folding into a stable postfusion form. In paramyxovirus-infected cells, the F protein is activated in the Golgi apparatus by cleavage adjacent to a hydrophobic fusion peptide that inserts into the target membrane, eventually bringing the membranes together by F refolding. However, it is not clear how the attachment protein, known as HN in parainfluenza virus 5 (PIV5), interacts with F and triggers F to initiate fusion. To understand the roles of various F protein domains in fusion triggering and metastability, single point mutations were introduced into the PIV5 F protein. By extensive study of F protein cleavage activation, surface expression, and energetics of fusion triggering, we found a role for an immunoglobulin-like (Ig-like) domain, where multiple hydrophobic residues on the PIV5 F protein may mediate F-HN interactions. Additionally, destabilizing mutations of PIV5 F that resulted in HN trigger-independent mutant F proteins were identified in a region along the border of F trimer subunits. The positions of the potential HN-interacting region and the region important for F stability in the lower part of the PIV5 F prefusion structure provide clues to the receptor-binding initiated, HN-mediated F trigger.
Collapse
|
36
|
Welch BD, Yuan P, Bose S, Kors CA, Lamb RA, Jardetzky TS. Structure of the parainfluenza virus 5 (PIV5) hemagglutinin-neuraminidase (HN) ectodomain. PLoS Pathog 2013; 9:e1003534. [PMID: 23950713 PMCID: PMC3738495 DOI: 10.1371/journal.ppat.1003534] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 06/18/2013] [Indexed: 01/07/2023] Open
Abstract
Paramyxoviruses cause a wide variety of human and animal diseases. They infect host cells using the coordinated action of two surface glycoproteins, the receptor binding protein (HN, H, or G) and the fusion protein (F). HN binds sialic acid on host cells (hemagglutinin activity) and hydrolyzes these receptors during viral egress (neuraminidase activity, NA). Additionally, receptor binding is thought to induce a conformational change in HN that subsequently triggers major refolding in homotypic F, resulting in fusion of virus and target cell membranes. HN is an oligomeric type II transmembrane protein with a short cytoplasmic domain and a large ectodomain comprising a long helical stalk and large globular head domain containing the enzymatic functions (NA domain). Extensive biochemical characterization has revealed that HN-stalk residues determine F specificity and activation. However, the F/HN interaction and the mechanisms whereby receptor binding regulates F activation are poorly defined. Recently, a structure of Newcastle disease virus (NDV) HN ectodomain revealed the heads (NA domains) in a "4-heads-down" conformation whereby two of the heads form a symmetrical interaction with two sides of the stalk. The interface includes stalk residues implicated in triggering F, and the heads sterically shield these residues from interaction with F (at least on two sides). Here we report the x-ray crystal structure of parainfluenza virus 5 (PIV5) HN ectodomain in a "2-heads-up/2-heads-down" conformation where two heads (covalent dimers) are in the "down position," forming a similar interface as observed in the NDV HN ectodomain structure, and two heads are in an "up position." The structure supports a model in which the heads of HN transition from down to up upon receptor binding thereby releasing steric constraints and facilitating the interaction between critical HN-stalk residues and F.
Collapse
Affiliation(s)
- Brett D. Welch
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Ping Yuan
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sayantan Bose
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Christopher A. Kors
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Robert A. Lamb
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois, United States of America
- * E-mail: (RAL); (TSJ)
| | - Theodore S. Jardetzky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (RAL); (TSJ)
| |
Collapse
|
37
|
Abstract
Paramyxoviruses include major pathogens with significant global health and economic impact. This large family of enveloped RNA viruses infects cells by employing two surface glycoproteins that tightly cooperate to fuse their lipid envelopes with the target cell plasma membrane, an attachment and a fusion (F) protein. Membrane fusion is believed to depend on receptor-induced conformational changes within the attachment protein that lead to the activation and subsequent refolding of F. While structural and mechanistic studies have considerably advanced our insight into paramyxovirus cell adhesion and the structural basis of F refolding, how precisely the attachment protein links receptor engagement to F triggering remained poorly understood. Recent reports based on work with several paramyxovirus family members have transformed our understanding of the triggering mechanism of the membrane fusion machinery. Here, we review these recent findings, which (i) offer a broader mechanistic understanding of the paramyxovirus cell entry system, (ii) illuminate key similarities and differences between entry strategies of different paramyxovirus family members, and (iii) suggest new strategies for the development of novel therapeutics.
Collapse
|
38
|
Zhang X, Lu G, Qi J, Li Y, He Y, Xu X, Shi J, Zhang CWH, Yan J, Gao GF. Structure of measles virus hemagglutinin bound to its epithelial receptor nectin-4. Nat Struct Mol Biol 2013; 20:67-72. [PMID: 23202587 DOI: 10.1038/nsmb.2432] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 10/01/2012] [Indexed: 12/14/2022]
Abstract
Measles virus is a major public health concern worldwide. Three measles virus cell receptors have been identified so far, and the structures of the first two in complex with measles virus hemagglutinin (MV-H) have been reported. Nectin-4 is the most recently identified receptor in epithelial cells, and its binding mode to MV-H remains elusive. In this study, we solved the structure of the membrane-distal domain of human nectin-4 in complex with MV-H. The structure shows that nectin-4 binds the MV-H β4-β5 groove exclusively via its N-terminal IgV domain; the contact interface is dominated by hydrophobic interactions. The binding site in MV-H for nectin-4 also overlaps extensively with those of the other two receptors. Finally, a hydrophobic pocket centered in the β4-β5 groove is involved in binding to all three identified measles virus receptors, representing a potential target for antiviral drugs.
Collapse
Affiliation(s)
- Xiaoai Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
|
40
|
Xu K, Chan YP, Rajashankar KR, Khetawat D, Yan L, Kolev MV, Broder CC, Nikolov DB. New insights into the Hendra virus attachment and entry process from structures of the virus G glycoprotein and its complex with Ephrin-B2. PLoS One 2012; 7:e48742. [PMID: 23144952 PMCID: PMC3489827 DOI: 10.1371/journal.pone.0048742] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/30/2012] [Indexed: 01/07/2023] Open
Abstract
Hendra virus and Nipah virus, comprising the genus Henipavirus, are recently emerged, highly pathogenic and often lethal zoonotic agents against which there are no approved therapeutics. Two surface glycoproteins, the attachment (G) and fusion (F), mediate host cell entry. The crystal structures of the Hendra G glycoprotein alone and in complex with the ephrin-B2 receptor reveal that henipavirus uses Tryptophan 122 on ephrin-B2/B3 as a "latch" to facilitate the G-receptor association. Structural-based mutagenesis of residues in the Hendra G glycoprotein at the receptor binding interface document their importance for viral attachments and entry, and suggest that the stability of the Hendra-G-ephrin attachment complex does not strongly correlate with the efficiency of viral entry. In addition, our data indicates that conformational rearrangements of the G glycoprotein head domain upon receptor binding may be the trigger leading to the activation of the viral F fusion glycoprotein during virus infection.
Collapse
Affiliation(s)
- Kai Xu
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Yee-Peng Chan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Kanagalaghatta R. Rajashankar
- The Northeastern Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Dimple Khetawat
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Momchil V. Kolev
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Dimitar B. Nikolov
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
41
|
Mechanism for active membrane fusion triggering by morbillivirus attachment protein. J Virol 2012; 87:314-26. [PMID: 23077316 DOI: 10.1128/jvi.01826-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The paramyxovirus entry machinery consists of two glycoproteins that tightly cooperate to achieve membrane fusion for cell entry: the tetrameric attachment protein (HN, H, or G, depending on the paramyxovirus genus) and the trimeric fusion protein (F). Here, we explore whether receptor-induced conformational changes within morbillivirus H proteins promote membrane fusion by a mechanism requiring the active destabilization of prefusion F or by the dissociation of prefusion F from intracellularly preformed glycoprotein complexes. To properly probe F conformations, we identified anti-F monoclonal antibodies (MAbs) that recognize conformation-dependent epitopes. Through heat treatment as a surrogate for H-mediated F triggering, we demonstrate with these MAbs that the morbillivirus F trimer contains a sufficiently high inherent activation energy barrier to maintain the metastable prefusion state even in the absence of H. This notion was further validated by exploring the conformational states of destabilized F mutants and stabilized soluble F variants combined with the use of a membrane fusion inhibitor (3g). Taken together, our findings reveal that the morbillivirus H protein must lower the activation energy barrier of metastable prefusion F for fusion triggering.
Collapse
|
42
|
Abstract
Paramyxoviruses contain glycoprotein fusion machineries that mediate membrane merger for infection. The molecular framework and mechanistic principles governing receptor-induced triggering of the machinery remain unknown. Using measles virus (MeV) fusion complexes, we demonstrate that receptor binding to only one dimer of the tetrameric attachment protein (H) dimer-of-dimers induces fusion-protein (F) triggering; receptor binding and F triggering can be communicated across the dimer-dimer interface of H; and the physical integrity of the tetramer is maintained during fusion. The central MeV H ectodomain stalk region requires structural flexibility for activation of F, and alanine substitutions in this section, physical stress, or exposure of H to soluble ligands trigger conformational rearrangements in native H tetramers. Binding of soluble receptor to H is sufficient to initiate refolding of F, underscoring the physiological significance of this rearrangement of the H tetramer. These data outline a model of the triggering of the physiological MeV fusion machinery in which unilateral receptor binding to one dimer pair in the H tetramer is sufficient to induce a reorganization of H that affects the conformation of the central stalk section, severing interactions between H and the F trimer and activating refolding of F.
Collapse
|
43
|
Structural and functional characterization of neuraminidase-like molecule N10 derived from bat influenza A virus. Proc Natl Acad Sci U S A 2012; 109:18897-902. [PMID: 23012237 DOI: 10.1073/pnas.1211037109] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recent discovery of the unique genome of influenza virus H17N10 in bats raises considerable doubt about the origin and evolution of influenza A viruses. It also identifies a neuraminidase (NA)-like protein, N10, that is highly divergent from the nine other well-established serotypes of influenza A NA (N1-N9). The structural elucidation and functional characterization of influenza NAs have illustrated the complexity of NA structures, thus raising a key question as to whether N10 has a special structure and function. Here the crystal structure of N10, derived from influenza virus A/little yellow-shouldered bat/Guatemala/153/2009 (H17N10), was solved at a resolution of 2.20 Å. Overall, the structure of N10 was found to be similar to that of the other known influenza NA structures. In vitro enzymatic assays demonstrated that N10 lacks canonical NA activity. A detailed structural analysis revealed dramatic alterations of the conserved active site residues that are unfavorable for the binding and cleavage of terminally linked sialic acid receptors. Furthermore, an unusual 150-loop (residues 147-152) was observed to participate in the intermolecular polar interactions between adjacent N10 molecules of the N10 tetramer. Our study of influenza N10 provides insight into the structure and function of the sialidase superfamily and sheds light on the molecular mechanism of bat influenza virus infection.
Collapse
|
44
|
Fusion activation by a headless parainfluenza virus 5 hemagglutinin-neuraminidase stalk suggests a modular mechanism for triggering. Proc Natl Acad Sci U S A 2012; 109:E2625-34. [PMID: 22949640 DOI: 10.1073/pnas.1213813109] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The Paramyxoviridae family of enveloped viruses enters cells through the concerted action of two viral glycoproteins. The receptor-binding protein, hemagglutinin-neuraminidase (HN), H, or G, binds its cellular receptor and activates the fusion protein, F, which, through an extensive refolding event, brings viral and cellular membranes together, mediating virus-cell fusion. However, the underlying mechanism of F activation on receptor engagement remains unclear. Current hypotheses propose conformational changes in HN, H, or G propagating from the receptor-binding site in the HN, H, or G globular head to the F-interacting stalk region. We provide evidence that the receptor-binding globular head domain of the paramyxovirus parainfluenza virus 5 HN protein is entirely dispensable for F activation. Considering together the crystal structures of HN from different paramyxoviruses, varying energy requirements for fusion activation, F activation involving the parainfluenza virus 5 HN stalk domain, and properties of a chimeric paramyxovirus HN protein, we propose a simple model for the activation of paramyxovirus fusion.
Collapse
|
45
|
Chang A, Dutch RE. Paramyxovirus fusion and entry: multiple paths to a common end. Viruses 2012; 4:613-36. [PMID: 22590688 PMCID: PMC3347325 DOI: 10.3390/v4040613] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 03/10/2012] [Accepted: 04/12/2012] [Indexed: 12/24/2022] Open
Abstract
The paramyxovirus family contains many common human pathogenic viruses, including measles, mumps, the parainfluenza viruses, respiratory syncytial virus, human metapneumovirus, and the zoonotic henipaviruses, Hendra and Nipah. While the expression of a type 1 fusion protein and a type 2 attachment protein is common to all paramyxoviruses, there is considerable variation in viral attachment, the activation and triggering of the fusion protein, and the process of viral entry. In this review, we discuss recent advances in the understanding of paramyxovirus F protein-mediated membrane fusion, an essential process in viral infectivity. We also review the role of the other surface glycoproteins in receptor binding and viral entry, and the implications for viral infection. Throughout, we concentrate on the commonalities and differences in fusion triggering and viral entry among the members of the family. Finally, we highlight key unanswered questions and how further studies can identify novel targets for the development of therapeutic treatments against these human pathogens.
Collapse
Affiliation(s)
| | - Rebecca E. Dutch
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| |
Collapse
|
46
|
Ader N, Brindley MA, Avila M, Origgi FC, Langedijk JPM, Örvell C, Vandevelde M, Zurbriggen A, Plemper RK, Plattet P. Structural rearrangements of the central region of the morbillivirus attachment protein stalk domain trigger F protein refolding for membrane fusion. J Biol Chem 2012; 287:16324-34. [PMID: 22431728 DOI: 10.1074/jbc.m112.342493] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It is unknown how receptor binding by the paramyxovirus attachment proteins (HN, H, or G) triggers the fusion (F) protein to fuse with the plasma membrane for cell entry. H-proteins of the morbillivirus genus consist of a stalk ectodomain supporting a cuboidal head; physiological oligomers consist of non-covalent dimer-of-dimers. We report here the successful engineering of intermolecular disulfide bonds within the central region (residues 91-115) of the morbillivirus H-stalk; a sub-domain that also encompasses the putative F-contacting section (residues 111-118). Remarkably, several intersubunit crosslinks abrogated membrane fusion, but bioactivity was restored under reducing conditions. This phenotype extended equally to H proteins derived from virulent and attenuated morbillivirus strains and was independent of the nature of the contacted receptor. Our data reveal that the morbillivirus H-stalk domain is composed of four tightly-packed subunits. Upon receptor binding, these subunits structurally rearrange, possibly inducing conformational changes within the central region of the stalk, which, in turn, promote fusion. Given that the fundamental architecture appears conserved among paramyxovirus attachment protein stalk domains, we predict that these motions may act as a universal paramyxovirus F-triggering mechanism.
Collapse
Affiliation(s)
- Nadine Ader
- Division of Experimental Clinical Research, Neurovirology Unit, DCR-VPH, Vetsuisse faculty, University of Bern, 3001 Bern, Switzerland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Griffin DE, Lin WH, Pan CH. Measles virus, immune control, and persistence. FEMS Microbiol Rev 2012; 36:649-62. [PMID: 22316382 DOI: 10.1111/j.1574-6976.2012.00330.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 12/31/2022] Open
Abstract
Measles remains one of the most important causes of child morbidity and mortality worldwide with the greatest burden in the youngest children. Most acute measles deaths are owing to secondary infections that result from a poorly understood measles-induced suppression of immune responses. Young children are also vulnerable to late development of subacute sclerosing panencephalitis, a progressive, uniformly fatal neurologic disease caused by persistent measles virus (MeV) infection. During acute infection, the rash marks the appearance of the adaptive immune response and CD8(+) T cell-mediated clearance of infectious virus. However, after clearance of infectious virus, MeV RNA persists and can be detected in blood, respiratory secretions, urine, and lymphoid tissue for many weeks to months. This prolonged period of virus clearance may help to explain measles immunosuppression and the development of lifelong immunity to re-infection, as well as occasional infection of the nervous system. Once MeV infects neurons, the virus can spread trans-synaptically and the envelope proteins needed to form infectious virus are unnecessary, accumulate mutations, and can establish persistent infection. Identification of the immune mechanisms required for the clearance of MeV RNA from multiple sites will enlighten our understanding of the development of disease owing to persistent infection.
Collapse
Affiliation(s)
- Diane E Griffin
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | | | | |
Collapse
|
48
|
Lobanova LM, Eng NF, Satkunarajah M, Mutwiri GK, Rini JM, Zakhartchouk AN. The recombinant globular head domain of the measles virus hemagglutinin protein as a subunit vaccine against measles. Vaccine 2012; 30:3061-7. [PMID: 22406109 DOI: 10.1016/j.vaccine.2012.02.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/09/2012] [Accepted: 02/25/2012] [Indexed: 10/28/2022]
Abstract
Despite the availability of live attenuated measles virus (MV) vaccines, a large number of measles-associated deaths occur among infants in developing countries. The development of a measles subunit vaccine may circumvent the limitations associated with the current live attenuated vaccines and eventually contribute to global measles eradication. Therefore, the goal of this study was to test the feasibility of producing the recombinant globular head domain of the MV hemagglutinin (H) protein by stably transfected human cells and to examine the ability of this recombinant protein to elicit MV-specific immune responses. The recombinant protein was purified from the culture supernatant of stably transfected HEK293T cells secreting a tagged version of the protein. Two subcutaneous immunizations with the purified recombinant protein alone resulted in the production of MV-specific serum IgG and neutralizing antibodies in mice. Formulation of the protein with adjuvants (polyphosphazene or alum) further enhanced the humoral immune response and in addition resulted in the induction of cell-mediated immunity as measured by the production of MV H-specific interferon gamma (IFN-γ) and interleukin 5 (IL-5) by in vitro re-stimulated splenocytes. Furthermore, the inclusion of polyphosphazene into the vaccine formulation induced a mixed Th1/Th2-type immune response. In addition, the purified recombinant protein retained its immunogenicity even after storage at 37°C for 2 weeks.
Collapse
Affiliation(s)
- Liubov M Lobanova
- Vaccine and Infectious Disease Organization - International Vaccine Center, University of Saskatchewan, Saskatoon, SK, S7N 5E3 Canada
| | | | | | | | | | | |
Collapse
|
49
|
Xu K, Broder CC, Nikolov DB. Ephrin-B2 and ephrin-B3 as functional henipavirus receptors. Semin Cell Dev Biol 2011; 23:116-23. [PMID: 22227101 DOI: 10.1016/j.semcdb.2011.12.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Accepted: 12/19/2011] [Indexed: 12/26/2022]
Abstract
Members of the ephrin cell-surface protein family interact with the Eph receptors, the largest family of receptor tyrosine kinases, mediating bi-directional signaling during tumorogenesis and various developmental events. Surprisingly, ephrin-B2 and -B3 were recently identified as entry receptors for henipaviruses, emerging zoonotic paramyxoviruses responsible for repeated outbreaks in humans and animals in Australia, Southeast Asia, India and Bangladesh. Nipah virus (NiV) and Hendra virus (HeV) are the only two identified members in the henipavirus genus. While the initial human infection cases came from contact with infected pigs (NiV) or horses (HeV), in the more recent outbreaks of NiV both food-borne and human-to-human transmission were reported. These characteristics, together with high mortality and morbidity rates and lack of effective anti-viral therapies, make the henipaviruses a potential biological-agent threat. Viral entry is an important target for the development of anti-viral drugs. The entry of henipavirus is initiated by the attachment of the viral G envelope glycoprotein to the host cell receptors ephrin-B2 and/or -B3, followed by activation of the F fusion protein, which triggers fusion between the viral envelop and the host membrane. We review recent progress in the study of henipavirus entry, particularly the identification of ephrins as their entry receptors, and the structural characterization of the ephrin/Henipa-G interactions.
Collapse
Affiliation(s)
- Kai Xu
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
| | | | | |
Collapse
|
50
|
Hashiguchi T, Maenaka K, Yanagi Y. Measles virus hemagglutinin: structural insights into cell entry and measles vaccine. Front Microbiol 2011; 2:247. [PMID: 22319511 PMCID: PMC3267179 DOI: 10.3389/fmicb.2011.00247] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 11/23/2011] [Indexed: 12/17/2022] Open
Abstract
Measles is one of the most contagious viral diseases, and remains a major cause of childhood morbidity and mortality worldwide. The measles virus (MV), a member of the family Paramyxoviridae, enters cells through a cellular receptor, the signaling lymphocyte activation molecule (SLAM), CD46 or nectin-4. Entry is mediated by two MV envelope glycoproteins, the hemagglutinin (H) and the fusion (F) protein. The H protein mediates receptor attachment, while the F protein causes membrane fusion. The interaction between the H and F proteins is essential to initiate the cell entry process. Recently determined crystal structures of the MV-H protein unbound and bound to SLAM or CD46 have provided insights into paramyxovirus entry and the effectiveness of measles vaccine.
Collapse
Affiliation(s)
- Takao Hashiguchi
- Department of Virology, Faculty of Medicine, Kyushu University Fukuoka, Japan
| | | | | |
Collapse
|