1
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Larsen BB, McMahon T, Brown JT, Wang Z, Radford CE, Crowe JE, Veesler D, Bloom JD. Functional and antigenic landscape of the Nipah virus receptor binding protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.589977. [PMID: 38659959 PMCID: PMC11042328 DOI: 10.1101/2024.04.17.589977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Nipah virus recurrently spills over to humans, causing fatal infections. The viral receptor-binding protein (RBP or G) attaches to host receptors and is a major target of neutralizing antibodies. Here we use deep mutational scanning to measure how all amino-acid mutations to the RBP affect cell entry, receptor binding, and escape from neutralizing antibodies. We identify functionally constrained regions of the RBP, including sites involved in oligomerization, along with mutations that differentially modulate RBP binding to its two ephrin receptors. We map escape mutations for six anti-RBP antibodies, and find that few antigenic mutations are present in natural Nipah strains. Our findings offer insights into the potential for functional and antigenic evolution of the RBP that can inform the development of antibody therapies and vaccines.
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Affiliation(s)
- Brendan B. Larsen
- Basic Sciences Division and Computational Biology Program, Fred Hutch Cancer Center, Seattle, WA 98109, USA
| | - Teagan McMahon
- Basic Sciences Division and Computational Biology Program, Fred Hutch Cancer Center, Seattle, WA 98109, USA
| | - Jack T. Brown
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Zhaoqian Wang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Caelan E. Radford
- Basic Sciences Division and Computational Biology Program, Fred Hutch Cancer Center, Seattle, WA 98109, USA
| | - James E. Crowe
- Department of Pathology Microbiology and Immunology, The Vanderbilt Vaccine Center, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Jesse D. Bloom
- Basic Sciences Division and Computational Biology Program, Fred Hutch Cancer Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute, Seattle, WA 98195, USA
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2
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Wang Z, McCallum M, Yan L, Gibson CA, Sharkey W, Park YJ, Dang HV, Amaya M, Person A, Broder CC, Veesler D. Structure and design of Langya virus glycoprotein antigens. Proc Natl Acad Sci U S A 2024; 121:e2314990121. [PMID: 38593070 PMCID: PMC11032465 DOI: 10.1073/pnas.2314990121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 03/04/2024] [Indexed: 04/11/2024] Open
Abstract
Langya virus (LayV) is a recently discovered henipavirus (HNV), isolated from febrile patients in China. HNV entry into host cells is mediated by the attachment (G) and fusion (F) glycoproteins which are the main targets of neutralizing antibodies. We show here that the LayV F and G glycoproteins promote membrane fusion with human, mouse, and hamster target cells using a different, yet unknown, receptor than Nipah virus (NiV) and Hendra virus (HeV) and that NiV- and HeV-elicited monoclonal and polyclonal antibodies do not cross-react with LayV F and G. We determined cryoelectron microscopy structures of LayV F, in the prefusion and postfusion states, and of LayV G, revealing their conformational landscape and distinct antigenicity relative to NiV and HeV. We computationally designed stabilized LayV G constructs and demonstrate the generalizability of an HNV F prefusion-stabilization strategy. Our data will support the development of vaccines and therapeutics against LayV and closely related HNVs.
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Affiliation(s)
- Zhaoqian Wang
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - Matthew McCallum
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD20814
| | - Cecily A. Gibson
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - William Sharkey
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - Young-Jun Park
- Department of Biochemistry, University of Washington, Seattle, WA98195
- HHMI, Seattle, WA98195
| | - Ha V. Dang
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD20814
| | - Ashley Person
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD20814
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA98195
- HHMI, Seattle, WA98195
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3
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Chen L, Sun M, Zhang H, Zhang X, Yao Y, Li M, Li K, Fan P, Zhang H, Qin Y, Zhang Z, Li E, Chen Z, Guan W, Li S, Yu C, Zhang K, Gong R, Chiu S. Potent human neutralizing antibodies against Nipah virus derived from two ancestral antibody heavy chains. Nat Commun 2024; 15:2987. [PMID: 38582870 PMCID: PMC10998907 DOI: 10.1038/s41467-024-47213-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 03/18/2024] [Indexed: 04/08/2024] Open
Abstract
Nipah virus (NiV) is a World Health Organization priority pathogen and there are currently no approved drugs for clinical immunotherapy. Through the use of a naïve human phage-displayed Fab library, two neutralizing antibodies (NiV41 and NiV42) targeting the NiV receptor binding protein (RBP) were identified. Following affinity maturation, antibodies derived from NiV41 display cross-reactivity against both NiV and Hendra virus (HeV), whereas the antibody based on NiV42 is only specific to NiV. Results of immunogenetic analysis reveal a correlation between the maturation of antibodies and their antiviral activity. In vivo testing of NiV41 and its mature form (41-6) show protective efficacy against a lethal NiV challenge in hamsters. Furthermore, a 2.88 Å Cryo-EM structure of the tetrameric RBP and antibody complex demonstrates that 41-6 blocks the receptor binding interface. These findings can be beneficial for the development of antiviral drugs and the design of vaccines with broad spectrum against henipaviruses.
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Affiliation(s)
- Li Chen
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mengmeng Sun
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Huajun Zhang
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Xinghai Zhang
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Yanfeng Yao
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Ming Li
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Kangyin Li
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Pengfei Fan
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China
| | - Haiwei Zhang
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Ye Qin
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhe Zhang
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Entao Li
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
- Key Laboratory of Anhui Province for Emerging and Reemerging Infectious Diseases, Hefei, China
| | - Zhen Chen
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Wuxiang Guan
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Shanshan Li
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Changming Yu
- Laboratory of Advanced Biotechnology, Beijing Institute of Biotechnology, Beijing, China.
| | - Kaiming Zhang
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
- Key Laboratory of Anhui Province for Emerging and Reemerging Infectious Diseases, Hefei, China.
- Center for Advanced Interdisciplinary Science and Biomedicine of IHM, MOE Key Laboratory for Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
- Department of Urology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
| | - Rui Gong
- CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China.
- University of Chinese Academy of Sciences, Beijing, China.
- Hubei Jiangxia Laboratory, Wuhan, Hubei, China.
| | - Sandra Chiu
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
- Key Laboratory of Anhui Province for Emerging and Reemerging Infectious Diseases, Hefei, China.
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4
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Oguntuyo KY, Haas GD, Azarm KD, Stevens CS, Brambilla L, Kowdle SS, Avanzato VA, Pryce R, Freiberg AN, Bowden TA, Lee B. Structure-guided mutagenesis of Henipavirus receptor-binding proteins reveals molecular determinants of receptor usage and antibody-binding epitopes. J Virol 2024; 98:e0183823. [PMID: 38426726 PMCID: PMC10949843 DOI: 10.1128/jvi.01838-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024] Open
Abstract
Nipah virus (NiV) is a highly lethal, zoonotic Henipavirus (HNV) that causes respiratory and neurological signs and symptoms in humans. Similar to other paramyxoviruses, HNVs mediate entry into host cells through the concerted actions of two surface glycoproteins: a receptor-binding protein (RBP) that mediates attachment and a fusion glycoprotein (F) that triggers fusion in an RBP-dependent manner. NiV uses ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3) as entry receptors. Ghana virus (GhV), a novel HNV identified in a Ghanaian bat, uses EFNB2 but not EFNB3. In this study, we employ a structure-informed approach to identify receptor-interfacing residues and systematically introduce GhV-RBP residues into a NiV-RBP backbone to uncover the molecular determinants of EFNB3 usage. We reveal two regions that severely impair EFNB3 binding by NiV-RBP and EFNB3-mediated entry by NiV pseudotyped viral particles. Further analyses uncovered two-point mutations (NiVN557SGhV and NiVY581TGhV) pivotal for this phenotype. Moreover, we identify NiV interaction with Y120 of EFNB3 as important for the usage of this receptor. Beyond these EFNB3-related findings, we reveal two domains that restrict GhV binding of EFNB2, confirm the HNV-head as an immunodominant target for polyclonal and monoclonal antibodies, and describe putative epitopes for GhV- and NiV-specific monoclonal antibodies. Cumulatively, the work presented here generates useful reagents and tools that shed insight to residues important for NiV usage of EFNB3, reveal regions critical for GhV binding of EFNB2, and describe putative HNV antibody-binding epitopes. IMPORTANCE Hendra virus and Nipah virus (NiV) are lethal, zoonotic Henipaviruses (HNVs) that cause respiratory and neurological clinical features in humans. Since their initial outbreaks in the 1990s, several novel HNVs have been discovered worldwide, including Ghana virus. Additionally, there is serological evidence of zoonotic transmission, lending way to concerns about future outbreaks. HNV infection of cells is mediated by the receptor-binding protein (RBP) and the Fusion protein (F). The work presented here identifies NiV RBP amino acids important for the usage of ephrin-B3 (EFNB3), a receptor highly expressed in neurons and predicted to be important for neurological clinical features caused by NiV. This study also characterizes epitopes recognized by antibodies against divergent HNV RBPs. Together, this sheds insight to amino acids critical for HNV receptor usage and antibody binding, which is valuable for future studies investigating determinants of viral pathogenesis and developing antibody therapies.
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Affiliation(s)
| | - Griffin D. Haas
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kristopher D. Azarm
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Christian S. Stevens
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Luca Brambilla
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Shreyas S. Kowdle
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Victoria A. Avanzato
- Division of Structural Biology, Wellcome Center for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Rhys Pryce
- Division of Structural Biology, Wellcome Center for Human Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Thomas A. Bowden
- Division of Structural Biology, Wellcome Center for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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5
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May AJ, Acharya P. Structural Studies of Henipavirus Glycoproteins. Viruses 2024; 16:195. [PMID: 38399971 PMCID: PMC10892422 DOI: 10.3390/v16020195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
Henipaviruses are a genus of emerging pathogens that includes the highly virulent Nipah and Hendra viruses that cause reoccurring outbreaks of disease. Henipaviruses rely on two surface glycoproteins, known as the attachment and fusion proteins, to facilitate entry into host cells. As new and divergent members of the genus have been discovered and structurally characterized, key differences and similarities have been noted. This review surveys the available structural information on Henipavirus glycoproteins, complementing this with information from related biophysical and structural studies of the broader Paramyxoviridae family of which Henipaviruses are members. The process of viral entry is a primary focus for vaccine and drug development, and this review aims to identify critical knowledge gaps in our understanding of the mechanisms that drive Henipavirus fusion.
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Affiliation(s)
- Aaron J. May
- Duke Human Vaccine Institute, Duke University, Durham, NC 27710, USA
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University, Durham, NC 27710, USA
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
- Department of Surgery, Duke University, Durham, NC 27710, USA
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6
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Oguntuyo KY, Haas GD, Azarm KD, Stevens CS, Brambilla L, Kowdle S, Avanzato VA, Pryce R, Freiberg AN, Bowden TA, Lee B. Structure guided mutagenesis of Henipavirus Receptor Binding Proteins reveals molecular determinants of receptor usage and antibody binding epitopes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568281. [PMID: 38045373 PMCID: PMC10690272 DOI: 10.1101/2023.11.22.568281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Nipah virus (NiV) is a highly lethal, zoonotic henipavirus (HNV) that causes respiratory and neurological signs and symptoms in humans. Similar to other paramyxoviruses, HNVs mediate entry into host cells through the concerted actions of two surface glycoproteins: a receptor binding protein (RBP) that mediates attachment and a fusion glycoprotein (F) that triggers fusion in an RBP-dependent manner. NiV uses ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3) as entry receptors. Ghana virus (GhV), a novel HNV identified in a Ghanaian bat, use EFNB2 but not EFNB3. In this study, we employ a structure-informed approach to identify receptor interfacing residues and systematically introduce GhV-RBP residues into a NiV-RBP backbone to uncover the molecular determinants of EFNB3 usage. We reveal two regions that severely impair EFNB3 binding by NiV-RBP and EFNB3-mediated entry by NiV pseudotyped viral particles. Further analyses uncovered two point mutations (NiVN557SGhV and NiVY581TGhV) pivotal for this phenotype. Moreover, we identify NiV interaction with Y120 of EFNB3 as important for usage of this receptor. Beyond these EFNB3-related findings, we reveal two domains that restrict GhV binding of EFNB2, identify the HNV-head as an immunodominant target for polyclonal and monoclonal antibodies, and describe putative epitopes for GhV and NiV-specific monoclonal antibodies. Cumulatively, the work presented here generates useful reagents and tools that shed insight to residues important for NiV usage of EFNB3, reveals regions critical for GhV binding of EFNB2, and describes putative HNV antibody binding epitopes.
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Affiliation(s)
- K Y Oguntuyo
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - G D Haas
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - K D Azarm
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - C S Stevens
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - L Brambilla
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - S Kowdle
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - V A Avanzato
- Division of Structural Biology, Wellcome Center for Human Genetics, University of Oxford, OX3 7BN Oxford, United Kingdom
| | - R Pryce
- Division of Structural Biology, Wellcome Center for Human Genetics, University of Oxford, OX3 7BN Oxford, United Kingdom
| | - A N Freiberg
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - T A Bowden
- Division of Structural Biology, Wellcome Center for Human Genetics, University of Oxford, OX3 7BN Oxford, United Kingdom
| | - B Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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7
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Dsouza N, C SK. Predicting the changes in neutralizing antibody interaction with G protein derived from Bangladesh isolates of Nipah virus: molecular dynamics based approach. J Biomol Struct Dyn 2023:1-11. [PMID: 37643003 DOI: 10.1080/07391102.2023.2252084] [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: 06/10/2023] [Accepted: 08/18/2023] [Indexed: 08/31/2023]
Abstract
The infectious Nipah virus (NiV) is categorized into NiV-M (Malaysia) and NiV-B (Bangladesh) groups based on its genome comparison, pathogenicity, and mortality rate. The development of therapeutic molecules has used NiV-M-derived data in multiple studies than NiV-B. In continuation with this, the protein level investigation is also less explored to understand the interaction with therapeutic neutralizing antibodies for NiV-B. So, this study focuses on understanding the impact of NiV-B-specific mutations on the interaction of therapeutic neutralizing antibodies with the G protein. The population-based comparative analysis of NiV-B G protein sequences with NiV-M sequence identified twenty-six mutations. These predominantly polar mutations were then used to model the mutant protein (G_MT). In a comparative study, the G protein G_MT and reference protein G_WT (Malaysian origin) were subjected to a protein docking with neutralizing human monoclonal antibody HENV26. The binding affinity and the free binding energy of the glycoprotein in complex with G-WT and G_MT were calculated using PRODIGY and MM/PBSA tools respectively. Based on the PRODIGY report, G-WT showed stronger binding (-13.8 kcal/mol) compared to that of the G_MT (-9.0 kcal/mol) with the HENV26 antibody. The stability of the complexes was evaluated using MM/PBSA which showed higher binding energy with HENV26 for G_WT (-75.11 kcal/mol) in contrast to G_MT (-41.66 kcal/mol). The results indicate that the mutant G protein has a reduced ability to bind to neutralizing antibodies, resulting in a decreased effectiveness against strains carrying these mutations.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Norine Dsouza
- School of Biotechnology and Bioinformatics, D.Y. Patil Deemed to be University, CBD Belapur, Navi Mumbai, India
- Department of Biotechnology, St. Xavier's College, Mumbai, India
| | - Selvaa Kumar C
- School of Biotechnology and Bioinformatics, D.Y. Patil Deemed to be University, CBD Belapur, Navi Mumbai, India
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8
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Wang Z, McCallum M, Yan L, Sharkey W, Park YJ, Dang HV, Amaya M, Person A, Broder CC, Veesler D. Structure and design of Langya virus glycoprotein antigens. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.20.554025. [PMID: 37645760 PMCID: PMC10462157 DOI: 10.1101/2023.08.20.554025] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Langya virus (LayV) is a recently discovered henipavirus (HNV), isolated from febrile patients in China. HNV entry into host cells is mediated by the attachment (G) and fusion (F) glycoproteins which are the main targets of neutralizing antibodies. We show here that the LayV F and G glycoproteins promote membrane fusion with human, mouse and hamster target cells using a different, yet unknown, receptor than NiV and HeV and that NiV- and HeV-elicited monoclonal and polyclonal antibodies do not cross-react with LayV F and G. We determined cryo-electron microscopy structures of LayV F, in the prefusion and postfusion states, and of LayV G, revealing previously unknown conformational landscapes and their distinct antigenicity relative to NiV and HeV. We computationally designed stabilized LayV G constructs and demonstrate the generalizability of an HNV F prefusion-stabilization strategy. Our data will support the development of vaccines and therapeutics against LayV and closely related HNVs.
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Affiliation(s)
- Zhaoqian Wang
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Matthew McCallum
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - William Sharkey
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Young-Jun Park
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
- Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Ha V. Dang
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - Ashley Person
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
- Howard Hughes Medical Institute, Seattle, WA 98195, USA
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9
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Huang X, Li Y, Li R, Wang S, Yang L, Wang S, Yin Y, Zai X, Zhang J, Xu J. Nipah virus attachment glycoprotein ectodomain delivered by type 5 adenovirus vector elicits broad immune response against NiV and HeV. Front Cell Infect Microbiol 2023; 13:1180344. [PMID: 37577376 PMCID: PMC10413271 DOI: 10.3389/fcimb.2023.1180344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/04/2023] [Indexed: 08/15/2023] Open
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are newly emerging dangerous zoonotic pathogens of the Henipavirus genus of the Paramyxoviridae family. NiV and HeV (HNVs) which are transmitted by bats cause acute respiratory disease and fatal encephalitis in humans. To date, as there is a lack of antiviral drugs or effective antiviral therapies, the development of vaccines against those two viruses is of primary importance, and the immunogen design is crucial to the success of vaccines. In this study, the full-length protein (G), the ectodomain (Ge) and the head domain (Gs) of NiV attachment glycoprotein were delivered by the replication-defective type 5 adenovirus vector (Ad5) respectively, and the recombinant Ad5-NiV vaccine candidates (Ad5-NiVG, Ad5-NiVGe and Ad5-NiVGs) were constructed and their immunogenicity were evaluated in mice. The results showed that all the vaccine candidates stimulated specific humoral and cellular immune responses efficiently and rapidly against both NiV and HeV, and the Ad5-NiVGe elicited the strongest immune responses after a single-dose immunization. Furthermore, the potent conserved T-cell epitope DTLYFPAVGFL shared by NiV and HeV was identified in the study, which may provide valid information on the mechanism of HNVs-specific cellular immunity. In summary, this study demonstrates that the Ad5-NiVGe could be a potent vaccine candidate against HNVs by inducing robust humoral and cellular immune responses.
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Affiliation(s)
- Xiaoyan Huang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yaohui Li
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Ruihua Li
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Shaoyan Wang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Lu Yang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Shuyi Wang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Ying Yin
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Xiaodong Zai
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Jun Zhang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Junjie Xu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, China
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10
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Novel Roles of the Nipah Virus Attachment Glycoprotein and Its Mobility in Early and Late Membrane Fusion Steps. mBio 2022; 13:e0322221. [PMID: 35506666 PMCID: PMC9239137 DOI: 10.1128/mbio.03222-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Paramyxoviridae family comprises important pathogens that include measles (MeV), mumps, parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). Paramyxoviral entry into cells requires viral-cell membrane fusion, and formation of paramyxoviral pathognomonic syncytia requires cell-cell membrane fusion. Both events are coordinated by intricate interactions between the tetrameric attachment (G/H/HN) and trimeric fusion (F) glycoproteins. We report that receptor binding induces conformational changes in NiV G that expose its stalk domain, which triggers F through a cascade from prefusion to prehairpin intermediate (PHI) to postfusion conformations, executing membrane fusion. To decipher how the NiV G stalk may trigger F, we introduced cysteines along the G stalk to increase tetrameric strength and restrict stalk mobility. While most point mutants displayed near-wild-type levels of cell surface expression and receptor binding, most yielded increased NiV G oligomeric strength, and showed remarkably strong defects in syncytium formation. Furthermore, most of these mutants displayed stronger F/G interactions and significant defects in their ability to trigger F, indicating that NiV G stalk mobility is key to proper F triggering via moderate G/F interactions. Also remarkably, a mutant capable of triggering F and of fusion pore formation yielded little syncytium formation, implicating G or G/F interactions in a late step occurring post fusion pore formation, such as the extensive fusion pore expansion required for syncytium formation. This study uncovers novel mechanisms by which the G stalk and its oligomerization/mobility affect G/F interactions, the triggering of F, and a late fusion pore expansion step-exciting novel findings for paramyxoviral attachment glycoproteins. IMPORTANCE The important Paramyxoviridae family includes measles, mumps, human parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). The deadly emerging NiV can cause neurologic and respiratory symptoms in humans with a >60% mortality rate. NiV has two surface proteins, the receptor binding protein (G) and fusion (F) glycoproteins. They mediate the required membrane fusion during viral entry into host cells and during syncytium formation, a hallmark of paramyxoviral and NiV infections. We previously discovered that the G stalk domain is important for triggering F (via largely unknown mechanisms) to induce membrane fusion. Here, we uncovered new roles and mechanisms by which the G stalk and its mobility modulate the triggering of F and also unexpectedly affect a very late step in membrane fusion, namely fusion pore expansion. Importantly, these novel findings may extend to other paramyxoviruses, offering new potential targets for therapeutic interventions.
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11
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Lawrence P, Escudero-Pérez B. Henipavirus Immune Evasion and Pathogenesis Mechanisms: Lessons Learnt from Natural Infection and Animal Models. Viruses 2022; 14:v14050936. [PMID: 35632678 PMCID: PMC9146692 DOI: 10.3390/v14050936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/27/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023] Open
Abstract
Nipah henipavirus (NiV) and Hendra henipavirus (HeV) are zoonotic emerging paramyxoviruses causing severe disease outbreaks in humans and livestock, mostly in Australia, India, Malaysia, Singapore and Bangladesh. Both are bat-borne viruses and in humans, their mortality rates can reach 60% in the case of HeV and 92% for NiV, thus being two of the deadliest viruses known for humans. Several factors, including a large cellular tropism and a wide zoonotic potential, con-tribute to their high pathogenicity. This review provides an overview of HeV and NiV pathogenicity mechanisms and provides a summary of their interactions with the immune systems of their different host species, including their natural hosts bats, spillover-hosts pigs, horses, and humans, as well as in experimental animal models. A better understanding of the interactions between henipaviruses and their hosts could facilitate the development of new therapeutic strategies and vaccine measures against these re-emerging viruses.
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Affiliation(s)
- Philip Lawrence
- Science and Humanities Confluence Research Centre (EA 1598), Catholic University of Lyon (UCLy), 69002 Lyon, France
- Correspondence: (P.L.); (B.E.-P.)
| | - Beatriz Escudero-Pérez
- WHO Collaborating Centre for Arbovirus and Haemorrhagic Fever Reference and Research, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
- German Centre for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel, 38124 Braunschweig, Germany
- Correspondence: (P.L.); (B.E.-P.)
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12
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Wang Z, Amaya M, Addetia A, Dang HV, Reggiano G, Yan L, Hickey AC, DiMaio F, Broder CC, Veesler D. Architecture and antigenicity of the Nipah virus attachment glycoprotein. Science 2022; 375:1373-1378. [PMID: 35239409 DOI: 10.1126/science.abm5561] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are zoonotic henipaviruses (HNVs) responsible for outbreaks of encephalitis and respiratory illness. The entry of HNVs into host cells requires the attachment (G) and fusion (F) glycoproteins, which are the main targets of antibody responses. To understand viral infection and host immunity, we determined a cryo-electron microscopy structure of the NiV G homotetrameric ectodomain in complex with the nAH1.3 broadly neutralizing antibody Fab fragment. We show that a cocktail of two nonoverlapping G-specific antibodies neutralizes NiV and HeV synergistically and limits the emergence of escape mutants. Analysis of polyclonal serum antibody responses elicited by vaccination of macaques with NiV G indicates that the receptor binding head domain is immunodominant. These results pave the way for implementing multipronged therapeutic strategies against these deadly pathogens.
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Affiliation(s)
- Zhaoqian Wang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814, USA
| | - Amin Addetia
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Ha V Dang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Gabriella Reggiano
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814, USA
| | - Andrew C Hickey
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA.,U.S. Public Health Services Commissioned Corps, Rockville, MD 20852, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Christopher C Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
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13
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Yeo YY, Buchholz DW, Gamble A, Jager M, Aguilar HC. Headless Henipaviral Receptor Binding Glycoproteins Reveal Fusion Modulation by the Head/Stalk Interface and Post-receptor Binding Contributions of the Head Domain. J Virol 2021; 95:e0066621. [PMID: 34288734 PMCID: PMC8475510 DOI: 10.1128/jvi.00666-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/13/2021] [Indexed: 11/20/2022] Open
Abstract
Cedar virus (CedV) is a nonpathogenic member of the Henipavirus (HNV) genus of emerging viruses, which includes the deadly Nipah (NiV) and Hendra (HeV) viruses. CedV forms syncytia, a hallmark of henipaviral and paramyxoviral infections and pathogenicity. However, the intrinsic fusogenic capacity of CedV relative to NiV or HeV remains unquantified. HNV entry is mediated by concerted interactions between the attachment (G) and fusion (F) glycoproteins. Upon receptor binding by the HNV G head domain, a fusion-activating G stalk region is exposed and triggers F to undergo a conformational cascade that leads to viral entry or cell-cell fusion. Here, we demonstrate quantitatively that CedV is inherently significantly less fusogenic than NiV at equivalent G and F cell surface expression levels. We then generated and tested six headless CedV G mutants of distinct C-terminal stalk lengths, surprisingly revealing highly hyperfusogenic cell-cell fusion phenotypes 3- to 4-fold greater than wild-type CedV levels. Additionally, similarly to NiV, a headless HeV G mutant yielded a less pronounced hyperfusogenic phenotype compared to wild-type HeV. Further, coimmunoprecipitation and cell-cell fusion assays revealed heterotypic NiV/CedV functional G/F bidentate interactions, as well as evidence of HNV G head domain involvement beyond receptor binding or G stalk exposure. All evidence points to the G head/stalk junction being key to modulating HNV fusogenicity, supporting the notion that head domains play several distinct and central roles in modulating stalk domain fusion promotion. Further, this study exemplifies how CedV may help elucidate important mechanistic underpinnings of HNV entry and pathogenicity. IMPORTANCE The Henipavirus genus in the Paramyxoviridae family includes the zoonotic Nipah (NiV) and Hendra (HeV) viruses. NiV and HeV infections often cause fatal encephalitis and pneumonia, but no vaccines or therapeutics are currently approved for human use. Upon viral entry, Henipavirus infections yield the formation of multinucleated cells (syncytia). Viral entry and cell-cell fusion are mediated by the attachment (G) and fusion (F) glycoproteins. Cedar virus (CedV), a nonpathogenic henipavirus, may be a useful tool to gain knowledge on henipaviral pathogenicity. Here, using homotypic and heterotypic full-length and headless CedV, NiV, and HeV G/F combinations, we discovered that CedV G/F are significantly less fusogenic than NiV or HeV G/F, and that the G head/stalk junction is key to modulating cell-cell fusion, refining the mechanism of henipaviral membrane fusion events. Our study exemplifies how CedV may be a useful tool to elucidate broader mechanistic understanding for the important henipaviruses.
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Affiliation(s)
- Yao Yu Yeo
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - David W. Buchholz
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Amandine Gamble
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Mason Jager
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Hector C. Aguilar
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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14
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Dong J, Cross RW, Doyle MP, Kose N, Mousa JJ, Annand EJ, Borisevich V, Agans KN, Sutton R, Nargi R, Majedi M, Fenton KA, Reichard W, Bombardi RG, Geisbert TW, Crowe JE. Potent Henipavirus Neutralization by Antibodies Recognizing Diverse Sites on Hendra and Nipah Virus Receptor Binding Protein. Cell 2021; 183:1536-1550.e17. [PMID: 33306954 DOI: 10.1016/j.cell.2020.11.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 10/04/2020] [Accepted: 11/12/2020] [Indexed: 01/01/2023]
Abstract
Hendra (HeV) and Nipah (NiV) viruses are emerging zoonotic pathogens in the Henipavirus genus causing outbreaks of disease with very high case fatality rates. Here, we report the first naturally occurring human monoclonal antibodies (mAbs) against HeV receptor binding protein (RBP). All isolated mAbs neutralized HeV, and some also neutralized NiV. Epitope binning experiments identified five major antigenic sites on HeV-RBP. Animal studies demonstrated that the most potent cross-reactive neutralizing mAbs, HENV-26 and HENV-32, protected ferrets in lethal models of infection with NiV Bangladesh 3 days after exposure. We solved the crystal structures of mAb HENV-26 in complex with both HeV-RBP and NiV-RBP and of mAb HENV-32 in complex with HeV-RBP. The studies reveal diverse sites of vulnerability on RBP recognized by potent human mAbs that inhibit virus by multiple mechanisms. These studies identify promising prophylactic antibodies and define protective epitopes that can be used in rational vaccine design.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/isolation & purification
- Antibodies, Neutralizing/immunology
- Antibodies, Viral/immunology
- Antigens, Viral/immunology
- Binding Sites
- Binding, Competitive
- Brain/pathology
- Chiroptera/virology
- Cross Reactions/immunology
- Crystallography, X-Ray
- Ephrin-B2/metabolism
- Female
- Ferrets/virology
- Hendra Virus/immunology
- Henipavirus/immunology
- Humans
- Interferometry
- Liver/pathology
- Models, Molecular
- Neutralization Tests
- Nipah Virus/immunology
- Protein Binding
- Protein Conformation
- Protein Domains
- Receptors, Virus/chemistry
- Receptors, Virus/immunology
- Receptors, Virus/metabolism
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Affiliation(s)
- Jinhui Dong
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert W Cross
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Michael P Doyle
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jarrod J Mousa
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Edward J Annand
- Sydney School of Veterinary Science and Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia; Black Mountain Laboratories & Australian Centre for Disease Preparedness, Health and Biosecurity, CSIRO, Canberra, ACT, Australia
| | - Viktoriya Borisevich
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Krystle N Agans
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Rachel Sutton
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel Nargi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Mahsa Majedi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Karla A Fenton
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Walter Reichard
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robin G Bombardi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Thomas W Geisbert
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - James E Crowe
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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15
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Marcink TC, Wang T, des Georges A, Porotto M, Moscona A. Human parainfluenza virus fusion complex glycoproteins imaged in action on authentic viral surfaces. PLoS Pathog 2020; 16:e1008883. [PMID: 32956394 PMCID: PMC7529294 DOI: 10.1371/journal.ppat.1008883] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 10/01/2020] [Accepted: 08/13/2020] [Indexed: 01/21/2023] Open
Abstract
Infection by human parainfluenza viruses (HPIVs) causes widespread lower respiratory diseases, including croup, bronchiolitis, and pneumonia, and there are no vaccines or effective treatments for these viruses. HPIV3 is a member of the Respirovirus species of the Paramyxoviridae family. These viruses are pleomorphic, enveloped viruses with genomes composed of single-stranded negative-sense RNA. During viral entry, the first step of infection, the viral fusion complex, comprised of the receptor-binding glycoprotein hemagglutinin-neuraminidase (HN) and the fusion glycoprotein (F), mediates fusion upon receptor binding. The HPIV3 transmembrane protein HN, like the receptor-binding proteins of other related viruses that enter host cells using membrane fusion, binds to a receptor molecule on the host cell plasma membrane, which triggers the F glycoprotein to undergo major conformational rearrangements, promoting viral entry. Subsequent fusion of the viral and host membranes allows delivery of the viral genetic material into the host cell. The intermediate states in viral entry are transient and thermodynamically unstable, making it impossible to understand these transitions using standard methods, yet understanding these transition states is important for expanding our knowledge of the viral entry process. In this study, we use cryo-electron tomography (cryo-ET) to dissect the stepwise process by which the receptor-binding protein triggers F-mediated fusion, when forming a complex with receptor-bearing membranes. Using an on-grid antibody capture method that facilitates examination of fresh, biologically active strains of virus directly from supernatant fluids and a series of biological tools that permit the capture of intermediate states in the fusion process, we visualize the series of events that occur when a pristine, authentic viral particle interacts with target receptors and proceeds from the viral entry steps of receptor engagement to membrane fusion.
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Affiliation(s)
- Tara C. Marcink
- Department of Pediatrics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Center for Host-Pathogen Interaction, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
| | - Tong Wang
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, United States of America
| | - Amedee des Georges
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, United States of America
- Department of Chemistry and Biochemistry, City College of New York, New York, New York, United States of America
| | - Matteo Porotto
- Department of Pediatrics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Center for Host-Pathogen Interaction, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Anne Moscona
- Department of Pediatrics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Center for Host-Pathogen Interaction, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Department of Microbiology & Immunology, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Department of Physiology & Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
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16
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Chi M, Liu Y, Wen H, Zhao L, Song Y, Liu N, Chi L, Wang Z. Role of the head-stalk linker region (aa115-122) of Newcastle disease virus haemagglutinin-neuraminidase in regulating fusion triggering. J Gen Virol 2020; 101:5-20. [PMID: 31702540 DOI: 10.1099/jgv.0.001349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
To gain insights into the role of the head-stalk linker region in the fusion triggering, we constructed mutants by deleting or substituting the linker region (115-NGAANNSG-122) of Newcastle disease virus (NDV) haemagglutinin-neuraminidase (HN) with the corresponding sequences of other paramyxoviruses. The results showed that these HN mutants exhibited different levels of fusion-triggering activity, but most of them maintained comparable levels with wide-type HN in both receptor recognition and neuraminidase activity. We tried to figure out reasons for fusion alteration through assessing the expression and the oligomeric state of HN mutants. Moreover, four mutants with significant fusion changes were introduced into the headless HN stem (HN1-123) to intensively investigate the role of the linker region in fusion triggering. Consequently, the stability of HN oligomers and the structural integrity of the 4 helical-bundle of stalk have complicated influences on the alteration of fusion-triggering activities for different mutants. These data suggested that the head-stalk linker could regulate the fusion triggering at both full-length and headless HN levels.
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Affiliation(s)
- Miaomiao Chi
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
| | - Ying Liu
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
| | - Hongling Wen
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
| | - Li Zhao
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
| | - Yanyan Song
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
| | - Na Liu
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
| | - Lianli Chi
- State Key Laboratory of Microbial Technology, National Glycoengineering Research Center, Shandong University, Jinan 250100, PR China
| | - Zhiyu Wang
- The Key Laboratory for Experimental Teratology of the Ministry of Education, Shandong University, Jinan 250012, PR China.,Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
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17
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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.
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18
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Navaratnarajah CK, Generous AR, Yousaf I, Cattaneo R. Receptor-mediated cell entry of paramyxoviruses: Mechanisms, and consequences for tropism and pathogenesis. J Biol Chem 2020; 295:2771-2786. [PMID: 31949044 DOI: 10.1074/jbc.rev119.009961] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Research in the last decade has uncovered many new paramyxoviruses, airborne agents that cause epidemic diseases in animals including humans. Most paramyxoviruses enter epithelial cells of the airway using sialic acid as a receptor and cause only mild disease. However, others cross the epithelial barrier and cause more severe disease. For some of these viruses, the host receptors have been identified, and the mechanisms of cell entry have been elucidated. The tetrameric attachment proteins of paramyxoviruses have vastly different binding affinities for their cognate receptors, which they contact through different binding surfaces. Nevertheless, all input signals are converted to the same output: conformational changes that trigger refolding of trimeric fusion proteins and membrane fusion. Experiments with selectively receptor-blinded viruses inoculated into their natural hosts have provided insights into tropism, identifying the cells and tissues that support growth and revealing the mechanisms of pathogenesis. These analyses also shed light on diabolically elegant mechanisms used by morbilliviruses, including the measles virus, to promote massive amplification within the host, followed by efficient aerosolization and rapid spread through host populations. In another paradigm of receptor-facilitated severe disease, henipaviruses, including Nipah and Hendra viruses, use different members of one protein family to cause zoonoses. Specific properties of different paramyxoviruses, like neurotoxicity and immunosuppression, are now understood in the light of receptor specificity. We propose that research on the specific receptors for several newly identified members of the Paramyxoviridae family that may not bind sialic acid is needed to anticipate their zoonotic potential and to generate effective vaccines and antiviral compounds.
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Affiliation(s)
| | - Alex R Generous
- Mayo Clinic Graduate School of Biomedical Sciences, Virology and Gene Therapy Track, Mayo Clinic, Rochester, Minnesota 55905
| | - Iris Yousaf
- Mayo Clinic Graduate School of Biomedical Sciences, Virology and Gene Therapy Track, Mayo Clinic, Rochester, Minnesota 55905
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota 55905.
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19
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A structural basis for antibody-mediated neutralization of Nipah virus reveals a site of vulnerability at the fusion glycoprotein apex. Proc Natl Acad Sci U S A 2019; 116:25057-25067. [PMID: 31767754 PMCID: PMC6911215 DOI: 10.1073/pnas.1912503116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Nipah virus (NiV) is a highly pathogenic paramyxovirus that causes frequent outbreaks of severe neurologic and respiratory disease in humans with high case fatality rates. The 2 glycoproteins displayed on the surface of the virus, NiV-G and NiV-F, mediate host-cell attachment and membrane fusion, respectively, and are targets of the host antibody response. Here, we provide a molecular basis for neutralization of NiV through antibody-mediated targeting of NiV-F. Structural characterization of a neutralizing antibody (nAb) in complex with trimeric prefusion NiV-F reveals an epitope at the membrane-distal domain III (DIII) of the molecule, a region that undergoes substantial refolding during host-cell entry. The epitope of this monoclonal antibody (mAb66) is primarily protein-specific and we observe that glycosylation at the periphery of the interface likely does not inhibit mAb66 binding to NiV-F. Further characterization reveals that a Hendra virus-F-specific nAb (mAb36) and many antibodies in an antihenipavirus-F polyclonal antibody mixture (pAb835) also target this region of the molecule. Integrated with previously reported paramyxovirus F-nAb structures, these data support a model whereby the membrane-distal region of the F protein is targeted by the antibody-mediated immune response across henipaviruses. Notably, our domain-specific sequence analysis reveals no evidence of selective pressure at this region of the molecule, suggestive that functional constraints prevent immune-driven sequence variation. Combined, our data reveal the membrane-distal region of NiV-F as a site of vulnerability on the NiV surface.
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20
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Keshwara R, Shiels T, Postnikova E, Kurup D, Wirblich C, Johnson RF, Schnell MJ. Rabies-based vaccine induces potent immune responses against Nipah virus. NPJ Vaccines 2019; 4:15. [PMID: 31016033 PMCID: PMC6465360 DOI: 10.1038/s41541-019-0109-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/04/2019] [Indexed: 12/25/2022] Open
Abstract
Nipah Virus (NiV) is a re-emerging zoonotic pathogen in the genus Henipavirus of the Paramyxoviridae family of viruses. NiV is endemic to Bangladesh and Malaysia and is highly fatal to both livestock and humans (human case fatality rate = 74.5%). Currently, there is no approved vaccine against NiV on the market. The goal of this study was to use a recombinant RABV vector expressing NiV glycoprotein (NiV G) to develop a bivalent candidate vaccine against NiV disease and rabies virus (RABV) disease, which is also a significant health burden in the regions where NiV is endemic. The rabies vector is a well-established vaccine strain that lacks neurovirulence and can stably expresses foreign antigens that are immunogenic in various animal models. Mice inoculated intranasally with the live recombinant RABV/NiV vaccine (NIPARAB) showed no signs of disease. To test the immunogenicity of the vaccine candidate, groups of C57BL/6 mice were immunized intramuscularly with a single dose of live vaccine particles or two doses of chemically inactivated viral particles. Both vaccination groups showed NiV G-specific seroconversion, and the inactivated (INAC) vaccine group yielded higher titers of NiV G-specific antibodies. Furthermore, cross-reactivity of NiV G-specific immune sera against Hendra virus (HeV), was confirmed by immunofluorescence (IF) and indirect ELISA against soluble recombinant HeV glycoprotein (HeV G). Both live and killed vaccines induced neutralizing antibodies. These results indicate that NIPARAB may be used as a killed virus vaccine to protect humans against NiV and RABV, and possibly as a preventative measure against HeV as well.
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Affiliation(s)
- Rohan Keshwara
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107 USA
| | - Thomas Shiels
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107 USA
| | - Elena Postnikova
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 USA
| | - Drishya Kurup
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107 USA
| | - Christoph Wirblich
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107 USA
| | - Reed F. Johnson
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Matthias J. Schnell
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107 USA
- Jefferson Vaccine Center, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107 USA
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21
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Behner L, Zimmermann L, Ringel M, Weis M, Maisner A. Formation of high-order oligomers is required for functional bioactivity of an African bat henipavirus surface glycoprotein. Vet Microbiol 2018; 218:90-97. [DOI: 10.1016/j.vetmic.2018.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 03/29/2018] [Accepted: 03/31/2018] [Indexed: 10/17/2022]
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22
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Wong JJW, Young TA, Zhang J, Liu S, Leser GP, Komives EA, Lamb RA, Zhou ZH, Salafsky J, Jardetzky TS. Monomeric ephrinB2 binding induces allosteric changes in Nipah virus G that precede its full activation. Nat Commun 2017; 8:781. [PMID: 28974687 PMCID: PMC5626764 DOI: 10.1038/s41467-017-00863-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 08/01/2017] [Indexed: 11/09/2022] Open
Abstract
Nipah virus is an emergent paramyxovirus that causes deadly encephalitis and respiratory infections in humans. Two glycoproteins coordinate the infection of host cells, an attachment protein (G), which binds to cell surface receptors, and a fusion (F) protein, which carries out the process of virus-cell membrane fusion. The G protein binds to ephrin B2/3 receptors, inducing G conformational changes that trigger F protein refolding. Using an optical approach based on second harmonic generation, we show that monomeric and dimeric receptors activate distinct conformational changes in G. The monomeric receptor-induced changes are not detected by conformation-sensitive monoclonal antibodies or through electron microscopy analysis of G:ephrinB2 complexes. However, hydrogen/deuterium exchange experiments confirm the second harmonic generation observations and reveal allosteric changes in the G receptor binding and F-activating stalk domains, providing insights into the pathway of receptor-activated virus entry.Nipah virus causes encephalitis in humans. Here the authors use a multidisciplinary approach to study the binding of the viral attachment protein G to its host receptor ephrinB2 and show that monomeric and dimeric receptors activate distinct conformational changes in G and discuss implications for receptor-activated virus entry.
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Affiliation(s)
- Joyce J W Wong
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | | | - Jiayan Zhang
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Shiheng Liu
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - George P Leser
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL, 60208-3500, USA
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208-3500, USA
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California San Diego, San Diego, CA, 92093, USA
| | - Robert A Lamb
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL, 60208-3500, USA
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208-3500, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | | | - Theodore S Jardetzky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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23
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Dutta P, Siddiqui A, Botlani M, Varma S. Stimulation of Nipah Fusion: Small Intradomain Changes Trigger Extensive Interdomain Rearrangements. Biophys J 2017; 111:1621-1630. [PMID: 27760350 DOI: 10.1016/j.bpj.2016.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/18/2016] [Accepted: 09/06/2016] [Indexed: 12/18/2022] Open
Abstract
Nipah is an emerging paramyxovirus that is of serious concern to human health. It invades host cells using two of its membrane proteins-G and F. G binds to host ephrins and this stimulates G to activate F. Upon activation, F mediates virus-host membrane fusion. Here we focus on mechanisms that underlie the stimulation of G by ephrins. Experiments show that G interacts with ephrin and F through separate sites located on two different domains, the receptor binding domain (RBD) and the F activation domain (FAD). No models explain this allosteric coupling. In fact, the analogous mechanisms in other paramyxoviruses also remain undetermined. The structural organization of G is such that allosteric coupling must involve at least one of the two interfaces-the RBD-FAD interface and/or the RBD-RBD interface. Here we examine using molecular dynamics the effect of ephrin binding on the RBD-RBD interface. We find that despite inducing small changes in individual RBDs, ephrin reorients the RBD-RBD interface extensively, and in a manner that will enhance solvent exposure of the FAD. While this finding supports a proposed model of G stimulation, we also find from additional simulations that ephrin induces a similar RBD-RBD reorientation in a stimulation-deficient G mutant, V209 VG → AAA. Together, our simulations suggest that while inter-RBD reorientation may be important, it is not, by itself, a sufficient condition for G stimulation. Additionally, we find that the mutation affects the conformational ensemble of RBD globally, including the RBD-FAD interface, suggesting the latter's role in G stimulation. Because ephrin induces small changes in individual RBDs, a proper analysis of conformational ensembles required that they are compared directly-we employ a method we developed recently, which we now release at SimTK, and show that it also performs excellently for non-Gaussian distributions.
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Affiliation(s)
- Priyanka Dutta
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida
| | - Ahnaf Siddiqui
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida
| | - Mohsen Botlani
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida
| | - Sameer Varma
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida.
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24
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Lam CW, AbuBakar S, Chang LY. Identification of the cell binding domain in Nipah virus G glycoprotein using a phage display system. J Virol Methods 2017; 243:1-9. [PMID: 28082163 DOI: 10.1016/j.jviromet.2017.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/06/2017] [Accepted: 01/06/2017] [Indexed: 10/25/2022]
Abstract
Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus with unusual broad host tropism and is designated as a Category C pathogen by the U.S. National Institute of Allergy and Infectious Diseases. NiV infection is initiated after binding of the viral G glycoprotein to the host cell receptor. The aim of this study was to map the NiV G glycoprotein cell binding domain using a phage display system. The NiV G extracellular domain was truncated and displayed as attachment proteins on M13 phage g3p minor coat protein. The binding efficiency of recombinant phages displaying different regions of NiV G to mammalian cells was evaluated. Results showed that regions of NiV G consisting of amino acids 396-602 (recombinant phage G4) and 498-602 (recombinant phage G5) demonstrated the highest binding to both Vero (5.5×103 cfu/ml and 5.6×103 cfu/ml) and THP-1 cells (3.5×103 cfu/ml and 2.9×103 cfu/ml). However, the binding of both of these recombinant phages to THP-1 cells was significantly lower than to Vero cells, and this could be due to the lack of primary host cell receptor expression on THP-1 cells. Furthermore, the binding between these two recombinant phages was competitive suggesting that there was a common host cell attachment site. This study employed an approach that is suitable for use in a biosafety level 2 containment laboratory without the need to use live virus to show that NiV G amino acids 498-602 play an important role for attachment to host cells.
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Affiliation(s)
- Chui-Wan Lam
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Sazaly AbuBakar
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; Tropical Infectious Diseases Research and Education Centre (TIDREC), University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Li-Yen Chang
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; Tropical Infectious Diseases Research and Education Centre (TIDREC), University of Malaya, 50603 Kuala Lumpur, Malaysia.
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25
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Multiple Strategies Reveal a Bidentate Interaction between the Nipah Virus Attachment and Fusion Glycoproteins. J Virol 2016; 90:10762-10773. [PMID: 27654290 DOI: 10.1128/jvi.01469-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/14/2016] [Indexed: 11/20/2022] Open
Abstract
The paramyxoviral family contains many medically important viruses, including measles virus, mumps virus, parainfluenza viruses, respiratory syncytial virus, human metapneumovirus, and the deadly zoonotic henipaviruses Hendra and Nipah virus (NiV). To both enter host cells and spread from cell to cell within infected hosts, the vast majority of paramyxoviruses utilize two viral envelope glycoproteins: the attachment glycoprotein (G, H, or hemagglutinin-neuraminidase [HN]) and the fusion glycoprotein (F). Binding of G/H/HN to a host cell receptor triggers structural changes in G/H/HN that in turn trigger F to undergo a series of conformational changes that result in virus-cell (viral entry) or cell-cell (syncytium formation) membrane fusion. The actual regions of G/H/HN and F that interact during the membrane fusion process remain relatively unknown though it is generally thought that the paramyxoviral G/H/HN stalk region interacts with the F head region. Studies to determine such interactive regions have relied heavily on coimmunoprecipitation approaches, whose limitations include the use of detergents and the micelle-mediated association of proteins. Here, we developed a flow-cytometric strategy capable of detecting membrane protein-protein interactions by interchangeably using the full-length form of G and a soluble form of F, or vice versa. Using both coimmunoprecipitation and flow-cytometric strategies, we found a bidentate interaction between NiV G and F, where both the stalk and head regions of NiV G interact with F. This is a new structural-biological finding for the paramyxoviruses. Additionally, our studies disclosed regions of the NiV G and F glycoproteins dispensable for the G and F interactions. IMPORTANCE Nipah virus (NiV) is a zoonotic paramyxovirus that causes high mortality rates in humans, with no approved treatment or vaccine available for human use. Viral entry into host cells relies on two viral envelope glycoproteins: the attachment (G) and fusion (F) glycoproteins. Binding of G to the ephrinB2 or ephrinB3 cell receptors triggers conformational changes in G that in turn cause F to undergo conformational changes that result in virus-host cell membrane fusion and viral entry. It is currently unknown, however, which specific regions of G and F interact during membrane fusion. Past efforts to determine the interacting regions have relied mainly on coimmunoprecipitation, a technique with some pitfalls. We developed a flow-cytometric assay to study membrane protein-protein interactions, and using this assay we report a bidentate interaction whereby both the head and stalk regions of NiV G interact with NiV F, a new finding for the paramyxovirus family.
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26
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Bender RR, Muth A, Schneider IC, Friedel T, Hartmann J, Plückthun A, Maisner A, Buchholz CJ. Receptor-Targeted Nipah Virus Glycoproteins Improve Cell-Type Selective Gene Delivery and Reveal a Preference for Membrane-Proximal Cell Attachment. PLoS Pathog 2016; 12:e1005641. [PMID: 27281338 PMCID: PMC4900575 DOI: 10.1371/journal.ppat.1005641] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 04/26/2016] [Indexed: 12/27/2022] Open
Abstract
Receptor-targeted lentiviral vectors (LVs) can be an effective tool for selective transfer of genes into distinct cell types of choice. Moreover, they can be used to determine the molecular properties that cell surface proteins must fulfill to act as receptors for viral glycoproteins. Here we show that LVs pseudotyped with receptor-targeted Nipah virus (NiV) glycoproteins effectively enter into cells when they use cell surface proteins as receptors that bring them closely enough to the cell membrane (less than 100 Å distance). Then, they were flexible in receptor usage as demonstrated by successful targeting of EpCAM, CD20, and CD8, and as selective as LVs pseudotyped with receptor-targeted measles virus (MV) glycoproteins, the current standard for cell-type specific gene delivery. Remarkably, NiV-LVs could be produced at up to two orders of magnitude higher titers compared to their MV-based counterparts and were at least 10,000-fold less effectively neutralized than MV glycoprotein pseudotyped LVs by pooled human intravenous immunoglobulin. An important finding for NiV-LVs targeted to Her2/neu was an about 100-fold higher gene transfer activity when particles were targeted to membrane-proximal regions as compared to particles binding to a more membrane-distal epitope. Likewise, the low gene transfer activity mediated by NiV-LV particles bound to the membrane distal domains of CD117 or the glutamate receptor subunit 4 (GluA4) was substantially enhanced by reducing receptor size to below 100 Å. Overall, the data suggest that the NiV glycoproteins are optimally suited for cell-type specific gene delivery with LVs and, in addition, for the first time define which parts of a cell surface protein should be targeted to achieve optimal gene transfer rates with receptor-targeted LVs. Pseudotyping of lentiviral vectors (LVs) with glycoproteins from other enveloped viruses has not only often been revealing in mechanistic studies of particle assembly and entry, but is also of practical importance for gene delivery. LVs pseudotyped with engineered glycoproteins allowing free choice of receptor usage are expected to overcome current limitations in cell-type selectivity of gene transfer. Here we describe for the first time receptor-targeted Nipah virus glycoproteins as important step towards this goal. LV particles carrying the engineered Nipah virus glycoproteins were substantially more efficient in gene delivery than their state-of-the-art measles virus-based counterparts, now making the production of receptor-targeted LVs for clinical applications possible. Moreover, the data define for the first time the molecular requirements for membrane fusion with respect to the position of the receptor binding site relative to the cell membrane, a finding with implications for the molecular evolution of paramyxoviruses using proteinaceous receptors for cell entry.
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Affiliation(s)
- Ruben R Bender
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Anke Muth
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Irene C Schneider
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Thorsten Friedel
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Jessica Hartmann
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Andrea Maisner
- Institute for Virology (BMFZ), Philipps-University Marburg, Marburg, Germany
| | - Christian J Buchholz
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
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27
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Stone JA, Nicola AV, Baum LG, Aguilar HC. Multiple Novel Functions of Henipavirus O-glycans: The First O-glycan Functions Identified in the Paramyxovirus Family. PLoS Pathog 2016; 12:e1005445. [PMID: 26867212 PMCID: PMC4750917 DOI: 10.1371/journal.ppat.1005445] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 01/19/2016] [Indexed: 01/13/2023] Open
Abstract
O-linked glycosylation is a ubiquitous protein modification in organisms belonging to several kingdoms. Both microbial and host protein glycans are used by many pathogens for host invasion and immune evasion, yet little is known about the roles of O-glycans in viral pathogenesis. Reportedly, there is no single function attributed to O-glycans for the significant paramyxovirus family. The paramyxovirus family includes many important pathogens, such as measles, mumps, parainfluenza, metapneumo- and the deadly Henipaviruses Nipah (NiV) and Hendra (HeV) viruses. Paramyxoviral cell entry requires the coordinated actions of two viral membrane glycoproteins: the attachment (HN/H/G) and fusion (F) glycoproteins. O-glycan sites in HeV G were recently identified, facilitating use of the attachment protein of this deadly paramyxovirus as a model to study O-glycan functions. We mutated the identified HeV G O-glycosylation sites and found mutants with altered cell-cell fusion, G conformation, G/F association, viral entry in a pseudotyped viral system, and, quite unexpectedly, pseudotyped viral F protein incorporation and processing phenotypes. These are all important functions of viral glycoproteins. These phenotypes were broadly conserved for equivalent NiV mutants. Thus our results identify multiple novel and pathologically important functions of paramyxoviral O-glycans, paving the way to study O-glycan functions in other paramyxoviruses and enveloped viruses.
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Affiliation(s)
- Jacquelyn A. Stone
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Anthony V. Nicola
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
| | - Linda G. Baum
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, California, United States of America
| | - Hector C. Aguilar
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
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28
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Borisevich V, Lee B, Hickey A, DeBuysscher B, Broder CC, Feldmann H, Rockx B. Escape From Monoclonal Antibody Neutralization Affects Henipavirus Fitness In Vitro and In Vivo. J Infect Dis 2015; 213:448-55. [PMID: 26357909 PMCID: PMC4704671 DOI: 10.1093/infdis/jiv449] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/01/2015] [Indexed: 11/30/2022] Open
Abstract
Henipaviruses are zoonotic viruses that can cause severe and acute respiratory diseases and encephalitis in humans. To date, no vaccine or treatments are approved for human use. The presence of neutralizing antibodies is a strong correlate of protection against lethal disease in animals. However, since RNA viruses are prone to high mutation rates, the possibility that these viruses will escape neutralization remains a potential concern. In the present study, we generated neutralization-escape mutants, using 6 different monoclonal antibodies, and studied the effect of these neutralization-escape mutations on in vitro and in vivo fitness. These data provide a mechanism for overcoming neutralization escape by use of cocktails of cross-neutralizing monoclonal antibodies that recognize residues within the glycoprotein that are important for virus replication and virulence.
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Affiliation(s)
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Andrew Hickey
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland
| | - Blair DeBuysscher
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Christopher C Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Barry Rockx
- Department of Pathology Department of Microbiology and Immunology Institute for Human Infections and Immunity Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana Department of Rare and Emerging Viral Infections and Response, Center for Infectious Disease Control, National Institute of Public Health and the Environment, Bilthoven, The Netherlands
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29
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Novel Functions of Hendra Virus G N-Glycans and Comparisons to Nipah Virus. J Virol 2015; 89:7235-47. [PMID: 25948743 DOI: 10.1128/jvi.00773-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 04/27/2015] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Hendra virus (HeV) and Nipah virus (NiV) are reportedly the most deadly pathogens within the Paramyxoviridae family. These two viruses bind the cellular entry receptors ephrin B2 and/or ephrin B3 via the viral attachment glycoprotein G, and the concerted efforts of G and the viral fusion glycoprotein F result in membrane fusion. Membrane fusion is essential for viral entry into host cells and for cell-cell fusion, a hallmark of the disease pathobiology. HeV G is heavily N-glycosylated, but the functions of the N-glycans remain unknown. We disrupted eight predicted N-glycosylation sites in HeV G by conservative mutations (Asn to Gln) and found that six out of eight sites were actually glycosylated (G2 to G7); one in the stalk (G2) and five in the globular head domain (G3 to G7). We then tested the roles of individual and combined HeV G N-glycan mutants and found functions in the modulation of shielding against neutralizing antibodies, intracellular transport, G-F interactions, cell-cell fusion, and viral entry. Between the highly conserved HeV and NiV G glycoproteins, similar trends in the effects of N-glycans on protein functions were observed, with differences in the levels at which some N-glycan mutants affected such functions. While the N-glycan in the stalk domain (G2) had roles that were highly conserved between HeV and NiV G, individual N-glycans in the head affected the levels of several protein functions differently. Our findings are discussed in the context of their contributions to our understanding of HeV and NiV pathogenesis and immune responses. IMPORTANCE Viral envelope glycoproteins are important for viral pathogenicity and immune evasion. N-glycan shielding is one mechanism by which immune evasion can be achieved. In paramyxoviruses, viral attachment and membrane fusion are governed by the close interaction of the attachment proteins H/HN/G and the fusion protein F. In this study, we show that the attachment glycoprotein G of Hendra virus (HeV), a deadly paramyxovirus, is N-glycosylated at six sites (G2 to G7) and that most of these sites have important roles in viral entry, cell-cell fusion, G-F interactions, G oligomerization, and immune evasion. Overall, we found that the N-glycan in the stalk domain (G2) had roles that were very conserved between HeV G and the closely related Nipah virus G, whereas individual N-glycans in the head quantitatively modulated several protein functions differently between the two viruses.
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30
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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: 79] [Impact Index Per Article: 8.8] [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.
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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.
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31
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Electron tomography imaging of surface glycoproteins on human parainfluenza virus 3: association of receptor binding and fusion proteins before receptor engagement. mBio 2015; 6:e02393-14. [PMID: 25691596 PMCID: PMC4337575 DOI: 10.1128/mbio.02393-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to deliver their genetic material to host cells during infection, enveloped viruses use specialized proteins on their surfaces that bind cellular receptors and induce fusion of the viral and host membranes. In paramyxoviruses, a diverse family of single-stranded RNA (ssRNA) viruses, including several important respiratory pathogens, such as parainfluenza viruses, the attachment and fusion machinery is composed of two separate proteins: a receptor binding protein (hemagglutinin-neuraminidase [HN]) and a fusion (F) protein that interact to effect membrane fusion. Here we used negative-stain and cryo-electron tomography to image the 3-dimensional ultrastructure of human parainfluenza virus 3 (HPIV3) virions in the absence of receptor engagement. We observed that HN exists in at least two organizations. The first were arrays of tetrameric HN that lacked closely associated F proteins: in these purely HN arrays, HN adopted a “heads-down” configuration. In addition, we observed regions of complex surface density that contained HN in an apparently extended “heads-up” form, colocalized with prefusion F trimers. This colocalization with prefusion F prior to receptor engagement supports a model for fusion in which HN in its heads-up state and F may interact prior to receptor engagement without activating F, and that interaction with HN in this configuration is not sufficient to activate F. Only upon receptor engagement by HN’s globular head does HN transmit its activating signal to F. Human parainfluenza virus 3 (HPIV3) is an enveloped, ssRNA virus that can cause serious respiratory illness, especially in children. HPIV3, like most other paramyxoviruses, uses two specialized proteins to mediate cell entry: the fusion protein (F) and the receptor binding protein, hemagglutinin-neuraminidase (HN). F becomes activated to mediate fusion during entry when it is triggered by a signal from HN. Here we used electron tomography to reconstruct the 3-dimensional ultrastructure of HPIV3. From these structures, we could discern the distribution and, in some cases, conformation of HN and F proteins, which provided an understanding of their interrelationship on virions. HN is found in arrays alone in one conformation and interspersed with prefusion F trimers in another. The data support a model of paramyxovirus membrane fusion in which HN associates with F before receptor engagement, and receptor engagement by the globular head of HN switches the HN-F interaction into one of fusion activation.
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Nipah virus attachment glycoprotein stalk C-terminal region links receptor binding to fusion triggering. J Virol 2014; 89:1838-50. [PMID: 25428863 DOI: 10.1128/jvi.02277-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Membrane fusion is essential for paramyxovirus entry into target cells and for the cell-cell fusion (syncytia) that results from many paramyxoviral infections. The concerted efforts of two membrane-integral viral proteins, the attachment (HN, H, or G) and fusion (F) glycoproteins, mediate membrane fusion. The emergent Nipah virus (NiV) is a highly pathogenic and deadly zoonotic paramyxovirus. We recently reported that upon cell receptor ephrinB2 or ephrinB3 binding, at least two conformational changes occur in the NiV-G head, followed by one in the NiV-G stalk, that subsequently result in F triggering and F execution of membrane fusion. However, the domains and residues in NiV-G that trigger F and the specific events that link receptor binding to F triggering are unknown. In the present study, we identified a NiV-G stalk C-terminal region (amino acids 159 to 163) that is important for multiple G functions, including G tetramerization, conformational integrity, G-F interactions, receptor-induced conformational changes in G, and F triggering. On the basis of these results, we propose that this NiV-G region serves as an important structural and functional linker between the NiV-G head and the rest of the stalk and is critical in propagating the F-triggering signal via specific conformational changes that open a concealed F-triggering domain(s) in the G stalk. These findings broaden our understanding of the mechanism(s) of receptor-induced paramyxovirus F triggering during viral entry and cell-cell fusion. IMPORTANCE The emergent deadly viruses Nipah virus (NiV) and Hendra virus belong to the Henipavirus genus in the Paramyxoviridae family. NiV infections target endothelial cells and neurons and, in humans, result in 40 to 75% mortality rates. The broad tropism of the henipaviruses and the unavailability of therapeutics threaten the health of humans and livestock. Viral entry into host cells is the first step of henipavirus infections, which ultimately cause syncytium formation. After attaching to the host cell receptor, henipaviruses enter the target cell via direct viral-cell membrane fusion mediated by two membrane glycoproteins: the attachment protein (G) and the fusion protein (F). In this study, we identified and characterized a region in the NiV-G stalk C-terminal domain that links receptor binding to fusion triggering via several important glycoprotein functions. These findings advance our understanding of the membrane fusion-triggering mechanism(s) of the henipaviruses and the paramyxoviruses.
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Varma S, Botlani M, Leighty RE. Discerning intersecting fusion-activation pathways in the Nipah virus using machine learning. Proteins 2014; 82:3241-54. [DOI: 10.1002/prot.24541] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/10/2014] [Accepted: 02/14/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Sameer Varma
- Department of Cell Biology; Microbiology and Molecular Biology, University of South Florida; Tampa Florida 33620
| | - Mohsen Botlani
- Department of Cell Biology; Microbiology and Molecular Biology, University of South Florida; Tampa Florida 33620
| | - Ralph E. Leighty
- Department of Cell Biology; Microbiology and Molecular Biology, University of South Florida; Tampa Florida 33620
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Yin F, Wang M, Tan Y, Deng F, Vlak JM, Hu Z, Wang H. Identification and functional analysis of inter-subunit disulfide bonds of the F protein of Helicoverpa armigera nucleopolyhedrovirus. J Gen Virol 2014; 95:2820-2830. [PMID: 25114029 DOI: 10.1099/vir.0.068122-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The major envelope fusion protein F of the budded virus of baculoviruses consists of two disulfide-linked subunits: an N-terminal F2 subunit and a C-terminal, membrane-anchored F1 subunit. There is one cysteine in F2 and there are 15 cysteines in F1, but their role in disulfide linking is largely unknown. In this study, the inter- and intra-subunit disulfide bonds of the Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearNPV) F protein were analysed by site-directed mutagenesis. Results indicated that in a functional F protein, an inter-subunit disulfide bond exists between amino acids C108 (F2) and C241 (F1). When C241 was mutated, an alternative disulfide bond was formed between C108 and C232, rendering F non-functional. No inter-subunit bridge was observed in a double C232/C241 mutant of F1. C403 was not involved in the formation of inter-subunit disulfide bonding, but mutation of this amino acid decreased viral infectivity significantly, suggesting that it might be involved in intra-subunit disulfide bonds. The influence of reductant [tris(2-carboxyethyl) phosphine (TCEP)] and free-thiol inhibitors [4-acetamido-4'-maleimidylstilbene 2,2'-disulfonic acid (AMS) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB)] on the infectivity of HearNPV was tested. The results indicated that TCEP greatly decreased the infection of HzAm1 cells by HearNPV. In contrast, AMS and DTNB had no inhibitory effect on viral infectivity. The data suggested that free thiol/disulfide isomerization was not likely to play a role in viral entry and infectivity.
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Affiliation(s)
- Feifei Yin
- School of Tropical and Laboratory Medicine, Hainan Medical University, Haikou 571101, PR China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan 430071, PR China
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan 430071, PR China
| | - Ying Tan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan 430071, PR China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan 430071, PR China
| | - Just M Vlak
- Laboratory of Virology, Wageningen University, 6708 PB Wageningen, The Netherlands
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan 430071, PR China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan 430071, PR China
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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.
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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
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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.
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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.
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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.
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38
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Liu Q, Stone JA, Bradel-Tretheway B, Dabundo J, Benavides Montano JA, Santos-Montanez J, Biering SB, Nicola AV, Iorio RM, Lu X, Aguilar HC. Unraveling a three-step spatiotemporal mechanism of triggering of receptor-induced Nipah virus fusion and cell entry. PLoS Pathog 2013; 9:e1003770. [PMID: 24278018 PMCID: PMC3837712 DOI: 10.1371/journal.ppat.1003770] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/01/2013] [Indexed: 01/13/2023] Open
Abstract
Membrane fusion is essential for entry of the biomedically-important paramyxoviruses into their host cells (viral-cell fusion), and for syncytia formation (cell-cell fusion), often induced by paramyxoviral infections [e.g. those of the deadly Nipah virus (NiV)]. For most paramyxoviruses, membrane fusion requires two viral glycoproteins. Upon receptor binding, the attachment glycoprotein (HN/H/G) triggers the fusion glycoprotein (F) to undergo conformational changes that merge viral and/or cell membranes. However, a significant knowledge gap remains on how HN/H/G couples cell receptor binding to F-triggering. Via interdisciplinary approaches we report the first comprehensive mechanism of NiV membrane fusion triggering, involving three spatiotemporally sequential cell receptor-induced conformational steps in NiV-G: two in the head and one in the stalk. Interestingly, a headless NiV-G mutant was able to trigger NiV-F, and the two head conformational steps were required for the exposure of the stalk domain. Moreover, the headless NiV-G prematurely triggered NiV-F on virions, indicating that the NiV-G head prevents premature triggering of NiV-F on virions by concealing a F-triggering stalk domain until the correct time and place: receptor-binding. Based on these and recent paramyxovirus findings, we present a comprehensive and fundamentally conserved mechanistic model of paramyxovirus membrane fusion triggering and cell entry. The medically-important Paramyxovirus family includes the deadly Nipah virus (NiV). After paramyxoviruses attach to a receptor at a cell surface, fusion between viral and cellular membranes must occur before the virus genetic material can enter the cell and replication of the virus inside the cell can begin. For most paramyxoviruses, viral/cell membrane fusion requires the concerted actions of two viral glycoproteins. After binding to a cell surface receptor, the viral attachment glycoprotein triggers the viral fusion glycoprotein to execute viral/cell membrane fusion so the genetic material of the virus can enter the cell. However, the mechanism of this receptor-induced triggering of membrane fusion is not well understood. We identified several sequential receptor-induced structural changes in the attachment glycoprotein of NiV that are part of the viral/cell membrane fusion-triggering cascade. Importantly, we propose a mechanism of cell receptor-induced paramyxovirus entry into cells, based on the findings described here, similarities between NiV and other paramyxoviruses, and other recent advances.
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Affiliation(s)
- Qian Liu
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Jacquelyn A. Stone
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Birgit Bradel-Tretheway
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Jeffrey Dabundo
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Javier A. Benavides Montano
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Departamento Ciencia Animal, Universidad Nacional de Colombia, Palmira Valle, Colombia
| | - Jennifer Santos-Montanez
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Scott B. Biering
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Anthony V. Nicola
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
| | - Ronald M. Iorio
- Department of Microbiology and Physiological Systems and Program in Immunology and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Xiaonan Lu
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hector C. Aguilar
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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Abstract
Paramyxoviruses, including the human pathogen measles virus (MV) and the avian Newcastle disease virus (NDV), enter host cells through fusion of the viral envelope with the target cell membrane. This fusion is driven by the concerted action of two viral envelope glycoproteins: the receptor binding protein and the fusion protein (F). The MV receptor binding protein (hemagglutinin [H]) attaches to proteinaceous receptors on host cells, while the receptor binding protein of NDV (hemagglutinin-neuraminidase [HN]) interacts with sialic acid-containing receptors. The receptor-bound HN/H triggers F to undergo conformational changes that render it competent to mediate fusion of the viral and cellular membranes. The mechanism of fusion activation has been proposed to be different for sialic acid-binding viruses and proteinaceous receptor-binding viruses. We report that a chimeric protein containing the NDV HN receptor binding region and the MV H stalk domain can activate MV F to fuse, suggesting that the signal to the stalk of a protein-binding receptor binding molecule can be transmitted from a sialic acid binding domain. By engineering the NDV HN globular domain to interact with a proteinaceous receptor, the fusion activation signal was preserved. Our findings are consistent with a unified mechanism of fusion activation, at least for the Paramyxovirinae subfamily, in which the receptor binding domains of the receptor binding proteins are interchangeable and the stalk determines the specificity of F activation.
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40
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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: 51] [Impact Index Per Article: 4.6] [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.
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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.
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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)
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Identification of a region in the stalk domain of the nipah virus receptor binding protein that is critical for fusion activation. J Virol 2013; 87:10980-96. [PMID: 23903846 DOI: 10.1128/jvi.01646-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paramyxoviruses, including the emerging lethal human Nipah virus (NiV) and the avian Newcastle disease virus (NDV), enter host cells through fusion of the viral and target cell membranes. For paramyxoviruses, membrane fusion is the result of the concerted action of two viral envelope glycoproteins: a receptor binding protein and a fusion protein (F). The NiV receptor binding protein (G) attaches to ephrin B2 or B3 on host cells, whereas the corresponding hemagglutinin-neuraminidase (HN) attachment protein of NDV interacts with sialic acid moieties on target cells through two regions of its globular domain. Receptor-bound G or HN via its stalk domain triggers F to undergo the conformational changes that render it competent to mediate fusion of the viral and cellular membranes. We show that chimeric proteins containing the NDV HN receptor binding regions and the NiV G stalk domain require a specific sequence at the connection between the head and the stalk to activate NiV F for fusion. Our findings are consistent with a general mechanism of paramyxovirus fusion activation in which the stalk domain of the receptor binding protein is responsible for F activation and a specific connecting region between the receptor binding globular head and the fusion-activating stalk domain is required for transmitting the fusion signal.
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43
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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.
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Abstract
Nipah (NiV) and Hendra (HeV) viruses are the deadliest human pathogens within the Paramyxoviridae family, which include human and animal pathogens of global biomedical importance. NiV and HeV infections cause respiratory and encephalitic illness with high mortality rates in humans. Henipaviruses (HNV) are the only Paramyxoviruses classified as biosafety level 4 (BSL4) pathogens due to their extreme pathogenicity, potential for bioterrorism, and lack of licensed vaccines and therapeutics. HNV use ephrin-B2 and ephrin-B3, highly conserved proteins, as viral entry receptors. This likely accounts for their unusually broad species tropism, and also provides opportunities to study how receptor usage, cellular tropism, and end-organ pathology relates to the pathobiology of HNV infections. The clinical and pathologic manifestations of NiV and HeV virus infections are reviewed in the chapters by Wong et al. and Geisbert et al. in this issue. Here, we will review the biology of the HNV receptors, and how receptor usage relates to HNV cell tropism in vitro and in vivo.
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Affiliation(s)
- Olivier Pernet
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1489, USA
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Individual N-glycans added at intervals along the stalk of the Nipah virus G protein prevent fusion but do not block the interaction with the homologous F protein. J Virol 2013; 87:3119-29. [PMID: 23283956 DOI: 10.1128/jvi.03084-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The promotion of membrane fusion by most paramyxoviruses requires an interaction between the viral attachment and fusion (F) proteins to enable receptor binding by the former to trigger the activation of the latter for fusion. Numerous studies demonstrate that the F-interactive sites on the Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) and measles virus (MV) hemagglutinin (H) proteins reside entirely within the stalk regions of those proteins. Indeed, stalk residues of NDV HN and MV H that likely mediate the F interaction have been identified. However, despite extensive efforts, the F-interactive site(s) on the Nipah virus (NiV) G attachment glycoprotein has not been identified. In this study, we have introduced individual N-linked glycosylation sites at several positions spaced at intervals along the stalk of the NiV G protein. Five of the seven introduced sites are utilized as established by a retardation of electrophoretic mobility. Despite surface expression, ephrinB2 binding, and oligomerization comparable to those of the wild-type protein, four of the five added N-glycans completely eliminate the ability of the G protein to complement the homologous F protein in the promotion of fusion. The most membrane-proximal added N-glycan reduces fusion by 80%. However, unlike similar NDV HN and MV H mutants, the NiV G glycosylation stalk mutants retain the ability to bind F, indicating that the fusion deficiency of these mutants is not due to prevention of the G-F interaction. These findings suggest that the G-F interaction is not mediated entirely by the stalk domain of G and may be more complex than that of HN/H-F.
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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.
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N-Glycans on the Nipah virus attachment glycoprotein modulate fusion and viral entry as they protect against antibody neutralization. J Virol 2012; 86:11991-2002. [PMID: 22915812 DOI: 10.1128/jvi.01304-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nipah virus (NiV) is the deadliest known paramyxovirus. Membrane fusion is essential for NiV entry into host cells and for the virus' pathological induction of cell-cell fusion (syncytia). The mechanism by which the attachment glycoprotein (G), upon binding to the cell receptors ephrinB2 or ephrinB3, triggers the fusion glycoprotein (F) to execute membrane fusion is largely unknown. N-glycans on paramyxovirus glycoproteins are generally required for proper protein conformational integrity, transport, and sometimes biological functions. We made conservative mutations (Asn to Gln) at the seven potential N-glycosylation sites in the NiV G ectodomain (G1 to G7) individually or in combination. Six of the seven N-glycosylation sites were found to be glycosylated. Moreover, pseudotyped virions carrying these N-glycan mutants had increased antibody neutralization sensitivities. Interestingly, our results revealed hyperfusogenic and hypofusogenic phenotypes for mutants that bound ephrinB2 at wild-type levels, and the mutant's cell-cell fusion phenotypes generally correlated to viral entry levels. In addition, when removing multiple N-glycans simultaneously, we observed synergistic or dominant-negative membrane fusion phenotypes. Interestingly, our data indicated that 4- to 6-fold increases in fusogenicity resulted from multiple mechanisms, including but not restricted to the increase of F triggering. Altogether, our results suggest that NiV-G N-glycans play a role in shielding virions against antibody neutralization, while modulating cell-cell fusion and viral entry via multiple mechanisms.
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