101
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Genomic and structural investigation on dolphin morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus). Sci Rep 2017; 7:41554. [PMID: 28134317 PMCID: PMC5278511 DOI: 10.1038/srep41554] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/21/2016] [Indexed: 01/22/2023] Open
Abstract
Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990–‘92 and the 2006–‘08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells.
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102
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Hashiguchi T. [Molecular basis for negative-strand RNA virus entry and neutralization by antibodies]. Uirusu 2017; 67:69-78. [PMID: 29593155 DOI: 10.2222/jsv.67.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mononegaviruses are non-segmented negative-strand RNA viruses, and include measles, mumps, Marburg, and Ebola viruses. Measles virus and mumps virus, members of the family Paramyxoviridae, are immunotropic and neurotropic, respectively. Marburg virus and Ebola virus, members of the family Filoviridae, cause highly lethal hemorrhagic fever. In this paper, I summarize the recent structural and functional studies on the viral glycoproteins (GPs) of these viruses, which have shed light on virus entry and the humoral response. The structural and functional analyses of the interaction between viral GPs and receptors/antibodies also illuminate directions toward therapeutics against the viruses.
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Affiliation(s)
- Takao Hashiguchi
- Affiliation; Department of Virology, Faculty of medicine, Kyushu University
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103
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Tahara M, Takeda M. [Measles Virus]. Uirusu 2017; 67:3-16. [PMID: 29593149 DOI: 10.2222/jsv.67.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Measles virus (MeV) is exceptionally contagious and still a major cause of death in child.However, recently significant progress towards the elimination of measles has been made through increased vaccination coverage of measles-containing vaccines. The hemagglutinin (H) protein of MeV interacts with a cellular receptor, and this interaction is the first step of infection. MeV uses two different receptors, signaling lymphocyte activation molecule (SLAM) and nectin-4 expressed on immune cells and epithelial cells, respectively. The interactions of MeV with these receptors nicely explain the immune suppressive and high contagious properties of MeV. Binding of the H protein to a receptor triggers conformational changes in the fusion (F) protein, inducing fusion between viral and host plasma membranes for entry. The stalk region of the H protein plays a key role in the F protein-triggering. Recent studies of the H protein epitopes have revealed that the receptor binding site of the H protein constitutes a major neutralizing epitope. The interaction with two proteinaceous receptors probably imposes strong functional constraints on this epitope for amino acid changes. This would be a reason why measles vaccines, which are derived from MV strains isolated more than 60 years ago, are still highly effective against all MV strains currently circulating.
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Affiliation(s)
- Maino Tahara
- Department of Virology III, National Institute of Infectious Diseases
| | - Makoto Takeda
- Department of Virology III, National Institute of Infectious Diseases
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104
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Morbillivirus Experimental Animal Models: Measles Virus Pathogenesis Insights from Canine Distemper Virus. Viruses 2016; 8:v8100274. [PMID: 27727184 PMCID: PMC5086610 DOI: 10.3390/v8100274] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 12/19/2022] Open
Abstract
Morbilliviruses share considerable structural and functional similarities. Even though disease severity varies among the respective host species, the underlying pathogenesis and the clinical signs are comparable. Thus, insights gained with one morbillivirus often apply to the other members of the genus. Since the Canine distemper virus (CDV) causes severe and often lethal disease in dogs and ferrets, it is an attractive model to characterize morbillivirus pathogenesis mechanisms and to evaluate the efficacy of new prophylactic and therapeutic approaches. This review compares the cellular tropism, pathogenesis, mechanisms of persistence and immunosuppression of the Measles virus (MeV) and CDV. It then summarizes the contributions made by studies on the CDV in dogs and ferrets to our understanding of MeV pathogenesis and to vaccine and drugs development.
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105
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Trisaccharide containing α2,3-linked sialic acid is a receptor for mumps virus. Proc Natl Acad Sci U S A 2016; 113:11579-11584. [PMID: 27671656 DOI: 10.1073/pnas.1608383113] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mumps virus (MuV) remains an important pathogen worldwide, causing epidemic parotitis, orchitis, meningitis, and encephalitis. Here we show that MuV preferentially uses a trisaccharide containing α2,3-linked sialic acid in unbranched sugar chains as a receptor. Crystal structures of the MuV attachment protein hemagglutinin-neuraminidase (MuV-HN) alone and in complex with the α2,3-sialylated trisaccharide revealed that in addition to the interaction between the MuV-HN active site residues and sialic acid, other residues, including an aromatic residue, stabilize the third sugar of the trisaccharide. The importance of the aromatic residue and the third sugar in the MuV-HN-receptor interaction was confirmed by computational energy calculations, isothermal titration calorimetry studies, and glycan-binding assays. Furthermore, MuV-HN was found to bind more efficiently to unbranched α2,3-sialylated sugar chains compared with branched ones. Importantly, the strategically located aromatic residue is conserved among the HN proteins of sialic acid-using paramyxoviruses, and alanine substitution compromised their ability to support cell-cell fusion. These results suggest that not only the terminal sialic acid but also the adjacent sugar moiety contribute to receptor function for mumps and these paramyxoviruses. The distribution of structurally different sialylated glycans in tissues and organs may explain in part MuV's distinct tropism to glandular tissues and the central nervous system. In the crystal structure, the epitopes for neutralizing antibodies are located around the α-helices of MuV-HN that are not well conserved in amino acid sequences among different genotypes of MuV. This may explain the fact that MuV reinfection sometimes occurs.
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106
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Lin LT, Richardson CD. The Host Cell Receptors for Measles Virus and Their Interaction with the Viral Hemagglutinin (H) Protein. Viruses 2016; 8:v8090250. [PMID: 27657109 PMCID: PMC5035964 DOI: 10.3390/v8090250] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/29/2016] [Accepted: 09/02/2016] [Indexed: 12/14/2022] Open
Abstract
The hemagglutinin (H) protein of measles virus (MeV) interacts with a cellular receptor which constitutes the initial stage of infection. Binding of H to this host cell receptor subsequently triggers the F protein to activate fusion between virus and host plasma membranes. The search for MeV receptors began with vaccine/laboratory virus strains and evolved to more relevant receptors used by wild-type MeV. Vaccine or laboratory strains of measles virus have been adapted to grow in common cell lines such as Vero and HeLa cells, and were found to use membrane cofactor protein (CD46) as a receptor. CD46 is a regulator that normally prevents cells from complement-mediated self-destruction, and is found on the surface of all human cells, with the exception of erythrocytes. Mutations in the H protein, which occur during adaptation and allow the virus to use CD46 as a receptor, have been identified. Wild-type isolates of measles virus cannot use the CD46 receptor. However, both vaccine/laboratory and wild-type strains can use an immune cell receptor called signaling lymphocyte activation molecule family member 1 (SLAMF1; also called CD150) and a recently discovered epithelial receptor known as Nectin-4. SLAMF1 is found on activated B, T, dendritic, and monocyte cells, and is the initial target for infections by measles virus. Nectin-4 is an adherens junction protein found at the basal surfaces of many polarized epithelial cells, including those of the airways. It is also over-expressed on the apical and basal surfaces of many adenocarcinomas, and is a cancer marker for metastasis and tumor survival. Nectin-4 is a secondary exit receptor which allows measles virus to replicate and amplify in the airways, where the virus is expelled from the body in aerosol droplets. The amino acid residues of H protein that are involved in binding to each of the receptors have been identified through X-ray crystallography and site-specific mutagenesis. Recombinant measles “blind” to each of these receptors have been constructed, allowing the virus to selectively infect receptor specific cell lines. Finally, the observations that SLAMF1 is found on lymphomas and that Nectin-4 is expressed on the cell surfaces of many adenocarcinomas highlight the potential of measles virus for oncolytic therapy. Although CD46 is also upregulated on many tumors, it is less useful as a target for cancer therapy, since normal human cells express this protein on their surfaces.
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Affiliation(s)
- Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
| | - Christopher D Richardson
- Department of Microbiology and Immunology, Dalhousie University, 5850 College St., Halifax, NS B3H 4R2, Canada.
- Department of Pediatrics and Canadian Center for Vaccinology, Izaak Walton Killam Health Centre, Halifax, NS B3K 6R8, Canada.
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107
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Measles Virus Hemagglutinin Protein Epitopes: The Basis of Antigenic Stability. Viruses 2016; 8:v8080216. [PMID: 27490564 PMCID: PMC4997578 DOI: 10.3390/v8080216] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/19/2016] [Accepted: 07/20/2016] [Indexed: 02/07/2023] Open
Abstract
Globally eliminating measles using available vaccines is biologically feasible because the measles virus (MV) hemagglutinin (H) protein is antigenically stable. The H protein is responsible for receptor binding, and is the main target of neutralizing antibodies. The immunodominant epitope, known as the hemagglutinating and noose epitope, is located near the receptor-binding site (RBS). The RBS also contains an immunodominant epitope. Loss of receptor binding correlates with an escape from the neutralization by antibodies that target the epitope at RBS. Another neutralizing epitope is located near RBS and is shielded by an N-linked sugar in certain genotype strains. However, human sera from vaccinees and measles patients neutralized all MV strains with similar efficiencies, regardless of the N-linked sugar modification or mutations at these epitopes. Two other major epitopes exist at a distance from RBS. One has an unstructured flexible domain with a linear neutralizing epitope. When MV-H forms a tetramer (dimer of dimers), these epitopes may form the dimer-dimer interface, and one of the two epitopes may also interact with the F protein. The neutralization mechanisms of antibodies that recognize these epitopes may involve inhibiting the H-F interaction or blocking the fusion cascade after MV-H binds to its receptors.
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108
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Abstract
Measles is an infectious disease in humans caused by the measles virus (MeV). Before the introduction of an effective measles vaccine, virtually everyone experienced measles during childhood. Symptoms of measles include fever and maculopapular skin rash accompanied by cough, coryza and/or conjunctivitis. MeV causes immunosuppression, and severe sequelae of measles include pneumonia, gastroenteritis, blindness, measles inclusion body encephalitis and subacute sclerosing panencephalitis. Case confirmation depends on clinical presentation and results of laboratory tests, including the detection of anti-MeV IgM antibodies and/or viral RNA. All current measles vaccines contain a live attenuated strain of MeV, and great progress has been made to increase global vaccination coverage to drive down the incidence of measles. However, endemic transmission continues in many parts of the world. Measles remains a considerable cause of childhood mortality worldwide, with estimates that >100,000 fatal cases occur each year. Case fatality ratio estimates vary from <0.01% in industrialized countries to >5% in developing countries. All six WHO regions have set goals to eliminate endemic transmission of MeV by achieving and maintaining high levels of vaccination coverage accompanied by a sensitive surveillance system. Because of the availability of a highly effective and relatively inexpensive vaccine, the monotypic nature of the virus and the lack of an animal reservoir, measles is considered a candidate for eradication.
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109
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Abstract
The family Paramyxoviridae includes many viruses that significantly affect human and animal health. An essential step in the paramyxovirus life cycle is viral entry into host cells, mediated by virus-cell membrane fusion. Upon viral entry, infection results in expression of the paramyxoviral glycoproteins on the infected cell surface. This can lead to cell-cell fusion (syncytia formation), often linked to pathogenesis. Thus membrane fusion is essential for both viral entry and cell-cell fusion and an attractive target for therapeutic development. While there are important differences between viral-cell and cell-cell membrane fusion, many aspects are conserved. The paramyxoviruses generally utilize two envelope glycoproteins to orchestrate membrane fusion. Here, we discuss the roles of these glycoproteins in distinct steps of the membrane fusion process. These findings can offer insights into evolutionary relationships among Paramyxoviridae genera and offer future targets for prophylactic and therapeutic development.
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110
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Shirogane Y, Watanabe S, Yanagi Y. Cooperative Interaction Within RNA Virus Mutant Spectra. Curr Top Microbiol Immunol 2016; 392:219-29. [PMID: 26162566 DOI: 10.1007/82_2015_461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RNA viruses usually consist of mutant spectra because of high error rates of viral RNA polymerases. Growth competition occurs among different viral variants, and the fittest clones predominate under given conditions. Individual variants, however, may not be entirely independent of each other, and internal interactions within mutant spectra can occur. Examples of cooperative and interfering interactions that exert enhancing and suppressing effects on replication of the wild-type virus, respectively, have been described, but their underlying mechanisms have not been well defined. It was recently found that the cooperation between wild-type and variant measles virus genomes produces a new phenotype through the heterooligomer formation of a viral protein. This observation provides a molecular mechanism underlying cooperative interactions within mutant spectra. Careful attention to individual sequences, in addition to consensus sequences, may disclose further examples of internal interactions within mutant spectra.
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Affiliation(s)
- Yuta Shirogane
- Department of Virology, Faculty of Medicine, Kyushu University, Fukuoka, 812-8582, Japan
| | - Shumpei Watanabe
- Department of Virology, Faculty of Medicine, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yusuke Yanagi
- Department of Virology, Faculty of Medicine, Kyushu University, Fukuoka, 812-8582, Japan.
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111
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Measles Virus Fusion Protein: Structure, Function and Inhibition. Viruses 2016; 8:112. [PMID: 27110811 PMCID: PMC4848605 DOI: 10.3390/v8040112] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 03/26/2016] [Accepted: 04/14/2016] [Indexed: 01/02/2023] Open
Abstract
Measles virus (MeV), a highly contagious member of the Paramyxoviridae family, causes measles in humans. The Paramyxoviridae family of negative single-stranded enveloped viruses includes several important human and animal pathogens, with MeV causing approximately 120,000 deaths annually. MeV and canine distemper virus (CDV)-mediated diseases can be prevented by vaccination. However, sub-optimal vaccine delivery continues to foster MeV outbreaks. Post-exposure prophylaxis with antivirals has been proposed as a novel strategy to complement vaccination programs by filling herd immunity gaps. Recent research has shown that membrane fusion induced by the morbillivirus glycoproteins is the first critical step for viral entry and infection, and determines cell pathology and disease outcome. Our molecular understanding of morbillivirus-associated membrane fusion has greatly progressed towards the feasibility to control this process by treating the fusion glycoprotein with inhibitory molecules. Current approaches to develop anti-membrane fusion drugs and our knowledge on drug resistance mechanisms strongly suggest that combined therapies will be a prerequisite. Thus, discovery of additional anti-fusion and/or anti-attachment protein small-molecule compounds may eventually translate into realistic therapeutic options.
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112
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Liang Z, Yuan R, Chen L, Zhu X, Dou Y. Molecular Evolution and Characterization of Hemagglutinin (H) in Peste des Petits Ruminants Virus. PLoS One 2016; 11:e0152587. [PMID: 27035347 PMCID: PMC4818033 DOI: 10.1371/journal.pone.0152587] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 11/24/2022] Open
Abstract
Peste des Petits Ruminants (PPR) is an acute, highly contagious, and febrile viral disease that affects both domestic and wild small ruminants. The disease has become a major obstacle to the development of sustainable Agriculture. Hemagglutinin (H), the envelope glycoprotein of Peste des Petits Ruminants Virus (PPRV), plays a crucial role in regulating viral adsorption and entry, thus determining pathogenicity, and release of newly produced viral particles. In order to accurately understand the epidemic of the disease and the interactions between the virus and host, we launch the work. Here, we examined H gene from all four lineages of the PPRV to investigate evolutionary and epidemiologic dynamics of PPRV by the Bayesian method. In addition, we predicted positive selection sites due to selective pressures. Finally, we studied the interaction between H protein and SLAM receptor based on homology model of the complex. Phylogenetic analysis suggested that H gene can also be used to investigate evolutionary and epidemiologic dynamics of PPRV. Positive selection analysis identified four positive selection sites in H gene, in which only one common site (aa246) was detected by two methods, suggesting strong operation structural and/or functional constraint of changes on the H protein. This target site may be of interest for future mutagenesis studies. The results of homology modeling showed PPRVHv-shSLAM binding interface and MVH-maSLAM binding interface were consistent, wherein the groove in the B4 blade and B5 of the head domain of PPRVHv bound to the AGFCC′ β-sheets of the membrane-distal ectodomain of shSLAM. The binding regions could provide insight on the nature of the protein for epitope vaccine design, novel drug discovery, and rational drug design against PPRV.
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Affiliation(s)
- Zhongxiang Liang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Ruyi Yuan
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Lei Chen
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Xueliang Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
| | - Yongxi Dou
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Epizootic Diseases of Grazing Animals of Ministry of Agriculture, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, Gansu, China
- * E-mail:
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113
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van Driel BJ, Liao G, Engel P, Terhorst C. Responses to Microbial Challenges by SLAMF Receptors. Front Immunol 2016; 7:4. [PMID: 26834746 PMCID: PMC4718992 DOI: 10.3389/fimmu.2016.00004] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/06/2016] [Indexed: 12/24/2022] Open
Abstract
The SLAMF family (SLAMF) of cell surface glycoproteins is comprised of nine glycoproteins and while SLAMF1, 3, 5, 6, 7, 8, and 9 are self-ligand receptors, SLAMF2 and SLAMF4 interact with each other. Their interactions induce signal transduction networks in trans, thereby shaping immune cell-cell communications. Collectively, these receptors modulate a wide range of functions, such as myeloid cell and lymphocyte development, and T and B cell responses to microbes and parasites. In addition, several SLAMF receptors serve as microbial sensors, which either positively or negatively modulate the function of macrophages, dendritic cells, neutrophils, and NK cells in response to microbial challenges. The SLAMF receptor-microbe interactions contribute both to intracellular microbicidal activity as well as to migration of phagocytes to the site of inflammation. In this review, we describe the current knowledge on how the SLAMF receptors and their specific adapters SLAM-associated protein and EAT-2 regulate innate and adaptive immune responses to microbes.
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Affiliation(s)
- Boaz Job van Driel
- Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, MA , USA
| | - Gongxian Liao
- Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, MA , USA
| | - Pablo Engel
- Immunology Unit, Department of Cell Biology, Immunology and Neurosciences, Medical School, University of Barcelona , Barcelona , Spain
| | - Cox Terhorst
- Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, MA , USA
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114
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Abstract
Peste des petits ruminants virus (PPRV) causes a severe contagious disease of sheep and goats and has spread extensively through the developing world. Because of its disproportionately large impact on the livelihoods of low-income livestock keepers, and the availability of effective vaccines and good diagnostics, the virus is being targeted for global control and eventual eradication. In this review we examine the origin of the virus and its current distribution, and the factors that have led international organizations to conclude that it is eradicable. We also review recent progress in the molecular and cellular biology of the virus and consider areas where further research is required to support the efforts being made by national, regional, and international bodies to tackle this growing threat.
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Affiliation(s)
- M D Baron
- The Pirbright Institute, Surrey, United Kingdom.
| | - A Diallo
- CIRAD, UMR Contrôle des maladies animales exotiques et émergentes (CMAEE), Montpellier, France; INRA, UMR CMAEE 1309, Montpellier, France
| | - R Lancelot
- CIRAD, UMR Contrôle des maladies animales exotiques et émergentes (CMAEE), Montpellier, France; INRA, UMR CMAEE 1309, Montpellier, France
| | - G Libeau
- CIRAD, UMR Contrôle des maladies animales exotiques et émergentes (CMAEE), Montpellier, France; INRA, UMR CMAEE 1309, Montpellier, France
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115
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Canine Distemper Virus Fusion Activation: Critical Role of Residue E123 of CD150/SLAM. J Virol 2015; 90:1622-37. [PMID: 26608324 DOI: 10.1128/jvi.02405-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/18/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Measles virus (MeV) and canine distemper virus (CDV) possess tetrameric attachment proteins (H) and trimeric fusion proteins, which cooperate with either SLAM or nectin 4 receptors to trigger membrane fusion for cell entry. While the MeV H-SLAM cocrystal structure revealed the binding interface, two distinct oligomeric H assemblies were also determined. In one of the conformations, two SLAM units were sandwiched between two discrete H head domains, thus spotlighting two binding interfaces ("front" and "back"). Here, we investigated the functional relevance of both interfaces in activating the CDV membrane fusion machinery. While alanine-scanning mutagenesis identified five critical regulatory residues in the front H-binding site of SLAM, the replacement of a conserved glutamate residue (E at position 123, replaced with A [E123A]) led to the most pronounced impact on fusion promotion. Intriguingly, while determination of the interaction of H with the receptor using soluble constructs revealed reduced binding for the identified SLAM mutants, no effect was recorded when physical interaction was investigated with the full-length counterparts of both molecules. Conversely, although mutagenesis of three strategically selected residues within the back H-binding site of SLAM did not substantially affect fusion triggering, nevertheless, the mutants weakened the H-SLAM interaction recorded with the membrane-anchored protein constructs. Collectively, our findings support a mode of binding between the attachment protein and the V domain of SLAM that is common to all morbilliviruses and suggest a major role of the SLAM residue E123, located at the front H-binding site, in triggering the fusion machinery. However, our data additionally support the hypothesis that other microdomain(s) of both glycoproteins (including the back H-binding site) might be required to achieve fully productive H-SLAM interactions. IMPORTANCE A complete understanding of the measles virus and canine distemper virus (CDV) cell entry molecular framework is still lacking, thus impeding the rational design of antivirals. Both viruses share many biological features that partially rely on the use of analogous Ig-like host cell receptors, namely, SLAM and nectin 4, for entering immune and epithelial cells, respectively. Here, we provide evidence that the mode of binding between the membrane-distal V domain of SLAM and the attachment protein (H) of morbilliviruses is very likely conserved. Moreover, although structural information revealed two discrete conformational states of H, one of the structures displayed two H-SLAM binding interfaces ("front" and "back"). Our data not only spotlight the front H-binding site of SLAM as the main determinant of membrane fusion promotion but suggest that the triggering efficiency of the viral entry machinery may rely on a local conformational change within the front H-SLAM interactive site rather than the binding affinity.
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116
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A Structurally Unresolved Head Segment of Defined Length Favors Proper Measles Virus Hemagglutinin Tetramerization and Efficient Membrane Fusion Triggering. J Virol 2015; 90:68-75. [PMID: 26446605 DOI: 10.1128/jvi.02253-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/05/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Paramyxoviruses include several insidious and ubiquitous pathogens of humans and animals, with measles virus (MeV) being a prominent one. The MeV membrane fusion apparatus consists of a receptor binding protein (hemagglutinin [H]) tetramer and a fusion (F) protein trimer. Four globular MeV H heads are connected to a tetrameric stalk through flexible linkers. We sought here to characterize the function of a 17-residue H-head segment proximal to the stalk that was unresolved in all five MeV H-head crystal or cocrystal structures. In particular, we assessed whether its primary sequence and length are critical for proper protein oligomerization and intracellular transport or for membrane fusion triggering. Extensive alanine substitutions had no effect on fusion triggering, suggesting that sequence identity is not critical for this function. Excessive shortening of this segment reduced or completely abrogated fusion trigger function, while length compensation restored it. We then characterized the mechanism of function loss. Mutated H proteins were efficiently transported to the cell surface, but certain alterations enhancing linker flexibility resulted in accumulation of high-molecular-weight H oligomers. Some oligomers had reduced fusion trigger capacity, while others retained this function. Thus, length and rigidity of the unresolved head segment favor proper H tetramerization and counteract interactions between subunits from different tetramers. The structurally unresolved H-head segment, together with the top of the stalk, may act as a leash to provide the right degree of freedom for the heads of individual tetramers to adopt a triggering-permissive conformation while avoiding improper contacts with heads of neighboring tetramers. IMPORTANCE Understanding the molecular mechanism of membrane fusion triggering may allow development of new antiviral strategies. The fusion apparatus of paramyxoviruses consists of a receptor binding tetramer and a fusion protein trimer. Structural analyses of the receptor binding hemagglutinin-neuraminidases of certain paramyxoviruses suggest that fusion triggering is preceded by relocation of its head domains, facilitated by flexible linkers. Having noted a structurally unresolved 17-residue segment linking the globular heads to the tetrameric stalk of the measles virus hemagglutinin (H), we asked whether and how it may facilitate membrane fusion triggering. We conclude that, together with the top of the stalk, the flexible linker keeps H heads on a leash long enough to adopt a triggering-permissive conformation but short enough to limit roaming and improper contacts with heads of neighboring tetramers. All morbillivirus H-protein heads appear to be connected to their stalks through a "leash," suggesting a conserved triggering mechanism.
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117
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Kimura H, Saitoh M, Kobayashi M, Ishii H, Saraya T, Kurai D, Tsukagoshi H, Shirabe K, Nishina A, Kozawa K, Kuroda M, Takeuchi F, Sekizuka T, Minakami H, Ryo A, Takeda M. Molecular evolution of haemagglutinin (H) gene in measles virus. Sci Rep 2015; 5:11648. [PMID: 26130388 PMCID: PMC4486977 DOI: 10.1038/srep11648] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/27/2015] [Indexed: 11/30/2022] Open
Abstract
We studied the molecular evolution of the haemagglutinin (H) gene (full length) in all genotypes (24 genotypes, 297 strains) of measles virus (MeV). The gene’s evolutionary timescale was estimated by the Bayesian Markov chain Monte Carlo (MCMC) method. We also analysed positive selection sites. The MCMC tree indicated that the MeV H gene diverged from the rinderpest virus (same genus) about 250 years ago and that 24 MeV genotypes formed 3 lineages dating back to a 1915 ancestor (95% highest posterior density [HPD] 1882–1941) with relatively rapid evolution (mean rate: 9.02 × 10−4 substitutions/site/year). The 3 lineages diverged in 1915 (lineage 1, 95% HPD 1882–1941), 1954 (lineage 2, 95% HPD 1937–1969), and 1940 (lineage 3, 95% HPD 1927–1952). These 24 genotypes may have diverged and emerged between the 1940s and 1990s. Selective pressure analysis identified many negative selection sites on the H protein but only a few positive selection sites, suggesting strongly operated structural and/or functional constraint of changes on the H protein. Based on the molecular evolution of H gene, an ancestor MeV of the 24 genotypes emerged about 100 years ago and the structure of H protein has been well conserved.
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Affiliation(s)
- Hirokazu Kimura
- Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan.,Department of Molecular Biodefence Research, Yokohama City University Graduate School of Medicine, Yokohama-shi, Kanagawa 236-0004, Japan
| | - Mika Saitoh
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Maebashi-shi, Gunma 371-0052, Japan
| | - Miho Kobayashi
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Maebashi-shi, Gunma 371-0052, Japan
| | - Haruyuki Ishii
- Department of Respiratory Medicine, Kyorin University, School of Medicine, Mitaka-shi, Tokyo 181-0004, Japan
| | - Takeshi Saraya
- Department of Respiratory Medicine, Kyorin University, School of Medicine, Mitaka-shi, Tokyo 181-0004, Japan
| | - Daisuke Kurai
- Department of Respiratory Medicine, Kyorin University, School of Medicine, Mitaka-shi, Tokyo 181-0004, Japan
| | - Hiroyuki Tsukagoshi
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Maebashi-shi, Gunma 371-0052, Japan
| | - Komei Shirabe
- Yamaguchi Prefectural Institute of Public Health and Environment, Yamaguchi-shi, Yamaguchi 753-0821, Japan
| | - Atsuyoshi Nishina
- College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan
| | - Kunihisa Kozawa
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Maebashi-shi, Gunma 371-0052, Japan
| | - Makoto Kuroda
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Fumihiko Takeuchi
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Tsuyoshi Sekizuka
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Hisanori Minakami
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo-shi, Hokkaido 060-8638, Japan
| | - Akihide Ryo
- Department of Molecular Biodefence Research, Yokohama City University Graduate School of Medicine, Yokohama-shi, Kanagawa 236-0004, Japan
| | - Makoto Takeda
- Department of Virology III, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan
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Ader-Ebert N, Khosravi M, Herren M, Avila M, Alves L, Bringolf F, Örvell C, Langedijk JP, Zurbriggen A, Plemper RK, Plattet P. Sequential conformational changes in the morbillivirus attachment protein initiate the membrane fusion process. PLoS Pathog 2015; 11:e1004880. [PMID: 25946112 PMCID: PMC4422687 DOI: 10.1371/journal.ppat.1004880] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/14/2015] [Indexed: 11/18/2022] Open
Abstract
Despite large vaccination campaigns, measles virus (MeV) and canine distemper virus (CDV) cause major morbidity and mortality in humans and animals, respectively. The MeV and CDV cell entry system relies on two interacting envelope glycoproteins: the attachment protein (H), consisting of stalk and head domains, co-operates with the fusion protein (F) to mediate membrane fusion. However, how receptor-binding by the H-protein leads to F-triggering is not fully understood. Here, we report that an anti-CDV-H monoclonal antibody (mAb-1347), which targets the linear H-stalk segment 126-133, potently inhibits membrane fusion without interfering with H receptor-binding or F-interaction. Rather, mAb-1347 blocked the F-triggering function of H-proteins regardless of the presence or absence of the head domains. Remarkably, mAb-1347 binding to headless CDV H, as well as standard and engineered bioactive stalk-elongated CDV H-constructs treated with cells expressing the SLAM receptor, was enhanced. Despite proper cell surface expression, fusion promotion by most H-stalk mutants harboring alanine substitutions in the 126-138 "spacer" section was substantially impaired, consistent with deficient receptor-induced mAb-1347 binding enhancement. However, a previously reported F-triggering defective H-I98A variant still exhibited the receptor-induced "head-stalk" rearrangement. Collectively, our data spotlight a distinct mechanism for morbillivirus membrane fusion activation: prior to receptor contact, at least one of the morbillivirus H-head domains interacts with the membrane-distal "spacer" domain in the H-stalk, leaving the F-binding site located further membrane-proximal in the stalk fully accessible. This "head-to-spacer" interaction conformationally stabilizes H in an auto-repressed state, which enables intracellular H-stalk/F engagement while preventing the inherent H-stalk's bioactivity that may prematurely activate F. Receptor-contact disrupts the "head-to-spacer" interaction, which subsequently "unlocks" the stalk, allowing it to rearrange and trigger F. Overall, our study reveals essential mechanistic requirements governing the activation of the morbillivirus membrane fusion cascade and spotlights the H-stalk "spacer" microdomain as a possible drug target for antiviral therapy.
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Affiliation(s)
- Nadine Ader-Ebert
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Mojtaba Khosravi
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Michael Herren
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Mislay Avila
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Lisa Alves
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Fanny Bringolf
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Claes Örvell
- Division of Laboratory Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | | | - Andreas Zurbriggen
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Richard K. Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
| | - Philippe Plattet
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health (DCR-VPH), Vetsuisse Faculty, University of Bern, Bern, Switzerland
- * E-mail:
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119
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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: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 01/21/2015] [Accepted: 02/18/2015] [Indexed: 11/30/2022]
Abstract
The Paramyxoviridae include some of the great and ubiquitous disease-causing viruses of humans and animals. In most paramyxoviruses, two viral membrane glycoproteins, fusion protein (F) and receptor binding protein (HN, H or G) mediate a concerted process of recognition of host cell surface molecules followed by fusion of viral and cellular membranes, resulting in viral nucleocapsid entry into the cytoplasm. The interactions between the F and HN, H or G viral glycoproteins and host molecules are critical in determining host range, virulence and spread of these viruses. Recently, atomic structures, together with biochemical and biophysical studies, have provided major insights into how these two viral glycoproteins successfully interact with host receptors on cellular membranes and initiate the membrane fusion process to gain entry into cells. These studies highlight the conserved core mechanisms of paramyxovirus entry that provide the fundamental basis for rational anti-viral drug design and vaccine development. New structural and functional insights into paramyxovirus entry mechanisms. Current data on paramyxovirus glycoproteins suggest a core conserved entry mechanism. Diverse mechanisms preventing premature fusion activation exist in these viruses. Precise spacio-temporal interplay between paramyxovirus glycoproteins initiate entry.
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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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120
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Maturation of human herpesvirus 6A glycoprotein O requires coexpression of glycoprotein H and glycoprotein L. J Virol 2015; 89:5159-63. [PMID: 25694589 DOI: 10.1128/jvi.00140-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 02/09/2015] [Indexed: 01/19/2023] Open
Abstract
Glycoprotein O (gO) is conserved among betaherpesviruses, but little is known about the maturation process of gO in human herpesvirus 6 (HHV-6). We found that HHV-6 gO maturation was accompanied by cleavage of its carboxyl terminus and required coexpression of gH and gL, which promoted the export of gO out of the endoplasmic reticulum (ER). Finally, we also found that gO was not required for HHV-6A growth in T cells.
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121
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Abstract
UNLABELLED Paramyxoviruses, including the human pathogen measles virus (MV), enter host cells by fusing their viral envelope with the target cell membrane. This fusion process is driven by the concerted actions of the two viral envelope glycoproteins, the receptor binding protein (hemagglutinin [H]) and the fusion (F) protein. H attaches to specific proteinaceous receptors on host cells; once the receptor engages, H activates F to directly mediate lipid bilayer fusion during entry. In a recent MV outbreak in South Africa, several HIV-positive people died of MV central nervous system (CNS) infection. We analyzed the virus sequences from these patients and found that specific intrahost evolution of the F protein had occurred and resulted in viruses that are "CNS adapted." A mutation in F of the CNS-adapted virus (a leucine-to-tryptophan change present at position 454) allows it to promote fusion with less dependence on engagement of H by the two known wild-type (wt) MV cellular receptors. This F protein is activated independently of H or the receptor and has reduced thermal stability and increased fusion activity compared to those of the corresponding wt F. These functional effects are the result of the single L454W mutation in F. We hypothesize that in the absence of effective cellular immunity, such as HIV infection, MV variants bearing altered fusion machinery that enabled efficient spread in the CNS underwent positive selection. IMPORTANCE Measles virus has become a concern in the United States and Europe due to recent outbreaks and continues to be a significant global problem. While live immunization is available, there are no effective therapies or prophylactics to combat measles infection in unprotected people. Additionally, vaccination does not adequately protect immunocompromised people, who are vulnerable to the more severe CNS manifestations of disease. We found that strains isolated from patients with measles virus infection of the CNS have fusion properties different from those of strains previously isolated from patients without CNS involvement. Specifically, the viral entry machinery is more active and the virus can spread, even in the absence of H. Our findings are consistent with an intrahost evolution of the fusion machinery that leads to neuropathogenic MV variants.
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122
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Biology of Viruses and Viral Diseases. MANDELL, DOUGLAS, AND BENNETT'S PRINCIPLES AND PRACTICE OF INFECTIOUS DISEASES 2015. [PMCID: PMC7152303 DOI: 10.1016/b978-1-4557-4801-3.00134-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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123
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Satoh Y, Hirose M, Shogaki H, Wakimoto H, Kitagawa Y, Gotoh B, Takahashi KI, Itoh M. Intramolecular complementation of measles virus fusion protein stability confers cell-cell fusion activity at 37 °C. FEBS Lett 2014; 589:152-8. [PMID: 25479085 DOI: 10.1016/j.febslet.2014.11.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 11/08/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
The fusion (F) protein of measles virus mediates membrane fusion. In this study, we investigated the molecular basis of the cell-cell fusion activity of the F protein. The N465H substitution in the heptad repeat B domain of the stalk region of the F protein eliminates this activity, but an additional mutation in the DIII domain of the head region - N183D, F217L, P219S, I225T or G240R - restores cell-cell fusion. Thermodynamically stabilized by the N465H substitution, the F protein required elevated temperature as high as 40 °C to promote cell-cell fusion, whereas all five DIII mutations caused destabilization of the F protein allowing the highest fusion activity at 30 °C. Stability complementation between the two domains conferred an efficient cell-cell fusion activity on the F protein at 37 °C.
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Affiliation(s)
- Yuto Satoh
- Division of Microbiology, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Mitsuhiro Hirose
- Division of Microbiology, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Hiroko Shogaki
- Division of Microbiology, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Hiroshi Wakimoto
- Division of Microbiology, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Yoshinori Kitagawa
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, Shiga 520-2192, Japan
| | - Bin Gotoh
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, Shiga 520-2192, Japan
| | - Ken-ichi Takahashi
- Division of Biophysics, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Masae Itoh
- Division of Microbiology, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan.
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Palgen JL, Jurgens EM, Moscona A, Porotto M, Palermo LM. Unity in diversity: shared mechanism of entry among paramyxoviruses. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 129:1-32. [PMID: 25595799 DOI: 10.1016/bs.pmbts.2014.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Paramyxoviridae family includes many viruses that are pathogenic in humans, including parainfluenza viruses, measles virus, respiratory syncytial virus, and the emerging zoonotic Henipaviruses. No effective treatments are currently available for these viruses, and there is a need for efficient antiviral therapies. Paramyxoviruses enter the target cell by binding to a cell surface receptor and then fusing the viral envelope with the target cell membrane, allowing the release of the viral genome into the cytoplasm. Blockage of these crucial steps prevents infection and disease. Binding and fusion are driven by two virus-encoded glycoproteins, the receptor-binding protein and the fusion protein, that together form the viral "fusion machinery." The development of efficient antiviral drugs requires a deeper understanding of the mechanism of action of the Paramyxoviridae fusion machinery, which is still controversial. Here, we review recent structural and functional data on these proteins and the current understanding of the mechanism of the paramyxovirus cell entry process.
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Affiliation(s)
- Jean-Louis Palgen
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA; Department of Biology, Ecole Normale Supérieure, Lyon, France
| | - Eric M Jurgens
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA
| | - Anne Moscona
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA; Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, New York, USA
| | - Matteo Porotto
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA.
| | - Laura M Palermo
- Department of Pediatrics, Weill Cornell Medical College, Cornell University, New York, USA; Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, New York, USA
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125
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Mateo M, Navaratnarajah CK, Willenbring RC, Maroun JW, Iankov I, Lopez M, Sinn PL, Cattaneo R. Different roles of the three loops forming the adhesive interface of nectin-4 in measles virus binding and cell entry, nectin-4 homodimerization, and heterodimerization with nectin-1. J Virol 2014; 88:14161-71. [PMID: 25275122 PMCID: PMC4249131 DOI: 10.1128/jvi.02379-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 09/23/2014] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Many viruses utilize cell adhesion molecules of the immunoglobulin superfamily as receptors. In particular, viruses of different classes exploit nectins. The large DNA viruses, herpes simplex and pseudorabies viruses, use ubiquitous nectins 1 and 2. The negative-strand RNA virus measles virus (MeV) uses tissue-specific nectin-4, and the positive-strand RNA virus poliovirus uses nectin-like 5 (necl-5), also known as poliovirus receptor. These viruses contact the BC, C'C", and FG loops on the upper tip of their receptor's most membrane-distal domain. This location corresponds to the newly defined canonical adhesive interface of nectins, but how viruses utilize this interface has remained unclear. Here we show that the same key residues in the BC and FG loops of nectin-4 govern binding to the MeV attachment protein hemagglutinin (H) and cell entry, nectin-4 homodimerization, and heterodimerization with nectin-1. On the other hand, residues in the C'C" loop necessary for homo- and heterotypic interactions are dispensable for MeV-induced fusion and cell entry. Remarkably, the C'C" loop governs dissociation of the nectin-4 and H ectodomains. We provide formal proof that H can interfere with the formation of stable nectin-1/nectin-4 heterodimers. Finally, while developing an alternative model to study MeV spread, we observed that polarized primary pig airway epithelial sheets cannot be infected. We show that a single amino acid variant in the BC loop of pig nectin-4 fully accounts for restricted MeV entry. Thus, the three loops forming the adhesive interface of nectin-4 have different roles in supporting MeV H association and dissociation and MeV-induced fusion. IMPORTANCE Different viruses utilize nectins as receptors. Nectins are immunoglobulin superfamily glycoproteins that mediate cell-cell adhesion in vertebrate tissues. They interact through an adhesive interface located at the top of their membrane-distal domain. How viruses utilize the three loops forming this interface has remained unclear. We demonstrate that while nectin-nectin interactions require residues in all three loops, the association of nectin-4 with the measles virus hemagglutinin requires only the BC and FG loops. However, we discovered that residues in the C'C" loop modulate the dissociation of nectin-4 from the viral hemagglutinin. Analogous mechanisms may support cell entry of other viruses that utilize nectins or other cell adhesion molecules of the immunoglobulin superfamily as receptors.
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Affiliation(s)
- Mathieu Mateo
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Robin C Willenbring
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA Virology and Gene Therapy track, Mayo Graduate School, Rochester, Minnesota, USA
| | - Justin W Maroun
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA Virology and Gene Therapy track, Mayo Graduate School, Rochester, Minnesota, USA
| | - Ianko Iankov
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Marc Lopez
- INSERM, UMR1068/CRCM, Institut Paoli-Calmettes and University of Aix-Marseille, Marseille, France
| | - Patrick L Sinn
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA Virology and Gene Therapy track, Mayo Graduate School, Rochester, Minnesota, USA
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Muñoz-Alía MÁ, Fernández-Muñoz R, Casasnovas JM, Porras-Mansilla R, Serrano-Pardo Á, Pagán I, Ordobás M, Ramírez R, Celma ML. Measles virus genetic evolution throughout an imported epidemic outbreak in a highly vaccinated population. Virus Res 2014; 196:122-7. [PMID: 25445338 DOI: 10.1016/j.virusres.2014.11.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 11/11/2014] [Accepted: 11/12/2014] [Indexed: 11/25/2022]
Abstract
Measles virus circulates endemically in African and Asian large urban populations, causing outbreaks worldwide in populations with up-to-95% immune protection. We studied the natural genetic variability of genotype B3.1 in a population with 95% vaccine coverage throughout an imported six month measles outbreak. From first pass viral isolates of 47 patients we performed direct sequencing of genomic cDNA. Whilst no variation from index case sequence occurred in the Nucleocapsid gene hyper-variable carboxy end, in the Hemagglutinin gene, main target for neutralizing antibodies, we observed gradual nucleotide divergence from index case along the outbreak (0% to 0.380%, average 0.138%) with the emergence of transient and persistent non-synonymous and synonymous mutations. Little or no variation was observed between the index and last outbreak cases in Phosphoprotein, Nucleocapsid, Matrix and Fusion genes. Most of the H non-synonymous mutations were mapped on the protein surface near antigenic and receptors binding sites. We estimated a MV-Hemagglutinin nucleotide substitution rate of 7.28 × 10-6 substitutions/site/day by a Bayesian phylogenetic analysis. The dN/dS analysis did not suggest significant immune or other selective pressures on the H gene during the outbreak. These results emphasize the usefulness of MV-H sequence analysis in measles epidemiological surveillance and elimination programs, and in detection of potentially emergence of measles virus neutralization-resistant mutants.
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Affiliation(s)
- Miguel Ángel Muñoz-Alía
- Virology Unit and National Reference Laboratory for Measles, Ramón y Cajal Hospital, Madrid, Spain
| | - Rafael Fernández-Muñoz
- Virology Unit and National Reference Laboratory for Measles, Ramón y Cajal Hospital, Madrid, Spain.
| | - José María Casasnovas
- Centro Nacional de Biotecnología, Laboratorio de Estructura de Proteínas. CSIC, Cantoblanco, Madrid, Spain
| | - Rebeca Porras-Mansilla
- Virology Unit and National Reference Laboratory for Measles, Ramón y Cajal Hospital, Madrid, Spain
| | - Ángela Serrano-Pardo
- Virology Unit and National Reference Laboratory for Measles, Ramón y Cajal Hospital, Madrid, Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and ETSI Agrónomos, Campus Montegancedo, Madrid, Spain
| | - María Ordobás
- Epidemiology Service, Madrid Health Ministry, Madrid, Spain
| | - Rosa Ramírez
- Epidemiology Service, Madrid Health Ministry, Madrid, Spain
| | - María Luisa Celma
- Virology Unit and National Reference Laboratory for Measles, Ramón y Cajal Hospital, Madrid, Spain
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127
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Measles virus glycoprotein complexes preassemble intracellularly and relax during transport to the cell surface in preparation for fusion. J Virol 2014; 89:1230-41. [PMID: 25392208 DOI: 10.1128/jvi.02754-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Measles virus (MeV), a morbillivirus within the paramyxovirus family, expresses two envelope glycoproteins. The attachment (H) protein mediates receptor binding, followed by triggering of the fusion (F) protein, which leads to merger of the viral envelope with target cell membranes. Receptor binding by members of related paramyxovirus genera rearranges the head domains of the attachment proteins, liberating an F-contact domain within the attachment protein helical stalk. However, morbillivirus glycoproteins first assemble intracellularly prior to receptor binding, raising the question of whether alternative protein-protein interfaces are involved or whether an entirely distinct triggering principle is employed. To test these possibilities, we generated headless H stem mutants of progressively shorter length. Conformationally restricted H stems remained capable of intracellular assembly with a standard F protein and a soluble MeV F mutant. Proteolytic maturation of F, but not the altered biochemical conditions at the cell surface, reduces the strength of glycoprotein interaction, readying the complexes for triggering. F mutants stabilized in the prefusion conformation interact with H intracellularly and at the cell surface, while destabilized F mutants interact only intracellularly, prior to F maturation. These results showcase an MeV entry machinery that functionally varies conserved motifs of the proposed paramyxovirus infection pathway. Intracellular and plasma membrane-resident MeV glycoprotein complexes employ the same protein-protein interface. F maturation prepares for complex separation after triggering, and the H head domains in prereceptor-bound conformation prevent premature stalk rearrangements and F activation. Intracellular preassembly affects MeV fusion profiles and may contribute to the high cell-to-cell fusion activity characteristic of the morbillivirus genus. IMPORTANCE Paramyxoviruses of the morbillivirus genus, such as measles, are highly contagious, major human and animal pathogens. MeV envelope glycoproteins preassemble intracellularly into tightly associated hetero-oligomers. To address whether preassembly reflects a unique measles virus entry strategy, we characterized the protein-protein interface of intracellular and surface-exposed fusion complexes and investigated the effect of the attachment protein head domains, glycoprotein maturation, and altered biochemical conditions at the cell surface on measles virus fusion complexes. Our results demonstrate that measles virus functionally varies conserved elements of the paramyxovirus entry pathway, providing a possible explanation for the high cell-to-cell fusion activity of morbilliviruses. Insight gained from these data affects the design of effective broad-spectrum paramyxovirus entry inhibitors.
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128
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Prevention of measles virus infection by intranasal delivery of fusion inhibitor peptides. J Virol 2014; 89:1143-55. [PMID: 25378493 DOI: 10.1128/jvi.02417-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
UNLABELLED Measles virus (MV) infection is undergoing resurgence and remains one of the leading causes of death among young children worldwide despite the availability of an effective measles vaccine. MV infects its target cells by coordinated action of the MV H and the fusion (F) envelope glycoprotein; upon receptor engagement by H, the prefusion F undergoes a structural transition, extending and inserting into the target cell membrane and then refolding into a postfusion structure that fuses the viral and cell membranes. By interfering with this structural transition of F, peptides derived from the heptad-repeat (HR) regions of F can potently inhibit MV infection at the entry stage. We show here that specific features of H's interaction with its receptors modulate the susceptibility of MV F to peptide fusion inhibitors. A higher concentration of inhibitory peptides is required to inhibit F-mediated fusion when H is engaged to its nectin-4 receptor than when H is engaged to its CD150 receptor. Peptide inhibition of F may be subverted by continued engagement of receptor by H, a finding that highlights the ongoing role of H-receptor interaction after F has been activated and that helps guide the design of more potent inhibitory peptides. Intranasal administration of these peptides results in peptide accumulation in the airway epithelium with minimal systemic levels of peptide and efficiently prevents MV infection in vivo in animal models. The results suggest an antiviral strategy for prophylaxis in vulnerable and/or immunocompromised hosts. IMPORTANCE Measles virus (MV) infection causes an acute illness that may be associated with infection of the central nervous system (CNS) and severe neurological disease. No specific treatment is available. We have shown that parenterally delivered fusion-inhibitory peptides protect mice from lethal CNS MV disease. Here we show, using established small-animal models of MV infection, that fusion-inhibitory peptides delivered intranasally provide effective prophylaxis against MV infection. Since the fusion inhibitors are stable at room temperature, this intranasal strategy is feasible even outside health care settings, could be used to protect individuals and communities in case of MV outbreaks, and could complement global efforts to control measles.
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129
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Verdaguer N, Ferrero D, Murthy MRN. Viruses and viral proteins. IUCRJ 2014; 1:492-504. [PMID: 25485129 PMCID: PMC4224467 DOI: 10.1107/s205225251402003x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/04/2014] [Indexed: 05/30/2023]
Abstract
For more than 30 years X-ray crystallography has been by far the most powerful approach for determining the structures of viruses and viral proteins at atomic resolution. The information provided by these structures, which covers many important aspects of the viral life cycle such as cell-receptor recognition, viral entry, nucleic acid transfer and genome replication, has extensively enriched our vision of the virus world. Many of the structures available correspond to potential targets for antiviral drugs against important human pathogens. This article provides an overview of the current knowledge of different structural aspects of the above-mentioned processes.
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Affiliation(s)
- Nuria Verdaguer
- Institut de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri i Reixac 15, 08028-Barcelona, Spain
| | - Diego Ferrero
- Institut de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri i Reixac 15, 08028-Barcelona, Spain
| | - Mathur R. N. Murthy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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130
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Canine distemper virus envelope protein interactions modulated by hydrophobic residues in the fusion protein globular head. J Virol 2014; 89:1445-51. [PMID: 25355896 DOI: 10.1128/jvi.01828-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Membrane fusion for morbillivirus cell entry relies on critical interactions between the viral fusion (F) and attachment (H) envelope glycoproteins. Through extensive mutagenesis of an F cavity recently proposed to contribute to F's interaction with the H protein, we identified two neighboring hydrophobic residues responsible for severe F-to-H binding and fusion-triggering deficiencies when they were mutated in combination. Since both residues reside on one side of the F cavity, the data suggest that H binds the F globular head domain sideways.
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131
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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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Abstract
The virus particles described in previous chapters are vehicles that transmit the viral genome and the infection from cell to cell. To initiate the infective cycle, the viral genome must therefore translocate from the viral particle to the cytoplasm. Via distinct proteins or motifs in their outermost shell, the particles attach initially to specific molecules on the host cell surface. These virus receptors thus mediate penetration of the viral genome inside the cell, where the intracellular infective cycle starts. The presence of these receptors on the cell surface is a principal determinant of virus host tropism. Viruses can use diverse types of molecules to attach to and enter into cells. In addition, virus-receptor recognition can evolve over the course of an infection, and virus variants with distinct receptor-binding specificities and tropism can appear. The identification of virus receptors and the characterization of virus-receptor interactions have been major research goals in virology for the last two decades. In this chapter, we will describe, from a structural perspective, several virus-receptor interactions and the active role of receptor molecules in virus entry.
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133
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Recent host range expansion of canine distemper virus and variation in its receptor, the signaling lymphocyte activation molecule, in carnivores. J Wildl Dis 2014; 50:596-606. [PMID: 24807184 DOI: 10.7589/2013-09-228] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The signaling lymphocyte activation molecule (SLAM) is a receptor for morbilliviruses. To understand the recent host range expansion of canine distemper virus (CDV) in carnivores, we determined the nucleotide sequences of SLAMs of various carnivores and generated three-dimensional homology SLAM models. Thirty-four amino acid residues were found for the candidates binding to CDV on the interface of the carnivore SLAMs. SLAM of the domestic dog (Canis lupus familiaris) were similar to those of other members of the suborder Caniformia, indicating that the animals in this group have similar sensitivity to dog CDV. However, they were different at nine positions from those of felids. Among the nine residues, four of domestic cat (Felis catus) SLAM (72, 76, 82, and 129) and three of lion (Panthera leo persica) SLAM (72, 82, and 129) were associated with charge alterations, suggesting that the felid interfaces have lower affinities to dog CDV. Only the residue at 76 was different between domestic cat and lion SLAM interfaces. The domestic cat SLAM had threonine at 76, whereas the lion SLAM had arginine, a positively charged residue like that of the dog SLAM. The cat SLAM with threonine is likely to have lower affinity to CDV-H and to confer higher resistance against dog CDV. Thus, the four residues (72, 76, 82, and 129) on carnivore SLAMs are important for the determination of affinity and sensitivity with CDV. Additionally, the CDV-H protein of felid strains had a substitution of histidine for tyrosine at 549 of dog CDV-H and may have higher affinity to lion SLAM. Three-dimensional model construction is a new risk assessment method of morbillivirus infectivity. Because the method is applicable to animals that have no information about virus infection, it is especially useful for morbillivirus risk assessment and wildlife conservation.
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134
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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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135
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The measles virus hemagglutinin stalk: structures and functions of the central fusion activation and membrane-proximal segments. J Virol 2014; 88:6158-67. [PMID: 24648460 DOI: 10.1128/jvi.02846-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED The measles virus (MeV) membrane fusion apparatus consists of a fusion protein trimer and an attachment protein tetramer. To trigger membrane fusion, the heads of the MeV attachment protein, hemagglutinin (H), bind cellular receptors while the 96-residue-long H stalk transmits the triggering signal. Structural and functional studies of the triggering mechanism of other paramyxoviruses suggest that receptor binding to their hemagglutinin-neuraminidase (HN) results in signal transmission through the central segments of their stalks. To gain insight into H-stalk structure and function, we individually replaced its residues with cysteine. We then assessed how stable the mutant proteins are, how efficiently they can be cross-linked by disulfide bonds, whether cross-linking results in loss of function, and, in this case, whether disulfide bond reduction restores function. While many residues in the central segment of the stalk and in the spacer segment above it can be efficiently cross-linked by engineered disulfide bonds, we report here that residues 59 to 79 cannot, suggesting that the 20 membrane-proximal residues are not engaged in a tetrameric structure. Rescue-of-function studies by disulfide bond reduction resulted in the redefinition and extension of the central fusion-activation segment as covering residues 84 to 117. In particular, we identified four residues located between positions 92 and 99, the function of which cannot be restored by disulfide bond reduction after cysteine mutagenesis. These mutant H proteins reached the cell surface as complex oligomers but could not trigger membrane fusion. We discuss these observations in the context of the stalk exposure model of membrane fusion triggering by paramyxoviruses. IMPORTANCE Measles virus, while being targeted for eradication, still causes significant morbidity and mortality. Here, we seek to understand how it enters cells by membrane fusion. Two viral integral membrane glycoproteins (hemagglutinin tetramers and fusion protein trimers) mediate the concerted receptor recognition and membrane fusion processes. Since previous studies have suggested that the hemagglutinin stalk transmits the triggering signal to the fusion protein trimer, we completed an analysis of its structure and function by systematic Cys mutagenesis. We report that while certain residues of the central stalk segment confer specificity to the interaction with the fusion protein trimer, others are necessary to allow folding of the H-oligomer in a standard conformation conducive to fusion triggering, and still other residues sustain the conformational change that transmits the fusion-triggering signal.
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136
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Antibody neutralization of retargeted measles viruses. Virology 2014; 454-455:237-46. [PMID: 24725950 DOI: 10.1016/j.virol.2014.01.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/04/2013] [Accepted: 01/31/2014] [Indexed: 12/20/2022]
Abstract
The measles virus (MV) vaccine lineage is a promising oncolytic but prior exposure to the measles vaccine or wild-type MV strains limits treatment utility due to the presence of anti-measles antibodies. MV entry can be redirected by displaying a polypeptide ligand on the Hemagglutinin (H) C-terminus. We hypothesized that retargeted MV would escape neutralization by monoclonal antibodies (mAbs) recognizing the H receptor-binding surface and be less susceptible to neutralization by human antisera. Using chimeric H proteins, with and without mutations that ablate MV receptor binding, we show that retargeted MVs escape mAbs that target the H receptor-binding surface by virtue of mutations that ablate infection via SLAM and CD46. However, C-terminally displayed domains do not mediate virus entry in the presence of human antibodies that bind to the underlying H domain. In conclusion, utility of retargeted oncolytic measles viruses does not extend to evasion of human serum neutralization.
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137
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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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138
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Liu YP, Russell SP, Ayala-Breton C, Russell SJ, Peng KW. Ablation of nectin4 binding compromises CD46 usage by a hybrid vesicular stomatitis virus/measles virus. J Virol 2014; 88:2195-204. [PMID: 24335299 PMCID: PMC3911550 DOI: 10.1128/jvi.02628-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 12/03/2013] [Indexed: 01/18/2023] Open
Abstract
Measles virus (MV) immunosuppression is due to infection of SLAM-positive immune cells, whereas respiratory shedding and virus transmission are due to infection of nectin4-positive airway epithelial cells. The vaccine lineage MV strain Edmonston (MV-Edm) acquired an additional tropism for CD46 which is the basis of its oncolytic specificity. VSVFH is a vesicular stomatitis virus (VSV) encoding the MV-Edm F and H entry proteins in place of G. The virus spreads faster than MV-Edm and is highly fusogenic and a potent oncolytic. To determine whether ablating nectin4 tropism from VSVFH might prevent shedding, increasing its safety profile as an oncolytic, or might have any effect on CD46 binding, we generated VSVFH viruses with H mutations that disrupt attachment to SLAM and/or nectin4. Disruption of nectin4 binding reduced release of VSVFH from the basolateral side of differentiated airway epithelia composed of Calu-3 cells. However, because nectin4 and CD46 have substantially overlapping receptor binding surfaces on H, disruption of nectin4 binding compromised CD46 binding and greatly diminished the oncolytic potency of these viruses on human cancer cells. Thus, our results support continued preclinical development of VSVFH without ablation of nectin4 binding.
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Affiliation(s)
- Yu-Ping Liu
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Samuel P. Russell
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- University of Wisconsin—Madison, Madison, Wisconsin, USA
| | | | - Stephen J. Russell
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Internal Medicine, Division of Hematology, Mayo Clinic, Rochester, Minnesota, USA
| | - Kah-Whye Peng
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota, USA
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139
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Molecular determinants defining the triggering range of prefusion F complexes of canine distemper virus. J Virol 2013; 88:2951-66. [PMID: 24371057 DOI: 10.1128/jvi.03123-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The morbillivirus cell entry machinery consists of a fusion (F) protein trimer that refolds to mediate membrane fusion following receptor-induced conformational changes in its binding partner, the tetrameric attachment (H) protein. To identify molecular determinants that control F refolding, we generated F chimeras between measles virus (MeV) and canine distemper virus (CDV). We located a central pocket in the globular head domain of CDV F that regulates the stability of the metastable, prefusion conformational state of the F trimer. Most mutations introduced into this "pocket'" appeared to mediate a destabilizing effect, a phenotype associated with enhanced membrane fusion activity. Strikingly, under specific triggering conditions (i.e., variation of receptor type and H protein origin), some F mutants also exhibited resistance to a potent morbillivirus entry inhibitor, which is known to block F triggering by enhancing the stability of prefusion F trimers. Our data reveal that the molecular nature of the F stimulus and the intrinsic stability of metastable prefusion F both regulate the efficiency of F refolding and escape from small-molecule refolding blockers. IMPORTANCE With the aim to better characterize the thermodynamic basis of morbillivirus membrane fusion for cell entry and spread, we report here that the activation energy barrier of prefusion F trimers together with the molecular nature of the triggering "stimulus" (attachment protein and receptor types) define a "triggering range," which governs the initiation of the membrane fusion process. A central "pocket" microdomain in the globular F head contributes substantially to the regulation of the conformational stability of the prefusion complexes. The triggering range also defines the mechanism of viral escape from entry inhibitors and describes how the cellular environment can affect membrane fusion efficiency.
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140
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Ludlow M, Rennick LJ, Nambulli S, de Swart RL, Duprex WP. Using the ferret model to study morbillivirus entry, spread, transmission and cross-species infection. Curr Opin Virol 2013; 4:15-23. [PMID: 24525290 DOI: 10.1016/j.coviro.2013.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 01/26/2023]
Abstract
Canine distemper virus (CDV) is an animal morbillivirus with a worldwide circulation that infects carnivores, including domestic dogs and an assortment of wildlife hosts. The development of reverse genetics systems for wild-type strains of CDV and the use of the resulting recombinant (r) viruses to infect ferrets by a natural route has shed new light on the temporal pathogenesis of distemper. Combining fluorescent protein expressing recombinant viruses and multimodal, macroscopic and microscopic imaging modalities has highlighted the differential role of the cellular receptors CD150 and PVRL4 in disease progression. This in turn has enabled pathways of viral spread, including multiple routes of entry into the central nervous system, to be mapped with unparalleled sensitivity.
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Affiliation(s)
- Martin Ludlow
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Linda J Rennick
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Sham Nambulli
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Rik L de Swart
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - W Paul Duprex
- Department of Microbiology, Boston University School of Medicine, Boston, MA, 02118, USA; School of Medicine, Dentistry and Biomedical Sciences, The Queen's University of Belfast, Belfast, Northern Ireland, UK.
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141
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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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142
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A stabilized headless measles virus attachment protein stalk efficiently triggers membrane fusion. J Virol 2013; 87:11693-703. [PMID: 23966411 DOI: 10.1128/jvi.01945-13] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paramyxovirus attachment and fusion (F) envelope glycoprotein complexes mediate membrane fusion required for viral entry. The measles virus (MeV) attachment (H) protein stalk domain is thought to directly engage F for fusion promotion. However, past attempts to generate truncated, fusion-triggering-competent H-stem constructs remained fruitless. In this study, we addressed the problem by testing the hypothesis that truncated MeV H stalks may require stabilizing oligomerization tags to maintain intracellular transport competence and F-triggering activity. We engineered H-stems of different lengths with added 4-helix bundle tetramerization domains and demonstrate restored cell surface expression, efficient interaction with F, and fusion promotion activity of these constructs. The stability of the 4-helix bundle tags and the relative orientations of the helical wheels of H-stems and oligomerization tags govern the kinetics of fusion promotion, revealing a balance between H stalk conformational stability and F-triggering activity. Recombinant MeV particles expressing a bioactive H-stem construct in the place of full-length H are viable, albeit severely growth impaired. Overall, we demonstrate that the MeV H stalk represents the effector domain for MeV F triggering. Fusion promotion appears linked to the conformational flexibility of the stalk, which must be tightly regulated in viral particles to ensure efficient virus entry. While the pathways toward assembly of functional fusion complexes may differ among diverse members of the paramyxovirus family, central elements of the triggering machinery emerge as highly conserved.
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143
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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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144
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Mateo M, Navaratnarajah CK, Syed S, Cattaneo R. The measles virus hemagglutinin β-propeller head β4-β5 hydrophobic groove governs functional interactions with nectin-4 and CD46 but not those with the signaling lymphocytic activation molecule. J Virol 2013; 87:9208-16. [PMID: 23760251 PMCID: PMC3754078 DOI: 10.1128/jvi.01210-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/09/2013] [Indexed: 12/12/2022] Open
Abstract
Wild-type measles virus (MV) strains use the signaling lymphocytic activation molecule (SLAM; CD150) and the adherens junction protein nectin-4 (poliovirus receptor-like 4 [PVRL4]) as receptors. Vaccine MV strains have adapted to use ubiquitous membrane cofactor protein (MCP; CD46) in addition. Recently solved cocrystal structures of the MV attachment protein (hemagglutinin [H]) with each receptor indicate that all three bind close to a hydrophobic groove located between blades 4 and 5 (β4-β5 groove) of the H protein β-propeller head. We used this structural information to focus our analysis of the functional footprints of the three receptors on vaccine MV H. We mutagenized this protein and tested the ability of individual mutants to support cell fusion through each receptor. The results highlighted a strong overlap between the functional footprints of nectin-4 and CD46 but not those of SLAM. A soluble form of nectin-4 abolished vaccine MV entry in nectin-4- and CD46-expressing cells but only reduced entry through SLAM. Analyses of the binding kinetics of an H mutant with the three receptors revealed that a single substitution in the β4-β5 groove drastically reduced nectin-4 and CD46 binding while minimally altering SLAM binding. We also generated recombinant viruses and analyzed their infections in cells expressing individual receptors. Introduction of a single substitution into the hydrophobic pocket affected entry through both nectin-4 and CD46 but not through SLAM. Thus, while nectin-4 and CD46 interact functionally with the H protein β4-β5 hydrophobic groove, SLAM merely covers it. This has implications for vaccine and antiviral strategies.
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Affiliation(s)
- Mathieu Mateo
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Chanakha K. Navaratnarajah
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Virology and Gene Therapy Track, Mayo Graduate School, Rochester, Minnesota, USA
| | - Sabriya Syed
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Virology and Gene Therapy Track, Mayo Graduate School, Rochester, Minnesota, USA
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145
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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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146
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Sakai K, Yoshikawa T, Seki F, Fukushi S, Tahara M, Nagata N, Ami Y, Mizutani T, Kurane I, Yamaguchi R, Hasegawa H, Saijo M, Komase K, Morikawa S, Takeda M. Canine distemper virus associated with a lethal outbreak in monkeys can readily adapt to use human receptors. J Virol 2013; 87:7170-5. [PMID: 23596291 PMCID: PMC3676118 DOI: 10.1128/jvi.03479-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 04/04/2013] [Indexed: 02/01/2023] Open
Abstract
A canine distemper virus (CDV) strain, CYN07-dV, associated with a lethal outbreak in monkeys, used human signaling lymphocyte activation molecule as a receptor only poorly but readily adapted to use it following a P541S substitution in the hemagglutinin protein. Since CYN07-dV had an intrinsic ability to use human nectin-4, the adapted virus became able to use both human immune and epithelial cell receptors, as well as monkey and canine ones, suggesting that CDV can potentially infect humans.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ryoji Yamaguchi
- Department of Veterinary Pathology, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | | | | | | | - Shigeru Morikawa
- Department of Virology 1,
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan
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147
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The receptor attachment function of measles virus hemagglutinin can be replaced with an autonomous protein that binds Her2/neu while maintaining its fusion-helper function. J Virol 2013; 87:6246-56. [PMID: 23536664 DOI: 10.1128/jvi.03298-12] [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
Cell entry of enveloped viruses is initiated by attachment to the virus receptor followed by fusion between the virus and host cell membranes. Measles virus (MV) attachment to its receptor is mediated by the hemagglutinin (H), which is thought to produce conformational changes in the membrane fusion protein (F) that trigger insertion of its fusion peptide into the target cell membrane. Here, we uncoupled receptor attachment and the fusion-helper function of H by introducing Y481A, R533A, S548L, and F549S mutations into the viral attachment protein that made it blind to its normal receptors. An artificial receptor attachment protein specific for Her2/neu was incorporated into the membranes of pseudotyped lentivirus particles as a separate transmembrane protein along with the F protein. Surprisingly, these particles entered efficiently into Her2/neu-positive SK-OV-3 as well as CHO-Her2 cells. Cell entry was independent of endocytosis but strictly dependent on the presence of H. H-specific monoclonal antibodies, as well as a mutation in H interfering with H/F cooperation, blocked cell entry. The particles mediated stable and specific transfer of reporter genes into Her2/neu-positive human tumor cells also in vivo, while exhibiting improved infectivity and higher titers than Her2/neu-targeted vectors displaying the targeting domain on H. Extending the current model of MV cell entry, the data suggest that receptor binding of H is not required for its fusion-helper function but that particle-cell contact in general may be sufficient to induce the conformational changes in the H/F complex and activate membrane fusion.
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148
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Bieringer M, Han JW, Kendl S, Khosravi M, Plattet P, Schneider-Schaulies J. Experimental adaptation of wild-type canine distemper virus (CDV) to the human entry receptor CD150. PLoS One 2013; 8:e57488. [PMID: 23554862 PMCID: PMC3595274 DOI: 10.1371/journal.pone.0057488] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/22/2013] [Indexed: 11/18/2022] Open
Abstract
Canine distemper virus (CDV), a close relative of measles virus (MV), is widespread and well known for its broad host range. When the goal of measles eradication may be achieved, and when measles vaccination will be stopped, CDV might eventually cross the species barrier to humans and emerge as a new human pathogen. In order to get an impression how fast such alterations may occur, we characterized required adaptive mutations to the human entry receptors CD150 (SLAM) and nectin-4 as first step to infect human target cells. Recombinant wild-type CDV-A75/17(red) adapted quickly to growth in human H358 epithelial cells expressing human nectin-4. Sequencing of the viral attachment proteins (hemagglutinin, H, and fusion protein, F) genes revealed that no adaptive alteration was required to utilize human nectin-4. In contrast, the virus replicated only to low titres (10(2) pfu/ml) in Vero cells expressing human CD150 (Vero-hSLAM). After three passages using these cells virus was adapted to human CD150 and replicated to high titres (10(5) pfu/ml). Sequence analyses revealed that only one amino acid exchange in the H-protein at position 540 Asp→Gly (D540G) was required for functional adaptation to human CD150. Structural modelling suggests that the adaptive mutation D540G in H reflects the sequence alteration from canine to human CD150 at position 70 and 71 from Pro to Leu (P70L) and Gly to Glu (G71E), and compensates for the gain of a negative charge in the human CD150 molecule. Using this model system our data indicate that only a minimal alteration, in this case one adaptive mutation, is required for adaptation of CDV to the human entry receptors, and help to understand the molecular basis why this adaptive mutation occurs.
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MESH Headings
- Adaptation, Physiological/genetics
- Amino Acid Substitution
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Cell Adhesion Molecules/genetics
- Cell Adhesion Molecules/metabolism
- Chlorocebus aethiops
- Communicable Diseases, Emerging/genetics
- Communicable Diseases, Emerging/metabolism
- Communicable Diseases, Emerging/transmission
- Distemper/genetics
- Distemper/metabolism
- Distemper/transmission
- Distemper Virus, Canine/physiology
- Dogs
- Humans
- Mutation, Missense
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Signaling Lymphocytic Activation Molecule Family Member 1
- Vero Cells
- Virus Replication
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Affiliation(s)
- Maria Bieringer
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Jung Woo Han
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Sabine Kendl
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Mojtaba Khosravi
- Department for Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Philippe Plattet
- Department for Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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149
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Nakashima M, Shirogane Y, Hashiguchi T, Yanagi Y. Mutations in the putative dimer-dimer interfaces of the measles virus hemagglutinin head domain affect membrane fusion triggering. J Biol Chem 2013; 288:8085-8091. [PMID: 23362271 DOI: 10.1074/jbc.m112.427609] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Measles virus (MV), an enveloped RNA virus belonging to the Paramyxoviridae family, enters the cell through membrane fusion mediated by two viral envelope proteins, an attachment protein hemagglutinin (H) and a fusion (F) protein. The crystal structure of the receptor-binding head domain of MV-H bound to its cellular receptor revealed that the MV-H head domain forms a tetrameric assembly (dimer of dimers), which occurs in two forms (forms I and II). In this study, we show that mutations in the putative dimer-dimer interface of the head domain in either form inhibit the ability of MV-H to support membrane fusion, without greatly affecting its cell surface expression, receptor binding, and interaction with the F protein. Notably, some anti-MV-H neutralizing monoclonal antibodies are directed to the region around the dimer-dimer interface in form I rather than receptor-binding sites. These observations suggest that the dimer-dimer interactions of the MV-H head domain, especially that in form I, contribute to triggering membrane fusion, and that conformational shift of head domain tetramers plays a role in the process. Furthermore, our results indicate that although the stalk and transmembrane regions may be mainly responsible for the tetramer formation of MV-H, the head domain alone can form tetramers, albeit at a low efficiency.
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Affiliation(s)
- Mai Nakashima
- Department of Virology, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan; Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309
| | - Yuta Shirogane
- Department of Virology, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan.
| | - Takao Hashiguchi
- Department of Immunology and Microbial Science, Scripps Research Institute, La Jolla, California 92037
| | - Yusuke Yanagi
- Department of Virology, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan.
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150
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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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