title: Rotavirus spike protein VP5* binds alpha2beta1 integrin on the cell surface and competes with virus for cell binding and infectivity.
abstract: Rotaviruses recognize several cell-surface molecules, including the alpha2beta1 integrin, and the processes of rotavirus cell attachment and entry appear to be multifactorial. The VP5* subunit of the rotavirus spike protein VP4 contains the alpha2beta1 ligand sequence Asp-Gly-Glu at residues 308-310. Binding to alpha2beta1 and infectivity of monkey rotavirus strain RRV and human rotavirus strain Wa, but not porcine rotavirus strain CRW-8, are inhibited by peptides containing Asp-Gly-Glu. Asp308 and Gly309 are necessary for the binding of RRV VP5* (aa 248-474) to expressed I domain of the alpha2 integrin subunit. Here, the ability of RRV VP5* to bind cells and affect rotavirus-integrin interactions was determined. Interestingly, VP5* bound to cells at 4 and 37 degrees C, both via alpha2beta1 and independently of this integrin. Prior VP5* binding at 37 degrees C eliminated RRV binding to cellular alpha2beta1 and reduced RRV and Wa infectivity in MA104 cells by 38-46 %. VP5* binding did not affect the infectivity of CRW-8. VP5* binding at 4 degrees C did not affect permissive-cell infection by RRV, indicating an energy requirement for VP5* competition with virus for infectivity. Mutagenesis of VP5* Asp308 and Gly309 eliminated VP5* binding to alpha2beta1 and the VP5* inhibition of rotavirus cell binding and infection, but not alpha2beta1-independent cell binding by VP5*. These studies show for the first time that expressed VP5* binds cell-surface alpha2beta1 using Asp308 and Gly309 and inhibits the infection of homologous and heterologous rotaviruses that use alpha2beta1 as a receptor.
authors.affiliation: Department of Microbiology and Immunology, The University of Melbourne, Victoria 3010, Australia.
authors.forename: Kate L
authors.initials: KL
authors.lastname: Graham
authors.affiliation: The University of California, Davis, UC Davis Medical Center, 4645 2nd Avenue, Sacramento, CA 95817, USA.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Takada
authors.affiliation: Department of Microbiology and Immunology, The University of Melbourne, Victoria 3010, Australia.
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Coulson
mesh_terms: D000818:Animals; D001224:Aspartic Acid; D036022:Capsid Proteins / Q000737:chemistry; D002460:Cell Line; D018698:Glutamic Acid; D005998:Glycine; D006801:Humans; D038982:Integrin alpha2beta1 / Q000737:chemistry / Q000378:metabolism*; D011991:Receptors, Virus / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D012401:Rotavirus / Q000502:physiology*; D012400:Rotavirus Infections / Q000517:prevention & control* / Q000821:virology; D013045:Species Specificity; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; D038982:Integrin alpha2beta1; D011991:Receptors, Virus; D011994:Recombinant Proteins; C060339:VP4 protein, Rotavirus; D017361:Viral Nonstructural Proteins; C104282:nsp1 protein, Rotavirus; D001224:Aspartic Acid; D018698:Glutamic Acid; D005998:Glycine