title: The cholesterol recognition/interaction amino acid consensus motif of the influenza A virus M2 protein is not required for virus replication but contributes to virulence.
abstract: Influenza A virus particles assemble and bud from plasma membrane domains enriched with the viral glycoproteins but only a small fraction of the total M2 protein is incorporated into virus particles when compared to the other viral glycoproteins. A membrane proximal cholesterol recognition/interaction amino acid consensus (CRAC) motif was previously identified in M2 and suggested to play a role in protein function. We investigated the importance of the CRAC motif on virus replication by generating recombinant proteins and viruses containing amino acid substitutions in this motif. Alteration or completion of the M2 CRAC motif in two different virus strains caused no changes in virus replication in vitro. Viruses lacking an M2 CRAC motif had decreased morbidity and mortality in the mouse model of infection, suggesting that this motif is a virulence determinant which may facilitate virus replication in vivo but is not required for basic virus replication in tissue culture.
authors.affiliation: W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, USA.
authors.forename: Shaun M
authors.initials: SM
authors.lastname: Stewart
authors.forename: Wai-Hong
authors.initials: WH
authors.lastname: Wu
authors.forename: Erin N
authors.initials: EN
authors.lastname: Lalime
authors.forename: Andrew
authors.initials: A
authors.lastname: Pekosz
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D016384:Consensus Sequence; D004847:Epithelial Cells / Q000821:virology; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000821:virology; D014132:Trachea / Q000166:cytology / Q000821:virology; D014763:Viral Matrix Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014774:Virulence; D019065:Virus Assembly; D014779:Virus Replication; D000086082:Viroporin Proteins
chemical_list: D002784:Cholesterol; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins