title: Influenza virus m2 ion channel protein is necessary for filamentous virion formation.
abstract: Influenza A virus buds from cells as spherical (approximately 100-nm diameter) and filamentous (approximately 100 nm x 2 to 20 microm) virions. Previous work has determined that the matrix protein (M1) confers the ability of the virus to form filaments; however, additional work has suggested that the influenza virus M2 integral membrane protein also plays a role in viral filament formation. In examining the role of the M2 protein in filament formation, we observed that the cytoplasmic tail of M2 contains several sites that are essential for filament formation. Additionally, whereas M2 is a nonraft protein, expression of other viral proteins in the context of influenza virus infection leads to the colocalization of M2 with sites of virus budding and lipid raft domains. We found that an amphipathic helix located within the M2 cytoplasmic tail is able to bind cholesterol, and we speculate that M2 cholesterol binding is essential for both filament formation and the stability of existing viral filaments.
authors.affiliation: Department of Biochemistry, Molecular Biology, and Cell Biology, and Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois 60208-3500, USA.
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Rossman
authors.forename: Xianghong
authors.initials: X
authors.lastname: Jing
authors.forename: George P
authors.initials: GP
authors.lastname: Leser
authors.forename: Victoria
authors.initials: V
authors.lastname: Balannik
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Pinto
authors.forename: Robert A
authors.initials: RA
authors.lastname: Lamb
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D004285:Dogs; D006801:Humans; D009980:Influenza A virus / Q000502:physiology*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011485:Protein Binding; D014763:Viral Matrix Proteins / Q000502:physiology*; D014771:Virion / Q000648:ultrastructure*; D019065:Virus Assembly; D000086082:Viroporin Proteins
chemical_list: D002784:Cholesterol; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins