Influenza virus assembly and lipid raft microdomains: a role for the cytoplasmic tails of the spike glycoproteins.
Influenza viruses encoding hemagglutinin (HA) and neuraminidase (NA) glycoproteins with deletions in one or both cytoplasmic tails (HAt- or NAt-) have a reduced association with detergent-insoluble glycolipids (DIGs). Mutations which eliminated various combinations of the three palmitoylation sites in HA exhibited reduced amounts of DIG-associated HA in virus-infected cells. The influenza virus matrix (M(1)) protein was also found to be associated with DIGs, but this association was decreased in cells infected with HAt- or NAt- virus. Regardless of the amount of DIG-associated protein, the HA and NA glycoproteins were targeted primarily to the apical surface of virus-infected, polarized cells. The uncoupling of DIG association and apical transport was augmented by the observation that the influenza A virus M(2) protein as well as the influenza C virus HA-esterase-fusion glycoprotein were not associated with DIGs but were apically targeted. The reduced DIG association of HAt- and NAt- is an intrinsic property of the glycoproteins, as similar reductions in DIG association were observed when the proteins were expressed from cDNA. Examination of purified virions indicated reduced amounts of DIG-associated lipids in the envelope of HAt- and NAt- viruses. The data indicate that deletion of both the HA and NA cytoplasmic tails results in reduced DIG association and changes in both virus polypeptide and lipid composition.
Zhang
J
J
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500, USA.
Pekosz
A
A
Lamb
R A
RA
D000818:Animals; D002460:Cell Line; D016764:Cell Polarity; D003902:Detergents; D006017:Glycolipids / Q000378:metabolism; D006367:HeLa Cells; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009980:Influenza A virus / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D009982:Gammainfluenzavirus / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D008563:Membrane Lipids / Q000032:analysis / Q000378:metabolism*; D009439:Neuraminidase / Q000737:chemistry / Q000378:metabolism*; D012995:Solubility; D014763:Viral Matrix Proteins / Q000378:metabolism; D014771:Virion / Q000378:metabolism; D019065:Virus Assembly
D003902:Detergents; D006017:Glycolipids; D019267:Hemagglutinin Glycoproteins, Influenza Virus; C031540:M-protein, influenza virus; D008562:Membrane Glycoproteins; D008563:Membrane Lipids; D014763:Viral Matrix Proteins; D009439:Neuraminidase