Palmitoylation of influenza virus proteins.

During and after their synthesis, the envelope proteins of influenza viruses are extensively modified by glycosylation, disulfide-bond formation, oligomerisation and proteolytical cleavage. These modifications have an enormous impact on folding and transport of the proteins to the plasma membrane and are also crucial for the infectivity and pathogenicity of the resulting virus particles. Here we summarize the results of 25 years of research on the linkage of fatty acids to proteins (palmitoylation), a modification we discovered with viral glycoproteins including the influenza virus spike proteins. The fundamental biochemistry of the attachment of fatty acids to the hemagglutinin (HA) and to the ion-channel M2 is described which has been instrumental in revealing similar modifications in cellular proteins. Finally, the functional consequences of palmitoylation for entry of viruses into target cells by HA-mediated membrane fusion and for assembly and release of virus particles from infected cells are discussed.