Influenza Virus Assembly and Budding in Lipid Rafts

Influenza A virus causes annual epidemics, and occasional pandemics that bring a significant global health threat. Influenza virus, which belongs to the Orthomyxoviridae family, is an enveloped virus that contains a segmented and negative-sense RNA genome. The assembly and budding of progeny influenza is a complicated and multi-step process involving many viral factors. Influenza budding occurs in lipid raft domains of cells membrane. Firstly, two viral glycoproteins HA and NA, concentrate in lipid rafts to initiate the budding process by causing membrane enlargement and curvature. Secondly Matrix protein 1 (MI), which forms the inner virion matrix, is then recruited to the budding site followed by the incorporation of viral VPNPs and M2 proteins. In the later stages of budding, M2 is concentrated to the bottom of the budding virion at the lipid rafts boundary, resulting in viral scission and virion release.