Autophagy protein ATG5 interacts transiently with the hepatitis polymerase (NS5B) early during infection

Autophagy is an important cellular process by which ATG5 initiates the formation of double membrane vesicles (DMVs). Upon infection, DMVs have been shown to harbor the replicase complex of positive-strand RNA viruses such as MHV, poliovirus. and equine arteritis virus. Recently, it has been shown that autophagy proteins are proviral factors that favor initiation of hepatitis C virus (HCV) infection Here, we identified ATG5 as an interacting protein for the HCV NS5B ATG5/NS5B interaction was confirmed by co-IP and metabolic labeling studies. Furthermore. ATG5 protein colocalizes with NS4B, a constituent of the membranous web Importantly, immunofluorescence staining demonstrated a strong colocalization of ATG5 and NS5B within perinuclear regions of infected cells at 2 days postinfection However, colocalization was completely lacking at 5 DPI, suggesting that HCV utilizes ATG5 as a proviral factor during the onset of viral infection Finally, inhibition of autophagy through ATG5 silencing blocks HCV replication. (C) 2010 Elsevier Inc All rights reserved