The ins and outs of hepatitis C virus entry and assembly

Hepatitis C virus (HCV) is an enveloped, positive-strand RNA virus. Unlike other enveloped RNA viruses, HCV particles interact with serum lipoproteins, which are important for the infectivity of HCV particles.New structural information is available for E2 glycoprotein of the related pestiviruses. Common features of HCV and pestiviruses suggest that these viruses use an uncharacterized mechanism of viral fusion.HCV particles enter cells via a multistep process involving numerous cell surface proteins, cellular processing of virus-associated lipoproteins, signal transduction events, clathrin-mediated internalization of the virus, and low-pH-induced membrane fusion.HCV particle assembly occurs via budding into the ER. This process requires recently defined interactions between the viral structural and non-structural proteins.Nascent HCV particles exit the cell via transit through the secretory pathway. During this process, HCV undergoes maturational events similar to those of serum lipoproteins.