Divergent Roles of Autophagy in Virus Infection

Chiramel, Abhilash I.; Brady, Nathan R.; Bartenschlager, Ralf

Upon replication of the viral genome, it has to be packaged into a virus particle (assembly) that is released from the infected cell (exit). For many viruses, autophagy has been reported to regulate also these late steps of the viral replication cycle [18, 28, 78] . For instance, in the case of hepatitis B virus (HBV), efficient envelopment of viral particles was shown to depend on induction of autophagy [88] ( Figure 4 ). Cells that are deficient in autophagy produce significantly lower amounts of nucleic acid-containing intra-and extracellular enveloped particles. Furthermore, the major HBV envelope protein (HBsAg) was shown to bind to and colocalize with LC3-I and LC3-II during HBV infection or upon ectopic expression of HBsAg, indicating that this interaction might be important for acquiring the viral envelope. Autophagosomes might serve as membrane source; alternatively, intermediate compartments might be used to transport HBV to the site of envelopment, which is thought to occur at a post-ER/ pre-Golgi site [88] .