That which does not degrade you makes you stronger: infectivity of poliovirus depends on vesicle acidification.

Several years ago, an explosion of research into pathogens and autophagy showed that viruses have a wide variety of relationships to this conserved homeostatic pathway. Often, autophagy acts as a host defense mechanism, degrading viruses before they can escape the host cell, and, as such, autophagy is suppressed or avoided by those viruses. A subset of viruses, however, induces and subverts the autophagic machinery to promote their own replication. Many of these viruses inhibit the degradative step in the autophagic pathway, presumably to prevent degradation of cytosolic virions before they exit the cell. Recently, we published a study showing that poliovirus (PV), a well-studied model virus, induces true autophagic degradation. The remainder of our study provided surprising clues about the role of autophagy in promoting virus production. The purpose of this punctum is to discuss the significance of our findings to a general understanding of the autophagic pathway and its relationship to a common class of cellular pathogens.