How Positive-Strand RNA Viruses Benefit from Autophagosome Maturation

The autophagic degradation pathway is a powerful tool in the host cell arsenal against cytosolic pathogens. Contents trapped inside cytosolic vesicles, termed autophagosomes, are delivered to the lysosome for degradation. In spite of the degradative nature of the pathway, some pathogens are able to subvert autophagy for their benefit. In many cases, these pathogens have developed strategies to induce the autophagic signaling pathway while inhibiting the associated degradation activity. One surprising finding from recent literature is that some viruses do not impede degradation but instead promote the generation of degradative autolysosomes, which are the endpoint compartments of autophagy. Dengue virus, poliovirus, and hepatitis C virus, all positive-strand RNA viruses, utilize the maturation of autophagosomes into acidic and ultimately degradative compartments to promote their replication. While the benefits that each virus reaps from autophagosome maturation are unique, the parallels between the viruses indicate a complex relationship between cytosolic viruses and host cell degradation vesicles.