The cell biology of receptor-mediated virus entry

Grove, Joe; Marsh, Mark

As with virtually all endocytic cargoes, regardless of the mechanism of uptake, most viruses internalized by endocytosis are delivered to endosomes. Many of these will use endosomal environmental cues, usually low pH, to trigger the membrane fusion/penetration reactions that deliver the viral genetic material to the cytoplasm ( Fig. 3 ; details of the fusion and penetration mechanisms used by different viruses will not be considered here; Kielian and Rey, 2006; Moyer and Nemerow, 2011) . Fusion or penetration from endosomes offers several potential advantages to a virus: it ensures that there is no cortical actin barrier to contend with, limits the display of viral components on the surface of the cell where they may be targets for the immune system, and, in the case of viruses that cause membrane lysis, such as adenoviruses, limits membrane damage to a single endosome.