No strings attached: the ESCRT machinery in viral budding and cytokinesis

TLDR

The ESCRT pathway, first identified as an endosomal sorting complex, is essential for multivesicular body biogenesis and has been implicated in membrane scission events such as viral budding and cytokinesis. This commentary aims to review recent advances in understanding how ESCRT proteins mediate diverse membrane scission processes. The authors discuss how ESCRT proteins are recruited to sites of membrane scission, including viral budding sites and the cytokinetic midbody, to facilitate the resolution of membrane tethers. ESCRT proteins drive the final scission step in both viral budding—resolving the tether between host cell and virus—and cytokinesis—separating daughter cells.

Abstract

Since the initial discovery of the endosomal sorting complex required for transport (ESCRT) pathway, research in this field has exploded. ESCRT proteins are part of the endosomal trafficking system and play a crucial role in the biogenesis of multivesicular bodies by functioning in the formation of vesicles that bud away from the cytoplasm. Subsequently, a surprising role for ESCRT proteins was defined in the budding step of some enveloped retroviruses, including HIV-1. ESCRT proteins are also employed in this outward budding process, which results in the resolution of a membranous tether between the host cell and the budding virus particle. Remarkably, it has recently been described that ESCRT proteins also have a role in the topologically equivalent process of cell division. In the same way that viral particles recruit the ESCRT proteins to the site of viral budding, ESCRT proteins are also recruited to the midbody - the site of release of daughter cell from mother cell during cytokinesis. In this Commentary, we describe recent advances in the understanding of ESCRT proteins and how they act to mediate these diverse processes.