Official websites use. Share sensitive information only on official, secure websites. Author for correspondence e-mail: juan. 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.
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. The endosomal sorting complex required for transport ESCRT proteins were initially identified in Saccharomyces cerevisiae as class E vacuolar protein sorting Vps gene products Katzmann et al. Since then, the majority of work aimed at characterising these proteins has focused on determining their function in the sorting and degradation of ubiquitylated membrane receptors in the late endosome-lysosome pathway.
Several models have been proposed to explain the association of the different complexes and the mechanics of membrane deformation and vesicle formation Hurley and Emr, ; Nickerson et al.
Surprisingly, work carried out more recently has revealed additional functions of the ESCRT proteins in viral budding and cytokinesis. It is not known whether viral budding requires the same membrane deformation activity as is involved in the biogenesis of multivesicular bodies MVBs , or whether this function is provided by the oligomerisation of the membrane-associated viral Gag proteins Gottlinger, Despite differences in the processes of MVB biogenesis, viral-particle release and cytokinesis, it is clear that they have in common the requirement for a membrane-scission event for the release of the progeny vesicle, virion or daughter cell Fig.
