Structure of cellular ESCRT-III spirals and their relationship to HIV budding
- Washington University School of Medicine, United States
Abstract
The ESCRT machinery along with the AAA+ ATPase Vps4 drive membrane scission for trafficking into multivesicular bodies in the endocytic pathway and for the topologically related processes of viral budding and cytokinesis, but how they accomplish this remains unclear. Using deep-etch electron microscopy, we find that endogenous ESCRT-III filaments stabilized by depleting cells of Vps4 create uniform membrane-deforming conical spirals which are assemblies of specific ESCRT-III heteropolymers. To explore functional roles for ESCRT-III filaments, we examine HIV-1 Gag-mediated budding of virus-like particles and find that depleting Vps4 traps ESCRT-III filaments around nascent Gag assemblies. Interpolating between the observed structures suggests a new role for Vps4 in separating ESCRT-III from Gag or other cargo to allow centripetal growth of a neck constricting ESCRT-III spiral.
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© 2014, Cashikar et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Structure of cellular ESCRT-III spirals and their relationship to HIV budding
eLife 3:e02184.
https://doi.org/10.7554/eLife.02184
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