ESCRT-III CHMP2A and CHMP3 form variable helical polymers in vitro and act synergistically during HIV-1 budding.

ABSTRACT: The endosomal sorting complex required for transport-III (ESCRT-III) proteins are essential for budding of some enveloped viruses, for the formation of intraluminal vesicles at the endosome and for the abscission step of cytokinesis. ESCRT-III proteins form polymers that constrict membrane tubes, leading to fission. We have used electron cryomicroscopy to determine the molecular organization of pleiomorphic ESCRT-III CHMP2A-CHMP3 polymers. The three-dimensional reconstruction at 22 Å resolution reveals a helical organization of filaments of CHMP molecules organized in a head-to-tail fashion. Protease susceptibility experiments indicate that polymerization is achieved via conformational changes that increase the protomer stability. Combinatorial siRNA knockdown experiments indicate that CHM

SUBMITTER: Effantin G 

PROVIDER: S-EPMC3783020 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature