Format

Send to

Choose Destination
Cell. 2012 Oct 12;151(2):356-71. doi: 10.1016/j.cell.2012.08.039.

The endosomal sorting complex ESCRT-II mediates the assembly and architecture of ESCRT-III helices.

Author information

1
Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.

Abstract

The endosomal sorting complexes required for transport (ESCRTs) constitute hetero-oligomeric machines that mediate topologically similar membrane-sculpting processes, including cytokinesis, retroviral egress, and multivesicular body (MVB) biogenesis. Although ESCRT-III drives membrane remodeling that creates MVBs, its structure and the mechanism of vesicle formation are unclear. Using electron microscopy, we visualize an ESCRT-II:ESCRT-III supercomplex and propose how it mediates vesicle formation. We define conformational changes that activate ESCRT-III subunit Snf7 and show that it assembles into spiraling ~9 nm protofilaments on lipid monolayers. A high-content flow cytometry assay further demonstrates that mutations halting ESCRT-III assembly block ESCRT function. Strikingly, the addition of Vps24 and Vps2 transforms flat Snf7 spirals into membrane-sculpting helices. Finally, we show that ESCRT-II and ESCRT-III coassemble into ~65 nm diameter rings indicative of a cargo-sequestering supercomplex. We propose that ESCRT-III has distinct architectural stages that are modulated by ESCRT-II to mediate cargo capture and vesicle formation by ordered assembly.

PMID:
23063125
DOI:
10.1016/j.cell.2012.08.039
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center