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Science. 2015 Dec 18;350(6267):1548-51. doi: 10.1126/science.aad8305. Epub 2015 Dec 3.

Structure and membrane remodeling activity of ESCRT-III helical polymers.

Author information

1
Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA.
2
Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
3
Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA. Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
4
Physical Bioscience Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
5
FEI Company, Hillsboro, OR 97124, USA.
6
Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA. wes@biochem.utah.edu phanson22@wustl.edu adam.frost@ucsf.edu.
7
Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA. wes@biochem.utah.edu phanson22@wustl.edu adam.frost@ucsf.edu.
8
Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA. Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA. wes@biochem.utah.edu phanson22@wustl.edu adam.frost@ucsf.edu.

Abstract

The endosomal sorting complexes required for transport (ESCRT) proteins mediate fundamental membrane remodeling events that require stabilizing negative membrane curvature. These include endosomal intralumenal vesicle formation, HIV budding, nuclear envelope closure, and cytokinetic abscission. ESCRT-III subunits perform key roles in these processes by changing conformation and polymerizing into membrane-remodeling filaments. Here, we report the 4 angstrom resolution cryogenic electron microscopy reconstruction of a one-start, double-stranded helical copolymer composed of two different human ESCRT-III subunits, charged multivesicular body protein 1B (CHMP1B) and increased sodium tolerance 1 (IST1). The inner strand comprises "open" CHMP1B subunits that interlock in an elaborate domain-swapped architecture and is encircled by an outer strand of "closed" IST1 subunits. Unlike other ESCRT-III proteins, CHMP1B and IST1 polymers form external coats on positively curved membranes in vitro and in vivo. Our analysis suggests how common ESCRT-III filament architectures could stabilize different degrees and directions of membrane curvature.

PMID:
26634441
PMCID:
PMC4684769
DOI:
10.1126/science.aad8305
[Indexed for MEDLINE]
Free PMC Article

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