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Structural analysis and modeling reveals new mechanisms governing ESCRT-III spiral filament assembly.
- Source :
-
Journal of Cell Biology . 9/15/2014, Vol. 206 Issue 6, p763-777. 15p. - Publication Year :
- 2014
-
Abstract
- The scission of biological membranes is facilitated by a variety of protein complexes that bind and manipulate lipid bilayers. ESCRT-III (endosomal sorting complex required for transport III) filaments mediate membrane scission during the ostensibly disparate processes of multivesicular endosome biogenesis, cytokinesis, and retroviral budding. However, mechanisms by which ESCRT-III subunits assemble into a polymer remain unknown. Using cryogenic electron microscopy (cryo-EM), we found that the full-length ESCRT-III subunit Vps32/CHMP4B spontaneously forms single-stranded spiral filaments. The resolution afforded by two-dimensional cryo-EM combined with molecular dynamics simulations revealed that individual Vps32/CHMP4B monomers within a filament are flexible and able to accommodate a range of bending angles. In contrast, the interface between monomers is stable and refractory to changes in conformation. We additionally found that the carboxyl terminus of Vps32/CHMP4B plays a key role in restricting the lateral association of filaments. Our findings highlight new mechanisms by which ESCRT-III filaments assemble to generate a unique polymer capable of membrane remodeling in multiple cellular contexts. [ABSTRACT FROM AUTHOR]
- Subjects :
- *STRUCTURAL analysis (Science)
*BIOLOGICAL membranes
*PROTEINS
*LIPIDS
*ENDOSOMES
Subjects
Details
- Language :
- English
- ISSN :
- 00219525
- Volume :
- 206
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Journal of Cell Biology
- Publication Type :
- Academic Journal
- Accession number :
- 98648029
- Full Text :
- https://doi.org/10.1083/jcb.201403108