Structural basis for activation, assembly and membrane binding of ESCRT-III Snf7 filaments
Year: 2015
Type: article
Abstract: The endosomal sorting complexes required for transport (ESCRTs) constitute hetero-oligomeric machines that catalyze multiple topologically similar membrane-remodeling processes. Although ESCRT-III subunits polymerize into spirals, how individual ESCRT-III subunits are activated and assembled together into a membrane-deforming filament remains unknown. Here, we determine X-ray crystal structures of the most abundant ESCRT-III subunit Snf7 in its active conformation. Using pulsed dipolar electron spin resonance spectroscopy (PDS), we show that Snf7 activation requires a prominent conformational rearrangement to expose protein-membrane and protein-protein interfaces. This promotes the assembly of Snf7 arrays with ~30 Å periodicity into a membrane-sculpting filament. Using a combination of biochemical and genetic approaches, both in vitro and in vivo, we demonstrate that mutations on these protein interfaces halt Snf7 assembly and block ESCRT function. The architecture of the activated and membrane-bound Snf7 polymer provides crucial insights into the spatially unique ESCRT-III-mediated membrane remodeling.
Source: eLife
DOI: 10.7554/elife.12548
Institution: Cornell University
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,500
Awards: Structural and Functional Studies of the Sac Family Phosphoinositide Phosphatases, G1117816530, G1205925815, G2292729022, G3149188989, G344770576, G3820945809, G403320550, G4543437078, G6337112251, G6711283272, G7186940599, G9000031648, G9000102233, G9000137912, G9000149892, G9000173621, G9000177307, G9000202897, G9000255390, G9000304317
OpenAlex ID: W2198297310