Abstract
The ESCRT-II-ESCRT-III interaction coordinates the sorting of ubiquitinated cargo with the budding and scission of intralumenal vesicles into multivesicular bodies. The interacting regions of these complexes were mapped to the second winged helix domain of human ESCRT-II subunit VPS25 and the first helix of ESCRT-III subunit VPS20. The crystal structure of this complex was determined at 2.0 A resolution. Residues involved in structural interactions explain the specificity of ESCRT-II for Vps20, and are critical for cargo sorting in vivo. ESCRT-II directly activates ESCRT-III-driven vesicle budding and scission in vitro via these structural interactions. VPS20 and ESCRT-II bind membranes with nanomolar affinity, explaining why binding to ESCRT-II is dispensable for the recruitment of Vps20 to membranes. Docking of the ESCRT-II-VPS20(2) supercomplex reveals a convex membrane-binding surface, suggesting a hypothesis for negative membrane curvature induction in the nascent intralumenal vesicle.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Membrane / metabolism
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Crystallography, X-Ray
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Endosomal Sorting Complexes Required for Transport
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Endosomes / metabolism*
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Humans
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Models, Molecular
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Molecular Sequence Data
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Multiprotein Complexes* / chemistry
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Multiprotein Complexes* / metabolism
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Protein Structure, Secondary*
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Protein Structure, Tertiary*
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Protein Subunits / chemistry
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Protein Subunits / genetics
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Protein Subunits / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Vesicular Transport Proteins / chemistry*
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Vesicular Transport Proteins / genetics
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Vesicular Transport Proteins / metabolism*
Substances
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CHMP6 protein, human
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Endosomal Sorting Complexes Required for Transport
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Multiprotein Complexes
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Protein Subunits
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Vesicular Transport Proteins
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Vps25 protein, human