title: The VPS-20 subunit of the endosomal sorting complex ESCRT-III exhibits an open conformation in the absence of upstream activation.
abstract: Members of the endosomal sorting complex required for transport (ESCRT) machinery function in membrane remodelling processes during multivesicular endosome (MVE) biogenesis, cytokinesis, retroviral budding and plasma membrane repair. During luminal vesicle formation at endosomes, the ESCRT-II complex and the ESCRT-III subunit vacuolar protein sorting (VPS)-20 play a specific role in regulating assembly of ESCRT-III filaments, which promote vesicle scission. Previous work suggests that Vps20 isoforms, like other ESCRT-III subunits, exhibits an auto-inhibited closed conformation in solution and its activation depends on an association with ESCRT-II specifically at membranes [1]. However, we show in the present study that Caenorhabditis elegans ESCRT-II and VPS-20 interact directly in solution, both in cytosolic cell extracts and in using recombinant proteins in vitro. Moreover, we demonstrate that purified VPS-20 exhibits an open extended conformation, irrespective of ESCRT-II binding, in contrast with the closed auto-inhibited architecture of another ESCRT-III subunit, VPS-24. Our data argue that individual ESCRT-III subunits adopt distinct conformations, which are tailored for their specific functions during ESCRT-mediated membrane reorganization events.
authors.affiliation: *Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, U.S.A.
authors.forename: Amber L
authors.initials: AL
authors.lastname: Schuh
authors.affiliation: *Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, U.S.A.
authors.forename: Michael
authors.initials: M
authors.lastname: Hanna
authors.affiliation: *Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, U.S.A.
authors.forename: Kyle
authors.initials: K
authors.lastname: Quinney
authors.affiliation: *Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, U.S.A.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: †Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, U.S.A.
authors.forename: Ali
authors.initials: A
authors.lastname: Sarkeshik
authors.affiliation: †Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, U.S.A.
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.affiliation: *Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, U.S.A.
authors.forename: Anjon
authors.initials: A
authors.lastname: Audhya
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry* / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D006801:Humans; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology
chemical_list: C481528:CHMP6 protein, human; D056827:Endosomal Sorting Complexes Required for Transport; D021122:Protein Subunits