title: Cryo-EM structure of dodecameric Vps4p and its 2:1 complex with Vta1p.
abstract: The type I AAA (ATPase associated with a variety of cellular activities) ATPase Vps4 and its co-factor Vta1p/LIP5 function in membrane remodeling events that accompany cytokinesis, multivesicular body biogenesis, and retrovirus budding, apparently by driving disassembly and recycling of membrane-associated ESCRT (endosomal sorting complex required for transport)-III complexes. Here, we present electron cryomicroscopy reconstructions of dodecameric yeast Vps4p complexes with and without their microtubule interacting and transport (MIT) N-terminal domains and Vta1p co-factors. The ATPase domains of Vps4p form a bowl-like structure composed of stacked hexameric rings. The two rings adopt dramatically different conformations, with the "upper" ring forming an open assembly that defines the sides of the bowl and the lower ring forming a closed assembly that forms the bottom of the bowl. The N-terminal MIT domains of the upper ring localize on the symmetry axis above the cavity of the bowl, and the binding of six extended Vta1p monomers causes additional density to appear both above and below the bowl. The structures suggest models in which Vps4p MIT and Vta1p domains engage ESCRT-III substrates above the bowl and help transfer them into the bowl to be pumped through the center of the dodecameric assembly.
authors.affiliation: Division of Biology, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Yu
authors.forename: Malgorzata D
authors.initials: MD
authors.lastname: Gonciarz
authors.forename: Wesley I
authors.initials: WI
authors.lastname: Sundquist
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Hill
authors.forename: Grant J
authors.initials: GJ
authors.lastname: Jensen
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D002850:Chromatography, Gel; D020285:Cryoelectron Microscopy; D056827:Endosomal Sorting Complexes Required for Transport; D008958:Models, Molecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D029701:Saccharomyces cerevisiae Proteins; C107528:VPS4 protein, S cerevisiae; C487285:VTA1 protein, S cerevisiae; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases