Structural and biochemical study of Vps4

Update item information
Publication Type dissertation
School or College School of Medicine
Department Biochemistry
Author Han, Han
Title Structural and biochemical study of Vps4
Date 2014
Description Vps4 is an AAA ATPase that functions in the ESCRT-mediated membrane fission process. Vps4 can use the energy from ATP hydrolysis to disassemble the ESCRT-III complexes. However, the mechanism of ESCRT-III disassembly by Vps4 is not clear. I have tried to address two major questions of Vps4 mechanism: how do monomers form the functional oligomer, and how does the functional Vps4 oligomer process its substrate ESCRT-III proteins. In Chapter 2, which was published recently, we reported that the functional state of Vps4 is a hexamer, and that the interface mediating hexamer formation has been conserved in highly diverse species. Chapter 3 describes my attempts to crystallize an assembled Vps4 hexamer. Despite considerable effort, I was not successful in obtaining crystals of assembled Vps4 that diffract to high resolution, although some preliminary crystals that appear to contain a complex of Vps4 hexamer and the substrate peptide were obtained and may serve as a guide for future efforts. In Chapter 4, I report that residues in helix5 of the Vps2/ESCRT-III protein form a secondary Vps4 binding site, and show that they bind to the pore loops of an asymmetric Vps4 hexamer in a 1:1 peptide:Vps4 hexamer stoichiometry. I further demonstrate that this interaction is negatively regulated by the N-terminal MIT domain of Vps4. These findings support a model of ESCRT-III disassembly in which the Vps4 hexamer pulls the C-terminal helix5 of ESCRT-III into/through the central pore of the asymmetric Vps4 hexamer. In Chapter 5, I suggest future experiments that could be pursued to confirm this model and further advance understanding of the Vps4 mechanism.
Type Text
Publisher University of Utah
Subject Biochemistry
Dissertation Name Doctor of Philosophy
Language eng
Rights Management (c) Han Han
Format Medium application/pdf
ARK ark:/87278/s6m08pzz
Setname ir_etd
Date Created 2019-07-23
Date Modified 2021-05-06
ID 1432609
Reference URL