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Updated: Jun 26, 2026

Measuring In Vitro ATPase Activity for Enzymatic Characterization
Published on: August 23, 2016
Regulation of Vps4 ATPase activity by ESCRT-III
Brian A Davies1, Ishara F Azmi, David J Katzmann
1Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First Street S.W., Rochester, MN 55905, USA.
Abstract:
MVB (multivesicular body) formation occurs when the limiting membrane of an endosome invaginates into the intraluminal space and buds into the lumen, bringing with it a subset of transmembrane cargoes. Exvagination of the endosomal membrane from the cytosol is topologically similar to the budding of retroviral particles and cytokinesis, wherein membranes bud away from the cytoplasm, and the machinery responsible for MVB sorting has been implicated in these phenomena. The AAA (ATPase associated with various cellular activities) Vps4 (vacuolar protein sorting 4) performs a critical function in the MVB sorting pathway. Vps4 appears to dissociate the ESCRTs (endosomal sorting complexes required for transport) from endosomal membranes during the course of MVB sorting, but it is unclear how Vps4 ATPase activity is synchronized with ESCRT release. We have investigated the mechanisms by which ESCRT components stimulate the ATPase activity of Vps4. These studies support a model wherein Vps4 activity is subject to spatial and temporal regulation via distinct mechanisms during MVB sorting.
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