title: Vta1p and Vps46p regulate the membrane association and ATPase activity of Vps4p at the yeast multivesicular body.
abstract: Previous two-hybrid analysis of the 17 soluble class E Vps yeast proteins revealed that Vps46p/Did2p interacts with Vta1p and the AAA (ATPase associated with a variety of cellular activities) ATPase Vps4p. Here we report that the binding of Vps46p to Vps4p and Vta1p is direct and not mediated by additional proteins, and the binding of Vps46p to Vps4p is ATP independent. Vps46p regulates the membrane association of Vps4p and is required for the interaction of Vta1p with Vps32p/Snf7p of the ESCRT-III complex. Vta1p is a potent activator of Vps4p, stimulating the ATPase activity by 6- to 8-fold. These results reveal functional roles for the Vps46p and Vta1p proteins in regulating the ESCRT complex assembly/disassembly cycle in protein sorting at the yeast late endosome.
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, OR 97403-1229, USA.
authors.forename: Jillian M
authors.initials: JM
authors.lastname: Lottridge
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Flannery
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Vincelli
authors.forename: Tom H
authors.initials: TH
authors.lastname: Stevens
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D004705:Endocytosis; D056827:Endosomal Sorting Complexes Required for Transport; D011992:Endosomes / Q000378:metabolism*; D008954:Models, Biological; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C511158:DID2 protein, S cerevisiae; 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