title: The RAVE complex is an isoform-specific V-ATPase assembly factor in yeast.
abstract: The regulator of ATPase of vacuoles and endosomes (RAVE) complex is implicated in vacuolar H(+)-translocating ATPase (V-ATPase) assembly and activity. In yeast, rav1 mutants exhibit a Vma(-) growth phenotype characteristic of loss of V-ATPase activity only at high temperature. Synthetic genetic analysis identified mutations that exhibit a full, temperature-independent Vma(-) growth defect when combined with the rav1 mutation. These include class E vps mutations, which compromise endosomal sorting. The synthetic Vma(-) growth defect could not be attributed to loss of vacuolar acidification in the double mutants, as there was no vacuolar acidification in the rav1 mutant. The yeast V-ATPase a subunit is present as two isoforms, Stv1p in Golgi and endosomes and Vph1p in vacuoles. Rav1p interacts directly with the N-terminal domain of Vph1p. STV1 overexpression suppressed the growth defects of both rav1 and rav1vph1, and allowed RAVE-independent assembly of active Stv1p-containing V-ATPases in vacuoles. Mutations causing synthetic genetic defects in combination with rav1 perturbed the normal localization of Stv1-green fluorescent protein. We propose that RAVE is necessary for assembly of Vph1-containing V-ATPase complexes but not Stv1-containing complexes. Synthetic Vma(-) phenotypes arise from defects in Vph1p-containing complexes caused by rav1, combined with defects in Stv1p-containing V-ATPases caused by the second mutation. Thus RAVE is the first isoform-specific V-ATPase assembly factor.
authors.affiliation: Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Smardon
authors.forename: Heba I
authors.initials: HI
authors.lastname: Diab
authors.forename: Maureen
authors.initials: M
authors.lastname: Tarsio
authors.forename: Theodore T
authors.initials: TT
authors.lastname: Diakov
authors.forename: Negin Dehdar
authors.initials: ND
authors.lastname: Nasab
authors.forename: Robert W
authors.initials: RW
authors.lastname: West
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Kane
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis / Q000235:genetics*; D011992:Endosomes / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000096:biosynthesis / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D029701:Saccharomyces cerevisiae Proteins; D025262:Vacuolar Proton-Translocating ATPases