title: Vma22p is a novel endoplasmic reticulum-associated protein required for assembly of the yeast vacuolar H(+)-ATPase complex.
abstract: The Saccharomyces cerevisiae vacuolar H(+)-ATPase (V-ATPase) is a multi-subunit complex that can be structurally and functionally divided into peripheral (V1) and integral membrane (V0) sectors. The vma22-1 mutation was isolated in a screen for mutants defective in V-ATPase function vma22 delta cells contain no V-ATPase activity due to a failure to assemble the enzyme complex; V1 subunits accumulate in the cytosol, and the V0 100-kDa subunit is rapidly degraded. Turnover of the 100-kDa integral membrane protein was found to occur in the endoplasmic reticulum (ER) of vma22 delta cells. The product of the VMA22 gene, Vma22p, is a 21-kDa hydrophilic protein that is not a subunit of the V-ATPase but rather is associated with ER membranes. The association of Vma22p with ER membranes was perturbed by mutations in VMA12, a gene that encodes an ER membrane protein (Vma12p) that is also required for V-ATPase assembly. These results indicate that Vma22p, along with Vma21p and Vma12p, form a set of ER proteins required for V-ATPase assembly.
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene 97403-1229, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Hill
authors.forename: T H
authors.initials: TH
authors.lastname: Stevens
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism*; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D017931:DNA Primers; D005656:Fungal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; C095635:VMA22 protein, S cerevisiae; D006180:Proton-Translocating ATPases