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- Title
A Genomic Screen for Yeast Vacuolar Membrane ATPase Mutants.
- Authors
Sambade, Maria; Alba, Mercedes; Smardon, Anne M.; West, Robert W.; Kane, Patricia M.
- Abstract
V-ATPases acidity multiple organelles, and yeast mutants lacking V-ATPase activity exhibit a distinctive set of growth defects. To better understand the requirements for organelle acidification and the basis of these growth phenotypes, ∼4700 yeast deletion mutants were screened for growth defects at pH 7.5 in 60 mm CaCl2. In addition to 13 of 16 mutants lacking known V-ATPase subunits or assembly factors, 50 additional mutants were identified. Sixteen of these also grew poorly in nonfermentable carbon sources, like the known V-ATPase mutants, and were analyzed further. The cwh36Δ mutant exhibited the strongest phenotype; this mutation proved to disrupt a previously uncharacterized V-ATPase subunit. A small subset of the mutations implicated in vacuolar protein sorting, vps34Δ, vps15Δ, vps45Δ, and vps16Δ, caused both Vma- growth phenotypes and lower V-ATPase activity in isolated vacuoles, as did the shp1Δ mutation, implicated in both protein sorting and regulation of the Glc7p protein phosphatase. These proteins may regulate V-ATPase targeting and/or activity. Eight mutants showed a Vma- growth phenotype but no apparent defect in vacuolar acidification. Like V-ATPase-deficient mutants, most of these mutants rely on calcineurin for growth, particularly at high pH. A requirement for constitutive calcineurin activation may he the predominant physiological basis of the Vma- growth phenotype.
- Subjects
YEAST; ADENOSINE triphosphatase genes; ORGANELLES; GENETIC testing; GENETIC mutation; GENOMES; GENETICS
- Publication
Genetics, 2005, Vol 170, Issue 4, p1539
- ISSN
0016-6731
- Publication type
Article
- DOI
10.1534/genetics.105.042812