Abstract
In Saccharomyces cerevisiae, the serine-threonine protein kinase activity of Dbf2p is required for tolerance to the weak organic acid sorbic acid. Here we show that Dbf2p is required for normal phosphorylation of the vacuolar H+-ATPase (V-ATPase) A and B subunits Vma1p and Vma2p. Loss of V-ATPase activity due to bafilomycin treatment or deletion of either VMA1 or VMA2 resulted in sorbic acid hypersensitivity and impaired vacuolar acidification, phenotypes also observed in both a kinase-inactive dbf2 mutant and cells completely lacking DBF2 (dbf2 Delta). Crucially, VMA2 is a multicopy suppressor of both the sorbic acid-sensitive phenotype and the impaired vacuolar-acidification defect of dbf2 Delta cells, confirming a functional interaction between Dbf2p and Vma2p. The yeast V-ATPase is therefore involved in mediating sorbic acid stress tolerance, and we have shown a novel and unexpected role for the cell cycle-regulated protein kinase Dbf2p in promoting V-ATPase function.
Original language | English |
---|---|
Pages (from-to) | 4016-4026 |
Number of pages | 11 |
Journal | Microbiology |
Volume | 153 |
DOIs | |
Publication status | Published - Dec 2007 |
Keywords
- MAJOR FACILITATOR SUPERFAMILY
- PLASMA-MEMBRANE TRANSPORTER
- SITE-DIRECTED MUTAGENESIS
- SACCHAROMYCES-CEREVISIAE
- CELL-CYCLE
- BUDDING YEAST
- SYSTEMATIC IDENTIFICATION
- CCR4-NOT COMPLEX
- ABC TRANSPORTER
- BINDING-SITE