%0 Journal Article %A Makrantoni, Vasso %A Dennison, Paul %A Stark, Michael J. R. %A Coote, Peter J. %T A novel role for the yeast protein kinase Dbf2p in vacuolar H+-ATPase function and sorbic acid stress tolerance %D 2007 %J Microbiology, %V 153 %N 12 %P 4016-4026 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.2007/010298-0 %K 2,4-D, 2,4-dichlorophenoxyacetic acid %K ABC, ATP-binding cassette %K V-ATPase, vacuolar H+-ATPase %K CIP, calf intestinal phosphatase %I Microbiology Society, %X 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 (dbf2Δ). Crucially, VMA2 is a multicopy suppressor of both the sorbic acid-sensitive phenotype and the impaired vacuolar-acidification defect of dbf2Δ 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. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.2007/010298-0