A novel role for the yeast protein kinase Dbf2p in vacuolar H+-ATPase function and sorbic acid stress tolerance

Vasso Makrantoni, Paul Dennison, Michael J. R. Stark, Peter J. Coote

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    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 languageEnglish
    Pages (from-to)4016-4026
    Number of pages11
    JournalMicrobiology
    Volume153
    DOIs
    Publication statusPublished - 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

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