Weak acid and alkali stress regulate phosphatidylinositol bisphosphate synthesis in Saccharomyces cerevisiae

Mollapour, Mehdi, Phelan, Oohn P., Millson, Stefan H. , Piper, Peter W. and Cooke, Frank T. (2006) Weak acid and alkali stress regulate phosphatidylinositol bisphosphate synthesis in Saccharomyces cerevisiae. Biochemical Journal, 395 (1). pp. 73-80. ISSN 0264-6021

Full content URL: http://dx.doi.org/10.1042/BJ20051765

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Item Type:Article
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Weak organic acids are used as food preservatives to inhibit the growth of spoilage yeasts, including Saccharomyces cerevisiae. Long-term adaptation to weak acids requires the increased expression of the ATP-binding cassette transporter Pdr12p, which catalyses the active efflux of the weak acids from the cytosol; however, very little is known about the signalling events immediately following application of weak acid stress. We have investigated the effects of weak acids on two stress-responsive signalling molecules, PtdIns(3,5)P2 and PtdIns(4,5)P2, which in S. cerevisiae are synthesized by Fab1p and Mss4p respectively. At low extracellular pH, benzoic acid, sorbic acid and acetic acid all cause a transient reduction in PtdIns(3,5)P2 accumulation and a more persistent rise in PtdIns(4,5)P2 levels. The increase in PtdIns(4,5)P2 levels is accompanied by a reorganization of the actin cytoskeleton. However, changes in PtdInsP2 levels are independent of weak acid-induced Pdr12p expression. In contrast, changing the extracellular medium to alkaline pH provokes a prolonged and substantial rise in PtdIns(3,5)P2 levels. As PtdIns(3,5)P2 synthesis is required for correct vacuole acidification, it is possible that levels of this molecule are modulated to maintain intracellular pH homoeostasis in response to weak acid and alkali stresses. In conclusion, we have expanded the repertoire of stress responses that affect PtdInsP2 levels to include weak acid and alkali stresses.

Additional Information:Received 1 November 2005; accepted 29 November 2005 Published as BJ Immediate Publication 29 November 2005, doi:10.1042/BJ20051765
Keywords:Alkali stress, Fab1p, Mss4p, PDR12, Phosphatidylinositol bisphosphate, Weak acid
Subjects:C Biological Sciences > C700 Molecular Biology, Biophysics and Biochemistry
C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
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ID Code:15352
Deposited On:21 Oct 2014 19:34

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