Three different transport systems exist to accumulate a sufficient amount of potassium cations in yeasts. The most common of these are Trk-type transporters, which are used by all yeast species. Though most yeast species employ two different types of transporters, we only identified one gene encoding a potassium uptake system (Trk-type) in the genome of the highly osmotolerant yeast Zygosaccharomyces rouxii, and our results showed that ZrTrk1 is its major (and probably only) specific potassium uptake system. When expressed in Saccharomyces cerevisiae, the product of the ZrTRK1 gene is localized to the plasma membrane and its presence efficiently complements the phenotypes of S. cerevisiae trk1∆ trk2∆ cells. Deletion of the ZrTRK1 gene resulted in Z. rouxii cells being almost incapable of growth at low K(+) concentrations and it changed some cell physiological parameters in a way that differs from S. cerevisiae. In contrast to S. cerevisiae, Z. rouxii cells without the TRK1 gene contained less potassium than the control cells and their plasma membrane was significantly hyperpolarized compared with those of the parental strain when grown in the presence of 100 mM KCl. On the other hand, subsequent potassium starvation led to a substantial depolarization which is again different from S. cerevisiae. Plasma-membrane hyperpolarization did not prevent the efflux of potassium from Z. rouxii trk1Δ cells during potassium starvation, and the activity of ZrPma1 is less affected by the absence of ZrTRK1 than in S. cerevisiae. The use of a newly constructed Z. rouxii-specific plasmid for the expression of pHluorin showed that the intracellular pH of the Z. rouxii wild type and the trk1∆ mutant is not significantly different. Together with the fact that Z. rouxii cells contain a significantly lower amount of intracellular potassium than identically grown S. cerevisiae cells, our results suggest that this highly osmotolerant yeast species maintain its intracellular pH and potassium homeostasis in way(s) partially distinct from S. cerevisiae.

Department of Membrane Transport Institute of Physiology Academy of Sciences of the Czech Republic Prague Czech Republic

Zobrazit více v PubMed

Biochim Biophys Acta. 2000 Mar 10;1469(1):1-30 PubMed

Nature. 1986 Feb 20-26;319(6055):689-93 PubMed

Mol Cell Biol. 1988 Jul;8(7):2848-59 PubMed

Nucleic Acids Res. 2009 Jan;37(Database issue):D274-8 PubMed

Cell Mol Life Sci. 2010 Aug;67(15):2511-32 PubMed

Mol Microbiol. 2003 Feb;47(3):767-80 PubMed

Microbiology (Reading). 1999 Jan;145 ( Pt 1):241-248 PubMed

Bioinformatics. 2007 Nov 1;23(21):2947-8 PubMed

Nature. 1998 Jul 9;394(6689):192-5 PubMed

Genetics. 2006 Feb;172(2):771-81 PubMed

FEMS Microbiol Lett. 2011 Apr;317(1):1-8 PubMed

Mol Microbiol. 2000 Aug;37(3):671-9 PubMed

FEMS Yeast Res. 2009 Mar;9(2):278-92 PubMed

Pflugers Arch. 2011 Aug;462(2):315-30 PubMed

FEMS Yeast Res. 2007 Dec;7(8):1285-94 PubMed

Mol Microbiol. 2001 May;40(3):656-68 PubMed

Folia Microbiol (Praha). 2011 Jan;56(1):23-8 PubMed

FEMS Yeast Res. 2012 Jun;12(4):439-46 PubMed

Yeast. 1986 Sep;2(3):163-7 PubMed

Microbiol Mol Biol Rev. 2010 Mar;74(1):95-120 PubMed

J Biochem. 1991 Aug;110(2):237-40 PubMed

J Biol Chem. 1998 Jun 12;273(24):14838-44 PubMed

FEMS Yeast Res. 2006 Nov;6(7):1039-46 PubMed

Microbiology (Reading). 2007 Sep;153(Pt 9):3034-3043 PubMed

Yeast. 2001 Jun;18(8):737-44 PubMed

FEMS Yeast Res. 2005 Feb;5(4-5):411-7 PubMed

Biophys J. 1999 Aug;77(2):789-807 PubMed

Yeast. 1998 Sep 30;14(13):1189-97 PubMed

Fungal Biol. 2010 Feb-Mar;114(2-3):144-50 PubMed

Nucleic Acids Res. 1996 Jul 1;24(13):2519-24 PubMed

Nature. 2011 Mar 17;471(7338):336-40 PubMed

Int J Food Microbiol. 2007 Mar 10;114(2):234-42 PubMed

Yeast. 2006 Jun;23(8):581-9 PubMed

FEMS Yeast Res. 2010 Aug 1;10(5):508-17 PubMed

Mol Biol Evol. 2007 Aug;24(8):1596-9 PubMed

J Biosci Bioeng. 1999;88(2):136-42 PubMed

Genes Cells. 2011 Feb;16(2):152-65 PubMed

J Biol Chem. 2005 Aug 26;280(34):30638-47 PubMed

Eukaryot Cell. 2004 Apr;3(2):359-68 PubMed

Yeast. 2010 Jun;27(6):317-25 PubMed

Genetics. 1990 Jun;125(2):305-12 PubMed

FEMS Yeast Res. 2004 Jan;4(4-5):505-10 PubMed

J Biol Chem. 2009 Jan 30;284(5):2795-2802 PubMed

Biochim Biophys Acta. 1990 Nov 16;1029(2):211-7 PubMed

Science. 1998 Apr 3;280(5360):69-77 PubMed

Fungal Genet Biol. 2008 Oct;45(10):1439-47 PubMed

Four Saccharomyces species differ in their tolerance to various stresses though they have similar basic physiological parameters

Potassium Uptake Mediated by Trk1 Is Crucial for Candida glabrata Growth and Fitness