A Yeast Mutant Deleted of GPH1 Bears Defects in Lipid Metabolism.
In a previous study we demonstrated up-regulation of the yeast GPH1 gene under conditions of phosphatidylethanolamine (PE) depletion caused by deletion of the mitochondrial (M) phosphatidylserine decarboxylase 1 (PSD1) (Gsell et al., 2013, PLoS One. 8(10):e77380. doi: 10.1371/journal.pone.0077380). Gph1p has originally been identified as a glycogen phosphorylase catalyzing degradation of glycogen to glucose in the stationary growth phase of the yeast. Here we show that deletion of this gene also causes decreased levels of phosphatidylcholine (PC), triacylglycerols and steryl esters. Depletion of the two non-polar lipids in a Δgph1 strain leads to lack of lipid droplets, and decrease of the PC level results in instability of the plasma membrane. In vivo labeling experiments revealed that formation of PC via both pathways of biosynthesis, the cytidine diphosphate (CDP)-choline and the methylation route, is negatively affected by a Δgph1 mutation, although expression of genes involved is not down regulated. Altogether, Gph1p besides its function as a glycogen mobilizing enzyme appears to play a regulatory role in yeast lipid metabolism.
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Martina
M
Gsell
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Ariane
A
Fankl
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Lisa
L
Klug
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Gerald
G
Mascher
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Claudia
C
Schmidt
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Claudia
C
Hrastnik
Institute of Plant Sciences, Karl Franzens University Graz, NaWi Graz, Austria.
Günther
G
Zellnig
Institute of Biochemistry, Graz University of Technology, NaWi Graz, Petersgasse 12/2, 8010, Graz, Austria.
Günther
G
Daum
D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D003566:Cytidine Diphosphate Choline / Q000235:genetics / Q000378:metabolism; D004952:Esters / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics*; D006003:Glycogen / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010713:Phosphatidylcholines / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000235:genetics / Q000378:metabolism; D015003:Yeasts / Q000235:genetics* / Q000378:metabolism
D004952:Esters; D010713:Phosphatidylcholines; D029701:Saccharomyces cerevisiae Proteins; D014280:Triglycerides; D003566:Cytidine Diphosphate Choline; D006003:Glycogen