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Regulation of the yeast PAH1 gene encoding Mg 2+ ‐dependent phosphatidate phosphatase
Author(s) -
Pascual Florencia,
Carman George M.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.807.4
Subject(s) - phosphatidate , diacylglycerol kinase , derepression , inositol , biochemistry , reporter gene , dephosphorylation , phosphatase , biology , chemistry , enzyme , microbiology and biotechnology , gene expression , gene , psychological repression , receptor , protein kinase c
The PAH1 gene in Saccharomyces cerevisiae encodes Mg 2+ ‐dependent phosphatidate (PA) phosphatase. PA phosphatase catalyzes the dephosphorylation of PA yielding diacylglycerol and Pi. This enzyme generates the diacylglycerol used for the synthesis of triacylglycerol, and may generate the diacylglycerol used for the synthesis of phosphatidylethanolamine and phosphatidylcholine via the Kennedy pathway. The PAH1 ‐encoded enzyme also controls the cellular concentration of its substrate PA, which is the precursor for phospholipids that are synthesized via the CDP‐diacylglycerol pathway. In this work, we examined the regulation of PAH1 expression in response to inositol supplementation and growth phase by utilization of a P PAH1 ‐ lacZ reporter gene plasmid transformed into wild type cells. In the absence of inositol, the β‐galactosidase activity driven by the reporter gene was 3‐fold higher in stationary phase cells when compared with exponential phase cells. In the presence of inositol, the activity in stationary phase cells was 10‐fold higher than that found in exponential phase cells. In stationary phase cells, inositol supplementation resulted in a 2‐fold increase in β‐galactosidase activity. Inositol did not affect the expression of PAH1 in the exponential phase of growth. The transcription factors involved are being examined. Supported by NIH grant GM 28140.