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Identification of cyclin‐dependent kinase phosphorylation sites in yeast phosphatidate phosphatase
Author(s) -
Choi HyeonSon,
Morgan Jeanelle M,
Su WenMin,
Han GilSoo,
Carman George M
Publication year - 2010
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.24.1_supplement.694.4
Subject(s) - cyclin dependent kinase , phosphorylation , phosphatidate , biochemistry , kinase , biology , serine , phosphatase , microbiology and biotechnology , protein kinase c , cell cycle , diacylglycerol kinase , cell
The PAH1 ‐encoded phosphatidate (PA) phosphatase (PAP) plays a major role in controlling the cellular content of PA in the yeast Saccharomyces cerevisiae . The enzyme is phosphorylated in vivo on multiple residues, and one of the protein kinases involved is cyclin‐dependent kinase (CDK). In vitro , CDK phosphorylates purified recombinant PAP on both serine and threonine residues. An analysis of purified truncated forms of PAP revealed that the sites of CDK phosphorylation were at the C‐terminal end of the enzyme. A site‐directed mutagenesis study showed that Ser602 and Thr723 were the major sites of phosphorylation. In vitro , the S723A mutation caused a 50 % reduction in the CDK phosphorylation of PAP, whereas the S602A mutation caused the complete loss of the CDK phosphorylation of the enzyme. This indicated that phosphorylation of Ser602 was required for the phosphorylation of Thr723. Yeast strains that express S602A, T723A, and S602A T723A mutant enzymes have been constructed to examine the effects of CDK phosphorylation on PAP function in lipid metabolism. Supported by NIH grant GM‐50679.