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Logo of jbcThe Journal of Biological Chemistry
J Biol Chem. 2012 November 23; 287(48): 40197.
PMCID: PMC3504733

All Phosphatidate Phosphatase Genes in Yeast Identified♦

The Saccharomyces cerevisiae Actin Patch Protein App1p Is a Phosphatidate Phosphatase Enzyme

♦ See referenced article, J. Biol. Chem. 2012, 287, 40186–40196

Phosphatidate phosphatase (PAP) catalyzes the dephosphorylation of phosphatidate to generate diacylglycerol and plays important roles in lipid metabolism and cell signaling. The enzyme activity in yeast was known to be encoded by PAH1, DPP1, and LPP1, but the mutant lacking these three genes still possessed significant PAP activity. Understanding the physiological role of PAP activity has been hampered because the missing gene encoding the enzyme was yet to be identified. In this Paper of the Week, George M. Carman and colleagues at Rutgers University purified PAP activity from yeast lacking the PAH1, DPP1, and LPP1 genes and demonstrated that APP1 encoded the remaining PAP activity. Analysis of cells missing all four PAP genes clarified that the PAP activity involved in the synthesis of triacylglycerol and in the regulation of phospholipid synthesis was encoded by PAH1. The product of APP1, whose molecular function was unknown, is an actin patch protein that interacts with several endocytic proteins. Carman states, “We speculate that the APP1-encoded PAP activity plays a role in vesicle formation through its recruitment from the cytosol to cortical actin patches via endocytic proteins.”

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SDS-PAGE and Western blot analysis of App1p purified from E. coli and the PAP activity of the purified enzyme.

Articles from The Journal of Biological Chemistry are provided here courtesy of American Society for Biochemistry and Molecular Biology