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The Saccharomyces cerevisiae PHM8 Gene Encodes a Soluble Magnesium-dependent Lysophosphatidic Acid Phosphatase

Reddy, Venky Sreedhar and Singh, Arjun Kumar and Rajasekharan, Ram (2008) The Saccharomyces cerevisiae PHM8 Gene Encodes a Soluble Magnesium-dependent Lysophosphatidic Acid Phosphatase. In: Journal of Biological Chemistry, 283 (14). 8846-8854.

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Abstract

Phosphate is the essential macronutrient required for the growth of all organisms. In Saccharomyces cerevisiae, phosphatases are up-regulated, and the level of lysophosphatidic acid (LPA) is drastically decreased under phosphate-starved conditions. The reduction in the LPA level is attributed to PHM8, a gene of unknown function. phm8 \Delta yeast showed a decreased LPA-hydrolyzing activity under phosphate-limiting conditions. Overexpression of PHM8 in yeast resulted in an increase in the LPA phosphatase activity in vivo. In vitro assays of the purified recombinant Phm8p revealed magnesium-dependent LPA phosphatase activity, with maximal activity at pH 6.5. The purified Phm8p did not hydrolyze any lipid phosphates other than LPA. In silico analysis suggest that Phm8p is a soluble protein with no transmembrane domain. Site-directed mutational studies revealed that aspartate residues in a DXDXT motif are important for the catalysis. These findings indicated that LPA plays a direct role in phosphate starvation. This is the first report of the identification and characterization of magnesium-dependent soluble LPA phosphatase.

Item Type: Journal Article
Additional Information: American Society for Biochemistry and Molecular Biology.
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 16 Apr 2008
Last Modified: 27 Aug 2008 13:20
URI: http://eprints.iisc.ernet.in/id/eprint/13740

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