HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 51, 37026-37035, December 21, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/51/37026    most recent M705777200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Han, G.-S. Articles by Carman, G. M. Search for Related Content PubMed PubMed Citation Articles by Han, G.-S. Articles by Carman, G. M. Social Bookmarking                      What's this?

The Cellular Functions of the Yeast Lipin Homolog Pah1p Are Dependent on Its Phosphatidate Phosphatase Activity^*

Gil-Soo Han, Symeon Siniossoglou, and George M. Carman¹

From the Department of Food Science and the Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901 and the Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, CB2 2XY Cambridge, United Kingdom

The Saccharomyces cerevisiae PAH1-encoded Mg²⁺-dependent phosphatidate phosphatase (PAP1, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) catalyzes the dephosphorylation of phosphatidate to yield diacylglycerol and P_i. This enzyme plays a major role in the synthesis of triacylglycerols and phospholipids in S. cerevisiae. PAP1 contains the DXDX(T/V) catalytic motif (DIDGT at residues 398-402) that is shared by the mammalian fat-regulating protein lipin 1 and the superfamily of haloacid dehalogenase-like proteins. The yeast enzyme also contains a conserved glycine residue (Gly⁸⁰) that is essential for the fat-regulating function of lipin 1 in a mouse model. In this study, we examined the roles of the putative catalytic motif and the conserved glycine for PAP1 activity by a mutational analysis. The PAP1 activities of the D398E and D400E mutant enzymes were reduced by >99.9%, and the activity of the G80R mutant enzyme was reduced by 98%. The mutant PAH1 alleles whose products lacked PAP1 activity were nonfunctional in vivo and failed to complement the pah1 mutant phenotypes of temperature sensitivity, respiratory deficiency, nuclear/endoplasmic reticulum membrane expansion, derepression of INO1 expression, and alterations in lipid composition. These results demonstrated that the PAP1 activity of the PAH1 gene product is essential for its roles in lipid metabolism and cell physiology.

Received for publication, July 13, 2007 , and in revised form, October 17, 2007.

^* This work was supported in part by United States Public Health Service Grant GM-28140 from the National Institutes of Health (to G. M. C.) and by a Wellcome Trust Career Development Fellowship in Basic Biomedical Science (to S. S.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ To whom correspondence should be addressed: Dept. of Food Science, Rutgers University, 65 Dudley Rd., New Brunswick, NJ 08901. Tel.: 732-932-9611 (Ext. 217); E-mail: carman{at}aesop.rutgers.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				V. S. Reddy, A. K. Singh, and R. Rajasekharan The Saccharomyces cerevisiae PHM8 Gene Encodes a Soluble Magnesium-dependent Lysophosphatidic Acid Phosphatase J. Biol. Chem., April 4, 2008; 283(14): 8846 - 8854. [Abstract] [Full Text] [PDF]