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

J. Biol. Chem., Vol. 280, Issue 46, 38328-38336, November 18, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: 280/46/38328    most recent M509622200v1 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?

Expression of Human CTP Synthetase in Saccharomyces cerevisiae Reveals Phosphorylation by Protein Kinase A^*

Gil-Soo Han, Avula Sreenivas, Mal-Gi Choi, Yu-Fang Chang, Shelley S. Martin, Enoch P. Baldwin, and George M. Carman1

From the Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick, New Jersey 08901 and Departments of Molecular and Cellular Biology and Chemistry, University of California, Davis, California 95616

CTP synthetase (EC 6.3.4.2 [EC] , UTP:ammonia ligase (ADP-forming)) is an essential enzyme in all organisms; it generates the CTP required for the synthesis of nucleic acids and membrane phospholipids. In this work we showed that the human CTP synthetase genes, CTPS1 and CTPS2, were functional in Saccharomyces cerevisiae and complemented the lethal phenotype of the ura7 ura8 mutant lacking CTP synthetase activity. The expression of the CTPS1- and CTPS2-encoded human CTP synthetase enzymes in the ura7 ura8 mutant was shown by immunoblot analysis of CTP synthetase proteins, the measurement of CTP synthetase activity, and the synthesis of CTP in vivo. Phosphoamino acid and phosphopeptide mapping analyses of human CTP synthetase 1 isolated from ³²P_i-labeled cells revealed that the enzyme was phosphorylated on multiple serine residues in vivo. Activation of protein kinase A activity in yeast resulted in transient increases (2-fold) in the phosphorylation of human CTP synthetase 1 and the cellular level of CTP. Human CTP synthetase 1 was also phosphorylated by mammalian protein kinase A in vitro. Using human CTP synthetase 1 purified from Escherichia coli as a substrate, protein kinase A activity was dose- and time-dependent, and dependent on the concentrations of CTP synthetase 1 and ATP. These studies showed that S. cerevisiae was useful for the analysis of human CTP synthetase phosphorylation.

Received for publication, August 31, 2005 , and in revised form, September 16, 2005.

^* This work was supported in part by United States Public Health Service, National Institutes of Health Grants GM-50679 (to G. M. C.) and GM-63109 (to E. P. B). 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 Road, New Brunswick, NJ 08901. Tel.: 732-932-9611 (ext. 217); Fax: 732-932-6776; 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:

				F. A. Lunn, J. E. MacDonnell, and S. L. Bearne Structural Requirements for the Activation of Escherichia coli CTP Synthase by the Allosteric Effector GTP Are Stringent, but Requirements for Inhibition Are Lax J. Biol. Chem., January 25, 2008; 283(4): 2010 - 2020. [Abstract] [Full Text] [PDF]

				M. J. Higgins, P. R. Graves, and L. M. Graves Regulation of Human Cytidine Triphosphate Synthetase 1 by Glycogen Synthase Kinase 3 J. Biol. Chem., October 5, 2007; 282(40): 29493 - 29503. [Abstract] [Full Text] [PDF]

				Y.-F. Chang, S. S. Martin, E. P. Baldwin, and G. M. Carman Phosphorylation of Human CTP Synthetase 1 by Protein Kinase C: IDENTIFICATION OF Ser462 AND Thr455 AS MAJOR SITES OF PHOSPHORYLATION J. Biol. Chem., June 15, 2007; 282(24): 17613 - 17622. [Abstract] [Full Text] [PDF]

				M.-G. Choi and G. M. Carman Phosphorylation of Human CTP Synthetase 1 by Protein Kinase A: IDENTIFICATION OF Thr455 AS A MAJOR SITE OF PHOSPHORYLATION J. Biol. Chem., February 23, 2007; 282(8): 5367 - 5377. [Abstract] [Full Text] [PDF]