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

This Article Summary Full Text Full Text (PDF) All Versions of this Article: fj.06-6245fjev1 20/12/2133    most recent Alert me when this article is cited Alert me if a correction is posted 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 Spruill, L. S. Articles by McDermott, P. J. Search for Related Content PubMed PubMed Citation Articles by Spruill, L. S. Articles by McDermott, P. J.

Regulation of c-jun mRNA expression in adult cardiocytes by MAP kinase interacting kinase-1 (MNK1)

Department of Medicine, The Gazes Cardiac Research Institute, Medical University of South Carolina, and The Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, South Carolina, USA

¹Correspondence: The Gazes Cardiac Research Institute, Strom Thurmond Biomedical Research Bldg., Rm. 303, 114 Doughty St., Charleston, SC 29403, USA. E-mail: mcdermp{at}musc.edu

ABSTRACT

Hypertrophic growth of adult myocardium is associated with increased expression of the early response gene c-jun. The purpose of this study was to determine whether eukaryotic initiation factor (elF) 4E (eIF4E) regulates translational efficiency of c-jun mRNA as measured by flux into polysomes. Adult feline cardiomyocytes in primary culture were treated with 0.2 µM 12-O-tetradecanoylphorbol 13-acetate (TPA), and c-jun mRNA was quantified in total, monosome, and polysome fractions by real-time polymerase chain reaction. After 1 h, TPA increased total c-jun mRNA by 10.5-fold. The corresponding flux into polysomes was significantly lower (5-fold). Adenoviral-mediated overexpression of either eIF4E or a nonphosphorylatable mutant (S209/A) did not affect total c-jun mRNA or its flux between monosomes and polysomes. Similar results were obtained following overexpression of the eIF4E kinase Mnk1. Thus, translational efficiency of c-jun mRNA was not affected by changes in activity or amount of eIF4E. In contrast, a kinase-deficient Mnk1 mutant significantly reduced total c-jun mRNA from 9.8-fold to 6.0-fold while flux between monosomes and polysomes remained constant. The decrease in total c-jun mRNA resulted from increased decay of c-jun mRNA incorporated into the polysomes. We conclude that Mnk1 activity stabilizes c-jun mRNA in polysomes independent of eIF4E phosphorylation.—Spruill, L. McDermott, P. Regulation of c-jun mRNA expression in adult cardiocytes by MAP kinase interacting kinase-1 (MNK1).

This article has been cited by other articles:

				S. M. DeWire, J. Kim, E. J. Whalen, S. Ahn, M. Chen, and R. J. Lefkowitz {beta}-Arrestin-mediated Signaling Regulates Protein Synthesis J. Biol. Chem., April 18, 2008; 283(16): 10611 - 10620. [Abstract] [Full Text] [PDF]

				C. A. Chrestensen, A. Eschenroeder, W. G. Ross, T. Ueda, R. Watanabe-Fukunaga, R. Fukunaga, and T. W. Sturgill Loss of MNK function sensitizes fibroblasts to serum-withdrawal induced apoptosis Genes Cells, October 1, 2007; 12(10): 1133 - 1140. [Abstract] [Full Text] [PDF]