QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online December 31, 2003
doi: 10.1242/10.1242/jcs.00889

This Article Figures Only Full Text Full Text (PDF) 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 Doble, B. W. Articles by Kardami, E. Search for Related Content PubMed PubMed Citation Articles by Doble, B. W. Articles by Kardami, E. Social Bookmarking                         What's this?

Phosphorylation of serine 262 in the gap junction protein connexin-43 regulates DNA synthesis in cell-cell contact forming cardiomyocytes

Bradley W. Doble^1,3,*, Xitong Dang^2,3, Peipei Ping^4,, Robert R. Fandrich^2,3, Barbara E. Nickel³, Yan Jin¹, Peter A. Cattini¹ and Elissavet Kardami^1,2,3,

² Department of Human Anatomy and Cell Sciences, Faculty of Medicine, University of Manitoba, Winnipeg MB R3E 3J7, Canada
¹ Physiology, Faculty of Medicine, University of Manitoba, Winnipeg MB R3E 3J7, Canada
³ Institute of Cardiovascular Sciences, SBGH Research Centre 3008, 351 Tache Avenue, Winnipeg MB R2H 2A6, Canada
⁴ Department of Medicine, University of Louisville, Louisville, KY 40292, USA

Author for correspondence (e-mail: ekardami{at}sbrc.ca)

Accepted 17 September 2003

Mitogenic stimulation of cardiomyocytes is associated with decreased gap junction coupling and protein kinase C (PKC)-mediated phosphorylation of the gap junction protein connexin43 (Cx43). Identification of and interference with the amino acid(s) that becomes phosphorylated in response to stimulation are important steps towards defining the relationship between Cx43 phosphorylation and cell cycle. Using immunoblotting and phosphospecific antibodies we were able to show that serine-262 (S262) on Cx43 becomes phosphorylated in response to growth factor or PKC stimulation of cardiomyocytes. To examine the effect of Cx43, S262 phosphorylation and cell-cell contact (and/or coupling) on DNA synthesis, we overexpressed wild-type (wt) or mutant Cx43, carrying a S262-to-alanine (S262A, simulating the unphosphorylated state) or a S262-to-aspartate (S262D, simulating constitutive phosphorylation) substitutions in cultures of cell-cell contact forming or isolated cardiomyocytes. Overexpression of wt-Cx43 caused a significant decrease in DNA synthesis irrespective of the presence of cell-cell contact. In cell-cell contact forming cultures, the S262D mutation reversed while the S262A mutation increased the inhibitory effect of Cx43. In the absence of cell-cell contact, the S262-Cx43 mutations had no significant effect on Cx43 inhibition of DNA synthesis. Dye-coupling, evaluated by scrape-loading, indicated increased gap junction permeability in S262A (compared to wt or S262D) overexpressing myocytes. We conclude that Cx43 inhibits cardiomyocyte DNA synthesis irrespectively of cell-cell contact or coupling. Cell-cell contact, and possibly gap junction-mediated communication is required, however, in order to reverse Cx43 inhibition of DNA synthesis by S262 phosphorylation.

Key words: Connexin43, Phosphorylation mutants, DNA synthesis, Cell-cell contact, Cardiomyocytes

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

This article has been cited by other articles:

				W. Srisakuldee, M. M. Jeyaraman, B. E. Nickel, S. Tanguy, Z.-S. Jiang, and E. Kardami Phosphorylation of connexin-43 at serine 262 promotes a cardiac injury-resistant state Cardiovasc Res, June 5, 2009; (2009) cvp142v2. [Abstract] [Full Text] [PDF]

				J. M. Burt, T. K. Nelson, A. M. Simon, and J. S. Fang Connexin 37 profoundly slows cell cycle progression in rat insulinoma cells Am J Physiol Cell Physiol, November 1, 2008; 295(5): C1103 - C1112. [Abstract] [Full Text] [PDF]

				S. F. Steinberg Structural Basis of Protein Kinase C Isoform Function Physiol Rev, October 1, 2008; 88(4): 1341 - 1378. [Abstract] [Full Text] [PDF]

				R. P. Norris, M. Freudzon, L. M. Mehlmann, A. E. Cowan, A. M. Simon, D. L. Paul, P. D. Lampe, and L. A. Jaffe Luteinizing hormone causes MAP kinase-dependent phosphorylation and closure of connexin 43 gap junctions in mouse ovarian follicles: one of two paths to meiotic resumption Development, October 1, 2008; 135(19): 3229 - 3238. [Abstract] [Full Text] [PDF]

				S. Y. Lu, D. P. Sontag, K. A. Detillieux, and P. A. Cattini FGF-16 is released from neonatal cardiac myocytes and alters growth-related signaling: a possible role in postnatal development Am J Physiol Cell Physiol, May 1, 2008; 294(5): C1242 - C1249. [Abstract] [Full Text] [PDF]

				S. Matsushita, H. Kurihara, M. Watanabe, T. Okada, T. Sakai, and A. Amano Alterations of Phosphorylation State of Connexin 43 during Hypoxia and Reoxygenation Are Associated with Cardiac Function J. Histochem. Cytochem., March 1, 2006; 54(3): 343 - 353. [Abstract] [Full Text] [PDF]

				B. E. Isakson, D. N. Damon, K. H. Day, Y. Liao, and B. R. Duling Connexin40 and connexin43 in mouse aortic endothelium: evidence for coordinated regulation Am J Physiol Heart Circ Physiol, March 1, 2006; 290(3): H1199 - H1205. [Abstract] [Full Text] [PDF]

				S. Dhein New, emerging roles for cardiac connexins. Mitochondrial Cx43 raises new questions Cardiovasc Res, August 1, 2005; 67(2): 179 - 181. [Full Text] [PDF]

				X. F. Figueroa, B. E. Isakson, and B. R. Duling Connexins: Gaps in Our Knowledge of Vascular Function Physiology, October 1, 2004; 19(5): 277 - 284. [Abstract] [Full Text] [PDF]

				M. S. Turner, G. A. Haywood, P. Andreka, L. You, P. E. Martin, W. H. Evans, K. A. Webster, and N. H. Bishopric Reversible Connexin 43 Dephosphorylation During Hypoxia and Reoxygenation Is Linked to Cellular ATP Levels Circ. Res., October 1, 2004; 95(7): 726 - 733. [Abstract] [Full Text] [PDF]