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

This Article Full Text Full Text (PDF) All Versions of this Article: 286/1/C22    most recent 00229.2003v1 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 ISI Web of Science 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 ISI Web of Science (16) Citing Articles via Google Scholar Google Scholar Articles by Huang, C. Articles by Miller, R. T. Search for Related Content PubMed PubMed Citation Articles by Huang, C. Articles by Miller, R. T.

RECEPTORS AND SIGNAL TRANSDUCTION

The Ca²⁺-sensing receptor couples to G_12/13 to activate phospholipase D in Madin-Darby canine kidney cells

Division of Nephrology, Department of Medicine, Case Western Reserve University, and Louis Stokes Veteran Affairs Medical Center, Cleveland, Ohio 44106

Submitted 2 June 2003 ; accepted in final form 29 August 2003

The Ca²⁺-sensing receptor (CaR) couples to multiple G proteins involved in distinct signaling pathways: G_i to inhibit the activity of adenylyl cyclase and activate ERK, G_q to stimulate phospholipase C and phospholipase A₂, and G to stimulate phosphatidylinositol 3-kinase. To determine whether the receptor also couples to G_12/13, we investigated the signaling pathway by which the CaR regulates phospholipase D (PLD), a known G_12/13 target. We established Madin-Darby canine kidney (MDCK) cell lines that stably overexpress the wild-type CaR (CaR^WT) or the nonfunctional mutant CaR^R796W as a negative control, prelabeled these cells with [³H]palmitic acid, and measured CaR-stimulated PLD activity as the formation of [³H]phosphatidylethanol (PEt). The formation of [³H]PEt increased in a time-dependent manner in the cells that overexpress the CaR^WT but not the CaR^R796W. Treatment of the cells with C₃ exoenzyme inhibited PLD activity, which indicates that the CaR activates the Rho family of small G proteins, targets of G_12/13. To determine which G protein(s) the CaR couples to in order to activate Rho and PLD, we pretreated the cells with pertussis toxin to inactivate G_i or coexpressed regulators of G protein-signaling (RGS) proteins to attenuate G protein signaling (RGS4 for G_i and G_q, and a p115RhoGEF construct containing the RGS domain for G_12/13). Overexpression of p115RhoGEF-RGS in the MDCK cells that overexpress CaR^WT inhibited extracellular Ca²⁺-stimulated PLD activity, but pretreatment of cells with pertussis toxin and overexpression of RGS4 were without effect. The involvement of other signaling components such as protein kinase C, ADP-ribosylation factor, and phosphatidylinositol biphosphate was excluded. These findings demonstrate that the CaR couples to G_12/13 to regulate PLD via a Rho-dependent mechanism and does so independently of G_i and G_q. This suggests that the CaR may regulate cytoskeleton via G_12/13, Rho, and PLD.

calcium-sensing receptor; G proteins; RGS proteins

This article has been cited by other articles:

				S. A. Kempson, J. M. Edwards, A. Osborn, and M. Sturek Acute inhibition of the betaine transporter by ATP and adenosine in renal MDCK cells Am J Physiol Renal Physiol, July 1, 2008; 295(1): F108 - F117. [Abstract] [Full Text] [PDF]

				E. Sabath, H. Negoro, S. Beaudry, M. Paniagua, S. Angelow, J. Shah, N. Grammatikakis, A. S. L. Yu, and B. M. Denker G{alpha}12 regulates protein interactions within the MDCK cell tight junction and inhibits tight-junction assembly J. Cell Sci., March 15, 2008; 121(6): 814 - 824. [Abstract] [Full Text] [PDF]

				C. Huang, A. Sindic, C. E. Hill, K. M. Hujer, K. W. Chan, M. Sassen, Z. Wu, Y. Kurachi, S. Nielsen, M. F. Romero, et al. Interaction of the Ca2+-sensing receptor with the inwardly rectifying potassium channels Kir4.1 and Kir4.2 results in inhibition of channel function Am J Physiol Renal Physiol, March 1, 2007; 292(3): F1073 - F1081. [Abstract] [Full Text] [PDF]

				S. L. Davies, C. E. Gibbons, T. Vizard, and D. T. Ward Ca2+-sensing receptor induces Rho kinase-mediated actin stress fiber assembly and altered cell morphology, but not in response to aromatic amino acids Am J Physiol Cell Physiol, June 1, 2006; 290(6): C1543 - C1551. [Abstract] [Full Text] [PDF]

				J. Ziembicki, R. Tandon, J. R. Schelling, J. R. Sedor, R. T. Miller, and C. Huang Mechanical force-activated phospholipase D is mediated by G{alpha}12/13-Rho and calmodulin-dependent kinase in renal epithelial cells Am J Physiol Renal Physiol, October 1, 2005; 289(4): F826 - F834. [Abstract] [Full Text] [PDF]