2007 JASN IMPACT FACTOR 7.111	HOME   AUTHOR INFO   EDITORIAL BOARD   SUBSCRIBE   FEEDBACK   ALERTS   HELP
advanced	CURRENT ISSUE	ARCHIVES	JASN Express	ONLINE SUBMISSION

This Article Full Text Full Text (PDF) All Versions of this Article: ASN.2005020190v1 16/10/2881    most recent 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 Tamma, G. Articles by Valenti, G. Search for Related Content PubMed PubMed Citation Articles by Tamma, G. Articles by Valenti, G.

Bradykinin Signaling Counteracts cAMP-Elicited Aquaporin 2 Translocation in Renal Cells

Grazia Tamma^*, Monica Carmosino^*, Maria Svelto^*, and Giovanna Valenti^*,

^* Dipartimento di Fisiologia Generale ed Ambientale; and Centro di Eccellenza in Genomica Comparata, University of Bari, Bari, Italy

Address correspondence to: Dr. Giovanna Valenti, Dipartimento di Fisiologia Generale e Ambientale, Via Amendola 165/A, Bari 70126, Italy. Phone: +39-080-544-3444; Fax: +39-080-544-3388; E-mail: g.valenti{at}biologia.uniba.it

Received for publication February 18, 2005. Accepted for publication July 12, 2005.

Bradykinin (BK) is one of the most important peptides regulating vascular tone, water, and ionic balance in the body, playing a key role in controlling BP. It is interesting that patients with essential hypertension excrete less BK than normotensive individuals. For elucidating the mechanism by which BK regulates renal water transport that contributes to its antihypertensive effect, aquaporin 2 (AQP2)-transfected collecting duct CD8 cells, expressing the BK type II receptor (BK2R), were used as an experimental model. In CD8 cells, BK pretreatment impaired forskolin-induced AQP2 translocation to the apical plasma membrane. For clarifying the signal transduction cascade associated with this effect, whether BK induced an increase in cytosolic calcium, via the G protein Gq, known to be coupled to BK2R, first was investigated. Spectrofluorometry using fura-2-AM revealed that 100 nM BK elicited a significant increase in Ca_i, which was abolished by the receptor antagonist HOE-140. BK acts through BK2R coupled to both Gq and G13, a known upstream effector of Rho protein. In CD8 cells, BK causes an increase in Rho activity, likely as a result of G13 activation. This results in stabilization of the cortical F-actin network, thus impairing AQP2 trafficking. These effects counteract physiologic vasopressin stimulation, which instead has an opposite effect on actin network organization through Rho inactivation.

This article has been cited by other articles:

				Y. Noda, S. Horikawa, E. Kanda, M. Yamashita, H. Meng, K. Eto, Y. Li, M. Kuwahara, K. Hirai, C. Pack, et al. Reciprocal interaction with G-actin and tropomyosin is essential for aquaporin-2 trafficking J. Cell Biol., August 11, 2008; 182(3): 587 - 601. [Abstract] [Full Text] [PDF]

				G. Tamma, G. Procino, A. Strafino, E. Bononi, G. Meyer, M. Paulmichl, V. Formoso, M. Svelto, and G. Valenti Hypotonicity Induces Aquaporin-2 Internalization and Cytosol-to-Membrane Translocation of ICln in Renal Cells Endocrinology, March 1, 2007; 148(3): 1118 - 1130. [Abstract] [Full Text] [PDF]

				K.-P. Yip Epac-mediated Ca2+ mobilization and exocytosis in inner medullary collecting duct Am J Physiol Renal Physiol, October 1, 2006; 291(4): F882 - F890. [Abstract] [Full Text] [PDF]

Copyright © 2008 by the American Society of Nephrology. Online ISSN: 1533-3450 Print ISSN: 1046-6673