|
|
||||||||
1 Division of Nephrology, Department of Medicine, Kidney Research Center, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada K1H 8L6; and 2 Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232
Angiotensin IV
(ANG IV), the COOH-terminal hexapeptide fragment of angiotensin II (ANG
II), binds to specific sites in the kidney, distinct from type 1 (AT1) and type 2 (AT2) receptors and designated
type 4 (AT4) receptors. We determined signaling pathways
for ANG IV in a proximal tubular cell line,
LLC-PK1/Cl4. In these cells, we found no
specific binding of [125I]-ANG II. In contrast, ANG IV
dose dependently competed for [125I]-labeled ANG IV
binding, with no displacement by either ANG II, the AT1
receptor antagonist losartan, or the AT2 antagonist PD-123319. Saturation binding indicated the presence of AT4
receptors of high affinity [dissociation constant
(Kd) = 1.4 nM]. ANG IV did not affect cAMP
or cGMP production and did not increase cytosolic calcium concentration
in these cells. In contrast, immunoprecipitation and immunoblotting
studies revealed that ANG IV caused dose-dependent tyrosine
phosphorylation of p125-focal adhesion kinase (p125-FAK) and
p68-paxillin within 2 min, with maximal stimulation at 30 min. ANG
IV-stimulated tyrosine phosphorylation of p125-FAK and paxillin was not
affected by pretreatment with either losartan or PD-123319, and ANG II
(10
7 M) did not induce protein tyrosine phosphorylation.
Our results indicate that LLC-PK1/Cl4 cells
express ANG IV receptors, which we demonstrate for the first time are
linked to tyrosine phosphorylation of focal adhesion-associated
proteins. This suggests that ANG IV, a product of ANG II metabolism,
may regulate function of the focal adhesion complex in proximal tubule cells.
renin-angiotensin system; receptor; signaling; tyrosine kinase; renal proximal tubular epithelial cells
This article has been cited by other articles:
![]() |
K. Kotlo, S. Shukla, U. Tawar, R. A. Skidgel, and R. S. Danziger Aminopeptidase N reduces basolateral Na+-K+-ATPase in proximal tubule cells Am J Physiol Renal Physiol, October 1, 2007; 293(4): F1047 - F1053. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Chen, J.-K. Chen, E. G. Neilson, and R. C. Harris Role of EGF Receptor Activation in Angiotensin II-Induced Renal Epithelial Cell Hypertrophy J. Am. Soc. Nephrol., June 1, 2006; 17(6): 1615 - 1623. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. C. Li, D. J. Campbell, M. Ohishi, S. Yuan, and J. L. Zhuo AT1 receptor-activated signaling mediates angiotensin IV-induced renal cortical vasoconstriction in rats Am J Physiol Renal Physiol, May 1, 2006; 290(5): F1024 - F1033. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Esteban, M. Ruperez, E. Sanchez-Lopez, J. Rodriguez-Vita, O. Lorenzo, H. Demaegdt, P. Vanderheyden, J. Egido, and M. Ruiz-Ortega Angiotensin IV Activates the Nuclear Transcription Factor-{kappa}B and Related Proinflammatory Genes in Vascular Smooth Muscle Cells Circ. Res., May 13, 2005; 96(9): 965 - 973. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. He, T. Podymow, J. Zimpelmann, and K. D. Burns NO inhibits Na+-K+-2Cl- cotransport via a cytochrome P-450-dependent pathway in renal epithelial cells (MMDD1) Am J Physiol Renal Physiol, June 1, 2003; 284(6): F1235 - F1244. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. D. Li, E. R. Block, and J. M. Patel Activation of multiple signaling modules is critical in angiotensin IV-induced lung endothelial cell proliferation Am J Physiol Lung Cell Mol Physiol, October 1, 2002; 283(4): L707 - L716. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Mustafa, Joo Hyung Lee, Siew Yeen Chai, A. L Albiston, S. G McDowall, and F. A. Mendelsohn Bioactive angiotensin peptides: focus on angiotensin IV Journal of Renin-Angiotensin-Aldosterone System, December 1, 2001; 2(4): 205 - 210. [PDF] |
||||
![]() |
R. K. Handa, S. E. Handa, and M. K. S. Elgemark Autoradiographic analysis and regulation of angiotensin receptor subtypes AT4, AT1, and AT(1---7) in the kidney Am J Physiol Renal Physiol, November 1, 2001; 281(5): F936 - F947. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |