Journal of the American Society of Nephrology : JASN
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J. Am. Soc. Nephrol. · Mar 2010
Atrap deficiency increases arterial blood pressure and plasma volume.
The angiotensin receptor-associated protein (Atrap) interacts with angiotensin II (AngII) type 1 (AT1) receptors and facilitates their internalization in vitro, but little is known about the function of Atrap in vivo. Here, we detected Atrap expression in several organs of wild-type mice; the highest expression was in the kidney where it localized to the proximal tubule, particularly the brush border. There was no Atrap expression in the renal vasculature or juxtaglomerular cells. ⋯ Plasma volume was significantly higher and plasma renin concentration was markedly lower in Atrap-/- mice compared with wild-type mice. (125)I-AngII binding showed enhanced surface expression of AT1 receptors in the renal cortex of Atrap-/- mice, accompanied by increased carboanhydrase-sensitive proximal tubular function. In summary, Atrap-/- mice have increased arterial pressure and plasma volume. Atrap seems to modulate volume status by acting as a negative regulator of AT1 receptors in the renal tubules.