Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-2772
Capuano, P; Bacic, D; Roos, M; Gisler, S M; Stange, G; Biber, J; Kaissling, B; Weinman, E J; Shenolikar, S; Wagner, C A; Murer, H (2007). Defective coupling of apical PTH receptors to phospholipase C prevents internalization of the Na+-phosphate cotransporter NaPi-IIa in Nherf1-deficient mice. American Journal of Physiology. Cell Physiology, 2(292):927-934.
Phosphate reabsorption in the renal proximal tubule occurs mostly via the type IIa Na(+)-phosphate cotransporter (NaP(i)-IIa) in the brush border membrane (BBM). The activity and localization of NaP(i)-IIa are regulated, among other factors, by parathyroid hormone (PTH). NaP(i)-IIa interacts in vitro via its last three COOH-terminal amino acids with the PDZ protein Na(+)/H(+)-exchanger isoform 3 regulatory factor (NHERF)-1 (NHERF1). Renal phosphate reabsorption in Nherf1-deficient mice is altered, and NaP(i)-IIa expression in the BBM is reduced. In addition, it has been proposed that NHERF1 and NHERF2 are important for the coupling of PTH receptors (PTHRs) to phospholipase C (PLC) and the activation of the protein kinase C pathway. We tested the role of NHERF1 in the regulation of NaP(i)-IIa by PTH in Nherf1-deficient mice. Immunohistochemistry and Western blotting demonstrated that stimulation of apical and basolateral receptors with PTH-(1-34) led to internalization of NaP(i)-IIa in wild-type and Nherf1-deficient mice. Stimulation of only apical receptors with PTH-(3-34) failed to induce internalization in Nherf1-deficient mice. Expression and localization of apical PTHRs were similar in wild-type and Nherf1-deficient mice. Activation of the protein kinase C- and A-dependent pathways with 1,2-dioctanoyl-sn-glycerol or 8-bromo-cAMP induced normal internalization of NaP(i)-IIa in wild-type, as well as Nherf1-deficient, mice. Stimulation of PLC activity due to apical PTHRs was impaired in Nherf1-deficient mice. These data suggest that NHERF1 in the proximal tubule is important for PTH-induced internalization of NaP(i)-IIa and, specifically, couples the apical PTHR to PLC.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Center for Integrative Human Physiology|
04 Faculty of Medicine > Institute of Anatomy
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
|DDC:||570 Life sciences; biology|
610 Medicine & health
|Deposited On:||29 Jul 2008 16:14|
|Last Modified:||23 Nov 2012 15:57|
|Publisher:||American Physiological Society|
|WoS Citation Count:||30|
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