Activation of the Ca2+-sensing receptor stimulates the activity of the epithelial Ca2+ channel TRPV5

Topala, Catalin, Schoeber, Joost, Searchfield, Lydia

, Riccardi, Daniela

, Hoenderop, Joost and Bindels, René 2009. Activation of the Ca2+-sensing receptor stimulates the activity of the epithelial Ca2+ channel TRPV5. Cell Calcium 45 (4) , pp. 331-339. 10.1016/j.ceca.2008.12.003

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Official URL: http://dx.doi.org/10.1016/j.ceca.2008.12.003

Abstract

The extracellular Ca2+-sensing receptor (CaR) is a key-player in plasma Ca2+ homeostasis. It is essentially expressed in the parathyroid glands and along the kidney nephron. The distal convoluted tubules (DCT) and connecting tubules (CNT) in the kidney are involved in active Ca2+ reabsorption, but the function of the CaR has remained unclear in these segments. Here, the Ca2+-selective Transient Receptor Potential Vanilloid-subtype 5 channel (TRPV5) determines active Ca2+ reabsorption by forming the apical entry gate. In this study we show that the CaR and TRPV5 co-localize at the luminal membrane of DCT/CNT. Furthermore, by patch-clamp and Fura-2-ratiometric measurements we demonstrate that activation of the CaR leads to elevated TRPV5-mediated currents and increases intracellular Ca2+ concentrations in cells co-expressing TRPV5 and CaR. Activation of CaR initiated a signaling cascade that activated phorbol-12-myristate-13-acetate (PMA)-insensitive protein kinase C (PKC) isoforms. Importantly, mutation of two putative PKC phosphorylation sites, S299 and S654, in TRPV5 prevented the stimulatory effect of CaR activation on channel activity, as did a dominant negative CaR construct, CaRR185Q. Interestingly, the activity of TRPV6, TRPV5′ closest homologue, was not affected by the activated CaR. We conclude that activation of the CaR stimulates TRPV5-mediated Ca2+ influx via a PMA-insensitive PKC isoform pathway.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Biosciences
Subjects:	Q Science > Q Science (General)
Uncontrolled Keywords:	CaR; TRPV5; distal convoluted tubule; neomycin; electrophysiology
Publisher:	Elsevier
ISSN:	0143-4160
Last Modified:	29 Aug 2024 01:08
URI:	https://orca.cardiff.ac.uk/id/eprint/19394

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