Concerted action of associated proteins in the regulation of TRPV5 and TRPV6.

Department of Physiology, NCMLS (Nijmegen Centre for Molecular Life Sciences), Radboud University Nijmegen Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, The Netherlands.

Ca(2+) is an essential ion in all organisms and many physiological functions in the body rely on the exact maintenance of the Ca(2+) balance. The epithelial Ca(2+) channels TRPV5 [TRP (transient receptor potential) vanilloid 5] and TRPV6 are the most Ca(2+)-selective members of the TRP superfamily and are generally considered as the gatekeepers of Ca(2+) entry across epithelia. TRPV5 is involved in Ca(2+) reabsorption from pro-urine, while TRPV6 has an essential role in intestinal Ca(2+) uptake. These channels are the prime targets of calciotropic hormonal regulation, including vitamin D and parathyroid hormone. In addition, extra- and intra-cellular signalling by associated proteins and Ca(2+) itself play key roles in TRPV5 and TRPV6 regulation. In this paper, we describe the present understanding of the concerted action of calbindin-D(28k), klotho and BSPRY (B-box and SPRY-domain-containing protein) at different levels throughout the epithelial cell to control Ca(2+) influx at the luminal entry gate.

PMID: 17233615 [PubMed - indexed for MEDLINE]