Learn More
The molecular assembly of the epithelial Ca(2+) channels (TRPV5 and TRPV6) was investigated to determine the subunit stoichiometry and composition. Immunoblot analysis of Xenopus laevis oocytes expressing TRPV5 and TRPV6 revealed two specific bands of 75 and 85-100 kDa, corresponding to the core and glycosylated proteins, respectively, for each channel.(More)
The calcium release-activated calcium channel (CRAC) is a highly Ca(2+)-selective ion channel that is activated on depletion of inositol triphosphate (IP(3))-sensitive intracellular Ca(2+) stores. It was recently reported that CaT1, a member of the TRP family of cation channels, exhibits the unique biophysical properties of CRAC, which led to the conclusion(More)
Blood calcium concentration is maintained within a narrow range despite large variations in dietary input and body demand. The Transient Receptor Potential ion channel TRPV5 has been implicated in this process. We report here that TRPV5 is stimulated by the mammalian hormone klotho. Klotho, a beta-glucuronidase, hydrolyzes extracellular sugar residues on(More)
The TRP superfamily includes a diversity of non-voltage-gated cation channels that vary significantly in their se-lectivity and mode of activation. Nevertheless, members of the TRP superfamily share significant sequence ho-mology and predicted structural similarities. Currently, most of the genes and proteins that comprise the TRP superfamily have multiple(More)
The recently cloned epithelial Ca(2+) channel (ECaC) constitutes the Ca(2+) influx pathway in 1,25-dihydroxyvitamin D(3)-responsive epithelia. We have combined patch-clamp analysis and fura-2 fluorescence microscopy to functionally characterize ECaC heterologously expressed in HEK293 cells. The intracellular Ca(2+) concentration in ECaC-expressing cells was(More)
Primary hypomagnesemia is a heterogeneous group of disorders characterized by renal or intestinal magnesium (Mg2+) wasting, resulting in tetany, cardiac arrhythmias, and seizures. The kidney plays an essential role in maintaining blood Mg2+ levels, with a prominent function for the Mg2+-transporting channel transient receptor potential cation channel,(More)
This study describes properties of monovalent cation currents through ECaC, a recently cloned epithelial Ca2+-permeable channel from rabbit. The kinetics of currents through ECaC was strongly modulated by divalent cations. Currents were inhibited in the presence of extracellular Ca2+. They showed an initial voltage-dependent decay in the presence of mM Mg2+(More)
The presence of a Na(+)-Ca2+ exchange system has been previously demonstrated at the basolateral side of the cortical collecting system. The role of such an exchanger in maintaining low intracellular [Ca2+] ([Ca2+]i) in this nephron segment is now investigated. Cells from the connecting tubule and cortical collecting duct of rabbit kidneys were isolated by(More)
Low extracellular calcium (Ca(2+)) promotes release of parathyroid hormone (PTH), which acts on multiple organs to maintain overall Ca(2+) balance. In the distal part of the nephron, PTH stimulates active Ca(2+) reabsorption via the adenylyl cyclase-cAMP-protein kinase A (PKA) pathway, but the molecular target of this pathway is unknown. The transient(More)
TRPV5 and TRPV6 are the most Ca2+-selective members of the transient receptor potential (TRP) family of cation channels and play a pivotal role in the maintenance of Ca2+ balance in the body. However, little is known about the mechanisms controlling the plasma membrane abundance of these channels to regulate epithelial Ca2+ transport. In this study, we(More)