Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-47066
J Biol Chem 2013 Feb 22;2888:5278-90. doi: 10.1074/jbc.M112.409482.
Show Gene links Show Anatomy links

Interplay between calmodulin and phosphatidylinositol 4,5-bisphosphate in Ca2+-induced inactivation of transient receptor potential vanilloid 6 channels.

Cao C , Zakharian E , Borbiro I , Rohacs T .


???displayArticle.abstract???
The epithelial Ca(2+) channel transient receptor potential vanilloid 6 (TRPV6) undergoes Ca(2+)-induced inactivation that protects the cell from toxic Ca(2+) overload and may also limit intestinal Ca(2+) transport. To dissect the roles of individual signaling pathways in this phenomenon, we studied the effects of Ca(2+), calmodulin (CaM), and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) in excised inside-out patches. The activity of TRPV6 strictly depended on the presence of PI(4,5)P(2), and Ca(2+)-CaM inhibited the channel at physiologically relevant concentrations. Ca(2+) alone also inhibited TRPV6 at high concentrations (IC(50) = ∼20 μM). A double mutation in the distal C-terminal CaM-binding site of TRPV6 (W695A/R699E) essentially eliminated inhibition by CaM in excised patches. In whole cell patch clamp experiments, this mutation reduced but did not eliminate Ca(2+)-induced inactivation. Providing excess PI(4,5)P(2) reduced the inhibition by CaM in excised patches and in planar lipid bilayers, but PI(4,5)P(2) did not inhibit binding of CaM to the C terminus of the channel. Overall, our data show a complex interplay between CaM and PI(4,5)P(2) and show that Ca(2+), CaM, and the depletion of PI(4,5)P(2) all contribute to inactivation of TRPV6.

???displayArticle.pubmedLink??? 23300090
???displayArticle.pmcLink??? PMC3581402
???displayArticle.link??? J Biol Chem
???displayArticle.grants??? [+]

Species referenced: Xenopus laevis
Genes referenced: trpv6

References [+] :
Bers, A practical guide to the preparation of Ca(2+) buffers. 2010, Pubmed