title: The Xenopus TRPV6 homolog encodes a Mg(2+) -permeant channel that is inhibited by interaction with TRPC1.
abstract: The TRP gene family encodes primarily cation non-selective, Ca2+ permeant channels that are involved in a dizzying array of sensory mechanisms. Two channels in this large family TRPV5 and TRPV6 are highly Ca2+ selective and are expressed in epithelia where they are important in Ca2+ uptake. TRPV5/6 are constitutively active, yet the mechanisms regulating their activation in native tissue remains elusive. Here we functionally characterize the Xenopus TRPV6 homolog. xTRPV6 is expressed in the oocyte and encodes a channel that is permeant to divalents including Ca2+ , and displays a high permeability to Mg2+ . The oocyte does not exhibit functional TRPV6-like current at rest, showing that the endogenous channel is somehow maintained in an inactive state. We show that endogenous as well as overexpressed xTRPV6 interacts with xTRPC1 and that this interaction inhibits xTRPV6 currents. As such TRPC1 is likely to regulate the activity of TRPV6 under physiological conditions.
authors.affiliation: Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City, Qatar Foundation, Doha, Qatar.
authors.forename: Raphael
authors.initials: R
authors.lastname: Courjaret
authors.forename: Satanay
authors.initials: S
authors.lastname: Hubrack
authors.forename: Arwa
authors.initials: A
authors.lastname: Daalis
authors.forename: Maya
authors.initials: M
authors.lastname: Dib
authors.forename: Khaled
authors.initials: K
authors.lastname: Machaca
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000502:physiology; D008274:Magnesium / Q000378:metabolism*; D009154:Mutation; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D002413:Cations, Divalent; D050052:TRPC Cation Channels; C502469:TRPC1 protein, Xenopus; D050916:TRPV Cation Channels; C120776:TRPV6 channel; D029867:Xenopus Proteins; D008274:Magnesium; D002118:Calcium