title: Inactivating properties of recombinant ROMK2 channels expressed in mammalian cells.
abstract: Biophysical properties of ROMK2 channel were investigated at physiological temperature, after reexpression of the recombinant ROMK2 protein in a mammalian cell expression system (COS-7). We observed that ROMK2 induced an inwardly rectifying K(+) current whether polyvalent cations were present or not. Above +10 mV, ROMK2-induced current exhibited a voltage- and time-dependent decay, consistent with an inactivation process. Inactivation of ROMK2-induced current was also seen in inside out patch from ROMK2-expressing Xenopus oocyte. In COS-7 cells, inactivation was found to account for most of the inward rectification. Mg(2+) and spermine modulated rectification by accelerating inactivation kinetics independently of membrane potential. These results establish for the first time ROMK2 properties in a mammalian cell expression system.
authors.affiliation: Laboratoire de Physiopathologie et de Pharmacologie Cellulaires et Moléculaires, INSERM U533, Hôtel Dieu, Nantes, 44093, France.
authors.forename: D F
authors.initials: DF
authors.lastname: Riochet
authors.forename: R
authors.initials: R
authors.lastname: Mohammad-Panah
authors.forename: S C
authors.initials: SC
authors.lastname: Hebert
authors.forename: G G
authors.initials: GG
authors.lastname: MacGregor
authors.forename: I
authors.initials: I
authors.lastname: Baró
authors.forename: G
authors.initials: G
authors.lastname: Guihard
authors.forename: D
authors.initials: D
authors.lastname: Escande
mesh_terms: D000818:Animals; D019556:COS Cells; D004553:Electric Conductivity; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D011994:Recombinant Proteins / Q000378:metabolism; D013095:Spermidine / Q000494:pharmacology; D014162:Transfection; D014981:Xenopus
chemical_list: D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011994:Recombinant Proteins; D008274:Magnesium; D013095:Spermidine