Expression of an inward-rectifying potassium channel by the Arabidopsis KAT1 cDNA.
Inward-rectifying potassium channels located in the plasma membrane of higher plant and animal cells contribute to cellular homeostasis and excitability. The genes encoding this specific class of K+ channels have not been functionally identified. This report shows that a single messenger RNA transcript from the Arabidopsis thaliana KAT1 complementary DNA confers the functional expression of a hyperpolarization-activated K+ channel in Xenopus oocytes. The channels encoded by KAT1 are highly selective for K+ over other monovalent cations, are blocked by tetraethylammonium and barium, and have a single channel conductance of 28 +/- 7 picosiemens with 118 millimolar K+ in the bathing solution. These functional characteristics, typical of inward-rectifying K+ channels in eukaryotic cells, demonstrate that KAT1 encodes an inward-rectifying K+ channel.
Schachtman
D P
DP
Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA.
Schroeder
J I
JI
Lucas
W J
WJ
Anderson
J A
JA
Gaber
R F
RF
D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D001464:Barium / Q000494:pharmacology; D001692:Biological Transport; D015870:Gene Expression; D017343:Genes, Plant; D006801:Humans; D007624:KB Cells / Q000378:metabolism*; D009865:Oocytes; D018408:Patch-Clamp Techniques; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000235:genetics; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D014981:Xenopus
D010940:Plant Proteins; D000644:Quaternary Ammonium Compounds; D017472:Receptors, Interleukin-1; D013757:Tetraethylammonium Compounds; D001464:Barium; D011188:Potassium