%0 Journal Article
%T A Cyclic Nucleotide-Gated Channel, HvCNGC2-3, Is Activated by the Co-Presence of Na+ and K+ and Permeable to Na+ and K+ Non-Selectively
%A Izumi C. Mori
%A Maki Katsuhara
%A Mineo Shibasaka
%A Takuya Furuichi
%A Yoshiki Nakahara
%A Yuichi Nobukiyo
%J Archive of "Plants".
%D 2018
%R 10.3390/plants7030061
%X Cyclic nucleotide-gated channels (CNGCs) have been postulated to contribute significantly in plant development and stress resistance. However, their electrophysiological properties remain poorly understood. Here, we characterized barley CNGC2-3 (HvCNGC2-3) by the two-electrode voltage-clamp technique in the Xenopus laevis oocyte heterologous expression system. Current was not observed in X. laevis oocytes injected with HvCNGC2-3 complementary RNA (cRNA) in a bathing solution containing either Na+ or K+ solely, even in the presence of 8-bromoadenosine 3¡ä,5¡ä-cyclic monophosphate (8Br-cAMP) or 8-bromoguanosine 3¡ä,5¡ä-cyclic monophosphate (8Br-cGMP). A weakly voltage-dependent slow hyperpolarization-activated ion current was observed in the co-presence of Na+ and K+ in the bathing solution and in the presence of 10 ¦ÌM 8Br-cAMP, but not 8Br-cGMP. Permeability ratios of HvCNGC2-3 to K+, Na+ and Cl£¿ were determined as 1:0.63:0.03 according to reversal-potential analyses. Amino-acid replacement of the unique ion-selective motif of HvCNGC2-3, AQGL, with the canonical motif, GQGL, resulted in the abolition of the current. This study reports a unique two-ion-dependent activation characteristic of the barley CNGC, HvCNGC2-3
%K cyclic nucleotide-gated channel
%K barley
%K sodium
%K potassium
%K roots
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161278/