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

Izumi Mori, Yuichi Nobukiyo, Yoshiki Nakahara, Mineo Shibasaka, Takuya Furuichi, Maki Katsuhara

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

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 3,5-cyclic monophosphate (8Br-cAMP) or 8-bromoguanosine 3,5-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 µM 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.

Original languageEnglish
Article number61
JournalPlants
Volume7
Issue number3
DOIs
Publication statusPublished - Sep 1 2018

Keywords

  • Barley
  • Cyclic nucleotide-gated channel
  • Potassium
  • Roots
  • Sodium

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science

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