Abstract
KAT1 encoding a K+in channel is expressed primarily in Arabidopsis thaliana guard cell and KAT1 contains six-membrane spanning regions. Several putative phosphorylated residues exist in the cytosolic region of the channel. It has been indicated that the activity and the gating of KAT1 channel is modulated by phosphorylation, such as cAMP-dependent protein kinase or ABA-responsive protein kinase mediating phosphorylation, and the evidence for KAT1 phosphorylation in planta has been provided by biochemical approaches. Thus phosphorylation could be considered as a switch that allows the channel to respond to their usual stimuli. In this study, we performed two-electrode voltage clamp analysis of KAT1 channel activity under the condition where protein kinase was activated. Recordings of KAT1 currents were performed in Xenopus laevis oocytes. Time course of changes in current were obtained in oocytes expressing wild type KAT1 and the mutants.
