TheArabidopsis thalianaK + channel KAT1 has been suggested to play a key role in the regulation of the aperture of stomatal pores on the surface of plant leaves. Calcium-dependent and calcium-independent signaling pathways are involved in abscisic acid-mediated regulation of guard cell turgidity. Although the activity of the KAT1 channel is thought to be regu-lated by calcium-dependent protein kinases, the effect of phosphorylation on KAT1 and the phosphorylated target sites remain elusive.
