Sandmann M.,Heisenberg Group of Biophysics and Molecular Plant Biology |
Sandmann M.,University of Potsdam |
Sklodowski K.,Heisenberg Group of Biophysics and Molecular Plant Biology |
Gajdanowicz P.,Heisenberg Group of Biophysics and Molecular Plant Biology |
And 13 more authors.
Plant Signaling and Behavior | Year: 2011
Potassium (K+) is an important nutrient for plants. It serves as a cofactor of various enzymes and as the major inorganic solute maintaining plant cell turgor. In a recent study, an as yet unknown role of K+ in plant homeostasis was shown. It was demonstrated that K+ gradients in vascular tissues can serve as an energy source for phloem (re)loading processes and that the voltage-gated K+ channels of the AKT2-type play a unique role in this process. The AKT2 channel can be converted by phosphorylation of specific serine residues (S210 and S329) into a non-rectifying channel that allows a rapid efflux of K+ from the sieve element/ companion cells (SE/CC) complex. The energy of this flux is used by other transporters for phloem (re)loading processes. Nonetheless, the results do indicate that post-translational modifications at S210 and S329 alone cannot explain AKT2 regulation. Here, we discuss the existence of multiple post-translational modification steps that work in concert to convert AKT2 from an inward-rectifying into a non-rectifying K+ channel. © 2011 Landes Bioscience.