The K+ battery-regulating Arabidopsis K+ channel AKT2 is under the control of multiple post-translational steps

• Published in: Plant signaling & behavior Vol. 6; no. 4; pp. 558 - 562
• Main Authors: Sandmann, Michael, Skłodowski, Kamil, Gajdanowicz, Pawel, Michard, Erwan, Rocha, Marcio, Gomez-Porras, Judith L., González, Wendy, Corrêa, Luiz Gustavo Guedes, Ramírez-Aguilar, Santiago J., Cuin, Tracey Ann, van Dongen, Joost T., Thibaud, Jean-Baptiste, Dreyer, Ingo
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 01.04.2011; Landes Bioscience
• Subjects: Addendum; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; behavior; Binding; Biology; Bioscience; Calcium; Cancer; Cell; Cycle; energy; homeostasis; Landes; Life Sciences; Models, Biological; Organogenesis; phosphorylation; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; post-translational modification; potassium; Potassium - metabolism; Potassium Channels - genetics; Potassium Channels - metabolism; Protein Processing, Post-Translational - genetics; Protein Processing, Post-Translational - physiology; Proteins; serine; sieve elements; solutes; turgor; Vegetal Biology; pholem; homeostasie; AKT2; plant; channel; voltage-gate; transport; Potassium
• ISSN: 1559-2316; 1559-2324; 1559-2324
• DOI: 10.4161/psb.6.4.14908

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.