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

Plant Signal Behav. 2011 Apr;6(4):558-62. doi: 10.4161/psb.6.4.14908. Epub 2011 Apr 1.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Models, Biological
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism*
  • Potassium / metabolism*
  • Potassium Channels / genetics
  • Potassium Channels / metabolism*
  • Protein Processing, Post-Translational / genetics
  • Protein Processing, Post-Translational / physiology

Substances

  • AKT2 protein, Arabidopsis
  • Arabidopsis Proteins
  • Potassium Channels
  • Potassium