KAT1 inactivates at sub-millimolar concentrations of external potassium

Brigitte Hertel, F. Horváth, Barnabás Wodala, Annette Hurst, Anna Moroni, Gerhard Thiel

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Structural analysis of K+ channel pores suggests that the selectivity filter of the pore is an inherent sensor for extracellular K + (Ko+); channels seem to be inactivated at low Ko+ because of a destabilization of the conducting state and a collapse of the pore. In the present study, the effect of depleting K o+ on the activity of a plant K+ channel, KAT1, from Arabidopsis thaliana was investigated. This channel is thought to be insensitive to Ko+. The channel was therefore expressed in mammalian HEK293 cells and measured with patch clamp technology in the whole cell configuration. The effect of Ko+ depletion on channel activity was monitored from the tail currents before, during, and after washing Ko+ from the medium. The data show that a depletion of Ko+ results in a decrease in channel conductance, irrespective of whether K+ is simply removed or replaced by either Na+ or Li+. Quantitative analysis suggests that the channel has two binding sites for K+ with the dissociation constant in the order of 20 μM. This high sensitivity of the channel to K o+ could serve as a safety mechanism, which inactivates the channel at low Ko+ and, in this way, prevents leakage of K+ from the cells via this type of channel.

Original languageEnglish
Pages (from-to)3103-3110
Number of pages8
JournalJournal of Experimental Botany
Volume56
Issue number422
DOIs
Publication statusPublished - Dec 2005

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Potassium
potassium
potassium channels
HEK293 Cells
Arabidopsis
Binding Sites
cells
Technology
Safety
washing
sensors (equipment)
quantitative analysis
binding sites
tail
Arabidopsis thaliana

Keywords

  • Cation sensitive gating
  • Hek293 cells
  • KAT1
  • Potassium affinity

ASJC Scopus subject areas

  • Plant Science

Cite this

KAT1 inactivates at sub-millimolar concentrations of external potassium. / Hertel, Brigitte; Horváth, F.; Wodala, Barnabás; Hurst, Annette; Moroni, Anna; Thiel, Gerhard.

In: Journal of Experimental Botany, Vol. 56, No. 422, 12.2005, p. 3103-3110.

Research output: Contribution to journalArticle

Hertel, Brigitte ; Horváth, F. ; Wodala, Barnabás ; Hurst, Annette ; Moroni, Anna ; Thiel, Gerhard. / KAT1 inactivates at sub-millimolar concentrations of external potassium. In: Journal of Experimental Botany. 2005 ; Vol. 56, No. 422. pp. 3103-3110.
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