%0 Journal Article %1 Hoth:2001:Plant-Cell:11283347 %A Hoth, S %A Geiger, D %A Becker, D %A Hedrich, R %D 2001 %J Plant Cell %K myown %N 4 %P 943-952 %T The pore of plant K(+) channels is involved in voltage and pH sensing: domain-swapping between different K(+) channel alpha-subunits %U https://www.ncbi.nlm.nih.gov/pubmed/11283347 %V 13 %X Plant K(+) uptake channel types differ with respect to their voltage, Ca(2)+, and pH dependence. Here, we constructed recombinant chimeric channels between KST1, a member of the inward-rectifying, acid-activated KAT1 family, and AKT3, a member of the weakly voltage-dependent, proton-blocked AKT2/3 family. The homologous pore regions of AKT3 (amino acids 216 to 287) and KST1 (amino acids 217 to 289) have been exchanged to generate the two chimeric channels AKT3/(p)KST1 and KST1/(p)AKT3. In contrast to AKT3 wild-type channels, AKT3/(p)KST1 revealed a strong inward rectification reminiscent of that of KST1. Correspondingly, the substitution of the KST1 by the AKT3 pore led to less pronounced rectification properties of KST1/(p)AKT3 compared with wild-type KST1. Besides the voltage dependence, the interaction between the chimera and extracellular H(+) and Ca(2)+ resembled the properties of the inserted rather than the respective wild-type pore. Whereas AKT3/(p)KST1 was acid activated and Ca(2)+ insensitive, extracellular protons and Ca(2)+ inhibited KST1/(p)AKT3. The regulation of the chimeric channels by cytoplasmic protons followed the respective wild-type backbone of the chimeric channels, indicating that the intracellular pH sensor is located outside the P domain. We thus conclude that essential elements for external pH and Ca(2)+ regulation and for the rectification of voltage-dependent K(+) uptake channels are located within the channel pore.

@article{Hoth:2001:Plant-Cell:11283347, abstract = {Plant K(+) uptake channel types differ with respect to their voltage, Ca(2)+, and pH dependence. Here, we constructed recombinant chimeric channels between KST1, a member of the inward-rectifying, acid-activated KAT1 family, and AKT3, a member of the weakly voltage-dependent, proton-blocked AKT2/3 family. The homologous pore regions of AKT3 (amino acids 216 to 287) and KST1 (amino acids 217 to 289) have been exchanged to generate the two chimeric channels AKT3/(p)KST1 and KST1/(p)AKT3. In contrast to AKT3 wild-type channels, AKT3/(p)KST1 revealed a strong inward rectification reminiscent of that of KST1. Correspondingly, the substitution of the KST1 by the AKT3 pore led to less pronounced rectification properties of KST1/(p)AKT3 compared with wild-type KST1. Besides the voltage dependence, the interaction between the chimera and extracellular H(+) and Ca(2)+ resembled the properties of the inserted rather than the respective wild-type pore. Whereas AKT3/(p)KST1 was acid activated and Ca(2)+ insensitive, extracellular protons and Ca(2)+ inhibited KST1/(p)AKT3. The regulation of the chimeric channels by cytoplasmic protons followed the respective wild-type backbone of the chimeric channels, indicating that the intracellular pH sensor is located outside the P domain. We thus conclude that essential elements for external pH and Ca(2)+ regulation and for the rectification of voltage-dependent K(+) uptake channels are located within the channel pore.}, added-at = {2017-03-21T20:26:23.000+0100}, author = {Hoth, S and Geiger, D and Becker, D and Hedrich, R}, biburl = {https://www.bibsonomy.org/bibtex/2d400264ed8337f8dd61520e75a319509/dirkbecker}, description = {The pore of plant K(+) channels is involved in voltage and pH sensing: domain-swapping between different K(+) channel alpha-subunits. - PubMed - NCBI}, interhash = {379e4e76b579fdbe0aa0cfc338b1fdaa}, intrahash = {d400264ed8337f8dd61520e75a319509}, journal = {Plant Cell}, keywords = {myown}, month = apr, number = 4, pages = {943-952}, pmid = {11283347}, timestamp = {2017-03-21T20:26:23.000+0100}, title = {The pore of plant K(+) channels is involved in voltage and pH sensing: domain-swapping between different K(+) channel alpha-subunits}, url = {https://www.ncbi.nlm.nih.gov/pubmed/11283347}, volume = 13, year = 2001 }