%0 Journal Article %1 RN1213 %A Hoth, S. %A Geiger, D. %A Becker, D. %A Hedrich, R. %D 2001 %J Plant Cell %K channel myOwn potassium %N 4 %P 943-952 %R DOI 10.1105/tpc.13.4.943 %T The pore of plant K channels is involved in voltage and pH sensing:: Domain-swapping between different K channel α-subunits %U /brokenurl#<Go to ISI>://WOS:000168219000017 %V 13 %X Plant K+ uptake channel types differ with respect to their voltage, Ca2+, 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 Ca2+ resembled the properties of the inserted rather than the respective wild-type pore. Whereas AKT3/(p)KST1 was acid activated and Ca2+ insensitive, extracellular protons and Ca2+ 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 Ca2+ regulation and for the rectification of voltage-dependent K+ uptake channels are located within the channel pore.

@article{RN1213, abstract = {Plant K+ uptake channel types differ with respect to their voltage, Ca2+, 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 Ca2+ resembled the properties of the inserted rather than the respective wild-type pore. Whereas AKT3/(p)KST1 was acid activated and Ca2+ insensitive, extracellular protons and Ca2+ 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 Ca2+ regulation and for the rectification of voltage-dependent K+ uptake channels are located within the channel pore.}, added-at = {2024-02-14T14:38:32.000+0100}, author = {Hoth, S. and Geiger, D. and Becker, D. and Hedrich, R.}, biburl = {https://www.bibsonomy.org/bibtex/29b86ada182beb9cdb45bbb9350cb83de/rainerhedrich_2}, doi = {DOI 10.1105/tpc.13.4.943}, interhash = {bee252ffa0020bfd3c30d5a1dc6f3be2}, intrahash = {9b86ada182beb9cdb45bbb9350cb83de}, issn = {1040-4651}, journal = {Plant Cell}, keywords = {channel myOwn potassium}, note = {424ek Times Cited:35 Cited References Count:40}, number = 4, pages = {943-952}, timestamp = {2024-02-14T14:38:32.000+0100}, title = {The pore of plant K channels is involved in voltage and pH sensing:: Domain-swapping between different K channel α-subunits}, type = {Journal Article}, url = {/brokenurl#<Go to ISI>://WOS:000168219000017}, volume = 13, year = 2001 }