| Title: | "Activation of an essential calcium signaling pathway in Saccharomyces cerevisiae by Kch1 and Kch2, putative low-affinity potassium transporters" |
| Author(s): | Stefan CP; Zhang N; Sokabe T; Rivetta A; Slayman CL; Montell C; Cunningham KW; |
| Address: | "Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA" |
| ISSN/ISBN: | 1535-9786 (Electronic) 1535-9778 (Print) 1535-9786 (Linking) |
| Abstract: | "In the budding yeast Saccharomyces cerevisiae, mating pheromones activate a high-affinity Ca(2+) influx system (HACS) that activates calcineurin and is essential for cell survival. Here we identify extracellular K(+) and a homologous pair of transmembrane proteins, Kch1 and Kch2 (Prm6), as necessary components of the HACS activation mechanism. Expression of Kch1 and especially Kch2 was strongly induced during the response to mating pheromones. When forcibly overexpressed, Kch1 and Kch2 localized to the plasma membrane and activated HACS in a fashion that depended on extracellular K(+) but not pheromones. They also promoted growth of trk1 trk2 mutant cells in low K(+) environments, suggesting they promote K(+) uptake. Voltage-clamp recordings of protoplasts revealed diminished inward K(+) currents in kch1 kch2 double-mutant cells relative to the wild type. Conversely, heterologous expression of Kch1 in HEK293T cells caused the appearance of inwardly rectifying K(+) currents. Collectively, these findings suggest that Kch1 and Kch2 directly promote K(+) influx and that HACS may electrochemically respond to K(+) influx in much the same way as the homologous voltage-gated Ca(2+) channels in most animal cell types" |
| Keywords: | Calcium Channels/metabolism Calcium Chloride/metabolism *Calcium Signaling Cation Transport Proteins/genetics/*metabolism Gene Expression Gene Knockout Techniques HEK293 Cells Humans Hydrogen-Ion Concentration Mating Factor Membrane Potentials Patch-Clamp; |
| Notes: | "MedlineStefan, Christopher P Zhang, Nannan Sokabe, Takaaki Rivetta, Alberto Slayman, Clifford L Montell, Craig Cunningham, Kyle W eng R01 GM053082/GM/NIGMS NIH HHS/ R01 GM085335/GM/NIGMS NIH HHS/ R01 GM060696/GM/NIGMS NIH HHS/ GM60696/GM/NIGMS NIH HHS/ GM053082/GM/NIGMS NIH HHS/ EY10852/EY/NEI NIH HHS/ R01 EY010852/EY/NEI NIH HHS/ R21 NS074072/NS/NINDS NIH HHS/ NS074072/NS/NINDS NIH HHS/ GM085335/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural 2012/12/04 Eukaryot Cell. 2013 Feb; 12(2):204-14. doi: 10.1128/EC.00299-12. Epub 2012 Nov 30" |
