Functional expression of the pore forming subunit of the ATP-sensitive potassium channel in Saccharomyces cerevisiae.
We have expressed the pore-forming subunits (Kir 6.1 and Kir 6.2) of the mammalian ATP-sensitive potassium channel in a potassium-transport deficient yeast strain (trk1 trk2). Functional expression of Kir 6.2 and Kir 6.1 can complement growth deficiency weakly and strongly respectively of the yeast strain on low-potassium medium. Mutations of Kir 6.2 that abolish ATP sensitivity (K185Q, I182Q) and enhance trafficking to the plasma membrane surface (Kir 6.2DeltaC36) lead to significantly better growth rescue. Growth rescue of Kir 6.1, Kir 6.2 and the above mutants can be inhibited by pharmacological agents (cesium ions, phentolamine and quinine) known to decrease channel activity by direct interaction with the pore forming subunit. Thus we have developed a system in yeast that can report both loss and gain of function mutations in these subunits and pharmacological interventions.
Graves
F M
FM
Centre for Clinical Pharmacology, Department of Medicine, University College London, The Rayne Institute, London, United Kingdom.
Tinker
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D015870:Gene Expression / Q000235:genetics*; D005816:Genetic Complementation Test; D005822:Genetic Vectors / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010646:Phentolamine / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying; D011803:Quinine / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D002712:Chlorides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D002586:Cesium; D000255:Adenosine Triphosphate; D011803:Quinine; C028019:cesium chloride; D011188:Potassium; D010646:Phentolamine