Reid J D, Lukas W, Shafaatian R, Bertl A, Scheurmann-Kettner C, Guy H R, North R A
Glaxo Institute for Molecular Biology, Geneva, Switzerland.
Recept Channels. 1996;4(1):51-62.
Potassium channel subunits have six or two transmembrane segments in addition to a conserved pore-forming (P) domain; four subunits come together to form a channel. A gene was identified in S. cerevisiae (J0911) encoding a protein with eight probable membrane-spanning segments and two such P regions. This protein (Duk1p) is a potassium channel because Xenopus oocytes injected with the corresponding RNA express potassium currents activated by depolarization that are not seen in control oocytes. Similar potassium currents were recorded from wildtype S. cerevisiae spheroplasts, but not from those in which the DUK1 locus had been disrupted. Cells carrying the duk1 delta 1::HIS disruption in addition to a chimeric gene comprising DUK1 behind the GAL1 promoter showed outward currents when grown in galactose, but not when grown in glucose. Additional sequences with the duplicate pore motif were found in C. elegans, suggesting that these proteins represent a novel structural family of potassium channel proteins.
钾通道亚基除了有一个保守的成孔（P）域外，还有六个或两个跨膜片段；四个亚基聚集在一起形成一个通道。在酿酒酵母中鉴定出一个基因（J0911），它编码一种含有八个可能的跨膜片段和两个此类P区域的蛋白质。这种蛋白质（Duk1p）是一种钾通道，因为注射了相应RNA的非洲爪蟾卵母细胞会表达由去极化激活的钾电流，而对照卵母细胞中则未观察到这种电流。从野生型酿酒酵母原生质体中记录到了类似的钾电流，但在DUK1基因座被破坏的原生质体中未记录到。携带duk1 delta 1::HIS缺失以及在GAL1启动子后包含DUK1的嵌合基因的细胞，在半乳糖中生长时显示出外向电流，而在葡萄糖中生长时则没有。在秀丽隐杆线虫中发现了具有重复孔基序的其他序列，这表明这些蛋白质代表了钾通道蛋白的一个新的结构家族。
