Schönherr Roland, Gessner Guido, Löber Karsten, Heinemann Stefan H
Arbeitsgruppe Molekulare und Zelluläre Biophysik, Klinikum der Friedrich-Schiller-Universität Jena, Drackendorfer Strasse 1, D-07747 Jena, Germany.
FEBS Lett. 2002 Mar 13;514(2-3):204-8. doi: 10.1016/s0014-5793(02)02365-7.
Human ether à go-go potassium channel 2 (hEAG2) was cloned and its properties were compared with the previously characterized isoform hEAG1. In the Xenopus oocyte expression system the time course of activation was about four times slower and the voltage required for half-maximal subunit activation was about 10 mV greater for hEAG2 channels. However, its voltage dependence was smaller and, therefore, hEAG2 channels start to open at more negative voltages than hEAG1. Coexpression of both isoforms and kinetic analysis of the resulting currents indicated that they can form heteromeric channel complexes in which the slow activation phenotype of hEAG2 is dominant. Upon expression in mammalian cells, quinidine blocked hEAG1 channels (IC(50) 1.4 microM) more potently than hEAG2 channels (IC(50) 152 microM), thus providing a useful tool for the functional distinction between hEAG1 and hEAG2 potassium channels.
人醚 - 去极化钾通道2（hEAG2）被克隆出来，并将其特性与先前已表征的同种型hEAG1进行比较。在非洲爪蟾卵母细胞表达系统中，hEAG2通道的激活时间进程约慢四倍，且亚基半最大激活所需电压比hEAG1通道高约10 mV。然而，其电压依赖性较小，因此hEAG2通道在比hEAG1更负的电压下开始开放。两种同种型的共表达以及对所得电流的动力学分析表明，它们可以形成异源通道复合物，其中hEAG2的缓慢激活性表型占主导。在哺乳动物细胞中表达时，奎尼丁对hEAG1通道（IC50 1.4 microM）的阻断作用比对hEAG2通道（IC50 152 microM）更强，从而为区分hEAG1和hEAG2钾通道的功能提供了一种有用的工具。
