Gating of IsK expressed in Xenopus oocytes depends on the amount of mRNA injected.
Gating of IsK expressed in Xenopus oocytes depends on the amount of mRNA injected.
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DOI：
10.1085/jgp.104.1.87
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发表时间：
1994-07
期刊：
影响因子：
--
通讯作者：
Cohen IS
中科院分区：
文献类型：
--
作者：
Cui J;Kline RP;Pennefather P;Cohen IS
IsK是一个延迟整流型的K+通道，广泛分布在可兴奋细胞和不可兴奋细胞中。它的结构与其他克隆K+通道不同，其门控的分子细节尚不清楚。本研究表明，非洲爪蟾卵母细胞中表达的IsK的激活动力学取决于其mRNA的注射量，注射量越大，激活动力学越慢，激活过程中的初始延迟时间越长。单次注射IsK mRNA后，随着时间的推移，激活动力学也会发生类似的变化。我们提出了两种动力学方案来说明我们的实验结果是如何产生的。两者都暗示在IsK激活过程中单个通道蛋白之间存在相互作用。通道门控对mRNA浓度的依赖性为离子电流动力学的长期调控提供了一种新的机制。
IsK is a K+ channel of the delayed rectifier type widely distributed throughout both excitable and nonexcitable cells. Its structure is different from other cloned K+ channels and molecular details of its gating remain obscure. Here we show that the activation kinetics of IsK expressed in Xenopus oocytes depend upon the amount of its mRNA injected, with larger amounts resulting in slower activation kinetics with a longer initial delay during activation. Similar changes in activation kinetics occur with time after a single injection of IsK mRNA. We present two kinetic schemes which illustrate how our experimental results could arise. Both imply an interaction among individual channel proteins during IsK activation. The dependence of channel gating on mRNA concentration provides a novel mechanism for long term regulation of ion current kinetics.