Potassium currents expressed from Drosophila and mouse eag cDNAs in Xenopus oocytes
Potassium currents expressed from Drosophila and mouse eag cDNAs in Xenopus oocytes
复制标题
DOI：
10.1016/0028-3908(96)00113-x
复制
发表时间：
1996-07-01
影响因子：
4.7
通讯作者：
Ganetzky, B
中科院分区：
文献类型：
--
作者：
Robertson, GA;Warmke, JW;Ganetzky, B
ether-a-go-go（eag）基因家族编码一组在从无脊椎动物到哺乳动物的生物体的可兴奋细胞中表达的相关离子通道多肽。早期的研究表明，果蝇的eag突变导致神经系统膜兴奋性增加。人类eag相关基因（HERG）的突变与心律失常有关，最近的研究表明，HERG亚基有助于介导I-Kr和心脏动作电位终末复极化的通道。M-EAG（果蝇eag的小鼠对应物）的生理作用尚未确定。在这里，我们描述的Lag和M-EAG通道在青蛙卵母细胞中表达的基本特性，使用双电极电压钳和膜片钳技术。fag和M-EAG通道都是电压依赖性的，向外整流的，并且对K+的选择性高于Na+离子。与以前的报道相反，我们没有发现Ca 2+通量通过fag通道的证据。这些密切相关的通道之间最显著的差异是，fag电流表现出部分失活，而M-EAG电流持续激活电压命令的持续时间。此外，滞后电流跑下来更迅速地比M-EAG电流在切除macropatches。通过将贴片插入卵母细胞的内部，Rundown是可逆的，这表明细胞溶质因子调节通道活性或稳定性。这些研究应有助于确定电流介导的fag和M-EAG通道在体内。版权所有（C）1996 Elsevier Science Ltd
The ether-a-go-go (eag) gene family encodes a set of related ion channel polypeptides expressed in the excitable cells of organisms ranging from invertebrates to mammals. Earlier studies demonstrated that eag mutations in Drosophila cause an increase in membrane excitability in the nervous system. Mutations in the human eag-related gene (HERG) have been implicated in cardiac arrhythmia, and recent studies show that HERG subunits contribute to the channels mediating I-Kr and the terminal repolarization of the cardiac action potential. A physiological role for M-EAG, the mouse counterpart to Drosophila eag, has not been determined. Here, we describe basic properties of Lag and M-EAG channels expressed in frog oocytes, using two-electrode voltage clamp and patch clamp techniques. Both fag and M-EAG channels are voltage-dependent, outwardly rectifying and highly selective for K+ over Na+ ions. In contrast to previous reports, we found no evidence for Ca2+ flux through fag channels. The most notable difference between these closely related channels is that fag currents exhibit partial inactivation, whereas M-EAG currents are sustained for the duration of an activating voltage command. In addition, Lag currents run down more rapidly than do M-EAG currents in excised macropatches. Rundown is reversible by inserting the patch into the interior of the oocyte, indicating that a cytosolic factor regulates channel activity or stability. These studies should facilitate identification of currents mediated by fag and M-EAG channels in vivo. Copyright (C) 1996 Published by Elsevier Science Ltd