COS-7细胞株中KCNE2与KChIP2c共表达对Kv4.2电流复活的影响  

The effect of co-expression of KCNE2 and KChIP2c on Kv42 current recovery from inactivation of COS-7 cells

作　　者：王芳[1] 吴红玲[1] 凌云[1] 张健[2] 徐明明[1] 

机构地区：[1]深圳市南山区人民医院VIP病房 [2]深圳大学医学院生理学教研室,广东深圳518052

出　　处：《临床和实验医学杂志》2012年第13期993-995,998,共4页Journal of Clinical and Experimental Medicine

基　　金：深圳市南山区卫生科技计划项目基金资助(项目编号:2009017)

摘　　要：目的探讨当钾通道相互作用蛋白(KChIP2)和KCNE2共表达时对电压依赖性钾通道Kv4.2电流复活的影响。方法采用COS-7株细胞表达系统模拟生理条件,将Kv4.2、KChIP2c和KCNE2 cDNA以3∶1∶1的分子比同时转染至COS-7株细胞,用膜片钳的方法记录全细胞电流,用免疫组化聚焦实验和免疫荧光成像证实细胞表达cDNAs编码的蛋白质。结果 KChIP2c加速了Kv4.2的复活,KCNE2与KChIP2c共表达进一步加速了电流的复活,导致了在Kv4.2电流恢复中的"超射"峰电流,一种人类瞬间外向电流(Ito)特有的现象。结论 Kv4.2与KChIP2c和KCNE2的共表达可产生与人类天然Ito相似的电流,提示KChIP2c和KCNE2同时参与构成心肌细胞Ito的电生理特性。Objective To study the effect of co-expression of KCNE2 and KChIP2c on voltage-dependent K＋ channel Kv4.2 current recovery from inactivation of COS-7 cells.Methods The expression of COS-7 cells was used to simulate physiological conditions.Kv4.2,KChIP2c and KCNE2 cDNA were simultaneously transfected into COS-7 cells at a molar ratio of 3：1：1.Whole-cell current was recorded by patch-clamp method.Proteins encoded by cDNAs were detected by immunocytochemical confocal experiment,and immunofluorescence was imaged with fluorescent microscopy.Results KChIP2c accelerated Kv4.2 recovery from inactivation.Co-expression of KCNE2 and KChIP2c further accelerated the recovery and caused an ＂over-shoot＂ of peak current amplitude during Kv4.2 current recovery,a phenomenon which has been uniquely described for human transient outward current（Ito）.Conclusion Co-expression of Kv4.2 with KChIP2c and KCNE2 yields a current profile similar to human native Ito.Both KChIP2c and KCNE2 simultaneously participate in recapitulation of electrophysiological properties of Ito in cardiomyocytes.

关 键 词：瞬间外向电流 钾通道相互作用蛋白 KCNE2 电生理 

分 类 号：R363[医药卫生—病理学]