DISTRIBUTION AND STRUCTURE OF HERG POTASSIUM CHANNELS

HERG已被确定为长QT综合征的一种形式的位点， LQT 2，可导致心律失常，通常导致突发性 死亡 HERG的异源表达导致钾电流非常 与内源性钾电流IKr相似（但不相同）， 有助于人类心脏的复极 这个目标 研究建议是确定HERG在 人类心脏，并确定HERG是否与其他钾 人心室和心房肌细胞中的通道亚基。 具体 目的如下：1）确定 使用RNA酶保护的人心室和心房的HERG mRNA和蛋白 免疫印迹分析; 2）免疫沉淀人心房肌HERG 和心室膜制备，并确定任何共组装 使用免疫印迹分析蛋白质;和3）表达心室心肌细胞 从所得钾电流的表征和比较 与人心室和心房IKr的关系。 测定分子 功能性人类心房和心室IKr的组成将使 产生表达这些IKr通道的稳定细胞系。 这些将 可用于通道生物物理学，生物合成， 组装和翻译后加工，重要的是， 靶向IKr通道的治疗剂。

HERG has been identified as the locus of one form of long QT syndrome, LQT2, which can result in cardiac arrhythmias often leading to sudden death. Heterologous expression of HERG results in potassium currents very similar (but not identical) to the endogenous potassium current IKr which contributes to repolarization in the human heart. The goal of this research proposal is to determine the expression levels of HERG in the human heart and to determine if HERG is associated with other potassium channels subunits in human ventricular and atrial myocytes. The specific aims are as follows: 1) to determine the relative expression levels of HERG mRNA and protein human ventricles and atria using RNase protection and Western blot analyses; 2) to immunoprecipitate HERG from human atrial and ventricular membrane preparations and to identify any coassembling proteins using immunoblots; and 3) to express ventricular cardiac myocytes from characterization for the resultant potassium currents and comparison to human ventricular and atrial IKr. Determination of the molecular composition of functional human atrial and ventricular IKr will enable the production of stable cell lines expressing these IKr channels. These will be useful for detailed studies of channel biophysics, biosynthesis, assembly and post translational processing and, importantly, for testing therapeutic agents targeted against IKr channels.