Structural Basis for KCNE Modulation of the KCNQ1 Channel

描述（由申请人提供）：人类KCNQ1电压门控钾通道通过与辅助亚基KCNE1的相互作用进行调节，这一过程对健康的心脏和听觉功能至关重要。KCNQ1和KCNE1基因突变可导致先天性长QT综合征（LQTS）和某些形式的耳聋。KCNE1既可以减缓电压刺激的通道激活，也可以显著提高打开状态的电导。其他kcnne家族成员的KCNQ1通道功能发生了截然不同的变化。在这个项目即将到来的阶段，目标是：目标1。利用核磁共振确定KCNE1在实际脂质双分子层中溶解的条件下的三维结构。这一目标将测试我们最近在经典胶束中确定的KCNE1的结构是否代表了脂质双层中蛋白质的真实结构，或者确定的结构中对于制定KCNE1功能的工作模型至关重要的元素是否实际上是胶束中工作的产物。目标2。利用KCNE1和KCNQ1的诱变、生化测量和KCNQ1通道特性的电生理记录，批判性地评估和完善KCNE1如何减缓KCNQ1通道打开和增强开放态电导的当前工作模型。目标3。确定双层中KCNE3的三维结构，建立KCNE3快速激活Q1通道功能的工作模型。目标4。对KCNE3如何快速激活KCNQ1通道功能的新模型进行结构-功能和生化测试/改进。目标5。确定双层中KCNE4的结构，并建立KCNE4如何抑制KCNQ1通道功能的工作模型。

DESCRIPTION (provided by applicant): The human KCNQ1 voltage-gated potassium channel is modulated by interactions with an accessory subunit, KCNE1, a process that is essential for healthy cardiac and auditory function. Mutations in KCNQ1 and KCNE1 result in congenital long QT syndrome (LQTS) and some forms of deafness. KCNE1 acts both to slow down voltages-stimulated channel activation and also dramatically enhances the conductance of the open state. Other KCNE family members exert radically different changes in KCNQ1 channel function. In the upcoming phase of this project the aims are: Aim 1. Use NMR to determine the 3-D structure of KCNE1 under conditions in which it is solubilized in actual lipid bilayers. This aim will test whether the structure of KCNE1 we recently determined in classical micelles represents the bona fide structure of the protein in lipid bilayers, or whether elements of the determined structure that were crucial in formulating our working model for KCNE1 function were, in fact, artifacts of working in micelles. Aim 2. Using mutagenesis of both KCNE1 and KCNQ1, biochemical measurements, and electrophysiological recordings of KCNQ1 channel properties, critically evaluate and refine the current working model for how KCNE1 slows down KCNQ1 channel opening and enhances open state conductance. Aim 3. Determine the 3-D structure of KCNE3 in bilayers and formulate a working model for how KCNE3 rapidly activates Q1 channel function. Aim 4. Carry out structure-function and biochemical testing/refinement of the new model for how KCNE3 rapidly activates KCNQ1 channel function. Aim 5. Determine the structure of KCNE4 in bilayers and formulate a working model for how KCNE4 inhibits KCNQ1 channel function.