Adrenergic Regulation of HERG Protein

描述（申请人提供）：离子通道功能的调节通过心肌细胞兴奋性的改变在控制心率和收缩力方面起着关键作用。体液介质和受体参与决定通道对心血管需求变化的反应。通过第二信使、激酶、g蛋白和蛋白-蛋白相互作用的复杂相互作用，自主刺激精确控制离子通道的动态搏动调节。HERG基因产生的快速激活延迟整流电流（IKr）由于其不同寻常的生物物理特性以及归因于该通道的第二信使和蛋白质相互作用数量的增加，具有独特的细胞/激素信号综合转导资格。我们已经开始绘制α和β肾上腺素能信号通路来调节HERG/IKr。-肾上腺素能刺激导致一系列复杂的事件，包括；cAMP与HERG的直接结合、与AKAPs的相互作用、pka介导的通道磷酸化以及14-3-3与HERG的结合。因此，一个不断发展的肾上腺素能调节HERG的图景正在出现。了解急性和慢性应激适应导致获得性和遗传性心脏病的心律失常和猝死的机制是至关重要的。因此，我们建议采用多学科方法，结合蛋白质生物化学、免疫化学和膜片钳电生理学，探索这些相互作用对异种表达蛋白质和内源性心脏组织的影响和机制。具体来说，我们的目标是：1。确定14-3-3e和PKA调控herg2的意义。检测akap对HERG通道的PKA靶向。3. 检查pka介导的HERG蛋白运输的控制。

DESCRIPTION (provided by applicant): Regulation of ion channel function plays a pivotal role in controlling heart rate and contractility via changes in cardiac myocyte excitability. Humoral mediators and receptors are involved in determining channel responses to changing cardiovascular demands. The dynamic beat-to-beat regulation of ion channels is precisely controlled by autonomic stimulation through complex interplay of second messengers, kinases, G-proteins, and protein-protein interactions. The rapidly activating delayed rectifier current (IKr) produced by the HERG gene is uniquely qualified for an integrative transduction of cellular/hormonal signals due to its unusual biophysical properties and the growing number of second-messenger and protein interactions ascribed to the channel. We have begun mapping alpha- and beta-adrenergic signaling pathways to modulation of HERG/IKr. Beta-adrenergic stimulation leads to a complex series of events that includes; direct binding of cAMP to HERG, interactions with AKAPs, PKA-mediated phosphorylation of the channel, and binding of 14-3-3 to HERG. Thus, an evolving picture of adrenergic regulation of HERG is emerging. It will be essential to understand the mechanisms by which acute and chronic stress adaptation leads to arrhythmia and sudden death in both acquired and hereditary cardiac disease. Accordingly, we propose to explore the effects and mechanisms of each of these interactions in a multidisciplinary approach combining protein biochemistry, immunochemistry, and patch clamp electrophysiology on heterologously expressed proteins and endogenous cardiac tissue. Specifically, we aim to: 1. Determine the significance of 14-3-3e and PKA regulation of HERG 2. Examine PKA targeting to HERG channels by AKAPs. 3. Examine PKA-mediated control of trafficking of HERG protein.