Channels with KCNE Subunits: Conformational Dynamics

描述(由申请人提供)：这项工作的目标是确定电压门控钾(Kv)通道是如何由KCNE亚基控制的。也被称为水貂相关肽(MiRPs)，这些单次通过的跨膜辅助亚单位值得研究，因为它们是心脏和其他依赖Kv通道的器官正常功能所必需的。MiRPs通过与Kv通道成孔亚基组装而发挥其强大的作用，从而直接指示位置和电平、电压敏感性、时间依赖性、单位电导、离子选择性以及对调节剂和药物的响应。识别和研究MiRPs对心脏疾病的诊断和治疗具有重要意义。这个应用程序的意义是双重的。首先，在过去的十年里，我们已经了解了很多关于MiRp在心脏中的作用，但还不知道它们是如何做到的。其次，现在可以使用工具来描述构象动力学，也就是实时蛋白质操作的机制基础。在这里，强大的光学、电生理和建模技术被应用于细胞中形成的通道，这种能力在十年前是无法想象的。结果不亚于此：我们现在可以回答人类生理学和疾病中的基本、突出的问题。这三个目标侧重于两个重要通道的运行，这些通道由相同的成孔Kv亚基(Kv7.1=KCNQ1=Q1)和两个不同的MiRPs(mink=E1和MiRP2=E3)形成。这项研究解决了生理学的核心问题。也就是说：为什么心脏和耳朵中的iKs(Q1+e1)对电压反应缓慢？心脏和结肠中的IK(Q1+E3)对电压有何即时反应？这些正常的功能会被遗传差异和后天疾病所破坏。更基本的是，这项研究可以揭示电压传感器和门的关键工作原理以及附属亚单位的影响；这些见解与全身相关。

DESCRIPTION (provided by applicant): The goal of this work is to determine how voltage-gated potassium (Kv) channels are controlled by KCNE subunits. Also called MinK-related peptides (MiRPs), these single-pass transmembrane accessory subunits merit investigation because they are required for normal function of the heart and other organs that depend on Kv channels. MiRPs exert their powerful effects by assembly with Kv channel pore-forming subunits and thereby direct location and level, voltage-sensitivity, time- dependence, unitary conductance, ion selectivity, and response to regulators and pharmaceuticals. Identifying and studying MiRPs has advanced diagnosis and treatment of cardiac disease. The significance of this application is two-fold. First, we have learned a great deal about what MiRPs do in the heart over the last decade but not yet how they do it. Second, tools are now available to delineate conformational dynamics, that is, the mechanistic basis for protein operation in real-time. Here, powerful optical, electrophysiological and modeling techniques are brought to bear on channels as they form in cells, a capability unimaginable just a decade ago. The result is no less than this: we can now answer basic, outstanding questions in human physiology and disease. The three aims focus on operation of two important channels formed by the same pore-forming Kv subunit (Kv7.1 = KCNQ1 = Q1) and two different MiRPs (MinK = E1 and MiRP2 = E3). The study addresses questions at the core of physiology. To wit: why does IKs (Q1 + E1) in the heart and ear respond slowly to voltage? How does IK (Q1 + E3) found in heart and colon react instantaneously to voltage? These normal functions are disrupted by inherited differences and acquired disease. More basically, the study can reveal key principles of operation of voltage sensors and gates and the impact of accessory subunits; these insights have relevance throughout the body.