Allosteric mechanisms of Ca activated K channel gating

描述（申请人提供）：离子通道动态调节 膜渗透性通过其打开和关闭（门）的能力， 对各种刺激的反应。在查明和 表征通道蛋白的功能组分，所述通道蛋白参与 该门控过程包括检测刺激的“传感器”和 调节离子通过通道孔的流动。然而，构象 连接传感器和门的动作的事件和交互仍然存在 很大程度上是未知的，可能对理解 通道如何正常工作以及它们如何被内源性因素调节， 药物或疾病。为了确定传感器之间的通信性质， 盖茨我以前研究过（在理查德·奥尔德里奇的实验室）， 大电导钙激活钾通道（mSlo）的功能; 能感知电压和细胞内钙离子存在变构机制 通过这种方式，传感器的激活和孔的打开似乎 代表构象上不同的事件， 但可以单独发生。mSlo提供了一个独特的学习机会， 传感器/门通信。通过在极端条件下研究mSlo， 该通道翼特定动力学和稳态特性的优点 能够孤立地研究传感器激活、通道开放和 传感器和门之间的相互作用。此外，方法和分析工具 先前针对WT通道开发的方法现在可以应用于突变mSlo通道 以识别参与传感器/门通信的残基。的 结果不仅对理解mSlo的门控很重要， 也用于阐明其他Ky中传感器和门之间的耦合， 频道

DESCRIPTION (provided by the applicant): Ion channels dynamically regulate membrane permeability through their ability to open and close (gate) in response to various stimuli. Progress has been made in identifying and characterizing functional components of channel proteins that are involved in this gating process including "sensors" that detect stimuli, and "gates" that regulate the flow of ions through the channel pore. However the conformational events and interactions that link the action of sensors and gates remain largely unknown and are likely to be of fundamental importance in understanding how channels normally work and how they are modulated by endogenous factors, drugs or disease. To determine the nature of communication between sensors and gates I have previously studied (in the laboratory of Richard Aldrich) the function of a large conductance Ca2+ -activated K channel (mSlo); a channel that senses both voltage and intracellular Ca2+. An allosteric mechanism exists by which the activation of sensors and the opening of the pore appear to represent conformationally distinct events that strongly influence each other but can occur in isolation. mSlo offers a unique opportunity for studying sensor/gate communication. By studying mSlo under extreme conditions and taking advantage of particular kinetic and steady state properties of this channel we are able to study, in isolation, sensor activation, channel opening and the interaction between sensor and gate. Moreover, the methods and analytical tools developed previously for WT channels can now be applied to mutant mSlo channels to identify residues that are involved in sensor/gate communication. The results will be important not only for understanding the gating of mSlo but also for elucidating the coupling between sensors and gates in other Ky channel.