Inactivation of Neuronal Kv4 Potassium Channels

描述（由申请人提供）：该项目的长期目标是了解控制神经元Kv4钾通道失活的分子机制。这些钾通道介导神经系统中编码、整合和放大电信号所必需的瞬态钾电流。Kv4通道可能利用了新的失活机制，这与我们熟知的Shaker钾通道不同。在上一个资助期内取得的发现开始揭示Kv4失活的生理基础以及新的亚基如何塑造这一过程。下一个资助期的具体目标是：(1)探索Kv4通道失活的重要途径背后的构象变化；(2)绘制控制Kv4通道失活门控的细胞质运动区域；(3)探讨Kv4特异性神经元钙传感器（KChlPs）重塑Kv4失活的分子机制；(4)研究具有独特调节特性的KChIP结构域的分子决定因素。利用重组DNA技术、膜片钳电生理学和硫醇特异性试剂研究异种表达系统（如爪蟾卵母细胞或哺乳动物细胞）中表达的Kv4通道的失活。应用核磁共振（NMR）求解了Kv4通道中假定的失活结构域的结构。通过研究这些目标，该项目可能会深入了解依赖于电信号精确定时的大脑功能的分子基础，在这个领域，Kv4通道的失活门控发挥着最重要的作用。可能从这项研究中受益的具体领域包括联想学习和癫痫的研究。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand the molecular mechanisms that control inactivation of neuronal Kv4 potassium channels. These potassium channels mediate the transient potassium current that is necessary for coding, integration and amplification of electrical signals in the nervous system. Kv4 channels probably utilize novel mechanisms of inactivation, which are distinct from those better known in Shaker potassium channels. Discoveries made during the last funding period are beginning to shed light on the physiological basis of Kv4 inactivation and how novel subunits shape this process. The specific aims for the next funding period are: (1) To probe conformational changes underlying a prominent pathway of inactivation in Kv4 channels; (2) To map the cytoplasmic moving regions controlling inactivation gating of Kv4 channels; (3) To investigate the molecular mechanisms underlying remodeling of Kv4 inactivation by Kv4-specific neuronal calcium sensors (KChlPs);(4) To investigate the molecular determinants of a KChIP domain with unique modulatory properties. Recombinant DNA technology, patch-clamp electrophysiology and thiol-specific reagents are applied to study inactivation of Kv4 channels expressed in heterologous expression systems (e.g., Xenopus oocytes or mammalian cells). Nuclear magnetic resonance (NMR) is applied to solve the structure of a putative inactivation domain in Kv4 channels. By investigating these aims, this project may gain insights into the molecular basis of brain functions that depend on the precise timing of electrical signaling, a domain where inactivation gating of Kv4 channels plays its most significant role. Specific areas that may benefit from this research include studies of associative learning and epilepsy.