Determinants of Dendritic Potassium Channel Localization

描述（由申请人提供）：树突和体树突电压门控钾或Kv通道是神经元信号传导的基本组成部分。该建议旨在确定通过动态调节内在兴奋性来确定神经元功能的基本机制。我们特别关注体树突延迟整流Kv2.1通道和树突A型Kv4.2通道的丰度，分布和功能的调节。我们有令人兴奋的新数据，这些重要的Kv通道的定位和功能都受到兴奋性神经递质刺激和缺氧/缺血的动态调节。这种调节是通过对通道蛋白的翻译后效应，通过磷酸化状态（Kv2.1，Kv4.2）的变化和与辅助亚基（Kv4.2）的相互作用。此外，Kv2.1和Kv4.2的动态变化与神经元电活动的显著变化相关。该建议旨在确定负责Kv2.1定位和功能动态变化的精确机制。拟议的项目采用最先进的质谱方法来识别通道蛋白上的磷酸化位点，然后通过实验直接解决这些位点在异源细胞和神经元中调节Kv2.1和Kv4.2定位和功能的作用。该项目还需要全面分析Kv4.2通道的辅助亚基在通过突触活动动态调节Kv4.2定位和功能中的作用。最后，我们将直接干预这些通道的表达和调节，并确定对培养和脑切片中神经元电活动的影响。这些研究将产生重要的见解Kv2.1，稳态可塑性的调节器，和Kv4.2，活性依赖性增强的决定因素的相互生理调节。

DESCRIPTION (provided by applicant): Dendritic and somatodendritic voltage-gated potassium or Kv channels are fundamental components of neuronal signaling. This proposal is aimed at determining the fundamental mechanisms that determine neuronal function through dynamic modulation of intrinsic excitability. We specifically focus on regulation of the abundance, distribution and function of the somatodendritic delayed rectifier Kv2.1 channel, and the dendritic A-type Kv4.2 channel. We have exciting new data that both localization and function of these important Kv channels are dynamically modulated by excitatory neurotransmitter stimulation, and by hypoxia/ischemia. This modulation is via posttranslational effects on the channel proteins, by changes in phosphorylation state (Kv2.1, Kv4.2) and interaction with auxiliary subunits (Kv4.2). Moreover, the dynamic changes in Kv2.1 and Kv4.2 correlate with significant changes in neuronal electrical activity. This proposal is aimed at determining the precise mechanism responsible for the dynamic changes in Kv2.1 localization and function. The proposed project employs state-of-the art mass spectrometric approaches to identify phosphorylation sites on the channel proteins, followed by experiments to directly address the role of such sites in regulating Kv2.1 and Kv4.2 localization and function in both heterologous cells and neurons. The project also entails a comprehensive analysis of the roles of auxiliary subunits of Kv4.2 channels in the dynamic regulation of Kv4.2 localization and function by synaptic activity. Finally, we will directly intervene in the expression and modulation of these channels and determine effects on electrical activity of neurons in culture and in brain slices. These studies will yield important insights into the reciprocal physiological regulation of Kv2.1, a regulator of homeostatic plasticity, and Kv4.2, a determinant of activity-dependent potentiation.