Clustering of individual and diverse ion channels together into complexes, and their functional coupling, mediated by A-kinase anchoring protein 79/150 in neurons

 描述（由申请人提供）：多蛋白复合物已成为多种细胞信号的功能和调节的时空特异性和效率的机制。特别是，许多离子通道要么与调节它们的受体聚集，要么与活性相关的其他离子通道聚集。通常，聚类是由支架蛋白介导的，例如本次资助重点关注的 AKAP79/150 蛋白。我们专注于对神经功能至关重要的三个不同通道。一种是“M 型”（KCNQ、Kv7）K 通道，在神经和肌肉兴奋性的调节中发挥重要作用。它被认为通过 AKAP79/150 与 Gq/11 偶联受体、蛋白激酶、钙调磷酸酶 (CaN)、钙调蛋白 (CaM) 和磷酸肌醇相关。另一个关注的通道是 TRPV1，它是感觉神经元中的一种伤害性通道，也被认为受到 AKAP79/150 招募的信号蛋白的调节。第三个是 L 型 Ca2 (CaV1.2) 通道，对突触可塑性、基因调控和神经元放电至关重要。我们将使用初级感觉神经元和异源表达的组织培养细胞的“超分辨率”STORM 成像来探测含有 AKAP79/150 和这三个通道的复合物，其中单个复合物可以用可见光以 10-20 nm 分辨率可视化，打破了物理的衍射障碍。我们假设 AKAP79/150 将其中几个通道结合在一起以实现功能耦合，我们将通过神经元的膜片钳电生理学来检查这一点。福斯特共振能量转移 (FRET) 还将在全内反射荧光 (TIRF) 或共焦显微镜下进行，进一步测试包含 KCNQ、TRPV1 和 CaV1.2 通道的复合物。由于所有这三个通道均与 AKAP79/150 结合，因此我们假设它们与某些 G 蛋白偶联受体一起在神经元中共同组装成复合物。此外，我们假设这些复合物不是静态的，而是受到其他细胞信号的动态调节，我们将使用激酶或磷酸酶的快速激活来检查这些信号。将使用几种类型的转基因 AKAP150 敲除或敲入小鼠群体。该项目利用最近开发的几种尖端、高性能方法，为神经元信号传导生理学开辟了新天地。

 DESCRIPTION (provided by applicant): Multi-protein complexes have emerged as a mechanism for spatiotemporal specificity and efficiency in the function and regulation of myriad cellular signals. In particular, many ion channels are clustered either with the receptors that modulate them, or with other ion channels whose activities are linked. Often, the clustering is mediated by scaffolding proteins, such as the AKAP79/150 protein that is a focus of this grant. We focus on three different channels critical to nervous function. One is the "M-type" (KCNQ, Kv7) K+ channel that plays fundamental roles in the regulation of excitability in nerve and muscle. It is thought to associate with Gq/11- coupled receptors, protein kinases, calcineurin (CaN), calmodulin (CaM) and phosphoinositides via AKAP79/150. Another channel of focus is TRPV1, a nociceptive channel in sensory neurons that is also thought to be regulated by signaling proteins recruited by AKAP79/150. The third are L-type Ca2+ (CaV1.2) channels that are critical to synaptic plasticity, gene regulation and neuronal firing. We will probe complexes containing AKAP79/150 and these three channels using "super-resolution" STORM imaging of primary sensory neurons and heterologously-expressed tissue-culture cells, in which individual complexes can be visualized at 10-20 nm resolution with visible light, breaking the diffraction barrier of physics. We hypothesize that AKAP79/150 brings several of these channels together to enable functional coupling, which we will examine by patch-clamp electrophysiology of the neurons. Förster resonance energy transfer (FRET) will also be performed under total internal reflection fluorescence (TIRF) or confocal microscopy, further testing for complexes containing KCNQ, TRPV1 and CaV1.2 channels. Since all three of these channels bind to AKAP79/150, we hypothesize that they co-assemble into complexes in neurons, together with certain G protein-coupled receptors. Furthermore, we hypothesize these complexes to not be static, but rather to be dynamically regulated by other cellular signals, which we will examine using rapid activation of kinases or phosphatases. Several types of mouse colonies of genetically altered AKAP150 knock-out or knock-in mice will be utilized. This project breaks new ground into the physiology of signaling in neurons, using several cutting-edge, high- powered approaches that have just recently been developed.