Specificity of calcium channels in neuronal signaling

电压门控钙通道(VGCC)是一种跨膜蛋白，允许钙离子进入 在激活时。除了它们的产电作用外，VGCC还在 膜的去极化和广泛的非电活动。钙离子通过不同的途径内流 不同类型的VGCC可以激活/调节不同的细胞信号级联反应。VGCC也是目标 用于由各种第二信使进行调制。磷酸化和去磷酸化是 快速调节钙通道活性的重要手段。新出现的证据表明 大分子信号复合体的形成是其特异性的机制之一。 钙离子通道的作用以及蛋白激酶和/或对通道活性的快速调节 磷酸酶。这个项目的长期目标是了解钙离子通道的独特作用 神经元信号转导中的伙伴蛋白。在本申请中，我们将重点研究三种新的钙离子通道 通过酵母双杂交筛选鉴定的配对蛋白，研究它们在PKC形成中的作用 信号复合体以及针对树突和/或轴突的mRNAs的活性依赖 局部蛋白质合成。几个不同的假设将被测试，使用组合 分子和细胞生物学、生物化学、荧光成像和电生理学的方法。 我们将解决：(1)生理因素，如蛋白激酶的磷酸化，调节 形成PKCE-ENH-N型钙通道复合体。(2)存在新的钙结合结构域， 负责PKCE-ENH和ENH-N型钙离子相互作用的差异调节 频道。(3)具有功能的PKC信号复合体包括一个蛋白磷酸酶PP2ca，它 直接与钙离子通道的C末端结合。(4)一种新的通道伙伴蛋白PQ-46，其 是一种RNA结合蛋白，与N-和P/Q-型钙离子通道结合，可能参与活性 依赖于以树突和/或轴突为靶的mRNAs。这一结果将有助于我们了解 通过蛋白质-蛋白质相互作用建立的细胞信号网络实现了其专一性。 这项研究的结果将提供大脑和大脑中信号转导的分子机制 将有助于了解正常的神经功能，如学习和记忆，并提供 导致神经紊乱的原因，如阿尔茨海默病。

Voltage-gated Ca channels (VGCCs) are transmembrane proteins, which allow Ca entry upon activation. In addition to their electrogenic role, VGCCs provide a pivotal link between membrane depolarization and a wide range of nonelectrical activities. Ca2+ influx through different types of VGCCs can activate/regulate distinct cellular signaling cascades. VGCCs are also targets for modulation by a variety of second messengers. Phosphorylation and dephosphorylation are important means of rapid regulation of the Ca2+ channel activity. Emerging evidence shows that formation of macromolecular signaling complexes is one the of the mechanisms for the specificity of the Ca2+ channel action as well as rapid regulation of the channel activity by protein kinases and/or phosphatases. The long term goal of this project is to understand the unique role of Ca2+ channel partner proteins in neuronal signaling. In this application we will focus on three novel Ca2+ channel partner proteins, identified via yeast two-hybrid screening, for their roles in formation of a PKC signaling complex as well as in targeting mRNAs to dendrites and/or axons for activity-dependent localized protein synthesis. Several different hypotheses will be tested, using the combined approaches of molecular and cell biology, biochemistry, fluorescent imaging and electrophysiology. We will address: (1) Physiological factors, such as phosphorylation by protein kinases, regulate formation of the PKCe-ENH-N-type Ca2+ channel complex. (2) Novel Ca2+ binding domains exist, responsible for differential regulation of the interactions between PKCe-ENH and ENH-N-type Ca2+ channels. (3) The functional PKC signaling complex includes a protein phosphatase, PP2ca, which binds directly to the C-terminus of Ca2+ channels. (4) A novel channel partner protein, PQ-46, which is an RNA binding protein and binds to N- and P/Q-type Ca2+ channels, may be involved in activity dependent targeting of mRNAs to dendrites and/or axons. The results will shed light on how the cellular signaling network, established via protein-protein interactions, achieves its specificity. Results of this study will provide molecular mechanisms of signal transduction in the brain and will help understand normal neurological functions, such as learning and memory, and provide reasons for neurological disorders, such as Alzheimer's disease.