Calcium Channel Signaling in Neurons

描述(由申请人提供)：电压门控钙(钙)通道在神经元功能中发挥核心作用，是将电活动转化为生化事件的关键。这项建议的主要目的是确定电压门控钙通道激活信号级联的分子机制，这些信号级联介导基因表达并促进神经元存活。神经元和肌肉细胞表达至少十种不同类型的电压门控钙通道，这些通道在亚细胞定位和生物物理特性上存在差异。L类通道(LTC)在激活转录通路和促进神经元存活方面特别有效。转录因子CREB和MEF-2是LTC信号的两个重要靶点，调节神经系统的分化和可塑性。LTCs激活基因表达和抑制细胞凋亡的生物物理和生化特征还不是很清楚。为了解决LTCs如何与信号通路相连的问题，提出了以下具体目标：1)确定允许L类钙通道激活转录的结构和生物物理特征。2)确定特定的L通道相互作用蛋白是否将该通道与导致转录激活的信号通路联系起来。3)明确L型钙通道的哪些特性使其具有抑制神经元凋亡、促进存活的作用。生化、细胞生物学和电生理学技术将被用来开发这些特定的目标。我们最近开发了一种方法，使用二氢吡啶不敏感的LTC来研究初级神经元中的LTC信号，我们计划将这种方法用于这些研究。我们还鉴定了几个LTC相互作用蛋白，它们可能对通道调节和信号转导很重要，我们计划研究它们对向细胞核发出信号的重要性。这些实验的结果将为电压门控通道如何激活调节神经系统结构和功能的信号通路提供关键的见解。

DESCRIPTION (provided by applicant): Voltage-gated calcium (Ca2+) channels play a central role in neuronal function and are essential for converting electrical activity into biochemical events. The main goal of this proposal is to identify the molecular mechanisms by which voltage-gated calcium channels activate signaling cascades that mediate gene expression and promote neuronal survival. Neurons and muscle cells express at least ten different kinds of voltage-gated calcium channels that vary in their subcellular localization and biophysical properties. L-type channels (LTCs) are particularly effective at activating transcriptional pathways and at promoting neuronal survival. The transcription factors CREB and MEF-2 are two important targets of LTC signaling that regulate differentiation and plasticity in the nervous system. The biophysical and biochemical features that allow LTCs to activate gene expression and suppress apoptosis are not well understood. To address the question of how LTCs are linked to signaling pathways the following specific aims are proposed: 1) To determine the structural and biophysical features that allow L-type calcium channels to activate transcription. 2) To determine whether specific L-type channel interacting proteins link the channel to signaling pathways that lead to the activation of transcription. 3) To determine what features of L-type calcium channels allow them to inhibit neuronal apoptosis and promote survival. Biochemical, cell biological and electrophysiological techniques will be used to develop these specific aims. We have recently developed a method of using dihydropyridine insensitive LTCs to investigate LTC signaling in primary neurons and we plan to use this approach for these studies. We have also identified several LTC-interacting proteins that may be important for channel regulation and signaling and we plan to investigate their importance for signaling to the nucleus. The results of these experiments will provide critical insights into how voltage-gated channels activate the signaling pathways that regulate the structure and function of the nervous system.