ION CHANNELS IN THE NERVOUS SYSTEM

电压门控钠通道(NAChs)对神经系统的电信号和传导至关重要。啮齿动物中至少有10个nach基因，每个基因在人类中都有一个已知的同源基因。每种NACH亚型的具体作用尚不清楚。一种假设是，亚型是不同的分布和调制的。这一建议主要集中在脑内NACH亚型调控和定位的分子基础上。目标1的目标是识别与脑NaChs细胞质区域结合的蛋白质(特别是。Nav1.6)，并且负责(A)调制信道功能和(B)以不同的亚蜂窝站点为目标。两种互补的方法被用来寻找和分离与NaChs相关的蛋白质：(1)酵母双杂交试验和(2)蛋白质纯化/质谱法。目的2研究用酵母双杂交方法分离得到的NaChs与钙调蛋白的相互作用。这种与大脑NaChs的相互作用将以生化和电生理学为特征。目的3利用成像技术研究脑钠通道(特别是NaV1.6)及其结合蛋白的亚细胞分布。在确定了这种分布的特征之后，将研究NaChs或AIM I中确定的结合蛋白突变的影响。这项研究既具有基础科学意义，又具有临床意义。离子通道存在于与其他膜、胞外和胞内蛋白质的复合体中。要了解这些通道的行为，重要的是要知道这些复合体中存在哪些蛋白质，并了解这些蛋白质与通道的相互作用。肌肉NaChs的突变与骨骼肌的某些疾病和心肌的长QT综合征有关。预计脑钠通道和与NaChs结合的蛋白质的突变将在人类中产生中枢神经系统疾病，拟议的研究将有助于我们对这些疾病的理解。

Voltage-gated sodium channels (NAChs) are vital for electrical signaling and conduction in the nervous system. There are at least ten NaCh genes in rodents, and each gene has a known ortholog in humans. The specific roles of each NaCh subtype are unknown. One hypothesis is that subtypes are differentially distributed and modulated. This proposal is focused upon the molecular basis for modulation and localization of brain NaCh subtypes. The goal of Aim 1 is to identify proteins that bind to the cytoplasmic domains of brain NaChs (esp. Nav1.6) and are responsible for (a) modulation of channel fiinction and (b) targeting to different subcellular sites. Two complementary methods are being used to find and isolate proteins associated with NaChs: (1) the yeast two-hybrid assay and (2) protein purification/mass spectrometry. Aim 2 is focused upon the interactions of NaChs with calmodulin, which was isolated with the yeast two-hybrid assay. This interaction with brain NaChs will be characterized biochemically and electrophysiologically. Aim 3 utilizes imaging techniques to study the subcellular distribution of brain sodium channels (esp., Nav 1.6) and their binding proteins. After characterizing this distribution, the effects of mutations in NaChs or in the binding proteins identified in Aim I will be studied. This research has both basic science and clinical relevance. Ion channels exist in complexes with other membrane, extracellular, and intracellular proteins. To understand the behavior of these channels, it is important to know which proteins are present in these complexes and hew the proteins interact with the channel. Mutations in muscle NaChs are responsible for some disorders of skeletal muscle and for long QT syndrome in cardiac muscle. It is expected that mutations in brain sodium channels and in the proteins that bind to NaChs will produce CNS disorders in humans, and the proposed studies will contribute to our understanding of these disorders.