MOLECULAR DETERMINANTS OF ACETYLCHOLINE RECEPTOR GATING

神经递质门控离子通道在整个神经系统中介导突触传递。来自骨骼肌的烟碱型乙酰胆碱受体(AChR)是了解受体超家族成员的原型，包括神经元型烟碱受体、甘氨酸受体、GABAA受体和5-HT3受体。这类蛋白质的基本功能是将神经递质结合转导到打开固有离子通道。为了更好地了解神经递质门控离子通道的功能，本申请中提出的工作将识别AChR跨膜区域中控制通道开放和关闭速率的氨基酸。该方法将跨膜区残基的定点突变和在哺乳动物细胞中的表达与单通道记录和动力学分析相结合。总的发现将跨膜区结构与AChR通道门控的基本步骤联系起来。

Neurotransmitter-gated ion channels mediate synaptic transmission throughout the nervous system. The nicotinic acetylcholine receptor (AChR) from skeletal muscle has served as a prototype for understanding the members of the superfamily of receptors, which includes neuronal nicotinic, glycine, GABAA, and 5-HT3 receptors. The essential function of this class of proteins is to transduce neurotransmitter binding into opening of an intrinsic ion channel. To better understand how neurotransmitter-gated ion channels function, the work proposed in this application will identify amino acids in transmembrane domains of the AChR that govern rates of opening and closing of the channel. The approach combines site-directed mutagenesis of residues in transmembrane domains and expression in mammalian cells with single channel recording and kinetic analysis. The overall findings will relate transmembrane domain structure to elementary steps underlying gating of the AChR channel.