RYANODINE RECEPTOR ISOFORMS AND E-C COUPLING

肌浆网钙释放通道(兰尼定受体， RyR)，在钙离子动态平衡和信号转导中起重要作用 转导。有三种不同的RyR亚型(RyR1 “骨骼”；RyR2“心脏”；RyR3“大脑”)描述)，但他们的许多 结构性质及其在激发中的功能作用- 收缩(EC)耦合仍有待确定。我建议采取 优势在于，与哺乳动物肌肉不同，非哺乳动物肌肉 含有大量的未知RyR3亚型。这就做 首先从鱼肉中提纯RyR3，然后比较其 其形态特征及其生理调控 雷亚尔。我们希望定义不同的差异，这些差异反映了每种亚型的 在EC耦合中的作用。使用分子和免疫学技术，我们将 还可以确定RyR3的组织定位，以区分其 表达式与功能属性相关，如频率 和/或肌肉收缩的速度。最后，由于非哺乳动物 包含表达两种RyR亚型的肌肉，也包含肌肉 它们只表达一种亚型，它们提供了一个理想的系统来 探讨RyRs在EC中共表达的功能意义 耦合。我们建议研究肌浆网制剂和 从两个肌群的单个纤维群来确定其作用 EC偶联中共表达。

The sarcoplasmic reticulum Ca2+ release channel (ryanodine receptor, RyR), plays an important role in Ca2+ homeostasis and signal transduction. There have been three different RyR isoforms (RyR1 "skeletal"; RyR2 "cardiac"; RyR3 "brain") described, but many of their structural properties as well as their functional roles in excitation- contraction (EC) coupling remain to be determined. I propose to take advantage of the fact that unlike mammalian muscle, non-mammalian muscle contains abundant quantities of the uncharacterized RyR3 isoform. I will first purify RyR3 from fish muscle, and secondly, compare its morphological characteristics and physiological regulation with the other RyRs. We hope to define distinct differences which reflect each isoform's role in EC coupling. Using molecular and immunological techniques we will also determine the tissue localization of RyR3 in order to discern if its expression is related to functional properties such as the frequency and/or the speed of contraction in muscles. Finally, since non-mammals contain muscles which express two RyR isoforms, and also contain muscles which express only one isoform, they provide an ideal system to investigate the functional significance of coexpression of RyRs in EC coupling. We propose to study sarcoplasmic reticulum preparations and single fibers from the two muscle populations to determine the role of coexpression in EC coupling.