RYANODINE RECEPTOR ISOFORMS AND E-C COUPLING

肌浆网Ca 2+释放通道（ryanodine受体， RyR），在Ca 2+稳态和信号转导中起重要作用 转导RyR有三种不同的亚型（RyR 1 “骨骼”; RyR 2“心脏”; RyR 3“大脑”）描述，但他们的许多人都是如此。 结构特性以及它们在激发中的功能作用- 收缩（EC）偶联仍有待确定。我提议 与哺乳动物肌肉不同，非哺乳动物肌肉 含有大量未表征的RyR 3同种型。我会 首先从鱼肌肉中纯化RyR 3，其次，比较其 形态特征和生理调控 RyRs。我们希望定义反映每个亚型的不同差异， 在EC耦合中的作用。利用分子和免疫学技术， 还确定RyR 3的组织定位，以辨别其是否 表达式与函数属性有关，例如频率 和/或肌肉收缩的速度。最后，由于非哺乳动物 含有表达两种RyR亚型的肌肉，也含有表达两种RyR亚型的肌肉， 它们提供了一个理想的系统， 探讨RyRs共表达在EC中的功能意义 偶合器.我们建议研究肌浆网制剂， 从两个肌肉群的单一纤维，以确定的作用， EC偶联共表达。

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.