CALCIUM RELEASE UNITS IN CARDIAC MUSCLE

描述（根据申请人的描述改编）： 这一建议是为了阐明结构组织的基础 心肌和骨骼肌的钙释放单位（CRU）， 兴奋-收缩偶联CRU由连接性肌浆细胞组成， 网织膜（jSR），其由管腔钙结合蛋白组成， 钙螯合蛋白（CSQ）和几种膜蛋白，包括 钙释放通道（ryanodine受体; RyRs）和支持蛋白 连接蛋白和三聚体蛋白。肌膜的邻近区域含有L型钙离子 通道（二氢吡啶受体; DHPR）。为确定 组装、组织和维护这些单元的结构完整性， 将通过电子显微镜，使用薄切片和 冷冻断裂方法和蛋白质组成将使用 通过免疫荧光偶联共聚焦显微镜和Western印迹。 三种策略将用于评估改变蛋白质的影响， 组成的结构。1)过表达一种基因的转基因小鼠 或更多的CRU蛋白将被研究。2)肌肉特异性CRU蛋白 将在非肌肉细胞中表达，以确定 这是组建CRU所必需的。3)骨骼肌中CRU的组成 利用分子生物学和超微结构技术对文昌鱼的形态结构进行了研究 接近。

DESCRIPTION (adapted from the applicant's description): The overall goal of this proposal is to elucidate the basis for structural organization of the calcium release units (CRUs) of cardiac and skeletal muscle which underlie excitation-contraction coupling. CRUs are comprised of junctional sarcoplasmic reticulum (jSR) which are composed of a luminal calcium-binding protein, calsequestrin (CSQ), and several membrane proteins which include the calcium-release channel (ryanodine receptor; RyRs), and supporting proteins junctin and triadin. The adjacent areas of sarcolemma include L-type calcium channels (dihydropyridine receptors; DHPRs). To determine the basis for the assembly, organization, and maintenance of structural integrity of these units, structure will be assessed by electron microscopy, using thin sections and freeze fracture methods, and protein composition will be assessed using immunofluorescence coupled to confocal microscopy and by Western blotting. Three strategies will be used to assess the effect of altered protein composition on the structure of CRUs. 1) Transgenic mice which overexpress one or more of the CRU proteins will be studied. 2) Muscle specific CRU proteins will be expressed in non-muscle cells in order to determine the proteins necessary for formation of CRUs. 3) The composition of CRUs in skeletal muscle of Amphioxus will be examined using molecular biology and ultrastructural approaches.