CALCIUM ION CONTROL IN CARDIAC FUNCTION

心脏和心脏的收缩活动或松弛状态 骨骼肌受钙离子升降的控制 在肌浆中的浓度。这项计划的目的是 描述钙离子从细胞中被去除的机制 肌浆产生松弛，并交替释放到 肌浆产生收缩活动。 该计划的一部分涉及肌浆网， 哪一种是参与钙离子清除的膜系统 主动运输。钙离子的催化和转运循环 肌浆网依赖的ATPase将在#年进行研究 细节，部分反应的特征是平衡和 动力学方法，研究了其催化机理。 反应酶残留物的化学修饰。方法： 免疫学和分子遗传学也将被用于产生 克隆并分析单抗、cDNAs和 编码ATPase基因，研究ATPase的表达 在哺乳动物系统中进行基因转移，并获得 编码ATPase的DNA的改变以产生 用于结构功能和生物调节研究的材料。 程序的另一部分涉及到 肌浆网钙离子释放。纤维制剂 和来自不同节段的微体组分 肌管膜系统将被测试其能力 根据需要释放钙离子以激活收缩。大自然 触发释放的信号的特性以及 涉及释放的渠道将被调查。反应的动力学 将通过测量放射性示踪剂来研究释放 磁通和记录重建的电流 膜双层和膜片钳实验。隔离 将尝试使用通道蛋白。

The state of contractile activation or relaxation of cardiac and skeletal muscle is controlled by rise or reduction of the Ca2+ concentration in the myoplasm. The aim of this program is to characterize the mechanism by which Ca2+ is removed from the myoplasm to produce relaxation, and alternatively released into the myoplasm to produce contractile activation. One section of the program deals with sarcoplasmic reticulum, which is the membrane system involved in Ca2+ removal by active transport. The catalytic and transport cycle of the Ca2+ dependent ATPase of sarcoplasmic reticulum will be studied in detail, the partial reactions characterized by equilibrium and kinetic methods, and the catalytic mechanism investigated by chemical modification of reactive enzyme residues. Methods of immunology and molecular genetics will be also used to generate monoclonal antibodies, clone and analyze the cDNAs and the genes encoding the ATPase, study the expression of the ATPase following gene transfer in mammalian systems, and obtain alterations of the DNAs encoding the ATPase to generate material for structure-function and bioregulation studies. Another section of the program deals with the mechanism of Ca2+ release from sarcoplasmic reticulum. Fiber preparations and microsomal fractions derived from various sections of the sarcotubular membrane system will be tested for their ability to release Ca2+ as required for contractile activation. The nature of the signal triggering release and the characteristics of the channels involved in release will be investigated. The kinetics of release will be studied by measurements of radioactive tracer fluxes, and recording electrical currents in reconstituted membrane bilayers and patch clamp experiments. Isolation of channel protein will be attempted.