CALCIUM ION CONTROL IN CARDIAC FUNCTION

心肌和骨骼肌细胞的肌丝主要依赖于 细胞内Ca ~（2+）浓度调节其收缩 反过来，细胞内Ca 2+浓度受到控制， 通过具有特定传输系统的膜结构 对于二价阳离子。 本提案的目的是将联合收割机 超微结构，生物化学和生理学的研究方法， 为了阐明钙离子的吸收和释放的机制， 膜。 拟议的研究将在一系列 实验系统包括分离的细胞、分离的肌浆 网囊泡，溶解和纯化的蛋白质（Ca 2 + ATP酶）和 重组膜。 特异性超微结构和/或构象 这些系统的功能将与功能活动相关， 具体涉及活性Ca 2+转运和偶联酶活性。 酶循环的顺序步骤将通过快速混合进行研究 技术在向前和向后的方向，导致积极的 运输和ATP合成。 被动Ca 2+通量也将是 研究，其与收缩调节的相关性将通过以下方式进行评估： 监测分离的细胞制备物中的肌节活化。 比较研究将在以下因素的影响下进行： 药理学试剂。 这些研究将有助于澄清基本的 生物学机制：离子转运、能量转导和收缩 控制

The myofilaments of cardiac and skeletal cells are critically dependent on the intracellular concentration of Ca2+ for regulation of their contractile activity, In turn, the intracellular concentration of Ca2+ is controlled by membrane structures which are endowed with specific transport systems for the divalent cation. It is the aim of this proposal to combine ultrastructural, biochemical and physiological methods of investigation on order to clarify the mechanisms of Ca2+ uptake and release by these membranes. The proposed research will be carried out with a range of experimental systems including dissociated cells, isolated sarcoplasmic reticulum vesicles, solubilized and purified proteins (Ca2+ ATPase) and reconstituted membranes. Specific ultrastructural and/or conformational features of these systems will be related to functional activities with specific reference to active Ca2+ transport and coupled enzyme activity. Sequential steps of the enzyme cycle will be studied by rapid mixing techniques in the forward and reverse directions, leading to active transport and ATP synthesis respectively. Passive Ca2+ fluxes will be also studied, and their relevance to contractile regulation will be evaluated by monitoring sarcomere activation in dissociated cell preparations. Comparative studies will be performed under the influence of pharmacological agents. These studies will lead to clarification of basic biological mechanisms: ion transport, energy transduction and contractile control.