CROSS BRIDGE KINETICS AND REGULATION

跨桥动力学和调节

• 批准号: 6302118
• 负责人: Avril V. Somlyo
• 金额: $ 39.96万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-20 至 2000-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6302118
• 关键词: G protein; adenosine diphosphate; adenosine triphosphate; biological signal transduction; calcium flux; clathrate; confocal scanning microscopy; creatine phosphate; crosslink; enzyme activity; enzyme mechanism; fluorescent dye /probe; hydrolysis; laboratory mouse; laboratory rabbit; molecular biology; muscle contraction; myosin light chain kinase; myosins; phosphatase inhibitor; phosphorylation; protein isoforms; protein kinase C; smooth muscle; vascular smooth muscle; vasomotion

Vascular smooth muscle is an essential regulator of the distribution of blood flow and its abnormalities contribute to high blood pressure, atherosclerosis, coronary restenosis and shock. Other smooth muscles play similarly important roles and regulate airway function and gastrointestinal, uterine and bladder movements. This project will determine the regulations and kinetics of crossbridge cycling, the fundamental mechanism of contraction of all smooth muscles, determines the kinetics of crossbridge cycling, and its structural basis is the variable, smooth muscle-specific expression of essential light chain and heavy chain myosin isoforms. Functional studies will be conducted on smooth muscles containing, respectively, myosins with or without the heavy chain insert and selectively modified by targeted expression or exchange of light chain isoforms. The off-rates of ADP and inorganic phosphate from crossbridges will be determined with novel fluorescent probes developed by The Core, and will be related to the rates of force development and shortening velocity. We will identify the kinases, phosphates and other proteins involved in fine-tuning the balance between myosin light chain kinase and phosphatase activities (collaboration with T. Haystead) and determine the physiological role of the phosphatase- regulating protein, telokin, through functional studies of mouse models deficient (knockout) or subjected to targeted over-expression of this protein (collaboration with G. Owens).

血管平滑肌是血流分布的重要调节者，其异常会导致高血压、动脉粥样硬化、冠状动脉再狭窄和休克。其他平滑肌也发挥着类似的重要作用，调节气道功能以及胃肠、子宫和膀胱运动。该项目将确定横桥循环的调节和动力学，所有平滑肌收缩的基本机制，确定横桥循环的动力学，其结构基础是必需的轻链和重链肌球蛋白的可变的、平滑肌特异性的表达同工型。将分别对含有肌球蛋白（带或不带重链插入物）的平滑肌进行功能研究，并通过轻链亚型的靶向表达或交换进行选择性修饰。 ADP 和无机磷酸盐从桥上的解离速率将通过 The Core 开发的新型荧光探针来确定，并将与力的产生速率和缩短速度相关。我们将鉴定参与微调肌球蛋白轻链激酶和磷酸酶活性之间平衡的激酶、磷酸盐和其他蛋白质（与 T. Haystead 合作），并通过以下功能研究确定磷酸酶调节蛋白 telokin 的生理作用：小鼠模型缺陷（敲除）或遭受该蛋白质的定向过度表达（与 G. Owens 合作）。