CALCIUM AND CALMODULIN IN SMOOTH MUSCLE CONTRACTION

钙和钙调蛋白在平滑肌收缩中的作用

• 批准号: 3073783
• 负责人: J DAVID JOHNSON
• 金额: $ 5.09万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-07-01 至 1990-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3073783
• 关键词: allosteric site; chemical structure function; coronary artery; coronary vasodilator; fluorescent dye /probe; heart pharmacology; ligands; muscle contraction; vascular smooth muscle

Calcium (Ca) is perhaps the most important messenger for the control of intracellular events. The action of Ca is mediated by Ca binding proteins (CBP). Calmodulin (CDR) appears to be the most universal CBP and it is directly involved in the regulation of a wide variety of Ca dependent events including: smooth muscle contraction, neurosecretion, cell proliferation and cell-cell interactions. In the presence of Ca, CDR binds to the proteins it activates, producing structural changes and activation of each protein. Presently, it is unclear how CDR mediates so many Ca dependent processes with such apparent harmony. Recently, we have demonstrated that some of the 3-4 drug binding sites on CDR are allosterically related and that drug binding to some sites can potentiate drug binding to other sites. We will continue our development of methods to monitor the interaction of drugs and various purified calmodulin binding proteins with calmodulin. We will determine which of these proteins are activated by binding to the same (or different) binding sites on calmodulin and determine the allosteric relationships among drug and protein binding sites. Our proposed studies with proteolytic fragments of calmodulin should allow us to more accurately map the regions of calmodulin which serve as the interfacial site for various drug and protein binding. We will determine if the allosteric mechanism that we have observed among drug binding sites on calmodulin occurs among protein binding sites on calmodulin. Further, we will determine if this allosteric mechanism is capable of regulating the interaction of purified calmodulin with myosin light chain kinase and of regulating tension in chemically skinned smooth muscle. We feel that these allosteric control mechanisms on calmodulin can perhaps explain how this "universal" Ca dependent regulatory protein is directed towards the activation of more than twenty different proteins with any degree of specificity. These studies should increase our understanding of the mechanism of action of calmodulin and of Ca binding proteins in general since allosteric regulatory mechanisms exist among the drug (and protein) binding sites of skeletal and cardiac troponin C and in the voltage dependent Ca channel of muscle.

钙 (Ca) 可能是控制体内最重要的信使。 细胞内事件。 Ca 的作用由 Ca 结合蛋白介导 （美国海关与边境保护局）。 钙调蛋白 (CDR) 似乎是最通用的 CBP，并且它是 直接参与多种钙依赖的调节 事件包括：平滑肌收缩、神经分泌、细胞 增殖和细胞间相互作用。 当 Ca 存在时，CDR 结合 它激活的蛋白质，产生结构变化和激活 每种蛋白质。 目前，尚不清楚 CDR 如何介导如此多的 Ca 相互依赖的过程具有如此明显的和谐。 最近，我们有 证明 CDR 上的一些 3-4 个药物结合位点是 变构相关并且药物与某些位点的结合可以增强 药物与其他位点的结合。 我们将继续开发方法 监测药物与各种纯化钙调蛋白结合的相互作用 含有钙调蛋白的蛋白质。 我们将确定这些蛋白质中哪些是 通过与钙调蛋白上相同（或不同）的结合位点结合而激活 并确定药物和蛋白质结合之间的变构关系 网站。 我们提出的钙调蛋白蛋白水解片段的研究 应该能让我们更准确地绘制钙调蛋白的区域 作为各种药物和蛋白质结合的界面位点。 我们 将确定我们在药物中观察到的变构机制是否 钙调蛋白上的结合位点发生在蛋白质结合位点之间 钙调蛋白。 此外，我们将确定这种变构机制是否是 能够调节纯化的钙调蛋白与肌球蛋白的相互作用 轻链激酶和调节化学皮肤光滑的张力 肌肉。 我们认为这些钙调蛋白的变构控制机制也许可以 解释这种“通用”Ca 依赖性调节蛋白是如何定向的 可以用任何方法激活二十多种不同的蛋白质 特异性程度。 这些研究应该会增加我们对 钙调蛋白和 Ca 结合蛋白的一般作用机制 由于药物（和蛋白质）之间存在变构调节机制 骨骼肌肌钙蛋白 C 和心肌肌钙蛋白 C 的结合位点以及电压 肌肉依赖性钙离子通道。