Role of phosphorylation in cardiac muscle myosin

磷酸化在心肌肌球蛋白中的作用

基本信息

批准号：
8746718
负责人：
James Sellers
金额：
$ 23.63万
依托单位：
NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

项目摘要

Understanding how cardiac myosin regulatory light chain (RLC) phosphorylation alters cardiac muscle mechanics is important because it is often altered in cardiac disease. The effect this protein phosphorylation has on muscle mechanics during a physiological range of shortening velocities, during which the heart generates power and performs work, has not been addressed. We have expressed and phosphorylated recombinant Rattus norvegicus left ventricular RLC. In vitro we have phosphorylated these recombinant species with cardiac myosin light chain kinase and zipper-interacting protein kinase. We compare rat permeabilized cardiac trabeculae, which have undergone exchange with differently phosphorylated RLC species. We were able to enrich trabecular RLC phosphorylation by 40% compared with controls and, in a separate series, lower RLC phosphorylation to 60% of control values. Compared with the trabeculae with a low level of RLC phosphorylation, RLC phosphorylation enrichment increased isometric force by more than 3-fold and peak power output by more than 7-fold and approximately doubled both maximum shortening speed and the shortening velocity that generated peak power. We augmented these measurements by observing increased RLC phosphorylation of human and rat HF samples from endocardial left ventricular homogenate. These results demonstrate the importance of increased RLC phosphorylation in the up-regulation of myocardial performance and suggest that reduced RLC phosphorylation is a key aspect of impaired contractile function in the diseased myocardium. We are currently using optical trapping and in vitro motility assays to explore the effect of phosphorylation on purified cardiac muscle myosin.

了解心脏肌球蛋白调节轻链（RLC）磷酸化如何改变心肌力学很重要，因为它经常在心脏病中改变。在缩短速度的生理范围内，这种蛋白质磷酸化对肌肉力学的影响尚未得到解决。我们已经表达并磷酸化的重组拉图斯·诺维古斯左心室RLC。在体外，我们用心脏肌球蛋白轻链激酶和拉链相互作用蛋白激酶磷酸化了这些重组物种。我们比较了大鼠透化心脏小梁，这些心脏小梁与磷酸化的RLC物种进行了交换。与对照组相比，我们能够将小梁RLC磷酸化富集40％，在单独的系列中，较低的RLC磷酸化至对照值的60％。与小梁的RLC磷酸化水平较低相比，RLC磷酸化富集增加了等距的3倍以上和峰值功率输出超过7倍以上，并且最大缩短速度和产生的产生功率的缩短速度均大约翻了一番。我们通过观察到心内膜左心室匀浆中人和大鼠HF样品的RLC磷酸化增加来增强这些测量结果。这些结果表明，增加RLC磷酸化在心肌性能上调中的重要性，并表明降低RLC磷酸化是患病心肌中收缩功能受损功能的关键方面。我们目前正在使用光学诱捕和体外运动测定法来探索磷酸化对纯化心肌肌球蛋白的影响。