Molecular Mechanisms of Heart Disease Resulting from Inherited Genetic Mutations

描述（由申请人提供）：肥厚性心肌病（HCM）是一种常见的心脏疾病，其特征是由于过度的肌瘤复制导致心脏组织增厚。在任何年龄组中，HCM都是导致意外心脏性猝死的重要原因，也是导致心脏症状丧失的原因之一。产生的力？？心肌肌球蛋白重链(？MHC是HCM中最常见的突变蛋白之一。如何单突变？HCM的MHC结果尚不清楚。这里提出的研究将研究不同的人类？MHC在单分子水平上发生突变。实验将测试：1)单分子水平的变化？？心肌肌球蛋白的产生和2)时间的变化？？心肌肌凝蛋白花费与细丝结合出整个ATP循环，占空比。即使一个人的力量？？心肌肌球蛋白突变体所能施加的力与野生型没有什么不同，马达占空比的变化会影响马达集合所能产生的总力（如在肌节中）。这些实验将涉及一个新的系统来表达和纯化人类？？-心肌球蛋白，光学捕获，运动测定和停流动力学测定。了解单点突变对单个分子的影响是理解突变马达在肥大中所起作用和开发针对疾病来源的治疗方法的必要前提。

DESCRIPTION (provided by applicant): Hypertrophic cardiomyopathy (HCM) is a prevalent cardiac disorder characterized by thickening of heart tissue due to excessive sarcomere replication. HCM contributes to a significant percentage of sudden unexpected cardiac death in any age group and is a cause of disabling cardiac symptoms. The force generating ??cardiac myosin heavy chain (?MHC) is one of the most common sarcomeric proteins mutated in HCM. How single mutations in the ?MHC result in HCM is unclear. The research proposed here will study different human ? MHC mutants on the single molecule level. The experiments will test: 1) changes at the single molecule level in ??cardiac myosin force production and 2) changes in the fraction of time the ??cardiac myosin spends bound to the filament out of the entire ATP cycle, the duty ratio. Even if the amount of force that an individual ??cardiac myosin mutant can exert does not differ from the wild type, a change in the motor's duty ratio influences the amount of total force that an ensemble of motors can produce (such as in the sarcomere). These experiments will involve a novel system to express and purify human??-cardiac myosin, optical trapping, motility assays and stop-flow kinetic assays. Understanding the effect of single point mutations on individual molecules is a necessary precursor to both understanding the role that ensembles of mutant motors play in hypertrophy and developing therapies that target the source of the disease. PUBLIC HEALTH RELEVANCE: Heart disease is an ever-present problem in the world, affecting all ages. Though we have made great progress in identifying symptoms and characteristics of heart disease, our current treatments and therapies are limited by a lack of information about the sources of the disease, on the level of the individual proteins that work together and make a heart function properly. I propose to directly study the influence of genetic mutations on these individual proteins that so that we can better develop treatments that target the source of heart disease.