Molecular Physiology of Myocardial Troponin I Variants

描述（由申请人提供）：心脏收缩是通过肌丝蛋白的调节相互作用发生的，以响应细胞内钙浓度的增加。最近的研究表明，特定的翻译后修饰的肌丝调节蛋白，肌钙蛋白I参与缺血/再灌注损伤的进展和发展。此外，肌钙蛋白I磷酸化的改变与心力衰竭有关。该建议的基本假设是，心脏肌钙蛋白I的疾病相关的翻译后修饰产生心脏功能异常，可以通过创建和表征体内模型来描绘。这项工作的长期目标是了解这些变异改变心脏功能的潜在分子机制，以设计预防或治疗心功能障碍的策略。肌钙蛋白I翻译后修饰的分子病理生理学的解剖将在一系列高度合作的综合研究中进行，重点是体内肌丝疾病相关蛋白质组学变化的建模。我们还将利用我们已经开发的肌钙蛋白I蛋白水解的转基因模型，以剖析这些小鼠中进行性心肌病的其他潜在修饰剂。为了实现这些目标，提出了以下目标：1。评估与肌钙蛋白I 1-193小鼠扩张型心肌病表型发育进展相关的基因组和蛋白质组变化，目的是识别基因组或特定亚蛋白质组的早期改变。2. A.确定蛋白激酶A位点肌钙蛋白I的组成性“假”磷酸化是否可保护心脏免受心力衰竭的有害影响，包括力频反应减弱和后负荷增加时舒张延迟。B。确定与心力衰竭相关的蛋白激酶A和蛋白激酶C引起的肌钙蛋白I位点特异性磷酸化的改变是否对体外心肌功能和体内心肌功能具有主要的有害作用。C.研究p21激活的激酶对肌钙蛋白I丝氨酸150磷酸化的影响。这项工作应提供洞察特定的翻译后修饰的肌丝，这有助于缺血性心肌疾病和心力衰竭的病理生理学在体内的影响。从长远来看，这将有助于开发新的治疗方法。

DESCRIPTION (provided by applicant): Contraction of the heart occurs through regulated interactions of the myofilament proteins in response to increasing intracellular calcium concentrations. Recent studies have shown that specific post-translational modifications to the myofilament regulatory protein, troponin I are involved in the progression and development of ischemia/reperfusion injury. Furthermore, alterations in the phosphorylation of troponin I are associated with heart failure. The underlying hypothesis of this proposal is that disease related posttranslational modifications of cardiac troponin I produce abnormalities of cardiac function that may be delineated by creating and characterizing in vivo models. The long-range goal of this work is to understand the underlying molecular mechanism by which these variants alter cardiac function in order to design strategies to prevent or treat cardiac dysfunction. The dissection of the molecular pathophysiology of troponin I post-translational modifications will be approached in a series of highly collaborative integrative studies focused on modeling of myofilament disease-related proteomic changes in vivo. We will also exploit a transgenic model of troponin I proteolysis we have developed in order to dissect other potential modifiers in the progressive cardiomyopathy in these mice. To address these goals the following aims are proposed: 1. To assess genomic and proteomic changes associated with the developmental progression in the phenotype of dilated cardiomyopathy in the troponin I 1-193 mice, with the goal of identifying early alterations in the genome or specific subproteomes. 2. A. To determine whether constitutive "pseudo" phosphorylation of troponin I at protein kinase A sites protects the heart from deleterious effects of heart failure including a diminished force frequency response and delayed relaxation in response to increased afterload. B. To determine whether alterations in site-specific phosphorylation of troponin I by protein kinase A and protein kinase C associated with heart failure have a primary deleterious effect on cardiac muscle function in vitro and myocardial function in vivo. C. To determine the effect of a novel phosphorylation of troponin I at Serine 150 by p21activated kinase in vivo. This work should provide insight into the in vivo effects of specific post-translational modifications of the myofilaments, which contribute to pathophysiology of ischemic myocardial diseases and heart failure. In the long-term this will contribute to the development of novel therapies.