Molecular Physiology of Myocardial Troponin I Variants

描述（由申请人提供）：心肌收缩是通过肌丝蛋白对细胞内钙浓度增加的反应而调节的相互作用发生的。最近的研究表明，肌丝调节蛋白肌钙蛋白I的特异性翻译后修饰参与了缺血/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。该提议的潜在假设是，与疾病相关的心肌肌钙蛋白I的翻译后修饰会产生心功能异常，这可能通过创建和表征体内模型来描述。这项工作的长期目标是了解这些变异改变心功能的潜在分子机制，以便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解剖将在一系列高度协作的综合研究中进行，重点是肌丝疾病相关的体内蛋白质组学变化的建模。我们还将利用我们开发的肌钙蛋白I蛋白水解的转基因模型，以解剖这些小鼠进行性心肌病的其他潜在修饰因子。为实现这些目标，提出了以下目标：评估肌钙蛋白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学变化，目的是确定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“伪”磷酸化是否保护心脏免受心力衰竭的有害影响，包括力频率反应减弱和后负荷增加后松弛延迟。B.确定与心力衰竭相关的蛋白激酶A和蛋白激酶C对肌钙蛋白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有主要的有害影响。C.确定p21活化激酶在体内对肌钙蛋白I丝氨酸150的新磷酸化的影响。这项工作将有助于深入了解肌丝的特定翻译后修饰在体内的作用，这有助于缺血性心肌疾病和心力衰竭的病理生理。从长远来看，这将有助于新疗法的发展。

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.