Proteolytic Regulation of Troponin T & Cardiac Function

肌钙蛋白 T 的蛋白水解调节

• 批准号: 8520384
• 负责人: Jian-Ping Jin
• 金额: $ 49.42万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8520384
• 关键词: ATP phosphohydrolase; Actomyosin Adenosinetriphosphatase; Acute; Affect; Alternative Splicing; Animals; Binding; Binding Sites; Biochemical; Biochemistry; C-terminal; Calcium; Calmodulin; Calpain; Cardiac; Cardiac Muscle Contraction; Cardiac Myocytes; Cessation of life; Chronic; Complex; Congestive Heart Failure; Development; Dose; Excision; Exercise; Family; Financial compensation; Foundations; Functional disorder; Future; Genes; Heart; Heart failure; Immunoglobulin Variable Region; Infarction; Injury; Ischemia; Knowledge; Lead; Life; Link; Mechanics; Microfilaments; Modeling; Modification; Molecular Conformation; Motor; Mus; Muscle; Muscle Cells; Myocardial; Myocardial Contraction; Myocardial Ischemia; Myocardial dysfunction; Myocardium; Myofibrils; Myosin ATPase; Myosin Light Chains; N-terminal; Nature; Phase; Phenotype; Physiologic intraventricular pressure; Physiological; Plant Roots; Post-Translational Protein Processing; Post-Translational Regulation; Preparation; Prevention approach; Production; Protein Binding; Protein Subunits; Proteolysis; Pump; Rattus; Regulation; Regulation of Proteolysis; Reperfusion Injury; Reperfusion Therapy; Reporting; Research Project Grants; Role; Skin; Stress; Stretching; Striated Muscles; Structure; Structure-Activity Relationship; System; Testing; Thin Filament; Time; Transgenic Mice; Transgenic Organisms; Translating; Tropomyosin; Troponin; Troponin C; Troponin I; Troponin T; Variant; Ventricular; Work; base; cardiogenesis; clinical application; connectin; coping; functional loss; genetic regulatory protein; heart function; improved; in vivo; novel; postnatal; pressure; protein complex; public health relevance; receptor; reconstitution; research study; response; therapeutic development

DESCRIPTION (provided by applicant): Cardiac muscle contraction is regulated by Ca2+ through the troponin complex that consists of three protein subunits: troponin C, troponin I, and troponin T (TnT). This research project investigates the role of a novel posttranslational modification of cardiac TnT (cTnT) in myocardial adaptation to energetic crisis. We recently reported a restricted N-terminal proteolysis of cTnT in myocardial ischemia-reperfusion (Zhang et al., Biochemistry 45:11681-94, 2006) and pressure overload (Feng et al., J. Physiol. 586:3537-50, 2008). This modification selectively removes the N-terminal variable region of cTnT but keeps the conserved middle and C-terminal regions intact. Initial studies in transgenic mouse hearts showed that the N-terminal truncated cTnT (cTnT-ND) remains functional in the myofilaments and alters myocardial contractility. This finding has lead to a hypothesis that the proteolytic removal of the N-terminal variable region of cTnT produces a functional state in cardiac muscle thin filaments as acute adaptation to energetic crisis. To test this hypothesis and understand the physiological and pathophysiological significance of cTnT- ND, three Specific Aims are proposed in this research project: Aim I will characterize the effects of the selective deletion of the N-terminal variable region on the function of cTnT. We will examine the interactions of cTnT-ND with other thin filament regulatory proteins and its functional impacts on the Ca2+ activation of myofibril ATPase and the contractility of cardiac muscle. Aim II will study the role of N-terminal truncated cTnT in compensating cardiac function and providing myocardial protection against ischemia-reperfusion injury. The acute and chronic effects of cTnT-ND on heart function and its role in overcoming energetic crisis will be investigated in ex vivo working hearts and in vivo. Aim III will investigate the role of mechanical stretch of the cardiac muscle in inducing the restricted proteolytic cleavage of cTnT N-terminal segment in order to understand the mechanisms that regulates this posttranslational regulation. Using integrated experimental systems, this study will gain new knowledge for the structure-function relationships of TnT and lay a foundation for future development of new treatment of ischemic heart disease and heart failure.

描述（由申请人提供）： 心肌收缩由Ca 2+通过肌钙蛋白复合物调节，肌钙蛋白复合物由三种蛋白质亚基组成：肌钙蛋白C、肌钙蛋白I和肌钙蛋白T（TnT）。本研究旨在探讨心肌肌钙蛋白T（cTnT）的一种新的翻译后修饰在心肌适应能量危机中的作用。我们最近报道了心肌缺血-再灌注中cTnT的限制性N-末端蛋白水解（Zhang等人，Biochemistry 45：11681-94，2006）和压力过载（Feng等人，586：3537-50，2008）。这种修饰选择性地去除cTnT的N-末端可变区，但保留保守的中间和C-末端区域完整。在转基因小鼠心脏中的初步研究表明，N-末端截短的cTnT（cTnT-ND）在肌丝中保持功能并改变心肌收缩力。这一发现导致了一种假设，即cTnT的N-末端可变区的蛋白水解去除在心肌细丝中产生功能状态，作为对能量危机的急性适应。为了验证这一假设，并了解cTnT- ND的生理和病理生理意义，本研究计划提出了三个具体目标：目的I将表征选择性缺失N-末端可变区对cTnT功能的影响。我们将研究cTnT-ND与其他细丝调节蛋白的相互作用及其对肌原纤维ATP酶的Ca 2+激活和心肌收缩力的功能影响。目的研究N端截短型cTnT在心肌缺血再灌注损伤中对心功能的代偿作用。将在离体工作心脏和体内研究cTnT-ND对心脏功能的急性和慢性影响及其在克服能量危机中的作用。目的III研究机械牵张对心肌肌钙蛋白N端的限制性蛋白酶切的影响，以了解这种翻译后调节的机制。 本研究将为TnT的结构与功能关系提供新的认识，并为将来开发缺血性心脏病和心力衰竭的新治疗方法奠定基础。