Mechanistic Understanding of Troponin T Role in Cardiac Thin Filament Activation

肌钙蛋白 T 在心脏细丝激活中作用的机制理解

• 批准号: 8235946
• 负责人: MURALI CHANDRA
• 金额: $ 37万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-14 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8235946
• 关键词: ATP phosphohydrolase; Affect; Area; Back; Binding; Cardiac; Cardiac Muscle Contraction; Complex; Contractile Proteins; Elements; Feedback; Foundations; Gene Transfer Techniques; Genetic; Goals; Head; Heart; Heart Diseases; Human; In Vitro; Kinetics; Knowledge; Length; Measurement; Measures; Mechanics; Mediating; Mediator of activation protein; Microfilaments; Molecular; Mus; Muscle; Muscle Fibers; Myocardium; Myosin ATPase; Outcome; Physiology; Play; Post-Translational Protein Processing; Progress Reports; Protein Isoforms; Proteins; Public Health; Recombinant Proteins; Recruitment Activity; Research; Research Proposals; Role; Sarcomeres; Shapes; Signal Transduction; Striated Muscles; Structure; Tail; Techniques; Testing; Thin Filament; Tropomyosin; Troponin; Troponin C; Troponin I; Troponin T; Work; base; feeding; genetic regulatory protein; improved; innovation; insight; interdisciplinary approach; mathematical model; novel; novel therapeutic intervention; protein protein interaction; protein structure; reconstitution; research study; response

PROJECT SUMMARY The lack of knowledge about the interactions among cardiac contractile regulatory proteins represents an important problem because it not only limits our understanding of how such interactions affect cardiac thin- filament activation, but it also precludes an understanding of mechanisms underlying many forms of heart disease. Cardiac muscle contraction depends on coordinated interactions among contractile regulatory pro- teins, which include cardiac troponin C (cTnC), troponin T (cTnT), troponin I (cTnI), and tropomyosin (Tm). Coordinated interactions among these proteins play key roles during contraction via Ca2+-, strong cros- sbridge (XB)-, and sarcomere length (SL)-mediated activation of thin filaments. However, very little is known about how cTnT influences the actions of Tm, cTnI, and cTnC to modulate Ca2+-, SL-, and XB- acti- vation of cardiac thin filaments. Our long-term goal, therefore, is to determine how structural differences in contractile regulatory proteins determine Ca2+-, SL-, and strong XB-mediated activation of cardiac muscle contraction, and how they are altered in heart disease. The overall objective of this proposal is to determine how cTnT interacts with Tm, cTnI, and cTnC to modulate cardiac thin-filament activation by Ca2+, SL, and strong XB. Our hypothesis is that the structural features of the tail (cT1) and the head (cT2) domains of cTnT are the key determinants of functional features of cardiac thin-filament activation. To test our hypo- thesis, we will measure force/ATPase, rate of tension redevelopment and myofiber dynamic stiffness in re- constituted cardiac muscle fibers. Further, complementary studies such as Ca2+ binding kinetics measure- ments and quantitative mathematical modeling will be performed. Specific Aim 1 will determine how cT1 modulates the dynamics of strong XB recruitment during cardiac thin-filament activation. This aim will be accomplished by determining: the specific region of cT1 that affects thin-filament activation; how changes in the overlapping ends of contiguous Tm impact cT1 effects on cardiac thin-filament activation; and how cT1 effects on thin-filament activation are modified by myosin isoforms. Specific Aim 2 will determine how cTnT modulates the cooperative feedback of strong XB on conformational changes in cTnC during cardiac thin- filament activation. In this aim, we will determine how key regions of cT2 modulate Ca2+- and XB-induced changes in cTnC structure. Specific Aim 3 will determine how interactions between cTnT and cTnI mediate the feedback effect of strong XB on cardiac thin-filament activation. This aim will be accomplished by de- termining: how cT2-cTnI interactions modulate cardiac thin-filament activation and how differences in myo- sin isoforms alter cT2-cTnI effect on thin-filament activation. The expected outcome from our comprehen- sive and multidisciplinary approach will have a positive impact because it will significantly advance our un- derstanding of the molecular mechanisms underlying cardiac thin-filament activation. Our study will lay a strong foundation for developing novel pharmacological strategies aimed at improving cardiac function in diseased hearts.

项目总结 缺乏关于心脏收缩调节蛋白之间相互作用的知识代表着一种 这是一个重要的问题，因为它不仅限制了我们对这种相互作用如何影响心脏厚度的理解 细丝激活，但它也排除了对许多形式心脏潜在机制的理解 疾病。心肌收缩依赖于收缩调节前体之间的协调相互作用。 包括心肌肌钙蛋白C(CTNC)、肌钙蛋白T(CTnT)、肌钙蛋白I(CTnI)和原肌球蛋白(TM)。 这些蛋白质之间的协调相互作用在收缩过程中起着关键作用，通过钙离子，强大的CROS- Sbridge(XB)和肌节长度(SL)介导的细丝激活。然而，很少有 已知cTnT如何影响TM、cTnI和cTNC调节Ca~(2+)、SL~-和XB~-活性的作用 心脏细丝的收缩。因此，我们的长期目标是确定结构性差异如何 收缩调节蛋白决定Ca~(2+)、SL和强XB介导的心肌激活 收缩，以及它们在心脏病中是如何改变的。这项提案的总体目标是确定 CTnT如何与TM、cTnI和cTNC相互作用，通过钙离子、SL和 很强的XB。我们的假设是，尾部(Ct1)和头部(Ct2)结构域的结构特征 CTnT是心脏细丝激活功能特征的关键决定因素。为了测试我们的次声- 本论文中，我们将测量肌力/ATPase，张力再发展速率和肌纤维动态硬度。 构成心肌纤维。此外，补充性研究，如钙结合动力学测量- 将进行分段和定量的数学建模。特定目标1将决定1号货柜码头如何 调节心脏细丝激活过程中XB强烈募集的动力学。这一目标将是 通过确定：影响细丝激活的CT1的特定区域；如何改变 连续TM的重叠末端影响CT1对心脏细丝激活的影响；以及CT1如何 肌球蛋白异构体可以改变对细丝激活的影响。特定目标2将决定cTnT如何 强XB对心脏变薄过程中cTNC构象变化的协同反馈调节作用 灯丝激活。在这个目标中，我们将确定ct2的关键区域是如何调节钙离子和xb诱导的。 CTNC结构的变化。具体目标3将确定cTnT和cTnI之间的相互作用如何调节 强XB对心脏细丝激活的反馈作用。这一目标将通过以下方式实现： 结束语：ct2-cTnI相互作用如何调节心脏细丝激活，以及心肌细胞中cTnI与cTnI之间的差异 SIN亚型改变ct2-cTnI对细丝激活的影响。我们的理解的预期结果是- 综合性和多学科方法将产生积极影响，因为它将极大地推动我们的联合国-- 了解心脏细丝激活的分子机制。我们的研究将为 为开发旨在改善心脏功能的新药物策略奠定了坚实的基础 病态的心脏。

项目成果

Interplay between the effects of a Protein Kinase C phosphomimic (T204E) and a dilated cardiomyopathy mutation (K211Δ or R206W) in rat cardiac troponin T blunts the magnitude of muscle length-mediated crossbridge recruitment against the β-myosin heavy cha

大鼠心肌肌钙蛋白 T 中蛋白激酶 C 拟磷 (T204E) 和扩张型心肌病突变 (K211α 或 R206W) 之间的相互作用减弱了肌肉长度介导的横桥募集对抗 β-肌球蛋白重链的程度

• DOI: 10.1007/s10974-016-9448-2
• 发表时间: 2016
• 期刊: Journal of muscle research and cell motility
• 影响因子: 2.7
• 作者: Michael,JohnJeshurun;Gollapudi,SampathK;Chandra,Murali
• 通讯作者: Chandra,Murali

Structural dynamics of C-domain of cardiac troponin I protein in reconstituted thin filament.

重构细丝中心肌肌钙蛋白 I 蛋白 C 结构域的结构动力学。

• DOI: 10.1074/jbc.m111.281600
• 发表时间: 2012
• 期刊: The Journal of biological chemistry
• 作者: Zhou,Zhiqun;Li,King-Lun;Rieck,Daniel;Ouyang,Yexin;Chandra,Murali;Dong,Wen-Ji
• 通讯作者: Dong,Wen-Ji

Divergent effects of α- and β-myosin heavy chain isoforms on the N terminus of rat cardiac troponin T.

• DOI: 10.1085/jgp.201310971
• 发表时间: 2013-10
• 期刊: The Journal of general physiology
• 作者: Mamidi R;Chandra M
• 通讯作者: Chandra M

Differences in myofilament calcium sensitivity in rat psoas fibers reconstituted with troponin T isoforms containing the alpha- and beta-exons.

用含有 α 和 β 外显子的肌钙蛋白 T 同种型重建的大鼠腰肌纤维中肌丝钙敏感性的差异。

• DOI: 10.1016/j.abb.2006.06.008
• 发表时间: 2006
• 期刊: Archives of biochemistry and biophysics
• 影响因子: 3.9
• 作者: Gallon,ClareE;Tschirgi,MatthewL;Chandra,Murali
• 通讯作者: Chandra,Murali

Cardiomyopathy-Related Mutations in Cardiac Troponin C, L29Q and G159D, Have Divergent Effects on Rat Cardiac Myofiber Contractile Dynamics.

• DOI: 10.1155/2012/824068
• 发表时间: 2012
• 期刊: Biochemistry research international
• 影响因子: 3
• 作者: Gollapudi SK;Chandra M
• 通讯作者: Chandra M