The Function of Slow Skeletal TnT in Muscle Contraction

慢骨骼 TnT 在肌肉收缩中的作用

• 批准号: 7586148
• 负责人: JAMES Douglas POTTER
• 金额: $ 30.97万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7586148
• 关键词: ATP phosphohydrolase; Actins; Actomyosin Adenosinetriphosphatase; Address; Affect; Affinity; Alternative Splicing; Amino Acids; Attention; C-terminal; Cardiac; Cardiac Myocytes; Complex; Development; Exons; Functional disorder; Genes; Goals; Heart; Human; In Vitro; Investigation; Kinetics; Laboratories; Libraries; Link; Messenger RNA; Molecular; Muscle; Muscle Contraction; Muscle Fibers; Mutation; Myocardium; Myosin ATPase; N-terminal; Nemaline Myopathies; Nucleotides; Physiological; Process; Property; Protein Isoforms; Proteins; Publications; RNA Splicing; Regulation; Relaxation; Reporting; Research Personnel; Role; Screening procedure; Site; Skeletal Muscle; Skin; Striated Muscles; Testing; Thin Filament; Transcript; Transgenic Organisms; Tropomyosin; Troponin; Troponin I; Troponin T; Work; base; interest; programs; research study; skeletal; tropomyosin-4

DESCRIPTION (provided by applicant): The overall goal of the proposed experiments is to determine the molecular mechanisms involved in the regulation of slow skeletal muscle contraction by troponin T (TnT) and to determine what regions of TnT are important for its physiological function. To accomplish this overall goal we will carry out two specific aims: SPECIFIC AIM 1. THE ROLE OF SLOW SKELETAL TROPONIN T ISOFORMS IN THE REGULATION OF MUSCLE CONTRACTION. Essentially nothing is known about the regulation of slow skeletal muscle by troponin T (TnT) and this is the prime focus of our study which will thoroughly investigate the function of slow skeletal muscle TnT (SSTnT) in the regulation of striated muscle contraction. The main hypothesis to be tested here is that the various N-terminal SSTnT isoforms modulate Ca2+- sensitivity and the relaxation properties of slow skeletal muscle contraction. We will answer the following questions: 1) Is the Ca2+-sensitivity of force development and/or ATPase activity affected by the N- or Cterminal regions of SSTnT? 2) Do SSTnT isoforms directly affect the affinity of TnC for Ca2+ or is there an indirect effect of SSTnT on the Ca2+ sensitivity of contraction (e.g., thin filament or crossbridge effect)? 3) Do the different SSTnT isoforms interact differently with tropomyosin? 4) Do SSTnT isoforms affect the activation and relaxation of force in skinned muscle fibers? 5) Are there other isoforms of SSTnT that have not been previously described? These studies will determine the role of the N-and C-terminal alternatively spliced regions of SSTnT on slow skeletal muscle contraction. SPECIFIC AIM 2. THE ROLE OF DIFFERENT REGIONS OF SLOW SKELETAL TROPONIN T IN THE PHYSIOLOGICAL FUNCTION OF TROPONIN T. To understand the role of different regions of TnT we will carry out the following: 1) Characterization of the region of SSTnT that is important for Ca2+-independent ATPase activity. 2) Characterization of the region(s) of SSTnT that interacts with SSTnl, CTnC (same isoform in slow skeletal and cardiac muscle) and tropomyosin. 3) Investigation of the importance of SSTnl in the function of SSTnT. No functional studies on any region of SSTnT have so far been reported. All the Specific Aims listed above focus on gaining a more detailed understanding of the role of SSTnT in slow skeletal muscle contraction, including the molecular mechanisms of SSTnT-linked activation of muscle contraction.

描述（由申请人提供）：所提议实验的总体目标是确定肌钙蛋白 T (TnT) 调节骨骼肌缓慢收缩的分子机制，并确定 TnT 的哪些区域对其生理功能很重要。为了实现这一总体目标，我们将实现两个具体目标： 具体目标 1. 慢速骨骼肌钙蛋白 T 同工型在肌肉收缩调节中的作用。基本上我们对肌钙蛋白 T (TnT) 对慢骨骼肌的调节一无所知，这是我们研究的主要焦点，我们将彻底研究慢骨骼肌 TnT (SSTnT) 在调节横纹肌收缩中的功能。这里要测试的主要假设是各种 N 末端 SSTnT 亚型调节 Ca2+- 敏感性和缓慢骨骼肌收缩的松弛特性。 我们将回答以下问题：1）力发展和/或 ATP 酶活性的 Ca2+ 敏感性是否受 SSTnT 的 N 或 C 末端区域影响？ 2) SSTnT 同种型是否直接影响 TnC 对 Ca2+ 的亲和力，或者 SSTnT 对 Ca2+ 收缩敏感性是否有间接影响（例如，细丝或横桥效应）？ 3) 不同的 SSTnT 亚型与原肌球蛋白的相互作用是否不同？ 4) SSTnT 同工型是否影响带皮肌纤维的力的激活和松弛？ 5) 是否还有其他先前未描述过的 SSTnT 亚型？这些研究将确定 SSTnT N 端和 C 端交替剪接区域对骨骼肌缓慢收缩的作用。具体目标 2. 慢骨骼肌钙蛋白 T 不同区域在肌钙蛋白 T 生理功能中的作用。为了了解 TnT 不同区域的作用，我们将执行以下操作： 1) SSTnT 区域的表征，该区域对于 Ca2+ 独立的 ATP 酶活性很重要。 2)与SSTnl、CTnC(慢骨骼肌和心肌中的相同亚型)和原肌球蛋白相互作用的SSTnT区域的表征。 3)研究SSTnl在SSTnT功能中的重要性。迄今为止，还没有关于 SSTnT 任何区域的功能研究的报道。上面列出的所有具体目标都集中于更详细地了解 SSTnT 在缓慢骨骼肌收缩中的作用，包括 SSTnT 相关的肌肉收缩激活的分子机制。