Mechanism of Calcium Regulation in Striated Muscle

描述(申请人提供)：肌肉收缩是基本的生物过程之一。尽管经过了多年的深入研究，但关于力的产生机制及其调控这两个主要问题仍未完全弄清楚。该项目的长期目标是破译钙离子、肌钙蛋白和原肌球蛋白调节横纹肌(骨骼和心脏)收缩的分子机制。这一建议的具体目的是：1)破译肌钙蛋白I与肌动蛋白在无钙情况下抑制肌肉收缩的机制。2)破译原肌球蛋白在F-肌动蛋白细丝中运动引起肌肉收缩抑制或激活的机制。3)确定肌钙蛋白T在细丝调节中的功能作用。主要的技术将是定点突变、二硫化物交联、光交联和Forster共振能量转移(FRET)。这一结果不仅将在肌肉领域做出重大贡献，而且还将在涉及钙调节的信号转导领域做出重大贡献。该项目的发现将与某些神经肌肉疾病的预防、诊断和治疗相关。心肌和骨骼肌细丝蛋白在氨基酸序列和功能上有很大的相似性。心脏Tn亚基已被用作心力衰竭的标志物。心脏细丝蛋白的点突变与某些心肌病有关。因此，我们的研究结果也将与缺血性心肌梗死和家族性肥厚型心肌病相关。

DESCRIPTION (provided by applicant): Muscle contraction is one of the fundamental biological processes. In spite of many years of intense research, the two major questions, the mechanisms of force generation and its regulation, remain incompletely understood. The long term objective of this project is to decipher the molecular mechanism for the regulation of striated (skeletal and cadiac) muscle contraction via Ca 2+, troponin and tropomyosin. The specific aims for this proposal are: 1) To decipher the mechanism whereby attachment of troponin I to actin inhibits muscle contraction in the absence of Ca2+. 2) To decipher the mechanism whereby the movement of tropomyosin in the F-actin filament gives rise to inhibition or activation of muscle contrction. 3) To determine the functional role of troponin T in thin filament regulation. The principal techniques will be site-directed mutagenesis, disulfide crosslinking, photocrosslinking and Forster resonance energy transfer (FRET). The results will make major contributions not only to the muscle field, but also to areas in signal transduction that involve regulation by Ca 2+. Findings derived from this project will be relevant to the prevention, diagnosis and cure of certain neuromuscular diseases. Cardiac and skeletal muscle thin filament proteins share a great deal of similarity in amino acid sequence and function. Cardiac Tn subunits have been used as markers for heart failure. Point mutations in the cardiac thin filament proteins have been implicated in certain cardiomyopathies. Thus our findings here will also be relevant to ischemic infarction and familial hypertrophic cardiomyopathy.