Signal Transduction Along Cardiac Thin Filaments

沿着心脏细丝的信号转导

• 批准号: 7098079
• 负责人: DARL Ray SWARTZ
• 金额: $ 33.64万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-18 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7098079
• 关键词: actins; animal tissue; biological signal transduction; calcium flux; cardiac myocytes; crosslink; fluorescence resonance energy transfer; laboratory rabbit; laboratory rat; microfilaments; muscle contraction; myocardium; myofibrils; phosphorylation; protein binding; protein engineering; protein isoforms; protein protein interaction; protein structure; protein structure function; striated muscles; troponin

DESCRIPTION (provided by applicant): Troponin (Tn) is the calcium-sensing protein of striated muscle thin filaments. Its subunits are biomarkers for disease as mutations of them are the cause of disease. Understanding how Tn interacts with the thin filament is essential in understanding its involvement in disease. Calcium and strong crossbridges induce transitions in the position of Tm on the thin filaments involved in activation of contraction. The strong crossbridge transduces a signal back to Tn to increase its apparent affinity for calcium, but how this occurs is unknown. Strong crossbridges are more important in signal transduction in cardiac than skeletal muscle. How Tn/ thin filament interactions differ between these striated tissues is unknown. Comparative protein exchange and binding studies of Tn or its subunits within and to cardiac and skeletal myofibrils, FRET, and crosslinking studies within Tn in cardiac and skeletal myofibrils are used to determine the Tn's interactions and how they influence activation of contraction. Our first hypothesis is that calcium and strong crossbridges dramatically increase Tn dissociation rate from thin filaments. Our second hypothesis is that the calcium influence on Tn and Tn subunit interactions is less in cardiac than skeletal myofibrils, making the strong crossbridge a more critical component of activation in cardiac muscle. Our third hypothesis is that signal transduction from the strong crossbridge to Tn involves a crossbridge-dependent dissociation of part of Tnl. We will test these by the following Specific Aims: 1) Determine the influence of calcium and strong crossbridges on Tn dissociation rate in cardiac and skeletal myofibrils. 2) Define Tn subunits responsible for the calcium and strong crossbridge effects upon Tn dissociation rate and on regulatory interactions between TnC and Tnl. 3) Determine how designed and disease-associated mutant Tn subunits alter Tn subunit interactions and calcium activation of force in single myofibrils.

描述（由申请人提供）：肌钙蛋白（TN）是条纹肌肉细丝的钙感应蛋白。它的亚基是疾病的生物标志物，因为它们的突变是疾病的原因。了解TN与细丝的相互作用对于理解其参与疾病至关重要。钙和强跨桥在TM的位置诱导过渡，这在收缩激活所涉及的薄丝上。强的Crossbridge将信号转换回TN，以增加其对钙的明显亲和力，但是这种情况的发生方式尚不清楚。强的杂交在心脏的信号转导而不是骨骼肌中更重要。这些条纹组织之间的TN/细丝相互作用如何不同。在心脏和骨骼肌原纤维中，TN和心脏和骨骼肌原纤维，FRET和交联研究的TN或其亚基的比较蛋白质交换和结合研究用于确定TN的相互作用以及它们如何影响收缩的激活。我们的第一个假设是，钙和强的跨桥大大提高了薄丝的TN解离速率。我们的第二个假设是，钙对TN和TN亚基相互作用的影响少于骨骼肌原纤维，这使得强的Crossbridge成为心脏肌肉激活的更为关键的成分。我们的第三个假设是，从强Crossbridge到TN的信号转导涉及TNL一部分的Crossbridge依赖性解离。我们将通过以下特定目的进行测试：1）确定钙和强跨桥对心脏和骨骼肌纤维中TN解离速率的影响。 2）定义负责TN亚基对TN解离率以及TNC与TNL之间的调节相互作用的影响。 3）确定设计和与疾病相关的突变体TN亚基如何改变TN亚基相互作用和单个肌纤维中力的钙激活。