SIGNIFICANCE OF TROPONIN C MUTATIONS IN HEART DISEASE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 新出现的证据表明，肌膜蛋白的突变与遗传性心肌病和心肌功能障碍的发生有关。肌钙蛋白C是负责传递钙结合信号并触发收缩周期的蛋白质。廖博士和她的同事从一名特发性扩张型心肌病患者身上发现了两个新的人心肌肌钙蛋白C错义突变，分别位于59(E59D)和75(D75Y)氨基酸残基，这是首次在人类疾病中发现的肌钙蛋白C突变。这些错义突变位于调节心肌收缩的钙结合区域内，并导致肌丝钙反应性降低。这些结果表明，肌钙蛋白C的突变导致了患病心脏收缩功能的下降。为了确定结构-功能关系，他们设计了一些肌钙蛋白C突变体，基于替换位于调节钙结合结构域的特定氨基酸残基。我们使用凝胶内蛋白水解酶，然后MALDI-TOF和串联质谱学来验证特定的突变。此外，合成突变多肽的半定量使相对表达水平的估计成为可能。这个突变模型系统正在帮助确定心肌肌钙蛋白C的突变如何改变心肌肌丝的钙反应，从而决定心肌的收缩能力。描述这些结果的论文刊登在《生物物理学》杂志的封面上。J.2008年5月。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Emerging evidence has linked mutations in myofiliment proteins to the development of genetic cardiomyopathies and myocardial dysfunction. Troponin C is the protein responsible for the transmission of the calcium-binding signal and triggering the contractile cycle. Dr. Liao and her associates identified two novel missense mutations in human cardiac troponin C at amino acid residues 59 (E59D) and 75 (D75Y) from a patient with idiopathic dialated cardiomyopathy, the first identified mutation of troponin C from any human disease. These missense mutations are located within the calcium-binding domain that regulates myocardial contraction, and result in decreased myofilament calcium responsiveness. These results showed mutations in troponin C contribute to the decreased contractile function in the diseased human heart. To determine the structure-function relationship, they designed a number of troponin C mutants based on replacing specific amino acid residues located within regulatory calcium-binding domains. We used in-gel proteolytic digestion, followed by MALDI-TOF and tandem mass spectrometry to structurally verify specific mutations. Additionally, semiquantitation of synthetic mutant peptides enabled estimation of relative expression levels. This mutational model system is helping to define how mutations in cardiac troponin C alter calcium responsiveness in cardiac myofilaments and, consequently, determine myocardial contractility. The paper describing these results was featured on the cover of Biophys. J. in May 2008.