A proteomics approach to titin kinase mechanosignaling in striated muscle.

肌节蛋白肌联蛋白是哺乳动物中已知最大的蛋白质，该基因的突变已被认为是遗传性心脏病最常见的原因。肌联蛋白最初被发现作为横纹肌中的支架蛋白，最近的证据表明其在信号转导中的作用：已经假设肌联蛋白的调节和催化激酶结构域的力依赖性相互作用可以提供机械传感器和催化结构域（Y170）的酪氨酸磷酸化的额外调节水平。遗传性肌肉疾病患者的突变分析将肌联蛋白与肥大/萎缩信号联系起来，我们已经表明激酶区域的丢失会导致肥厚型心肌病。在这里，我们将建立与肌联蛋白激酶（TK）和横纹肌肥大/萎缩信号传导相关的分子通路，建立在我们在蛋白质组学以及生成和分析心血管疾病动物模型方面的优势基础上。我们将使用定位蛋白质组学来探测肌联蛋白激酶结构域在体内的环境，并剖析其在机械传导和肥大信号传导中的作用。结合敲除（KO）的催化结构域和不同来源的机械应力和应变的应用，我们将阐明的类型的机械输入，激活TK随后的候选人和蛋白质组学方法来分析下游事件。这包括TK作为枢纽与催化活性激酶的分析以及对压力和体积的差异反应。这项研究对维持固定患者或老年人的肌肉质量以及心脏的生理性与病理性肥大有意义。

The sarcomeric protein titin is the largest known protein in mammals and mutations in the gene have been recognized as the most common cause of inherited heart disease. Titin was originally discovered as scaffolding protein in striated muscle, with recent evidence suggesting a role in signal transduction: It has been hypothesized that the force dependent interaction of titin’s regulatory and catalytic kinase domain could provide a mechanosensor and tyrosine phosphorylation of the catalytic domain (Y170) an additional level of regulation. The analysis of mutations in patients with hereditary muscle disease has linked titin to hypertrophy/atrophy signaling and we have shown that loss of the kinase region leads to hypertrophic cardiomyopathy. Here, we will establish the molecular pathways relating titin kinase (TK) and hypertrophy/atrophy signaling in striated muscle, building on our strength in proteomics and in generating and analyzing animal models of cardiovascular disease. We will use localization proteomics to probe the environment of the titin kinase domain in vivo and dissect its role in mechanotransduction and hypertrophy signaling. Combined with the knockout (KO) of the catalytic domain and application of different sources of mechanical stress and strain we will elucidate the type of mechanical input that activates the TK followed by a candidate and proteomics approach to analyze the downstream events. This includes the analysis of TK as a hub versus a catalytically active kinase and the differential response to pressure and volume. This research has implications for maintaining muscle mass in immobilized patients or the elderly and for physiological versus pathological hypertrophy of the heart.