Mechanisms of p130Cas-mediated mechano-sensing in cells

贴壁细胞在机械压力下表现出广泛的反应，包括机械行为和基因表达模式的大规模变化。这在一定程度上是通过力诱导的构象变化激活局灶黏附蛋白p130Cas，从而导致下游途径的激活，如细胞外信号调节激酶（ERK1/2）磷酸化。我们最近证明了p130Cas上的磷酸化位点Y12调节了它与vinculin的结合，vinculin是黏附复合物中一个重要的机械偶联蛋白。初步数据显示，Y12的磷酸化或与磷酸化模拟谷氨酸Y12E的突变抑制了p130Cas与血管蛋白的结合，导致p130Cas在局灶黏附中的定位下降，并导致拉伸诱导的p130Cas激活和下游ERK1/2信号的减少。这些观察结果表明，vinculin是细胞中p130cas介导的机械转导途径的重要调节剂。这个项目的主要目的是验证一个假设，即vinculin对于p130Cas结合到黏附复合物中以及将力传递给p130Cas分子是至关重要的。

Adherent cells, when mechanically stressed, show a wide range of responses including large-scale changes in their mechanical behavior and gene expression pattern. This is in part facilitated by activating the focal adhesion protein p130Cas through force-induced conformational changes that subsequently lead to activation of downstream pathways such as extracellular-signal-regulated kinase (ERK1/2) phosphorylation. We have recently demonstrated that the phosphorylation site Y12 on p130Cas modulates the binding with vinculin, which is a prominent mechano-coupling protein in the focal adhesion complex. Preliminary data show that phosphorylation of Y12 or mutation with phospho-mimicking glutamate Y12E suppresses the binding of p130Cas to vinculin, leads to a decline of p130Cas localization in focal adhesions, and to a reduction of stretch-induced p130Cas activation and downstream ERK1/2 signaling. These observations demonstrate that vinculin is an important modulator of the p130Cas-mediated mechano-transduction pathway in cells. The central aim of this project is to test the hypothesis that vinculin is critical for p130Cas incorporation into the focal adhesion complex and for transmitting forces to the p130Cas molecule.