Hierarchical cleavage of focal adhesion kinase by caspases alters signal transduction during apoptosis of intestinal epithelial cells
Hierarchical cleavage of focal adhesion kinase by caspases alters signal transduction during apoptosis of intestinal epithelial cells
复制标题
DOI：
10.1053/gast.2001.20879
复制
发表时间：
2001-01-01
期刊：
影响因子：
29.4
通讯作者：
Levine, AD
中科院分区：
文献类型：
--
作者：
Grossmann, J;Artinger, M;Levine, AD
背景和目标：纯化的肠上皮细胞由于分离过程中细胞锚定丧失而死于凋亡诱导的凋亡，锚定依赖性细胞形成粘着斑，粘着斑是增强细胞-基质附着的位点，赋予存活信号，粘着斑激酶（FAK），粘着斑信号复合物的一个组分，转导这些抗凋亡信号。定义了在细胞凋亡过程中导致半胱天冬酶切割FAK的分子事件及其功能意义。研究方法：结果：FAK被caspase-3家族的两个不同成员的有序蛋白酶活性切割，第一次切割由caspase-3介导，产生一个94/92 kD末端片段，该片段被caspase-6加工成一个84 kD末端片段。凋亡启动后，FAK磷酸化水平迅速下降，FAK相关蛋白的磷酸化模式发生显著改变，显示信号转导的显著但不同的变化。正常人细胞凋亡期间FAH的裂解是半胱天冬酶的顺序、高度调节和协调作用的一个例子，半胱天冬酶不仅通过蛋白水解分解细胞，也改变了细胞的信号机制
Background & Aims: Purified intestinal epithelial cells die of detachment-induced apoptosis due to loss of cell anchorage during isolation, Anchorage-dependent cells form focal adhesions, sites of enhanced cell-matrix attachment that confer survival signals, Focal adhesion kinase (FAK), a component of the focal adhesion signaling complex, transduces these antiapoptotic signals, In this report, the molecular events leading to cleavage of FAK by caspases during apoptosis and its functional implications are defined. Methods: Cytosolic extracts of human intestinal epithelial cells undergoing detachment-induced apoptosis were analyzed by Western blotting immunoprecipitation, and kinase assay, Results: FAK is cleaved by the ordered proteolytic activity of 2 different members of the caspase-3 family, The first cleavage is mediated by caspase-3, generating a 94/92-kilodalton-terminal fragment, which is processed by caspase-6 to an 84-kilodalton fragment. After apoptosis is initiated, the level of FAK phosphorylation is rapidly decreased, and the phosphorylation pattern of FAK-associated proteins is dramatically modified, showing significant yet divergent changes in signal transduction, Conclusions: Cleavage of FAH during apoptosis of normal human cells is an example of the sequential, highly regulated, and coordinate action of caspases that not only dismantle a cell by proteolysis, but also alter the cell's signaling machinery.