Individual Cas phosphorylation sites are dispensable for processive phosphorylation by Src and anchorage-independent cell growth
Individual Cas phosphorylation sites are dispensable for processive phosphorylation by Src and anchorage-independent cell growth
复制标题
DOI：
10.1074/jbc.m602311200
复制
发表时间：
2006-07-28
影响因子：
4.8
通讯作者：
Miller, W. Todd
中科院分区：
文献类型：
--
作者：
Patwardhan, Parag;Shen, Yongquan;Miller, W. Todd
Cas是一种多结构域信号蛋白，存在于粘着斑中。Cas具有一个大的中央底物结构域，含有15个重复的序列YXXP，其被Src磷酸化。磷酸化位点对于Cas在细胞迁移和调节肌动蛋白细胞骨架中的作用是必不可少的。我们先前表明，Src通过进行性机制催化Cas的多位点磷酸化。在这项研究中，我们创造了Cas的突变形式，以确定进行性磷酸化的决定因素。含有单个或多个YXXP突变的突变体被Src磷酸化，这表明单个位点被磷酸化。结果还表明，Cas磷酸化事件没有确定的顺序。我们还通过将Cas重新引入Cas缺陷的成纤维细胞来研究这些突变的影响。缺乏部分或全部YXXP位点的突变体增强了Src促进锚定非依赖性生长的能力。另一方面，YXXP位点的缺失损害了Cas促进肿瘤细胞迁移的能力。
Cas is a multidomain signaling protein that resides in focal adhesions. Cas possesses a large central substrate domain containing 15 repeats of the sequence YXXP, which are phosphorylated by Src. The phosphorylation sites are essential for the roles of Cas in cell migration and in regulation of the actin cytoskeleton. We showed previously that Src catalyzes the multisite phosphorylation of Cas via a processive mechanism. In this study, we created mutant forms of Cas to identify the determinants for processive phosphorylation. Mutants containing single or multiple YXXP mutations were phosphorylated processively by Src, suggesting that individual sites are dispensable. The results also suggest that there is no defined order to the Cas phosphorylation events. We also studied the effects of these mutations by reintroducing Cas into Cas-deficient fibroblasts. Mutants lacking some or all YXXP sites augment the ability of Src to promote anchorage-independent growth. On the other hand, deletion of YXXP sites compromises the ability of Cas to promote tumor cell migration.