Goldberg Gary S, Alexander David B, Pellicena Patricia, Zhang Zhong-Yin, Tsuda Hiroyuki, Miller W Todd
Department of Physiology and Biophysics, School of Medicine, Basic Science Tower T6, Health Science Complex, State University of New York at Stony Brook, Stony Brook, NY 11794-8661, USA.
J Biol Chem. 2003 Nov 21;278(47):46533-40. doi: 10.1074/jbc.M307526200. Epub 2003 Sep 11.
Cas is a member of the focal adhesion complex. Phosphorylation of Cas by Src is an important event leading to cell transformation. Using mass spectrometry, we have mapped 11 sites in Cas that are phosphorylated by Src. These sites are all located between residues 132 and 414 of Cas, in a region that is required for binding to a number of other proteins including Crk. We tested synthetic peptides modeled on Cas phosphorylation sites, and found that the sequence containing tyrosine 253 was phosphorylated by Src most efficiently. Using cells derived from Cas-deficient mice, we confirmed that Cas greatly enhanced the ability of Src to transform cells. Phosphorylation of Cas on tyrosine 253 was not required for Src to increase growth rate, suppress contact inhibition, or suppress anchorage dependence. Yet, in contrast to these growth characteristics, phosphorylation of Cas on tyrosine 253 was required for Src to promote cell migration. Thus, a single phosphorylation site on this focal adhesion adaptor protein can effectively separate cell migration from other transformed growth characteristics.
Cas是粘着斑复合体的成员。Src对Cas的磷酸化是导致细胞转化的一个重要事件。我们利用质谱法确定了Cas中11个被Src磷酸化的位点。这些位点都位于Cas的132位和414位残基之间，该区域是与包括Crk在内的许多其他蛋白质结合所必需的。我们测试了以Cas磷酸化位点为模型的合成肽，发现含有酪氨酸253的序列被Src磷酸化的效率最高。利用来自Cas基因缺陷小鼠的细胞，我们证实Cas极大地增强了Src转化细胞的能力。Src提高生长速率、抑制接触抑制或抑制锚定依赖性并不需要Cas的酪氨酸253磷酸化。然而，与这些生长特性相反，Src促进细胞迁移需要Cas的酪氨酸253磷酸化。因此，这种粘着斑衔接蛋白上的单个磷酸化位点可以有效地将细胞迁移与其他转化生长特性区分开来。
