Sanjay A, Houghton A, Neff L, DiDomenico E, Bardelay C, Antoine E, Levy J, Gailit J, Bowtell D, Horne W C, Baron R
Department of Cell Biology and Orthopedics, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
J Cell Biol. 2001 Jan 8;152(1):181-95. doi: 10.1083/jcb.152.1.181.
The signaling events downstream of integrins that regulate cell attachment and motility are only partially understood. Using osteoclasts and transfected 293 cells, we find that a molecular complex comprising Src, Pyk2, and Cbl functions to regulate cell adhesion and motility. The activation of integrin alpha(v)beta(3) induces the Ca(2+)-dependent phosphorylation of Pyk2 Y402, its association with Src SH2, Src activation, and the Src SH3-dependent recruitment and phosphorylation of c-Cbl. Furthermore, the PTB domain of Cbl is shown to bind to phosphorylated Tyr-416 in the activation loop of Src, the autophosphorylation site of Src, inhibiting Src kinase activity and integrin-mediated adhesion. Finally, we show that deletion of c Src or c-Cbl leads to a decrease in osteoclast migration. Thus, binding of alpha(v)beta(3) integrin induces the formation of a Pyk2/Src/Cbl complex in which Cbl is a key regulator of Src kinase activity and of cell adhesion and migration. These findings may explain the osteopetrotic phenotype in the Src(-/-) mice.
整联蛋白下游调节细胞黏附和运动的信号事件仅得到部分理解。利用破骨细胞和转染的293细胞，我们发现由Src、Pyk2和Cbl组成的分子复合物发挥调节细胞黏附和运动的作用。整联蛋白α(v)β(3)的激活诱导Pyk2 Y402的Ca(2+)依赖性磷酸化、其与Src SH2的结合、Src激活以及c-Cbl的Src SH3依赖性募集和磷酸化。此外，Cbl的PTB结构域显示与Src激活环中磷酸化的Tyr-416（Src的自磷酸化位点）结合，抑制Src激酶活性和整联蛋白介导的黏附。最后，我们表明c Src或c-Cbl的缺失导致破骨细胞迁移减少。因此，α(v)β(3)整联蛋白的结合诱导Pyk2/Src/Cbl复合物的形成，其中Cbl是Src激酶活性以及细胞黏附和迁移的关键调节因子。这些发现可能解释了Src(-/-)小鼠中的骨质石化表型。
