SHP-2 inhibits tyrosine phosphorylation of Cas-L and regulates cell migration

The Src homology 2 (SH2) domain-containing protein tyrosine phosphatase, SHP-2, plays an important role in cell migration by interacting with various proteins. In this report, we demonstrated that SHP-2 inhibits tyrosine phosphorylation of Crk-associated substrate lymphocyte type (Cas-L), a docking protein which mediates cell migration, and found that SHP-2 negatively regulates migration of A549 lung adenocarcinoma cells induced by fibronectin (FN). We showed that overexpressed SHP-2 co-localizes with Cas-L at focal adhesions and that exogenous expression of SHP-2 abrogates cell migration mediated by Cas-L. SHP-2 inhibits tyrosine phosphorylation of Cas-L, and associates with Cas-L to form a complex in a tyrosine phosphorylation-dependent manner. Finally, immunoprecipitation experiments with deletion mutants revealed that both SH2 domains of SHP-2 are necessary for this association. These results suggest that SHP-2 regulates tyrosine phosphorylation of Cas-L, hence opposing the effect of kinases, and SHP-2 is a negative regulator of cell migration mediated by Cas-L.