Active Src elevates the expression of β-catenin by enhancement of cap-dependent translation

The proto-oncogene pp60^c-Src (c-Src) is activated in many types of cancer and contributes to the transformed phenotype of the tumor, although its role is not yet fully understood. Here we report that active Src elevates the levels of β-catenin by enhancing cap-dependent translation. Src induces phosphorylation of the eukaryotic initiation factor 4E via the Ras/Raf/ERK pathway and the phosphorylation of its inhibitor 4E-BP1 via the PI3K/mTOR pathway. Activated Src enhances the accumulation of nuclear β-catenin and enhances its transcriptional activity, elevating target genes such as cyclin D1. This novel activation of the Wnt pathway by Src most probably contributes to the oncogenic phenotype of cancer cells.