The α5β1 integrin selectively enhances epidermal growth factor signaling to the phosphatidylinositol-3-kinase/Akt pathway in intestinal epithelial cells

Abstract We have investigated EGF-driven signaling processes in rat intestinal epithelial cell lines that overexpress either the α5β1 integrin or the α2β1 integrin. Both cell types display efficient activation of Erk/MAP kinase, but only the α5β1 expressing cells display a strong activation of Akt. A complex is formed between activated EGFR and α5β1, but not with α2β1; this complex also contains ErbB3 and p85. Thus α5β1 can support efficient activation of both the Erk and the phosphatidylinositol-3-kinase/Akt branches of the EGFR signaling cascade, whereas α2β1 can support only the Erk branch.