Akt1 promotes focal adhesion disassembly and cell motility through phosphorylation of FAK in growth factor-stimulated cells

Abstract

The crosstalk between spatial adhesion signals and temporal soluble signals is key in regulating cellular responses such as cell migration. Here we show that soluble growth factors (GFs) enhance integrin signaling through Akt phosphorylation of FAK at Ser695 and Thr700. PDGF treatment or overexpression of active Akt1 in fibroblasts increased autophosphorylation of FAK at Tyr397, an essential event for integrin turnover and cell migration. Phosphorylation-defective mutants of FAK (S695A and T700A) underwent autophosphorylation at Tyr397 and promoted cell migration in response to the integrin ligand fibronectin (FN), but importantly, not in response to PDGF. This study has unveiled a novel function of Akt as an “ignition kinase” of FAK in GF signaling and may shed light on the mechanism by which GFs regulate integrin signaling.