Figure 1.

Convergence of integrin and growth factor receptor pathways. Integrin-mediated adhesion regulates transmission of growth factor receptor signals in at least four steps. These steps are: autophosphorylation and activation of the receptors themselves; hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP₂) to produce diacylglycerol and inositol triphosphate, leading to activation of protein kinase C (PKC); activation of Raf and/or MEK in the MAP kinase pathway; and activation of PI 3-kinase, leading to activation of p70^RSK and Akt protein kinases.