Figure 1.

Alterations of the AKT pathway in human cancer. Activation of tyrosine kinase receptors through growth factor stimulation or constitutive activation of the receptor through mutation/amplification leads to activation of the AKT signaling pathway. Other mechanisms observed in cancer resulting in AKT signaling include activation of proteins encoded by oncogenes (shown in green) and/or inactivation of tumor suppressors (shown in red). Germline mutations of genes encoding some of these tumor suppressors have been found to be responsible for various hereditary cancer syndromes. AKT-mediated phosphorylation of different downstream proteins converges on signaling pathways important in tumorigenesis, such as cell survival and cell cycle progression (convergence of pathways indicated with a thin, black arrow at the lower part of the figure).