Stress signaling and Myc downregulation: implications for cancer.

The transcription factor Myc forms a complex with its partner Max and with the regulatory DNA sequences on its target genes. Formation of this complex is required for Myc functions and Myc-induced oncogenic transformation. We have recently shown that formation of the Myc/Max/DNA complex is inhibited by the stress-responsive protein kinase Pak2 signaling pathway through phosphorylation of Myc. As a consequence of the phosphorylation, Myc loses its gene activation activity and the ability to induce proliferation and cellular transformation. Additionally, phosphorylation induces degradation of the Myc protein. Activation of stress signaling pathways, including Pak2 activity, may be a potential therapeutic approach to block Myc-induced neoplasia.