FIG 5.

Schematic illustrating the cross talk between Wnt/β-catenin and p38 MAPK/MEF2 signaling. Wnt-mediated inactivation of the GSK3–β-catenin destruction complex results in suppressed degradation of β-catenin. Activation of p38 MAPK signaling results in phosphorylation and activation of MEF2 in the nucleus, which enhance its physical interaction with nuclear β-catenin. This results in nuclear β-catenin retention, synergistic activation of the Wnt target genes c-myc and c-jun, and increased cell proliferation.