Fig. 7. Schematic representation of role of p38 MAPK in canonical Wnt–β-catenin signaling pathway. Activation of Fz1 by Wnt3a leads to accumulation of β-catenin, Lef/Tcf-sensitive transcriptional response and primitive endoderm formation in mouse F9 cells through G-proteins and Dishevelleds. p38 MAPK plays a crucial role in canonical signaling by inactivating GSK3β and by operating downstream of Dishevelleds.