Fig. 1
The canonical and non-canonical Wnt signaling pathways. The canonical pathway is characterized by the stabilization and intracellular accumulation of β-catenin through the deactivation of β-catenin-destruction complex (APC, AXIN, GSK3, and CK1α) mediated by DVL proteins. In this pathway, β-catenin is translocated into the nucleus and by forming a complex with other elements, such as CBF, activates the expression of target genes. However, the non-canonical Wnt signaling is a β-catenin-independent pathway. This pathway is triggered by the binding of Wnt ligands to the ROR-Frizzled receptor complex, leading to the activation of DVL. In turn, DVL protein activates Rho small GTPase by the de-inhibition of cytoplasmic protein DAAM, and stimulates Rac1 signaling. Rho and Rac1 mediate the activation of ROCK and JNK and promote polarized cell migration (PCP signaling). Besides, non-canonical Wnt signaling leads to the production of DAG and IP3 by PLC activity. DAG activates PKC signaling, and IP3 production stimulates Ca+2 pathway (also provokes PKC signaling) and NFAT-dependent transcriptional response