Fig. 1. A schematic diagram of the Wnt signaling pathway.

(A) Wnt-off. In the absence of Wnt stimulation, β-catenin is phosphorylated by CK1α and GSK3β followed by ubiquitin-proteasome mediated proteolysis. (B) Wnt-on. Upon Wnt stimulation, the destruction complex is not functional, so the β-catenin protein is translocated into the nucleus and acts as a transcriptional co-activator to regulate oncogenic target genes. APC, Adenomatous polyposis; DVL, Disheveled.