The dual role of β-catenin in cell adhesion and transcriptional activation. β-Catenin (β) and plakoglobin (Pg) bind to cadherin adhesion receptors, and via α-catenin (α) they associate with the actin cytoskeleton to form AJs. When the Wnt signaling pathway is inactive, free β-catenin is degraded by a complex including glycogen synthase kinase (GSK), adenomatous polyposis coli (APC), and Axin, which phosphorylate β-catenin (PP). This protein complex recruits β-TrCP, which, together with Skp1, Cul1, and the E1 and E2 ubiquitination components, mediates the ubiquitination of β-catenin (Ub) and directs it to degradation by the 26S proteasome. The binding of Wnt to Frizzled (Frz) receptors activates Wnt signaling, and disheveled (Dsh) inhibits β-catenin phosphorylation by GSK. This results in β-catenin accumulation in the nucleus, where it complexes with T cell factor (TCF) and transactivates target genes such as Cyclin D1 and Myc. Modified from ref. 56.