Schematic diagram of the simplified Wnt/β-catenin pathway. Left panel: in the absence of Wnt ligand, β-catenin is sequentially phosphorylated by CK1 and GSK3 in the cytoplasmic β-catenin destruction complex. Ubiquitin E3 ligase β-TrCP recognizes phosphorylated β-catenin and promotes its ubiquitination and proteasome degradation. Right panel: Wnt/β-catenin signaling is activated by the binding of Wnt ligand to Fz receptor and LRP5/6 coreceptors, resulting in the recruitment of Dvl and destruction complex to the membrane, which inactivates destruction complex, leading to stabilization of β-catenin. Accumulated β-catenin enters nucleus and activates target gene transcription.