Fig. 2.

Wnt/β-catenin signalling pathway. a. In the absence of Wnt ligand, β-catenin is recruited by the Axin destruction complex, sequentially phosphorylated by CK1 and GSK and targeted for degradation. Cytosolic levels of β-catenin (β-cat) are maintained at a low level, and β-catenin is mainly found at adherens junction. b. Extracellular Wnt binds to Frizzled (Fzd) and LRP5/6 co-receptors at the cell membrane and activates signalling. Subsequently, Dishevelled (Dvl) inactivates the destruction complex and β-cat accumulates in the cytosol. This allows translocation of β-cat to the nucleus where it activates transcription of target genes upon binding to LEF/TCF transcription factors