Fig. 2

Wnt/β-catenin signal transduction pathway. Wnt binding to the FZD/LRP5/6 receptor complex leads to inhibition of GSK3 enzyme activity and the β-catenin destruction complex, which allows newly synthesized β-catenin to accumulate and translocate to the nucleus (orange arrows), where it binds with co-factors to form a transcriptionally active complex. Wnt signalling can be inhibited at the cell surface by various naturally occurring pathway inhibitors such as sFRPs and DKK, which bind to Wnt and LRP5/6 respectively. [secreted Frizzled Related Protein (sFRP); Frizzled (FZD); Dickkopf (DKK); Glycogen Synthase Kinase 3 (GSK3); Adenomatous Polyposis Coli (APC), Casein Kinase 1 (CK1)]