Fig. 1.

Simplified overview of the canonical Wnt (β-catenin) pathway. Upon pathway activation, Wnt binding causes the dimerization of the Fz (Fzd in vertebrates) receptor and the LRP5/6 co-receptor. The receptor complex then recruit a Dsh/Dvl-Axin multimer, which leads to the disassembly of the “destruction complex,” which—in the inactive state—includes Axin, APC, GSK-3β and CK1 among other proteins, and β-catenin. Thus upon the disassembly of the DC, β-catenin is freed and relieved from proteasome-dependent degradation and accumulates in the cytoplasm. Subsequently, β-catenin translocates to the nucleus, where its associates with the TCF/Lef transcription factors and several co-activators to turn on Wnt target gene transcription, which regulates cell fate decisions, proliferation, and cell survival. See main text for details.