The Wnt pathway (named as a hybrid of Wingless and Int ) regulates cell fate decisions during development of a vide variety of animal species. Secreted Wnt glycoproteins bind to the Frizzled receptor, a family of serpentine receptors, to activate Dishevelled, a PDZ domain protein. Dishevelled acts to inhibit a cytoplasmic complex involving GSK-3, axin and APC that acts to degrade beta- catenin. GSK-3 phosphorylates beta-catenin leading to ubiquitination and degradation by the proteosome. Activation of the Wnt pathway inhibits degradation of beta-catenin allowing its nuclear transport and gene induction via binding to TCF. During the elaboration of cell types and tissues, the Wnt pathway often interacts with the FGF and TGF-beta path
