| Modification Notes |
The catenins, å, ∫ and ©, are proteins that bind to the highly conserved, intracellular cytoplasmic tail of E-cadherin. Together, the catenin/cadherin complexes play critical roles in mediating cellular adhesion. ∫-catenin associates with the cytoplasmic portion of E-cadherin, which is necessary for the function of E-cadherin as an adhesion molecule. ∫-catenin also forms complexes with the tumor suppressor protein APC. Amino acid alterations at residues around Ser 33, one of the targets for phosphorylation of glycogen synthase kinase-3∫, result in accumulation of the ∫-catenin protein in the cytoplasm and nucleus. Pin1 is a novel regulator of ∫-catenin signaling that directly binds a phosphorylated Ser-Pro motif next to the APC-binding site in ∫-catenin, inhibiting the interaction with APC and increasing ∫-catenin translocation into the nucleus. Thus, Pin1 overexpression may contribute to the upregulation of ∫-catenin in tumors such as breast cancer. |