Catenin is one of the key downstream effectors in the Wnt signaling pathway. It has been implicated to play an important role in early embryonic development and tumorigenesis. β-catenin can be destabilized by GSK-3β or other kinases by phosphorylating it at serines 33, 37, 45 and threonine 41. Mutations of these phosphorylation sites in β-catenin have been found in many tumor cell lines.