The catenins, ?, ? and ?, are proteins which bind to the highly conserved,intracellular cytoplasmic tail of E-cadherin. Together, the catenin/cadherincomplexes play an important role mediating cellular adhesion. ?-catenin was initially described as an E-cadherin associated protein, and since has been shown to associate with other members of the cadherin family, such as N-cadherin and P-cadherin. ?-catenin associates with the cytoplasmic portion of E-cadherin, which is necessary for the function of E-cadherin as an adhesion molecule. ?-catenin has also been found in complexes with the tumor suppressor protein APC. ?-catenin, also known as plakoglobin, binds with ?-catenin and N-cadherin. It has been shown that the transmembrane phosphatase PTP? associates with catenin/cadherin complexes and may regulate complex signaling.