The (alpha), (beta), (delta), and (gamma) -catenins are proteins that bind to the highly conserved, intracellular cytoplasmic tail of E-cadherin. (delta)-catenin interacts with Presenilin 1 and is expressed in the brain. The gene encoding (delta)-catenin maps to human chromosome 5p15.2. A hemizygous loss of the gene encoding (delta)-catenin leads to the mental retardation associated with Cri-du-Chat syndrome. (gamma)-catenin, also known as plakoglobin, is an 80-88 kDa protein that binds (alpha)-catenin and N-cadherin. In addition, the transmembrane phosphatase PTPm associates with catenin/cadherin complexes and may regulate complex signaling.