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.