Catenin Alpha 1 (CTNNa1)

In adherens junctions, alpha-catenin links the cadherin/beta-catenin complex to the actin-based cytoskeleton. Alpha-catenin is a homodimer in solution, but forms a 1:1 heterodimer with beta-catenin. Pokutta and Weis (2000) determined the crystal structure of the alpha-catenin dimerization domain, residues 82 to 279. The crystal structure showed that alpha-catenin dimerizes through formation of a 4-helix bundle in which 2 antiparallel helices are contributed by each protomer. A slightly larger fragment, containing residues 57 to 264, bound to beta-catenin. The crystal structure of a chimera consisting of the alpha-catenin-binding region of beta-catenin linked to the N terminus of alpha-catenin residues 57 to 264 revealed the interaction between alpha- and beta-catenin and provided a basis for understanding adherens junction assembly.