Alpha-catenin was suggested to function as a linking protein between cadherins and actin-containing filaments of the cytoskeleton. It has been reported that the actin binding proteins vinculin and alpha-actinin can bind to alpha-catenin. However, a protein complex including a cadherin, actin, beta-catenin and alpha-catenin has not been isolated. It has been suggested that alpha-catenin does not bind with high affinity to both actin filaments and the E-cadherin-beta-catenin complex at the same time. It has been observed that when alpha-catenin is not in a molecular complex with beta-catenin, it dimerizes and functions to regulate actin filament assembly, possibly by competing with Arp2/3 protein.
The amino acid sequence of alpha-catenin has sequence similarity to that of vinculin.