Armadillo repeats

Armadillo repeats are named after the β-catenin-like Armadillo protein of the fruit fly Drosophila. These repeats are about 40 amino acids long and proteins that contain them have many tandemly repeated copies. Each Armadillo repeat is composed of a pair of alpha helices that form a hairpin structure. Multiple copies of the repeat form what is known as an alpha solenoid structure. β-catenin is a protein involved in linking cadherin cell adhesion proteins to the cytoskeleton, but the Armadillo repeat is found in a wide range of proteins with other functions. This type of protein domain is important in transducing WNT signals during embryonic development.