 This type of protein domain is important in transducing WNT signals during embryonic development.The 3-dimensional fold of an armadillo repeat was first observed in the crystal structure of beta-catenin, where the 12 tandem repeats form a superhelix of alpha helices with three helices per unit.The cylindrical structure features a positively charged groove, which presumably interacts with the acidic surfaces of the known interaction partners of beta-catenin.