Armadillo/plakoglobin ARM repeat

Introduction

A tandemly repeated domain of ~ 40 amino acid residues 1st identified in the Drosophila segment polarity gene product armadillo, a protein that mediates cell adhesion. The domain is involved in protein-protein interactions.

Repeats occur in:

• mammalian armadillo homolog beta-catenin
• junctional plaque protein plakoglobin
• adenomatous polyposis coli (APC) tumor suppressor protein
• other proteins

In beta-catenin the 12 armidillo repeats form a superhelix of alpha-helices, with 3 helices per unit. The cylindrical structure features a positively charged grove which presumably interacts with the acidic surfaces of the known interaction partners of beta-catenin.

More general terms

• peptide motif
• consensus repeat