PROSITE documentation PDOC50176
Armadillo/plakoglobin ARM repeat profile


The armadillo repeat is an approximately 40 amino acids long tandemly repeated sequence motif first identified in the Drosophila segment polarity gene product armadillo, a protein that mediates cell adhesion. Similar repeats were later found in the mammalian armadillo homolog β-catenin, the junctional plaque protein plakoglobin, the adenomatous polyposis coli (APC) tumor suppressor protein, and a number of other proteins [1]. These proteins exert several functions through interactions of their tandem armadillo repeats domain with diverse binding partners. The proteins combine structural roles as cell-contact and cytoskeleton-associated proteins and signaling functions by generating and transducing signals affecting gene expression [1,2,3].

The three-dimensional fold of an armadillo repeat is known from the crystal structure of β-catenin [4]. There, the 12 repeats form a superhelix of α-helices, with three helices per unit. The cylindrical structure features a positively charged grove which presumably interacts with the acidic surfaces of the known interaction partners of β-catenin.

Last update:

December 2001 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

ARM_REPEAT, PS50176; Armadillo/plakoglobin ARM repeat profile  (MATRIX)


1AuthorsPeifer M. Berg S. Reynolds A.B.
TitleA repeating amino acid motif shared by proteins with diverse cellular roles.
SourceCell 76:789-791(1994).
PubMed ID7907279

2AuthorsGroves M.R. Barford D.
TitleTopological characteristics of helical repeat proteins.
SourceCurr. Opin. Struct. Biol. 9:383-389(1999).
PubMed ID10361086

3AuthorsHatzfeld M.
TitleThe armadillo family of structural proteins.
SourceInt. Rev. Cytol. 186:179-224(1999).
PubMed ID9770300

4AuthorsHuber A.H. Nelson W.J. Weis W.I.
TitleThree-dimensional structure of the armadillo repeat region of beta-catenin.
SourceCell 90:871-882(1997).
PubMed ID9298899

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