Armadillo repeat is the name of a characteristic, repetitive amino acidsequence found in β-catenin and many other proteins, like α-importin,plakoglobin, or adenomatous polyposis coli (APC). Its name derives from the historical name of the β-catenin gene in the fruitfly Drosophila: where they were first discovered. Armadillo repeats are approximately 40 amino acids long and proteins that contain them usually have many tandemly repeated copies. These tandem repeats usually fold together to form a single, rigid protein domain called the armadillo (ARM) domain. Because ARM domains can consist of a variable number of repeats, they are a good example of solenoid protein domains. The best characterized example of armadillo domains is found in β-catenin. 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.
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