CTNNB1 protein is a dual function protein. It is a subunit of a complex of proteins that from adherens junctions, which are important for the establishment and maintenance of epithelial cell layers by regulating cell growth and adhesion between adjacent cells. CTNNB1 protein also pulls double duty as an intracellular signal transducer in the Wnt signaling pathway. Mutations of CTNNB1 have been implicated in the pathogenesis of several cancers.