Has a critical role in neuronal development, particularly in the formation and/or maintenance of dendritic spines and synapses (PubMed:17993462) (PubMed:25807484). Involved in the regulation of canonical Wnt signaling (By similarity). It probably acts on beta-catenin turnover, facilitating beta-catenin interaction with GSK3B, phosphorylation, ubiquitination and degradation (PubMed:20623542). May be involved in neuronal cell adhesion and tissue morphogenesis and integrity by regulating adhesion molecules. Functions as a transcriptional activator when bound to ZBTB33 (PubMed:15282317). Binds to E-cadherin at a juxtamembrane site within the cytoplasmic domain. Binds to PSEN1. Interacts with PDZD2 (By similarity). Interacts (via the extreme C-terminus) with FRMPD2 (via the PDZ 2 domain) (By similarity). Interacts with ZBTB33. Interacts with ARHGEF28 (PubMed:17993462). Interacts with CDK5 (By similarity). Interacts with CTNNB1 (By similarity). Interacts with GSK3A and GSK3B (PubMed:20623542) (PubMed:19706605). Interacts with DNM2 (By similarity). Interacts with CCDC85B (By similarity). Expressed in neurons and glial cells. Isoform 2 was found to be the most predominant isoform in various brain regions. Expressed at neuromuscular junctions. Increasingly expressed by 10 dpc. Expression peaks at postnatal day P7 and stays at lower levels in adulthood. First expressed within proliferating neuronal progenitor cells of the neuroepithelium, becomes down-regulated during neuronal migration, and is later reexpressed in the dendritic compartment of postmitotic neurons. In the developing neocortex, it is strongly expressed in the proliferative ventricular zone and the developing cortical plate, yet is conspicuously less prominent in the intermediate zone, which contains migrating cortical neurons, it forms a honeycomb pattern in the neuroepithelium by labeling the cell periphery in a typical adherens junction pattern. By 18 dpc, its expression shifts primarily to nascent apical dendrites, a pattern that continues through adulthood. By retinoic acid. O-glycosylated. Phosphorylated by CDK5 (By similarity). Phosphorylated by GSK3B (PubMed:19706605). Belongs to the beta-catenin family.