alpha-catenin binding domain found in catenin beta-1 (CTNNB1) and similar proteins
CTNNB1, also called beta-catenin, is a key downstream component of the canonical Wnt signaling pathway. In the absence of Wnt, it forms a complex with AXIN1, AXIN2, APC, CSNK1A1 and GSK3B that promotes phosphorylation on N-terminal Ser and Thr residues, and ubiquitination of CTNNB1 via BTRC and its subsequent degradation by the proteasome. In the presence of Wnt ligand, CTNNB1 is not ubiquitinated and accumulates in the nucleus, where it acts as a coactivator for transcription factors of the TCF/LEF family, leading to activation of Wnt responsive genes. CTNNB1 is involved in the regulation of cell adhesion as a component of an E-cadherin:catenin adhesion complex. It acts as a negative regulator of centrosome cohesion. It is involved in the CDK2/PTPN6/CTNNB1/CEACAM1 pathway of insulin internalization. It blocks anoikis of malignant kidney and intestinal epithelial cells and promotes their anchorage-independent growth by down-regulating DAPK2. It disrupts PML function and PML-NB formation by inhibiting RANBP2-mediated sumoylation of PML. This model corresponds to a small region at the C-terminus of CTNNB1, which is responsible for alpha-catenin binding.
Jiyao W et al.(2023). "The conserved domain database in 2023.",