beta-Catenin
beta-Catenin (catenin beta-1, encoded by CTNNB1) is a key downstream component of the canonical Wnt signalling pathway and a structural part of cadherin-based adherens junctions. It is also known as armadillo or CTNNB, and belongs to the beta-catenin family. Browse Assay Genie's current range of beta-Catenin research reagents below, or read on for the biology behind the target.
beta-Catenin has two well-described roles: it transduces canonical Wnt signals and it contributes to cell-cell adhesion. In the absence of Wnt, it is held in a complex with AXIN1, AXIN2, APC, CSNK1A1 and GSK3B, which promotes phosphorylation of N-terminal serine and threonine residues. The protein is then ubiquitinated via BTRC and degraded by the proteasome. When Wnt ligand is present, beta-catenin is not ubiquitinated and accumulates in the nucleus. There it acts as a coactivator for TCF/LEF transcription factors and switches on Wnt-responsive genes. It also acts as a coactivator for other factors, such as NR5A2, and by driving CTNNB1/TCF-target genes it promotes epithelial to mesenchymal and mesenchymal to epithelial transitions.
At the membrane, beta-catenin is a component of the E-cadherin:catenin adhesion complex. Adherens junctions are needed to create and maintain epithelial cell layers, and the protein anchors the actin cytoskeleton and may transmit the contact inhibition signal that stops cell division once an epithelial sheet is complete. UniProt also reports localisation to the cytoplasm, nucleus, centrosome, spindle pole, cilium basal body and synapse. The protein acts as a negative regulator of centrosome cohesion and takes part in the CDK2/PTPN6/CTNNB1/CEACAM1 pathway of insulin internalisation. In kidney and intestinal epithelial cells it blocks anoikis by down-regulating DAPK2, and it disrupts PML function by inhibiting RANBP2-mediated sumoylation of PML.
Developmental roles include promoting neurogenesis by keeping sympathetic neuroblasts in the cell cycle, and positively regulating odontoblast differentiation through LEF1, BMP2 and BMP4 transcription. Binding of SOX9 competes with TCF/LEF for beta-catenin and so inhibits Wnt signalling during chondrocyte differentiation. The CTNNB1 gene is a member of the armadillo repeat containing and beta catenins HGNC groups, and alternative splicing yields multiple transcript variants. beta-Catenin binds the product of the APC gene, and mutations in CTNNB1 are a cause of colorectal cancer, pilomatrixoma, medulloblastoma and ovarian cancer.
beta-Catenin stability and nuclear accumulation are the central readout of canonical Wnt activity, controlled by the AXIN, APC, CSNK1A1 and GSK3B destruction complex.
As part of the E-cadherin:catenin complex, it links adherens junctions to the actin cytoskeleton and helps maintain epithelial cell layers.
Mutations in CTNNB1 are linked to colorectal cancer, pilomatrixoma, medulloblastoma and ovarian cancer, and it binds the colon polyposis-associated APC protein.
It influences neurogenesis, chondrocyte differentiation and odontoblast differentiation during tooth germ formation, through partners including SOX9 and LEF1.
beta-Catenin has a dual role. At the cell membrane it is part of the E-cadherin:catenin adhesion complex and anchors the actin cytoskeleton. In the nucleus it acts as a coactivator for TCF/LEF transcription factors, activating Wnt-responsive genes when Wnt ligand is present.
The HGNC symbol is CTNNB1, with the name catenin beta 1. Aliases include beta-catenin, armadillo and CTNNB. Earlier HGNC names were catenin (cadherin-associated protein), beta 1, 88kDa. UniProt lists the protein as catenin beta-1, and alternative splicing produces multiple transcript variants.
Mouse and rat both have a Ctnnb1 ortholog. In humans, mutations in the CTNNB1 gene are a cause of colorectal cancer, pilomatrixoma, medulloblastoma and ovarian cancer. Check the datasheet of any product for its validated reactivity.
Pathway partners of beta-catenin and related Wnt signalling targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P35222; product specifications from Assay Genie datasheets.