beta-catenin


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beta-catenin

A cell–cell adhesion protein that binds to the cytoplasmic domain of E-cadherin. The beta-catenin-cadherin complex recruits alpha-catenin, which in turn binds actin of the cytoskeleton, together forming intercellular adherens junction. Beta-catenin also acts as a component of the Wnt signal transduction pathway, which regulates cell proliferation and differentiation. Tissue concentrations of free beta-catenin are controlled by a protein complex (adenomatous polyposis coli protein and glycogen synthetase kinase3a) which facilitates its breakdown. Wnt inactivates glycogen synthetase kinase3b, allowing beta-catenin to accumulate in cytoplasm and in the nucleus, where it activates the TCF/LEF transcription factors, which in turn act on c-myc, tcf-1 and cyclin D1.

Normal expression
Normal cells show membrane staining for beta-catenin. Beta-catenin expression is regulated by the adenomatous polyposis coli (APC) gene.
 
Abnormal expression
Cytoplasmic and/or nuclear staining is abnormal. Mutant CTNNB1 can lead to stabilisation of beta-catenin in the cytoplasm and translocation to the nucleus; disregulation of beta-catenin occurs in Gardner syndrome, leading to familial adenomatous polyposis and fibromatosis. Beta-catenin expression is increased in aggressive fibromatosis, synovial sarcoma, osteosarcoma, liposarcoma and malignant fibrous histiocytoma. High nuclear expression is seen in some mesenchymal tumours; cytoplasmic staining is seen in many. In contrast, cytoplasmic accumulation of beta-catenin is a generally good prognostic marker in upper and lower GI adenocarcinomas.
References in periodicals archive ?
B: This photomicrograph demonstrates the mass's reactivity to beta-catenin (original magnification x200).
Beta-catenin aggregate formation was accompanied by a decrease in the expression of the[beta]-catenin target genes used in this study.
Vitamin A converts stem cells to neuronal precursors, and activation of beta-catenin by Wnt can either support pluripotency or promote non-neural differentiation, depending on what other signals are present.
Galectin-3 mediates nuclear beta-catenin accumulation and Wnt signaling in human colon cancer cells by regulation of glycogen synthase kinase-3beta activity.
In colorectal adenomas and carcinomas where both APC alleles are defective, destruction of the free pool of beta-catenin is impaired, and active beta-catenin accumulates in the cytoplasm and nucleus to reactivate Wnt/beta-catenin target genes in CRC [8].
Su prevalencia aumenta en el sindrome de Gardner, en el rol de la poliposis adenomatosa colonica con mutacion genetica y la regulacion de la beta-catenin aun esta siendo investigada.
Beta-catenin as a potential key target for tumor suppression.
p120, a novel substrate of protein tyrosine kinase receptors and of p60v-src, is related to cadherin-binding factors beta-catenin, plakoglobin and armadillo.
Cheng H, Liang H, Qin Y, Liu Y: Nuclear beta-catenin overexpression in metastatic sentinel lymph node is associated with synchronous liver metastasis in colorectal cancer.