Description
Beta-catenin is a cytosolic, 88 kDa, 781 amino acid protein belongs to the beta-catenin family. The N-terminus domain, containing the binding site and the phosphorylation sites. Beta-Catenin serves as a link between cytoskeleton actin and transmembrane cadherin (s). It is believed to contribute to tight cell-to-cell adhesion. It can enter the nucleus and interact with the TCF/LEF family of transcription factors, initiating gene expression. Normally, beta-catenin transcriptional activity is suppressed by a Ser/Thr kinase termed GSK3beta and/or Casein Kinase I (CK1). Kinases are constitutively active and phosphorylates beta-catenin at multiple sites, including S33 and S37, Y96, Y228, Y280 etc. Phosphorylation of beta-catenin targets the molecule for degradation via a ubiquination-mediated pathway. GSK3beta activity can be blocked by upstream signaling events such as Wnt-Frizzled interaction. This inhibits GSK3beta, allowing unphosphorylated beta-catenin to enter the nucleus and initiate gene activation. The phosphorylation of beta-catenin might contribute to tumorigenesis