Beta-catenin

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Beta catenin 1
Identifiers
Symbol	CTNNB1
HUGO	2514
Entrez	1499
OMIM	116806
RefSeq	NM_001904
UniProt	P35222
Other data
Locus	Chr. 3 p21

Beta-catenin is a subunit of the cadherin protein complex. In Drosophila, the homologous protein is called armadillo. Beta-catenin in the canonical Wnt signaling pathway. Beta-catenin has been implicated as an integral component in the Wnt signaling pathway.

The Role of Beta-Catenin in The Wnt Signaling Pathway

When Wnt is not present, GSK3 (a kinase) constitutively phosphorylates the beta-catenin protein. Beta-catenin is associated with Axin (scaffolding protein) complexed with GSK3 and APC (adenomatosis polyposis coli). The APC in this pathway is completely separate and unrelated to the Anaphase Promoting Complex involved in cell cycle regulation. The creation of said complex acts to substantially increase the phosphorylation of beta-catenin by facilitating the the action of GSK3. When beta-catenin is phosphorylated it is degraded and thus will not build up in the cell to a significant level. When Wnt binds to Frizzled (Fz), its receptor, dishevelled (Dsh) is recruited to the membrane. GSK3 is inhibited by the activation of Dsh by Fz. Because of this, beta-catenin is permited to build up in the cytosol and can be subsequently translocated into the nucleus to perform a variety of functions. It can act in conjunction with TCF to activate specific genes as well as cause the export of TCF from the nucleus.