β-Catenin (Tyr-333) [γ-Catenin (Tyr-324) ], Phosphospecific Antibody

β-Catenin is a 92 kDa protein that binds to the cytoplasmic tail of E-Cadherin. The cadherins, transmembrane adhesion molecules, are found with catenins at adherens junctions. Deletions in the cytoplasmic domain of E-Cadherin eliminate catenin binding and result in a loss of cell adhesion. Tyrosine phosphorylation of β-Catenin can regulate its interaction with critical components of adherens junctions. Both Fer and Fyn kinases phosphorylate tyrosine 142 in vitro. Overexpression of these kinases in epithelial cells disrupts interactions between α- and β-Catenins. The phosphorylation of tyrosine 142 may act as a switch from the transcriptional to the adhesive role of β-Catenin. Src family kinases can also phosphorylate tyrosine 86 and 654 in β-Catenin. The Tyr-654 phosphorylation regulates β-Catenin binding to E-cadherin. Thus, site-specific tyrosine phosphorylation of β-Catenin may regulate protein-protein interactions leading to changes in cell adhesion.

The antibody detects a 92kDa* protein corresponding to the molecular mass of β-Catenin on SDS-PAGE immunoblots of human A431 cells treated with pervanadate, but not in control cells. In addition, the pervanadate induced reactivity is not observed after alkaline phosphatase treatment. This peptide sequence is highly conserved in rat and mouse β-Catenin, and has high homology to the conserved site in γ-Catenin (Tyr-324) .