Tyrosine phosphorylation of β-catenin affects its subcellular localization and transcriptional activity of β-catenin in Hela and Bcap-37 cells.

In order to investigate the relationship between tyrosine phosphorylation of β-catenin and transcriptional activity of β-catenin in Hela and Bcap-37 cells, genistein (a tyrosine kinase inhibitor) was used to inhibit tyrosine phosphorylation in cells. Our results showed the total β-catenin protein levels were mainly equal in Hela, Bcap-37 and HK-2 cells, β-catenin was mainly present in nucleus in Hela and Bcap-37cells, while in HK-2 cell β-catenin was mainly located in cytoplasm. Genistein could inhibit tyrosine phosphorylation of β-catenin and downregulate nuclear β-catenin expression in Hela and Bcap-37 cells. In addition, genistein suppressed Ki-67 promoter activity and Ki-67 protein level, thus promoted cell apoptosis. Furthermore, β-catenin could increase the Ki-67 promoter activity in Hela and Bcap-37 cells. From these findings we conclude that tyrosine phosphorylation of β-catenin can regulate the cellular distribution of β-catenin and affect the transcriptional activity of β-catenin.