Figure 3

Cd²⁺-induced nuclear translocation of β-catenin and Wnt signaling are abolished in confluent kidney PTC, which show increased E-cadherin expression. (A) Immunoblots with β-catenin or α-catenin antisera in ~50% and 100% confluent WKPT-0293 Cl.2 cells (25 μM Cd²⁺, 6 h). For statistical analysis of immunoblots β-catenin signals were normalized to the loading markers and compared to controls, which were set to 100%. Means ± SEM (n = 3) are shown. Student's unpaired t-test compares Cd²⁺ treated cells to respective controls. (B) Cd²⁺-induced TCF transcriptional activity depends on the confluence of kidney PTC. WKPT-0293 Cl.2 cells transfected with TOPflash, FOPflash or ΔN-β-catenin were treated with 25 μM Cd²⁺ for 6 h. Data presented are means ± SEM of 4-5 experiments. Student's unpaired t-test compares Cd²⁺ treated or ΔN-β-catenin-transfected cells to respective controls. (C) To determine association of TCF4 with β-catenin in ~50% and 100% confluent cells, nuclear fractions were immunoprecipitated with an antibody against β-catenin and immunoblotted for TCF4. (D) Expression of E-cadherin in whole cell lysates of ~50% and 100% confluent cells by immunoblotting.