Cx43 over-expression sequesters β-catenin at the cell membrane in MDA-MB-231 cells. (a) Western blotting of β-catenin in cellular fractions of MDA-MB-231 cells, shCx43 cells and Cx43D cells. Proteins from the cytosolic (C), intermediate (I) and nuclear (N) fractions were blotted with compartment-specific antibodies, GAPDH, GM130 and Lamin A/C, respectively. (b) Bar graph displaying the densitometry analysis of nuclear versus cytosolic β-catenin expression with respect to total β-catenin protein levels. Two independent experiments were performed and plotted. (c) Representative immunofluorescence images of β-catenin expression in parental MDA-MB-231, shCx43 and Cx43D cells, counterstained with DAPI. Micrographs are representative of at least ten different fields per cell line. Scale bar represents 20 µm. * p < 0.05.