APC is colocalized with beta-catenin and hDLG in Henle's loop of the mousekidney

The tumor suppressor gene adenomatous polyposis coli (Apc) is mutated in fa milial adenomatous polyposis (FAP) and sporadic colorectal tumors. The prod uct of the Ape gene (APC) has been found to bind to beta -catenin and human homolog of discs large (hDLG), and to be involved in the Wnt/Wingless sign aling pathway. In this study, we examined distribution and subcellular loca lization of APC and its colocalization with beta -catenin and hDLG in the m ouse kidney by immunohistochemistry and immunoelectron microscopy. APC was highly expressed throughout the medullary region of the kidney, and localiz ed mainly in the basal cytoplasm of epithelial cells of the thin portion of Henle's loop. It was found that APC was colocalized with beta -catenin and hDLG by double-immunolabelling at both light- and electron-microscopic lev els. These results suggest that APC complexed with beta -catenin and hDLG m ay be involved in some signaling pathways regulating cellular functions of Henle's loop epithelial cells.