BINDING OF APC TO THE HUMAN HOMOLOG OF THE DROSOPHILA DISCS LARGE TUMOR-SUPPRESSOR PROTEIN

The adenomatous polyposis coli gene (APC) is mutated in familial adeno matous polyposis and in sporadic colorectal tumors, and its product bi nds to the adherens junction protein beta-catenin. Overexpression of A PC blocks cell cycle progression, The APC-beta-catenin complex was sho wn to bind to DLG, the human homolog of the Drosophila discs large tum or suppressor protein, This interaction required the carboxyl-terminal region of APC and the DLG homology repeat region of DLG. APC colocali zed with DLG at the lateral cytoplasm in rat colon epithelial cells an d at the synapse in cultured hippocampal neurons. These results sugges t that the APC-DLG complex may participate in regulation of both cell cycle progression and neuronal function.