BETA-APP GAMMA-SECRETASE AND SREBP SITE-2 PROTEASE ARE 2 DIFFERENT ENZYMES

THE cleavage process of sterol regulatory element binding proteins (SR EBPs) shares several characteristics with that of beta-amyloid precurs or protein (beta APP). We studied the secretion of amyloid beta protei n (A beta) from mutant M19 Chinese hamster ovary (CHO) cells that are defective in the site 2 cleavage of SREBPs. The levels as well as the C-terminal properties of A beta secreted from M19 cells were similar t o those from wild-type CHO cells, demonstrating that gamma-cleavage of beta APP occurs normally in M19 cells. The present data indicated tha t gamma-secretase of beta APP and SREBP site 2 protease are distinct e nzymes. (C) 1998 Rapid Science Ltd.