(A) Extracts of HEK293 cells transfected with the cDNA encoding for APP and the myc-tag bearing vector, pRK5 (lane 1) or the cDNA for mycBRI2 (lane 2) were assayed by western blot for the expression of mycBRI2 (panel a), APP (panel b), sAPPα (panel c) and sAPPβ (panel d) using the antibodies 9E10, R1(57), 6E10 and 192wt respectively. (B) Extracts of HEK293 cells transfected with the cDNA encoding for APP and pRK5 vector (lane 1), the cDNA encoding for BACE1 (lane 2) or the cDNA encoding for mycBRI2 (lane 3) were analyzed by western blot for the expression of mycBRI2 (panel a), BACE1 (panel b) and APP (panel c), using the antibodies 9E10, 7523 and R1(57) respectively.