Figure 5.

BACE1 and BACE2 β site and internal Aβ cleavage events are independent but can occur successively. (A) HEK293T cells were transfected with tagged C99 with vector alone or plasmids encoding BACE1 or BACE2 as indicated. Cell lysates were immunoprecipitated as in Fig. 1 and analyzed by SDS/PAGE. (B) HEK293T cells were transfected with wild-type tagged APP or tagged APP bearing a M671V mutation with vector alone, BACE1 or BACE2, and analyzed as in Fig. 1. (C) HEK293T were cells transfected with wild-type tagged APP alone, wild-type tagged BACE1 or BACE2, or BACE1 and BACE2 bearing an Arg → Lys mutation adjacent to their respective active sites, as indicated, and analyzed as in Fig. 1.