Figure 4. BACE1 interacts via its transmembrane domain with adenylate cyclase. A, N2a cells were cotransfected with adenylate cyclase (AC) and with wild-type or mutant BACE1 (D93A). Cell lysates were immunoprecipitated with mouse IgG (mIgG), rabbit IgG (rIgG), HA, or AC antibodies, and immunoblotted with HA or AC antibodies. B, Wild-type mice brain lysates were immunoprecipitated with rabbit rIgG, BACE1, or AC antibodies, and immunoblotted with BACE1 or AC antibodies. C, N2a cells were cotransfected with AC and wild-type BACE1 or BACE1 carrying the nicastrin transmembrane domain (BACE1-N). Cell lysates were immunoprecipitated with mIgG, rIgG, HA, or AC antibodies, and immunoblotted with HA or AC antibodies. D, E, N2a cells were transfected with a control, wild-type BACE1, or BACE1-N vector. Cell lysates were either immunoblotted for total and phosphorylated CREB (D) or were analyzed for PKA activity and cAMP levels (E). *p < 0.05; **p < 0.01. n = 3.