Figure 1

siRNA-mediated depletion of p23 in N2a cells affects APP metabolism. A and B, Lysates of N2a cells transfected with control non-specific (NS) or p23 siRNA were probed with antibodies specific for four p24 family members, three components of the γ-secretase, β-COP, and calnexin. Knockdown of p23 expression causes co-ordinate diminution the steady-state levels of p24, p25 and tp24. Also note the increased accumulation of immature and mature nicastrin in p23-depleted cells. C, Lysates of siRNA transfected N2aSwe cells were probed with antibodies specific for APP, calnexin, p115, and Grasp55. D, Secreted Aβ₄₀ and Aβ₄₂ in the media conditioned by N2aSwe were quantified using two-site ELISAs. The data represent mean ± SEM of three sets of transfections. * p < 0.05; ** p < 0.01. E, N2aSwe cells were labeled with [³⁵S]met/cys for 15 min and APP FL were immunoprecipitated from cell lysates using Ab 369 (top); sAPP were immunoprecipitated using mAb P2-1 from media of cells labeled for 3 h (bottom).