Fig 1: PS2 but not PS1 knockdown reduced Aß34 levels from BACE1 overexpressing cells. Expression of PS1 and PS2 and Aß levels were analyzed by Western blot, ELISA and MSD assays, respectively. Representative Western blots from 7 independent experiments for combinatorial PS1 and PS2 knockdown in SH-SY5Y BACE1 overexpressing cells (a). Uncropped blots are included in a Supplementary Information file. Quantification of relative amounts of PS1 (b) and of PS2 (c), and absolute amounts of Aß34 (d), Aß40 (e), and Aß42 (f) in cell media by ELISA and Aß34 (g), Aß40 (h), and Aß42 (i) in cell lysates by MSD. Bars and error bars indicate mean ± s.e.m. Dunnett’s post-hoc tests were performed for pairwise comparisons; selected comparisons are highlighted ***p < 0.001, **p < 0.01, *p < 0.05. (b) PS1, 1-WAY ANOVA, F(5,36) = 20.06, p < 0.0001, (c) PS2, 1-WAY ANOVA, F(5,36) = 26.37, p < 0.0001, (d) Aß34, 1-WAY ANOVA, F(5,35) = 4.268, p < 0.005, (e) Aß40, 1-WAY ANOVA, F(5,36) = 0.6677, p = 0.6504, (f) Aß42, 1-WAY ANOVA, F(5,36) = 2.502, p = 0.0523, (g) Aß34, 1-WAY ANOVA, F(5,23) = 0.8428, p = 0.5334, (h) Aß40, 1-WAY ANOVA, F(5,24) = 2.276, p = 0.0791, (i) Aß42, 1-WAY ANOVA, F(5,21) = 1.869, p = 0.1429.