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. 2008 Aug 15;283(33):22529–22540. doi: 10.1074/jbc.M801925200

FIGURE 4.

FIGURE 4.

Effect of cholesterol on the cleavage efficiency of purified γ-secretase in detergent-free proteoliposomes. A, the effect of various concentrations of cholesterol on Aβ40 production in proteoliposomes of optimal phospholipid or sphingolipid compositions from Fig. 3 (PC(90)/PE(10), PC(90)/PS(10), PC(90)/PA(10), PC(90)/SM(10), PC(95)/CS(5), PC(90)/GS(10)) was examined. Error bars represent mean ± S.E. Data were statistically analyzed using the unpaired, two-tailed Student's t test with Bonferroni correction. Statistical significance of p < 0.05 (*), p < 0.01 (**), p < 0.001 (***), and p < 0.0001 (****) versus the PC/PE-detergent-containing control is indicated. B, the effect of various concentrations of cholesterol on Aβ42 production in proteoliposomes (PC(90)/PE(10) and PC(90)/GS(10)) was examined. Error bars represent mean ± S.E. Data were statistically analyzed using the unpaired, two-tailed Student's t test with Bonferroni correction. Statistical significance of p < 0.05 (*), p < 0.001 (**), and p < 0.0001 (***) versus the 0% cholesterol control is indicated. C, AICD levels of samples from the C100FLAG assay in A and B were analyzed by Western blot. AICD fragments were detected with the M2 FLAG antibody. D, the effect of various concentrations of cholesterol on NICD production in proteoliposomes of PC/PE in detergent, PC(100), PC(90)/PE(10)/0.0063% cholesterol, and PC(90)/GS(10)/0.013% cholesterol was examined. NICD levels were analyzed by Western blot and the NICD was detected with the 1744 antibody (Cell Signaling Technologies).