Figure 7.

Conformational changes in TMD4 associated with altered Aβ₄₂ ratio. A, Sandwich ELISA of secreted Aβ from APPNL-stable DKO cells expressing I213C/L383C mt PS1/Cys(−) after preincubation with 30 μm GSM-1 (n = 3, means ± SEs; **p < 0.01 by Student's t test). B, Cross-linking experiments of I213C/L383C mt PS1 with a catalyst (Cu-Phe) after preincubation with GSM-1 (30 μm). Immunoblot analysis was performed using an anti-M5 antibody. PS1 CTFs and cross-linked products (NTF–CTF heterodimers) are indicated by the white arrowhead and black arrows, respectively. Densitometric analysis of the results are shown in C (n = 3, means ± SEs; *p < 0.05 by Student's t test). D, Sandwich ELISA of secreted Aβ from APPNL-stable DKO cells expressing I213C/L383C mt PS1 with an FAD-linked mutation (I213C/L383C/P117L or I213C/L383C/M139V; n = 3, means ± SEs; *p < 0.05, **p < 0.01 by Student's t test). E, Cross-linking experiments of I213C/L383C mt PS1 with or without FAD-linked mutations and a catalyst (Cu-Phe). Immunoblot analysis was performed using an anti-G1Nr5 antibody. PS1 NTFs and cross-linked products are indicated by a black arrowhead and black arrows, respectively. Densitometric analysis of the results are shown in F (n = 3, means ± SEs; *p < 0.05 by Student's t test). G, Sandwich ELISA of secreted Aβ from APPNL-stable DKO cells expressing I213C/I387C or G206L/I213C/I387C mt PS1 (n = 3, means ± SEs; *p < 0.05 by Student's t test). H, Cross-linking experiments of I213C/L383C or G206L/I213C/I387C mt PS1 with MTS cross-linkers. Immunoblot analysis was performed using an anti-G1Nr5 antibody. PS1 NTFs, and cross-linked products are indicated by black arrowheads and black arrows, respectively.