FAD-linked PS1 mutations alter APP CT positioning . FLIM analysis of the myrGFP lifetime in PS1/2 dKO cells stably (A) or transiently (B) expressing wild-type or mutant PS1. The cells were co-transfected with myrGFP and wild-type APP-RFP as a FRET pair, and the proximity between myrGFP (membrane) and RFP (APP-CT) was monitored. All FAD-linked PS1 mutations significantly shortened myrGFP lifetime compared to that in the wild-type PS1 expressing cells. The expression of E318G PS1 caused no significant difference in the donor lifetime. Three independent experiments were performed. Data from a representative experiment is shown (n: number of cells; mean ± SD;*p < 0.05; **p < 0.01; ANOVA).