Figure 1.

Locations of the PS1 cysteine mutations used in this study. Schematic depiction of human PS1 is shown. Endogenous Cys residues that were replaced with serine in PS1/Cys(−) are indicated as black circles. Amino acid residues substituted to Cys in the present and previous studies are shown by circles with a single-letter character representing the original amino acids. Residues analyzed in this study are indicated by orange circles. Residues in which Cys substitution caused a loss of γ-secretase activity are indicated as gray circles. Catalytic aspartates are shown by yellow stars.