Figure 3.

Effects of the mutant PS1 derivatives on endoproteolysis of Notch. (A) Mutant cell lines were transfected with the NotchΔE cDNA (19). NICD formation was analyzed in pulse–chase experiments as described (6). Note that PS1 L286E and PS1 L286R inhibit NICD formation. All other PS1 derivatives, including the naturally occurring PS1 L286V mutation, allow normal NICD formation. NICV1744 represents recombinant NICD, which was used as a marker to monitor NICD production (6, 19). (B) Quantification of the experiments shown in A by phosphorimaging. Bars represent the mean ± SE of three independent experiments.