Fig. 2. Binding of mature nicastrin to PS. (A) PS1 NTF, PS1 CTF and nicastrin were immunoprecipitated from total cell extracts of wild-type MEFs and blotted with B59.2 (-nicastrin). As a control, pre-immune serum (PI) was used for immunoprecipitation. Both PS1 NTFs and CTFs interact preferentially with the mature form of nicastrin (NCT_m). (B) Wild-type MEFs were treated for 24 or 48 hours with MNJ (0.2 mg/ml). This treatment inhibits mannosidase I and therefore the full maturation of the glycosylation of nicastrin. Only endoH-sensitive nicastrin is found. (C) Wild-type MEFs were treated for 48 hours with MNJ (0.2 mg/ml). PS1 NTF and NCT were immunoprecipitated from total cell extracts and blotted with B59.2 (-NCT). As a control, PI was used for immunoprecipitation. Note that deglycosylation of nicastrin does not inhibit interaction with PS1.