Fig. 3. Surface expression of nicastrin is disturbed in PS-deficient cells. Wild-type (WT) and PS1^–/–PS2^–/– MEFs (KO) were surface biotinylated. Biotinylated proteins were precipitated using streptavidin beads and immunoblotted with B59.2 (-nicastrin). Western blot analysis of total cell extracts is shown as a control. Note that only in WT MEFs is mature nicastrin labeled.