Fig. 5. Endogenous nicastrin and PS1. PS-deficient MEFs stably expressing human PS1 were grown on coverslips at 37°C, then fixed and triple labeled using antibodies against calnexin, human PS1 and nicastrin. Alexa-488, -647 and -555 conjugated secondary antibodies were used to detect the respective primary antibodies. Individual stainings and the merged picture of the whole cell (top panels), as well as detailed areas (bottom panels and insets), are shown. Both human PS1 and endogenous nicastrin only partially colocalize with the ER marker calnexin. Whereas human PS1 and nicastrin can be clearly seen together in discrete structures, in many cases no co-localization is observed (pink versus blue color in merged pictures and insets). Bar, 10 µm.