Fig. 2.

PS1 is a resident protein of the endoplasmic reticulum in SH-SY5Y neuroblastoma cells. A, SH-SY5Y neuroblastoma cells show a reticular pattern of PS1 immunoreactivity (Ab R28) characteristic of the ER. B, C, Localization of PS1 in the endoplasmic reticulum is confirmed by double label immunofluorescence with the PS1 C-terminal loop antibody R28 (B) and anti-BiP (C). Confocal microscopy demonstrates the overlap of both antigens in an image section taken 5 μm above the substrate plane. PS1 does not co-localize with the Golgi marker JE4 in SH-SY5Y cells (data not shown). Scale bars, 10 μm.