Figure 4

Subcellular localization of total APP was not affected by OSBP1 overexpression. A, H4 cells were transfected with GFP-tagged APP with or without OSBP1 and then treated with 1 μM 25OH or vehicle for 24 h. Cells were examined under 40× magnification. B, H4 cells overexpressing APP were transfected with vector only (left panel) or OSBP1 (right panel); 48 h later cells were homogenized and separated by sucrose gradient fractionation. Gradient fractions were analyzed by Western blotting using antibodies to the APP C-terminus and to OSBP1. C, Fractions were also blotted with an antibody to the ER marker GRP78.