Figure 2.
Effects of cellular cholesterol status and LY294002 treatment on processing of a PLAP-BP2 fusion protein. (A) 13A/PS cells were incubated for 16 h in medium B in the absence or presence of compactin (CPN, 5 μM) and were coincubated in the absence or presence of mevalonate (Mev, 5 mM). (B) 13A/PS cells were incubated for 16 h in medium B in the absence or presence of compactin (CPN, 5 μM) and/or an inhibitor of squalene epoxidase (SEi, GR144000X, 5 μM). Cells were coincubated in the absence or presence of cholesterol complexed to methyl β-cyclodextrin (chol, 20 μg/ml). (C) 13A/PS cells were incubated for 16 h in medium B in the absence or presence of compactin (CPN, 5 μM) and/or an inhibitor of squalene epoxidase (SEi, GR144000X, 5 μM). Cells were coincubated in the absence or presence of LY294002 (LY, 20 μM). (D) 13A/PS cells were incubated for 16 h in medium B containing varying concentrations of hydroxypropyl-β-cyclodextrin (HPβCD, wt/vol) to deplete cellular cholesterol levels in the absence or presence of LY294002 (LY, 20 μM). For all experiments, medium was assayed for PLAP secretion by luminometry and cell protein determined. Values are means + SEM (n = 3 replicate cultures).