Figure 4.

Cells expressing fluorescent protein-tagged SR-BI exhibit wild-type levels of cell-associated HDL, selective uptake of HDL-COE and selective uptake efficiency. COS-7 cells transiently expressing wild-type SR-BI or the fluorescent protein-tagged fusion proteins were incubated at 37° C for 1.5 h with [¹²⁵I]DLT/[³H]COE-labeled HDL (10 μg of HDL protein/ml), after which cells were processed as previously described [35]. Cell-associated HDL-COE (Panel A), selective uptake of HDL-COE (Panel B), and selective uptake efficiency (Panel C) are shown. The efficiency of HDL-COE selective uptake was determined by subtracting the values from vector-transfected cells and normalizing the amount of HDL-COE selective uptake to the amount of cell-associated HDL particles. Values represent the mean ± SD of three replicates and are representative of three independent experiments.