FIG. 2.

Effect of calphostin C on induction of human LDL receptor promoter transcription in response to sterol depletion in HepG2 cells. HepG2 cells were transfected with a human LDL receptor-luciferase reporter construct A (0.6 μg/plate), as described earlier (33). After 24 h, the indicated concentration of calphostin C was added, and the cells were incubated for an additional 12 h in 10% LPDS medium before harvesting. Luciferase activity was determined and normalized to the protein content of each extract. The X-fold suppression in luciferase activity by treatment with calphostin C was calculated relative to the expression level of the untreated cells. Results are expressed as X-fold induction compared with untreated cells incubated in 10% LPDS plus sterols (given an arbitrary value of 1). The values obtained are the mean ± standard error of three separate experiments.