Figure 4.

Effect of various LXR agonists on SREBP processing in McA-RH7777 cells in the absence or presence of compactin. On day 0, cells were set up and treated identically to those described in Fig. 3. On day 3, after a 16-h incubation at 37°C, the cells received ALLN at 25 μg/ml and were harvested 1 h later. Membrane and nuclear extract fractions were prepared, and aliquots (80 μg protein) were subjected to SDS/PAGE. Immunoblot analysis was carried out with 5 μg/ml rabbit anti-rat SREBP-1 (A) or anti-rat SREBP-2 (B). Filters were exposed for 1–10 s at room temperature. P, SREBP precursor forms; N, nuclear cleaved forms of SREBP-1c (A) and SREBP-2 (B); 25-HC, 25-hydroxycholesterol; 22(R)-HC, 22(R)-hydroxycholesterol.