Figure 4.

Lack of RA-induced AP-1 activity antagonizes the ability of RA to inhibit ATF-2 phosphorylation. Wild-type B16 cells, an A-Fos expressing clone (#71), and a non-expressing A-Fos clone (#27) were treated with or without 10 μM RA for 24 hours and 48 hours. Cells were harvested and protein (40 μg) from each group was analyzed by western blotting using total or anti-phospho-ATF-2 antibody as described in Materials and Methods. The data shown are from a representative experiment, which was replicated three additional times with similar results.