FIGURE 5.

IL1R2 forms a complex with c-Fos and activates the IL-6 and VEGF-A promoters. A, total lysates of HCT116-Vec and HCT116-IL1R2 cells (left column), as well as HT29-shV and HT29-shIL1R2 cells (right column), were immunoprecipitated using 5 μg of anti-c-Fos (upper panel) or anti-IL1R2 antibodies (lower panel), and Western blotting was performed using the indicated antibodies. B, the extracts of HCT116 cells that had expressed Myc-tagged full-length IL1R2 or its truncated mutant were subjected to immunoprecipitation with 5 μg of anti-Myc tag antibody followed by Western blot with anti-c-Fos or anti-Myc tag antibody. C, the protein lysates of HCT116 cells expressing Myc-tagged full-length IL1R2 or its truncated mutant were harvested and subjected for Western blotting using the indicated antibodies. D, ChIP was performed as follows. Crude lysates from HT29-shV, HT29-shIL1R2, HCT116-Vec, and HCT116-IL1R2 cells were immunoprecipitated using 5 μg of anti-c-Fos, anti-IL1R2, or rabbit IgG and then captured with protein A-agarose beads. The precipitated DNA samples were amplified by PCR to detect a fragment in the IL-6 (upper panel) or VEGF-A (lower panel) promoter containing the AP-1 binding site. The results shown are representative of three independent experiments with similar results. IB, immunoblot; IP, immunoprecipitation.