Fig. 5.

Distinct coactivator usage in the ERα, AP-1, and ERα/AP-1 pathways. Effects of polypeptide and chemical inhibitors on ERα-, AP-1-, and ERα/AP-1-dependent transcription. Templates containing two AP-1 sites or two EREs upstream of the adenovirus E4 promoter were assembled into chromatin and transcribed in the presence or absence of c-Fos/c-Jun heterodimers, ERα, and ligands, as indicated. Each bar or point represents the mean ± SEM for three or more determinations. (A) Schematic representation of protein–protein interactions blocked by the GST-fused polypeptide inhibitors and enzymatic activities blocked by the chemical inhibitors. (B) Distinct protein–protein interactions are differentially required by the ERα, AP-1, and ERα/AP-1 pathways. Shown is a summary of multiple experiments performed in the presence of the GST-fused polypeptide inhibitors, as indicated. (C) p300/CBP and PCAF acetyltransferase activities are differentially required by the ERα, AP-1, and ERα/AP-1 pathways. Shown is a summary of multiple experiments performed in the presence of the chemical inhibitors, as indicated.