Figure 3.

Induction of association of prohibitin with Brg1/Brm by estrogen antagonists. (A) MCF7 cells were treated with 4HT or ICI182780 for the indicated time intervals. Cell extracts were immunoprecipitated (IP) by anti-cMyc (control), -Brg1, or -Brm antibodies, followed by immunoblot analysis (IB), using anti-prohibitin or -p38 (as control) antibodies. The reciprocal IP–immunoblot was performed using anti-cMyc or -prohibitin antibodies for the IP, and anti-Brg1, -Brm, or -p38 antibodies for the immunoblot. Increases in associations between prohibitin and Brg1/Brm were evident as early as 20 min after treatment. Immunoblotting with the anti-p38 antibody failed to detect any protein in the immunoprecipitates, indicating the specificity of the prohibitin–Brm/Brg1 associations. (B) The same cell extracts used in panel A were analyzed by immunoblot using anti-Brg1, -Brm, or -prohibitin antibodies. The results shown are representative of experiments that were repeated four times, which yielded identical results.