Figure 1.
EGF-induced phosphorylation of PR Ser294. A. Regulation of PR Ser294 by EGF. T47D cells stably expressing wt PR-B were treated with vehicle control (C), EGF (30ng/ml) (E), or R5020 (10nM) (R) for 5–60 min and PRs were visualized in cell lysates by Western blotting using phospho-Ser294- or total PR-specific antibodies. Total and active p42/p44 MAPKs were similarly measured in the same lysates using phospho- and total MAPK-specific antibodies. A darker exposure indicates the progestin-induced activation of MAPKs at 5 min. B. T47D cells expressing wt or S294A PR-B were treated with either EGF or R5020 for 15 or 60min, cells were harvested and Western blots performed using phospho-294 PR or PR specific antibodies.