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. 2011 Aug 4;25(10):1710–1724. doi: 10.1210/me.2011-1042

Fig. 4.

Fig. 4.

P42/44 MAPK control proteasome-dependent turnover of ligand-bound PRB. A, MDA-MB-231 cells (MDA) stably expressing PRB were treated with vehicle or RU486 (10−8 m) during 24 h, and whole cell extracts were immunoblotted as in Fig. 3. B, MDA-MB-231-PRB or Ishikawa-PRB cells were pretreated with dimethylsulfoxide (DMSO) or U0126 (10 μm) during 30 min and then incubated without or with progesterone (P4) (10−8 m) during 24 h. Whole cell extracts were immunoblotted as in A. C, MDA-MB-231 PRB cells were pretreated with DMSO or U0126 (10 μm) during 30 min and then incubated with vehicle or R5020 (10−8 m) or RU486 (10−8 m) during 24 h. Immunofluorescence analysis was performed as described in Materials and Methods using anti-PR antibody, and images were obtained for an identical time exposure. D, Ishikawa PRB cells were pretreated without or with MG132 (5 μm) and/or U0126 (10 μm) during 30 min and then treated without or with R5020 (10−8 m) or RU486 (10−8 m) during 6 h. Immunoblot analysis was performed as in A. Cell lysates from the same RU486-treated cells were also immunoblotted for either GR detection using anti-GR antibody or tubulin as loading control (inset).