Fig. 3.

Phosphorylated p42/44 MAPK stabilize PRB but not PRA in a ligand-dependent manner. A, Ishikawa PRB or PRA cells were pretreated with dimethylsulfoxide (DMSO) or U0126 (10 μm) during 30 min and then incubated without or with R5020 (10⁻⁸ m) or RU486 (10⁻⁸ m) during 1, 6, or 24 h. Whole cell extracts were immunoblotted using either phospho-specific (pS294-PRB, pS130-PRA) or anti-PR antibody (PRB, PRA). From the same immunoblot, either total p42/p44 or their phosphorylated species (P-p42/44) were analyzed using the corresponding antibodies. B, Ishikawa PRB cells were pretreated without or with U0126 (5, 10, or 20 μm) during 30 min and then treated without or with R5020 (10⁻⁸ m) or RU486 (10⁻⁸ m) during 6 h. Whole cell extracts were immunoblotted as in A.