FIG 5.

Endogenous and overexpressed JNKs and p38s coimmunoprecipitate with Imp3, -7, and -9. (A) A CoIP screen to detect the interactions of importins with JNK1/2 and p38α/β in MCF7 cells. MCF7 cells were grown to 70% confluence, serum starved, and then were stimulated with either Anis (0.5 μg/ml, 15 min) or TPA (250 nM, 15 min) or left untreated (NT). Cells extracts were then subjected to CoIP with the indicated Abs. Imps, IPed MAPKs, and input proteins were detected by Western blotting with the indicated Abs. (B) Interaction of overexpressed MAPKs with Imp3/7/9 in HeLa cells. HeLa cells were transfected with either JNK2-GFP, p38β-GFP, or GFP alone. Cells were serum starved, then treated as described above, and subjected to CoIP with anti-GFP Abs. The interacting Imps and the loading extracts were subjected to Western blot analysis with the indicated Abs. Arrows indicate the interacting Imps. (C) Loading control for overexpressed JNK2 and p38β. Extracts of HeLa cells overexpressing either JNK2-GFP or p38β-GFP or GFP alone were subjected to Western blot analysis with anti-GFP Abs.