Fig. 6. Imps 3, 7 and 9 are required for JNK and p38 translocation and phosphorylation of downstream nuclear transcription factors. (A) siRNA of Imp3, 7, 9 but not of Imp5 inhibits the stimulated-nuclear translocation of JNKs and p38s. HeLa cells were grown on cover slides to 30% confluence. Si RNAs of the indicated Imps and siRNA control (scambled siRNA of Imp3; si Scr) were transfected to the cells. 48 hr after transfection, cells were serum starved, stimulated or left untreated (NT), fixed and stained using the indicated anti MAPK Abs. The bar in the upper right panel is of 20 µM. (B) Quantification of JNKs/p38s nuclear localization prior and upon stimulation. The nuclear localization of JNKs and p38s was calculated as the number of cells presenting nuclear staining (nuclear staining was considered for all cells in which > 30% of the stain was inside the nucleus) per the total cell number. The data shown represents mean ± S.E of three different experiments (* - p<0.0003, ** - p<0.00001). (C) SiRNA of Imp3, 7, 9 inhibits the induction of transcription regulated by JNKs/p38s. HeLa cells were transfected with the indicated siRNAs or control of scrambled siRNA of Imp3 (Scr), serum starved and then either stimulated with anisomycin (Anis 0.5 µg/ml) for the indicated times, or left untreated (NT). Cell extracts were subjected to a Western blot analysis with the indicated Abs. The experiments were reproduced twice.