Fig. 5. The IB1/JIP-1 content is critical for mediating JNK activity. Western blot analysis and a solid phase kinase assay using GST-Jun as the substrate revealed a decrease in IB1/JIP-1 expression associated and an increase of JNK activity (P-GST-Jun) in empty bladders of mice heterozygous (KO+/–) compared with wild-type mice (WT). The JNK content was evaluated by western blotting. Equal loading of substrate was confirmed by Coomassie blue staining of the gel (GST-jun). Quantitative assessments of IB1/JIP-1 and c-Jun phosphorylation in urothelium of mice, which had had the IB1/JIP-1 gene selectively disrupted, demonstrated an inverse relationship between the levels of IB1/JIP-1 content and the JNK activity compared to basal level in wild-type mice.
