Cells were grown to confluency and pretreated with DMSO, 500 nm CEP-1347, or 10 μm SB203580 for 1 hr before treatment with UV irradiation (5 min in Stratolinker, followed by 1 hr incubation at 37°C), sorbitol (500 mm sorbitol for 1 hr), or tunicamycin (50 μg/ml for 5 hr). Lysates were collected, normalized for protein, and immunoprecipitated with the JNK1 or MAPKAP2 antibody, as described in Materials and Methods. Experiments were performed at least two times, and results from a representative experiment are shown. Results are expressed as the fold increase relative to untreated control.