Figure 4. Effect of fisetin on UVB-induced phosphorylation of the MAPK pathway. SRA01/04 cells were exposed to UVB (30 mJ/ cm²) with or without pretreatment with fisetin (25 μg/ml) for 1 h. Cells were harvested at different time points (30, 60, and 120 min) after UVB exposure, and cell lysates were prepared. The phosphorylated and total protein levels of ERK1/2, JNK, and p38 were detected with specific antibodies using western blot analysis as described in Methods. A representative blot from three independent experiments with identical observations is shown.