FIGURE 5.

Protegrin-1 activates MAPK signaling pathway. Cultured SGCs were co-transfected with a plasmid, pFR-Luc- a luciferase reporter plasmid, containing a synthetic promoter with five tandem repeats of the GAL4 binding site, and pFA2-CREB, pFA2-Elk1, pFA2-C-Jun, or pFA2-CHOP that expresses the activation domain of each transcription factor fused to the GAL4 DNA binding domain. Eighteen hours after transfection the cells were serum starved and treated with or without Protegrin-1 for 16 h. Luciferase activity, which is indicative of transcription factor dependent activation, is expressed as relative light units compared to control. Data represent the mean ± SEM of three independent experiments *P < 0.05 compared to control.