Figure 3: Protein expression analysis. Western blot analysis was performed to detect wildtype (Wt) and mutant (M) DSP in the cell lysate and culture media. The cell lysate was normalized with GAPDH. The secreted amount of wildtype DSP was more than 7-fold greater compared to the P17L mutant DSP ( ). Cellular retention of the mutant DSP was detected in the cell lysate. Western blot of the cell lysate showed that intracellular retention of the P17L mutant DSP was much higher (12.1 folds) than the wildtype DSP ( ). The asterisk indicates a statistically significant difference ( ). Fold increase values are shown in the bar.