Figure 4. Effects of Syk inhibitor on the KLH-induced Erk phosphorylation. (A) THP-1 cells were pre-treated or non-treated 10 µM Syk inhibitor (Bay 61-3606) at 37° C for two hours. THP-1 cells were then stimulated with 500 µg/ml KLH at 37° C for various periods of time. At the end of the incubation period, cells were lysed in a RIPA buffer with inhibitors for 30 min on ice. After centrifugation (20,000 g, 10 min, 4° C), supernatant proteins were evaluated through the Western blot with antibodies, anti-Erk1/2 antibody (EPR 17526) and anti-phospho-Erk1/2 (Tyr 202/204). (B) Phosphorylation signals were normalized to total Erk1/2 signal intensities in the panel (A). The graphs represent mean ± SD of values obtained from three independent experiments.

*Significantly different from the initial value in the absence of the inhibitor, *P < 0.05 (one-way ANOVA and Dunnett's test). †There is a significant difference between values with and without the inhibitor at 2 min, †P < 0.001 (one-way ANOVA and Student's t-test).