FIGURE 2.

S100B activates ERK1/2, p38 MAPK, JNK, Src (Ser-416), Akt, and NF-κB in microglia, and S100B-induced migration of microglia is differentially regulated by signaling molecules downstream of RAGE. A, BV-2 microglia were treated with 1 μm S100B for 30 min. Where required BV-2 microglia were pretreated with 20 μm PP2 (inhibitor of Src), 10 μm LY294002 (inhibitor of PI3K), or 50 μm NSC23766 (inhibitor of Rac1) before exposure to 1 μm S100B. The cells were harvested and processed for Western blotting to detect phosphorylated Src (Ser-416), ERK1/2, Akt, p38 MAPK, JNK, and NF-κB (p65), as indicated. Shown is one representative experiment of three. B, conditions were as described in the legend to Fig. 1D except that BV-2 microglia were pretreated for 30 min with the indicated inhibitors and then transferred to the upper chambers for migration assay. The results are expressed as the means ± S.D. (n = 3). C, S100B stimulates microglia migration via RAGE-dependent activation of Ras, Rac1, Cdc42, and RhoA. Conditions were as described in the legend to Fig. 1B except that BV-2 microglia were transiently transfected with dominant negative mutant (DN) of Ras, Rac1, Cdc42 or RhoA, IκBα-SR, or empty vector and then transferred to the upper chambers for migration assay. The results are expressed as the means ± S.D. (n = 3). *, significantly different from control (first column from left in A and B).