FPR1-, FPRL1- and RAGE-mediated ERK1/2 phosphorylation in transfected HEK293 cells. For analysis of ERK1/2 phosphorylation, (A) untransfected (a) or ΔRAGE (b), RAGE (c); (B) FPRL1 (a) and ΔRAGE (b) or RAGE (c); (C) FPR1 (a) and ΔRAGE (b) or RAGE (c) expressing HEK293 cells were treated with 1 μM Aβ1–42, 1 μM fMLF, 2.4 μM S100B or 0.75 μM AGE-BSA (AGE) for 5 min at 37°C. Cells were lysed, equal amounts of protein (5 μg) were dissolved by SDS sample buffer, and levels of total ERK2 and phosphorylated ERK1/2 were determined by immunoblotting. The positions of molecular mass markers are indicated on the right (in kDa). The mean ± SD of the three independent experiments were evaluated by densitometric quantification normalised to ERK2 expression. Asterisks indicate a significant difference (*, p < 0.05; **, p < 0,001) compared to control (one-way ANOVA followed by the Bonferroni test).