CXCR3 agonists stimulate activation of p44/p42 MAPK in CXCR3-transfected COS-7 cells. (A) COS-7 cells transiently transfected with CXCR3 (2.0 μg plasmid/106 cells) were stimulated for different periods of time with 30 nM CXCL11. Phosphorylation of p44/p42 MAPK was determined by Western blot analysis using specific anti–phosho-p44/p42 (P-p44/p42) antibodies. Phosphorylation was quantified by chemiluminescence and corrected for total MAPK (T-p44/p42) expression on stripped blots. (B) CXCR3-expressing COS-7 cells were incubated with CXCL10 and 11 (30 nM) for 15 minutes before lysis of the cells. (C-E) Involvement of Raf-MEK–(C), Gi- (D), and PI3K–signaling pathway (E) in CXCL11-induced (15 minutes, 30 nM) p44/p42 MAPK phosphorylation. CXCR3-expressing COS-7 cells were grown in serum-free medium in the presence of U0126 (10 μM, 30 minutes; C), PTX (100 ng/mL, 48 h; D), or wortmannin (wort) (100 nM, 30 minutes; E) before lysis and Western blot analysis. A representative experiment of at least 2 independent experiments is shown.
