ZAP-70 is involved in CXCL12 activation of the ERK pathway.

(A) Jurkat cells were left untreated (control) or were preincubated with piceatannol (25 μM), U0126 (50 μM), or pertussis toxin (PT, 10 ng/mL) for 3 hours at 37°C. Cells were then activated by CXCL12 (50 ng/mL) for different periods of time. Phosphorylated ERK was revealed by immunoblot analysis with an anti–phospho-ERK antibody. The amount of ERK was controlled by immunoblot analysis with anti-ERK polyclonal antibody. (B) Jurkat, ZAP-70⁺-P116, and P116 cells were activated by CXCL12 (50 ng/mL) for 1 minute, and ERK phosphorylation was analyzed as in panel A. (C) Jurkat cells were left untreated (control) or were preincubated with U0126 (50 μM), SB202190 (40 μM), or piceatannol (25 μM) for 3 hours at 37°C and then were added to the upper well of a Transwell chamber. Medium alone or medium plus CXCL12 (100 ng/mL) was added to the lower chamber. Transendothelial migration and quantification of cell migration was performed as in Figure 1A.