MCP-1–induced kinase activities are abrogated by their respective specific inhibitors.

MonoMac6 cells, untreated or preincubated 2 hours either with 10 μM PP2, 5 μg/mL piceatannol, 40 μM PD98059, 40 μM SB202190, or 40 μM SB202580, were exposed following different time courses to 20 nM MCP-1. The activity and the amount of Src (A), Syk (B), ERKs (C), and SAPK1/JNK1 (D) kinases were evaluated as described in Figure 1 and in “Materials and methods.” (E) CREB phosphorylation was analyzed by Western blot using antibodies (New England Biolabs, Beverly MA) specific for phosphorylated Ser133 of CREB (P-CREB) or phosphorylated Ser63 of ATF1 (P-ATF1). CREB expression was analyzed by Western blot using anti-CREB antibodies (Santa Cruz Biotechnology). Results are representative of 2 experiments.