MCP-1 stimulates with distinct time courses ERKs, JNK1, and p38 activities in MonoMac6 cells.

MonoMac6 cells incubated with 20 nM MCP-1 for the indicated times and proteins extracted from lysates, resolved by SDS-PAGE, and electrophoretically transferred to Immobilon-P membrane were detected by immunoblotting with antiactive ERKs (A) or p38 (C) antibodies. JNK1 activity (B) was performed, from cell lysates, by in vitro kinase assay using GST-ATF2 as substrate after immunoprecipitation (IP) with specific antibodies as described in “Materials and methods.” The amounts of ERKs, JNK1, or p38 in immunoprecipitates were assessed by Western blotting analysis with the appropriate antibodies (WB). The results are representative of 5 experiments.