FIG. 6.

The AP-1 binding complex is constitutively expressed in A549 cells. (A) Nuclear extracts containing equal protein concentrations from A549 cells unstimulated or stimulated with PNR were analyzed for AP-1 binding activity by EMSA. The IL-8 AP-1 probe was incubated with nuclear extracts from unstimulated cells (lane 1) or PNR-stimulated A549 cells alone (lanes 2 to 5), without (lane 2) or with (lanes 3 to 5) a 25-fold excess of the indicated competitors. (B) Anti-Fra-2 and anti-JunD sera recognize AP-1 binding complex in nuclear extracts from A549 cells. Nuclear extracts from A549 cells that were unstimulated were analyzed for AP-1 binding by EMSA. The AP-1 probe was incubated with nuclear extracts from A549 cells. The nuclear extracts were preincubated for 45 min with the indicated antibodies (Ab) (lanes 2 to 8). Arrows indicate the specific complex.