Rac1 activation is involved in transcriptional regulation and cytokine secretion. (A) Dominant negative RacN17 and Rac inhibitor PAKN block vGPCR stimulation of a κB-responsive element in COS-7 cells. (B) Dominant negative RacN17 and Rac inhibitor PAKN also block vGPCR stimulation of AP-1 and NF-AT but not CREB-responsive element in COS-7 cells. Data represent the mean ± SEM of triplicate samples from a typical experiment and are expressed as fold induction with respect to control. (C) Dominant negative RacN17 and Rac inhibitor PAKN block secretion of cytokines in conditioned media from transiently transfected 293T cells.