The Rac1 carboxy-terminal peptide efficiently blocks actin polymerization in murine cells. (a) Representative histograms of F-actin staining in T cells isolated from mice spleens that were exposed for 15 minutes to 200 μg/mL of Ctrl or Rac1 peptide followed by stromal cell-derived factor 1 (SDF-1) stimulation. (b) Fold increase in F-actin. Data are depicted as mean fold increase (MFI) of F-actin ± standard error of the mean (n = 3). *P < 0.05. Ctrl, control.