Impact of overexpression of wild-type (WT) or dominant-negative (DN) Rac1 on endothelial barrier function and local lamellipodia dynamics.

<p><i>A</i>. <i>P</i>_s^albumin of HUVEC monolayers expressing GFP, GFP-Rac1-WT, or GFP-Rac1-DN (N = 4 for each group) ~16 h after transfection. Panels <i>B</i>, <i>C</i>, and <i>D</i> show expression of each construct, also shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117970#pone.0117970.s022" target="_blank">S11 Movie</a>. These images were obtained ~16 h after transfection. The small arrows indicate lamellipodia, while the arrows with wider arrowheads show filopodia that were prevalent in cells expressing GFP-Rac1-DN. Lamellipodia parameters were also evaluated over a 10-min period: <i>E</i>. Protrusion frequency, <i>F</i>. Protrusion distance, <i>G</i>. Withdrawal Time, <i>H</i>. %Protrusions with a withdrawal time > 5 min. *P<0.05 between the indicated groups. N = 9 cells studied in each group.