RapGEF2 siRNA-mediated gene ablation reduces adhesion responses. (A) Effects of Rap1A and RapGEF2 knockdown (via synthetic siRNA transfections) on the CD3/CD28-induced LFA-1 activation of primary CD3⁺ T cells. Results shown are the mean plus or minus SE. (B) The modulation of LFA-1 avidity by Rap1A knockdown was correlated with the siRNA-mediated down-regulation of Rap1A and RapGEF2 proteins, respectively. Vertical lines have been inserted to indicate a repositioned gel lane. (C) As controls, CD3 ligation-induced MAPK activation and (D) LFA-1 surface expression on siRNA-transfected CD3⁺ T cells remained intact. Experiments were repeated at least 3 times, with similar results.