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Figure S2. RhoG is recruited around αICAM1 beads but not around αMHC beads. (A) αICAM1 beads but not αMHC class I beads induced F-actin-rich protrusions. Quantification of F-actin-rich membrane projections by z-stack analysis showed that αICAM1-coated beads induced significantly more protrusions than αMHC class I beads. The experiment was performed three times. Data are means ± SEM (error bars). (B) Beads coated with ICAM1 antibodies recruited GFP-RhoG-Q61L. Confocal imaging was used to visualize the baso-lateral (+0 µm) and the apical surface (+2 µm) of transfected HUVECs incubated with either αICAM1 beads (a-h) or αMHC class I beads (i-p). GFP-RhoG-Q61L was recruited (visualized in green) to αICAM1 beads (arrowheads; e and g) but not to αMHC class I beads (arrowheads; m and o). Images b, f, j, and n represent F-actin, and images c, g, k, and o are merged images of GFP-RhoG-Q61L and F-actin. Images d, h, l, and p show the beads (arrowheads; h and p) in white. (C) Beads coated with ICAM1 antibodies recruited GFP-actin. Confocal imaging was used to visualize the apical surface (a and c) and the baso-lateral plane (b and d). GFP-actin is transiently expressed in endothelial cells (a and b) and is recruited to adhesion sites, triggered by the αICAM1 beads in red (arrowheads; a and b). Bars, 10 µm.