Figure 5.

Extension formation does not require Rac Activity. NIH 3T3 cells were cotransfected with MSE55 and dominant-negative Rac. N17Rac transfected cells were detected with rabbit polyclonal anti-Myc antibody and goat anti-rabbit IgG-FITC (green). N17Rac-expressing cells produce multiple thin filopodia (a and b). N17Rac, MSE55, and F-actin were detected by using triple immunofluorescence. Cells coexpressing N17Rac and MSE55 form multiple thin filopodia and additionally form a single, long cellular extension (c and d). MSE55 was detected with M2 anti-FLAG mouse mAb and goat anti-mouse IgG-Alexa 350 (data not shown). Expression of dominant-negative N17Rac (green) was detected with a rabbit polyclonal antibody against c-Myc and with anti-rabbit IgG-FITC. F-actin was detected with Texas Red-phalloidin (red). (Bar = 20 μm.)