Time-lapse microscopy images of localization of WAVE1 tagged with EGFP in the NG108 growth cone. The left panel shows fluorescence images of WAVE1-EGFP and the right panel shows differential interference contrast (DIC) images corresponding to the left images. WAVE1-EGFP localized along the leading edge and concentrated in the extending region. Neither was found at the filopodial tips. Images were recorded every 22 seconds (see also Fig. 5A,B).

Time-lapse microscopy images of localization of WAVE2 tagged with EGFP in the NG108 growth cone. The left panel shows fluorescence images of WAVE2-EGFP and the right panel shows differential interference contrast (DIC) images corresponding to the left images. WAVE2-EGFP condensed as dot-like spots at the site where microspikes encounter the leading edge. They correspond to the tips of filopodia and project extracellularly with elongation. WAVE2-EGFP remained at the tips of extending filopodia and sometimes moved with time laterally along the leading edge with the lateral motion of actin bundles through the lamellipodium. By contrast, WAVE2-EGFP spots disappeared at the tips of retracting filopodia. Images were recorded every 22 seconds (see also Fig. 5C,D).

Time-lapse microscopy images of localization of WAVE3 tagged with EGFP in the NG108 growth cone. The left panel shows differential interference contrast (DIC) images and the right panel shows fluorescence images of WAVE3-EGFP corresponding to the left images. WAVE3-EGFP localized at the tips of extending filopodia and remained there during elongation, and also distributed along the leading edge of extending lamellipodia. Images were recorded every 22 seconds (see also Fig. 5E,F).