Fig. 1.

Expressing Myo10 leads to a massive increase in dorsal filopodia. (A and B) The dorsal surfaces of control COS-7 cells transfected with GFP alone are smooth and lack dorsal filopodia. (C and D) Cells transfected with GFP-Myo10, however, exhibit a massive increase in dorsal filopodia. A few substrate-attached filopodia also are visible. (E–G) Fluorescence microscopy demonstrates that the dorsal structures induced by GFP-Myo10 contain known markers of filopodia, including F-actin (E) and fascin (F), which label filopodial shafts, and VASP (G), which is present in filopodial tips. Note that GFP-Myo10 is visible at the tips of the numerous dorsal filopodia induced in these cells and, in some cases, forms streaks extending into the filopodial shaft. Although the SEM images in this figure were obtained from an experiment where FACS was used to isolate transfected cells before SEM, similar results were obtained when fluorescence-correlative SEM was used to image transfected cells (Figs. 6 A–C and 7A, which are published as supporting information on the PNAS web site).