Figure 4.
Relative localization of actin and T-plastin to filopodia. (a) Live cell time-lapse of B16F1 mouse melanoma cell co-transfected with GFP-T-plastin and mCherry-actin, showing just the leading edge. Turquoise arrows track a filopodium from initiation of bright dots or short rods, growth of fishtail-shaped filament bundles, and elongatation,. Red arrows indicate lateral filopodia. T-plastin and actin were found throughout stationary filopodia at all stages, but T-plastin was missing from the tips of lateral filopodia. The entire movie can be found in Supplementary Data, Movie 2. (b, c) Quantitative analysis of fluorescence intensity of GFP-T-plastin (green) and mCherry-actin (red) at 1′ for stationary filopodia (b) and 7.5′ for lateral filopodia (c). The x axis represents the distance from the proximal to distal end of the filopodia in pixels. Scale Bar 10 μm.