Barbed-end cappers inhibit disassembly of dynamic actin at the ruffling cell edge. (A–C) Time-lapse images of ruffling edges in BSC-1 cells expressing mRFP-PAGFP-actin taken before CytoD addition (A), after LatB addition (B), or after CytoD addition (C). The red channel shows bulk actin and the green channel shows photoactivated fluorescence. Images were taken before activation (left), immediately after activation (middle), and 100 s after activation (right). (D–F) Kymographs taken along the lines shown in A, B, and C, respectively. The color kymograph shows bulk actin in red and photoactivated actin in green. The black and white kymograph shows photoactivated actin alone. Arrows show the time of CytoD addition (D and F) or LatB addition (E). (A and D) Before drug treatment, photoactivated subpopulations of actin decayed within 100 s. (B and E) LatB did not inhibit actin disassembly. Both bulk and photoactivated subpopulations of actin disappeared within 100 s. (C and F) CytoD inhibited disassembly of dynamic actin assemblies at the ruffling edge. Photoactivated actin subpopulations remained visible for >100 s, and bulk actin fluorescence persisted at the ruffling cell edge. Bar, 5 μm.