Video 1

Movie S1. Typical time-lapse images of cofilin binding to an actin filament. An actin filament was tethered to a coverslip and imaged with TIRF microscopy. Several Alexa-488-cofilin bindings are shown by arrowheads in the right column (cofilin is colored green and the actin filament is colored red). A double arrowhead shows an additional binding of cofilin to the filament. The fluorescence images of actin filaments in the left column and the fluorescence images of cofilin in the middle column are merged in the right column. The total cofilin concentration was 100 nM. The length of this movie is 5 s (15 frames per s), and the area is 1.3 × 3.0 μm (width × height). ORCA Flash D4 was used for taking the images.