Simultaneous observation of actin motion and substrate deformation in migrating keratocytes. (A) The image of phalloidin-labeled actin (cyan) is superimposed on the image of the fluorescent beads (red) spread on the substrate surface (Video 1). (B–D) Kymographs generated along the lines labeled with B, C, and D in A. In each group of kymographs, the order of presentation from left to right is substrate (red), actin (cyan), and a merger of the two. The arrowheads in D indicate the change of bead motion direction corresponding to the release of the substrate at the lateral margin of the cell. For the kymograph: vertical bar, 10 µm; horizontal bar, 20 s. Bar, 10 µm.