Figure 2.

Proposed schematic of retrograde flow of actin bundle and kymographic analysis. (A) A chronological series of schematic snapshots showing a radial actin bundle inside a filopodium and the lamellipodium. Retrograde flow in the lamellipodium moves the actin bundle out of the filopodium in which actin units are continuously added to the bundle end. A kink in the actin bundle (segments A, B, C, D) is maintained during retrograde transport. (B) A kymograph assembled from image portions indicated by dashed frames in A. The image portions were arranged in chronological order along the horizontal direction. The actin bundle in the kymograph should be similar in appearance to the bundle shown in the last frame (15 sec) in A, if the bundle does not significantly change its shape or assembly state during retrograde flow.