Local protrusions caused by activation of cofilin. (A) MTLn3 cells in serum after microinjection of caged cofilin (B) Spatial uncaging of cofilin (C) 1 min after uncaging (D) DAIS perimeter time-lapse images taken before and after photoactivation; showing site of photoactivation (blue), protrusion (green) and retraction (red). From M. Ghosh, X. Song, G. Mouneimne, M. Sidani, D.S. Lawrence, J.S. Condeelis, Cofilin promotes actin polymerization and defines the direction of cell motility, 304, 2004, 743–746. Reprinted with permission from AAAS.