Many cell types, including fi broblasts and epithelial cells, move forward by forming an actin-rich membrane protrusion, called a lamellipodium, at the front of the cell. In the early 1990s, researchers thought that lamellipodial protrusion was driven by the polymerization of linear actin fi laments. In two JCB papers published in 1997 and 1999, however, Tatyana Svitkina and colleagues revealed...
