Shifting views on the leading role of the lamellipodium in cell migration: speckle tracking revisited

Migrating cells advance by first protruding a lamellipodium, a thin sheet of cytoplasm that consists mostly of filamentous actin (F-actin). The region immediately behind the lamellipodium is also relatively flat and has been termed the lamella ([Heath and Holifield, 1991][1]). Adhesion to the matrix