ABSTRACT
This chapter describes the role of actin filaments in crawling movements. It emphasizes the actin-based cytoskeleton. The chapter shows that the migration of other cells shows some similarities to that of nematode sperm, but in other respect seems much more complicated. It discusses the molecular minutiae of locomotion in fibroblasts and amoebae, that some of these interactions may be icing on the cake. The chapter examines that there must be a 'polymerizing machine' carried at the leading margin of the cell that responds to external influences by adding or removing actin molecules from the ends of actin filaments. The surface of an animal cell is pliable and easily deformed, so it is not surprising that the appearance of cortical flow varies according to the type of cell and its surroundings. In both migrating cells and dividing cells, a meshwork of actin-containing structures beneath the plasma membrane moves as a continuous unit.
