Actin dynamics in filopodia of nerve growth cone

Growth cone is an actin-rich apparatus located at the tip of axon in developing neurons. Two typical structures, lamellipodium and filopodium exist in the peripheral region of growth cone. The former is a flat-sheet F-actin network, and the latter a highly motile bundle of F-actin projecting from lamellipodia (Fig. 1). Recently, evidences have been accumulating for the involvement of filopodia dynamics in path finding of axon. In this review, we will focus on the possible molecular mechanism of regulating system in filopodial dynamics with respect to growth cone behavior.