Abl signaling directs growth of a pioneer axon in Drosophilaby shaping the intrinsic fluctuations of actin

Live imaging reveals that a forward bias of the stochastic actin fluctuations in the distal part of an axon drives axon extension by advancing the protrusive, filopodial domain of the growth cone. The actin mass is itself shaped by guidance signaling via Abl tyrosine kinase, which regulates growth cone length and minimizes its disorder.