Axonal growth is one of the hallmarks of neuronal polarization, and requires membrane expansion by exocytosis of plasmalemmal precursor vesicles (PPVs) at the growth cone. We have demonstrated that IGF-1 stimulates the exocytosis of PPVs via activation of PI3k. Few details are known about the PPVs targeting mechanisms. Our results show that a cascade critical for the regulation of membrane expansion in neurons includes TC10 and the exocyst complex. We have also examined the role of growth factors in polarization and established that IGF-1 is (one of) the growth (s) factor (s) initiating polarization and that a  particularly early event, in neurons that do not yet exhibit an axon, is the segregation of activatable IGF-1 receptors (IGF-1r) to one neurite. Activation of the IGF-1r requires its insertion into the plasmalemma controlled by TC10 activity and the exocyst complex. Since IGF-1 activates TC10 and triggers exocyst assembly it may regulate the insertion of its own receptor. This is a positive-feedback mechanism that could rapidly amplify the membrane expansion response to IGF-1. We propose, therefore, that the process of IGF-1r insertion to neurite membrane/receptor activation /and further membrane expansion may be (one of) the self-reinforcing mechanism(s) necessary for neuronal polarization.