Contributions of multiple forms of myosin to nerve outgrowth

This chapter focuses on the role of myosins in growth cone locomotion, axon assembly and transport. Myosins appear likely to have multiple functional roles in neurons. At least seven families of myosin have been identified in vertebrate cells. Although it has not yet been determined whether representatives from each of these families are expressed in nervous tissue, myosins I, II and V are abundant in neurons and therefore are likely to be involved in growth cone locomotion and axon assembly. Myosin V forms dimers but does not form filaments. Homozygous myosin V deletion mutations in mice result in lethal convulsions indicating that myosin V could be crucial to nervous system function. It is important to understand these roles and the results of their interactions in living cells to fully explain the mechanisms that underlie growth cone locomotion and axonal assembly. An understanding of the mechanisms underlying axon growth will help guide the development of strategies designed to facilitate axonal regeneration following nerve injury.