Structure and function of myelinated axons

Myelinated axons are divided into distinct membrane domains that underlie the generation and propagation of electrical impulses. Action potentials are first initiated in the axon initial segment and then regenerated at gaps in the myelin sheath, called nodes of Ranvier. Nodes consist of polarized subdomains characterized by clusters of ion channels, cell adhesion molecules, and cytoskeletal and scaffolding proteins. Nodes are assembled through neuron-glia interactions. Here, we discuss the mechanisms of node assembly and maintenance and explore their functional roles. We also highlight the emergence of nodal proteins as disease targets in nervous system disorders.