Molecular mechanisms of node of Ranvier formation.

Action potential propagation along myelinated nerve fibers requires high-density protein complexes that include voltage-gated Na(+) channels at the nodes of Ranvier. Several complementary mechanisms may be involved in node assembly including: (1) interaction of nodal cell adhesion molecules with the extracellular matrix; (2) restriction of membrane protein mobility by paranodal junctions; and (3) stabilization of ion channel clusters by axonal cytoskeletal scaffolds. In the peripheral nervous system, a secreted glial protein at the nodal extracellular matrix interacts with axonal cell adhesion molecules to initiate node formation. In the central nervous system, both glial soluble factors and paranodal axoglial junctions may function in a complementary manner to contribute to node formation.