Editing Node of Ranvier (section)

===Composition===
The nodes of Ranvier Na+/Ca2+ exchangers and high density of voltage-gated Na+ channels that generate action potentials.  A sodium channel consists of a pore-forming α subunit and two accessory β subunits, which anchor the channel to extra-cellular and intra-cellular components.  The nodes of Ranvier in the central and peripheral nervous systems mostly consist of αNaV1.6 and β1 subunits.<ref>{{cite journal | doi = 10.1016/S0896-6273(01)00266-5 | pmid = 11343648 | author1 = Kaplan M.R. | author2 = Cho M.H. | author3 = Ullian E.M. | author4 = Isom L.L. | author5 = Levinson S.R. | author6 = Barres B.A. | year = 2001 | title = Differential control of clustering of the sodium channels Na(v)1.2 and Na(v)1.6 at developing CNS nodes of Ranvier | journal = [[Neuron (journal)|Neuron]] | volume = 30 | issue = 1 | pages = 105–119 | s2cid = 10252129 | doi-access = free }}</ref> The extra-cellular region of β subunits can associate with itself and other proteins, such as tenascin R and the cell-adhesion molecules [[neurofascin]] and contactin.  Contactin is also present at nodes in the CNS and interaction with this molecule enhances the surface expression of Na+ channels.

[[Ankyrin]] has been found to be bounded to βIV spectrin, a spectrin isoform enriched at nodes of Ranvier and axon initial segments.   The PNS nodes are surrounded by Schwann cell microvilli, which contain ERMs and EBP50 that may provide a connection to actin microfilaments. Several extracellular matrix proteins are enriched at nodes of Ranvier, including [[tenascin-R]], [[HAPLN2|Bral-1]], and proteoglycan NG2, as well as [[phosphacan]] and [[versican]] V2. At CNS nodes, the axonal proteins also include contactin; however, different from the PNS, Schwann cell microvilli are replaced by [[astrocyte]] perinodal extensions.