title: Contactin orchestrates assembly of the septate-like junctions at the paranode in myelinated peripheral nerve.
abstract: Rapid nerve impulse conduction depends on specialized membrane domains in myelinated nerve, the node of Ranvier, the paranode, and the myelinated internodal region. We report that GPI-linked contactin enables the formation of the paranodal septate-like axo-glial junctions in myelinated peripheral nerve. Contactin clusters at the paranodal axolemma during Schwann cell myelination. Ablation of contactin in mutant mice disrupts junctional attachment at the paranode and reduces nerve conduction velocity 3-fold. The mutation impedes intracellular transport and surface expression of Caspr and leaves NF155 on apposing paranodal myelin disengaged. The contactin mutation does not affect sodium channel clustering at the nodes of Ranvier but alters the location of the Shaker-type Kv1.1 and Kv1.2 potassium channels. Thus, contactin is a crucial part in the machinery that controls junctional attachment at the paranode and ultimately the physiology of myelinated nerve.
authors.affiliation: Neurobiology Program, The Burnham Institute, La Jolla, CA 92037, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Boyle
authors.forename: E O
authors.initials: EO
authors.lastname: Berglund
authors.forename: K K
authors.initials: KK
authors.lastname: Murai
authors.forename: L
authors.initials: L
authors.lastname: Weber
authors.forename: E
authors.initials: E
authors.lastname: Peles
authors.forename: B
authors.initials: B
authors.lastname: Ranscht
mesh_terms: D000375:Aging; D000818:Animals; D001369:Axons / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D058966:Contactins; D003433:Crosses, Genetic; D018507:Gene Expression Regulation, Developmental; D051662:Kv1.1 Potassium Channel; D051663:Kv1.2 Potassium Channel; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008854:Microscopy, Electron; D008959:Models, Neurological; D009413:Nerve Fibers, Myelinated / Q000502:physiology* / Q000648:ultrastructure; D009457:Neuroglia / Q000502:physiology; D015221:Potassium Channels / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated; D011901:Ranvier's Nodes / Q000502:physiology* / Q000648:ultrastructure; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology; D012583:Schwann Cells / Q000502:physiology*; D012584:Sciatic Nerve / Q000502:physiology*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; C491322:Cntnap1 protein, mouse; D058966:Contactins; C496947:Kcna1 protein, mouse; C496970:Kcna2 protein, mouse; D051663:Kv1.2 Potassium Channel; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011956:Receptors, Cell Surface; D051662:Kv1.1 Potassium Channel