Neurofascin is a glial receptor for the paranodin/Caspr-contactin axonal complex at the axoglial junction.
In myelinated fibers of the vertebrate nervous system, glial-ensheathing cells interact with axons at specialized adhesive junctions, the paranodal septate-like junctions. The axonal proteins paranodin/Caspr and contactin form a cis complex in the axolemma at the axoglial adhesion zone, and both are required to stabilize the junction. There has been intense speculation that an oligodendroglial isoform of the cell adhesion molecule neurofascin, NF155, expressed at the paranodal loop might be the glial receptor for the paranodin/Caspr-contactin complex, particularly since paranodin/Caspr and NF155 colocalize to ectopic sites in the CNS of the dysmyelinated mouse Shiverer mutant. We report that the extracellular domain of NF155 binds specifically to transfected cells expressing the paranodin/Caspr-contactin complex at the cell surface. This region of NF155 also binds the paranodin/Caspr-contactin complex from brain lysates in vitro. In support of the functional significance of this interaction, NF155 antibodies and the extracellular domain of NF155 inhibit myelination in myelinating cocultures, presumably by blocking the adhesive relationship between the axon and glial cell. These results demonstrate that the paranodin/Caspr-contactin complex interacts biochemically with NF155 and that this interaction is likely to be biologically relevant at the axoglial junction.
Charles
Perrine
P
INSERM U-495, Biologie des Interactions Neurones/Glie, UPMC, Hôpital de la Salpêtrière, 75651 Paris Cedex 13, France.
Tait
Steven
S
Faivre-Sarrailh
Catherine
C
Barbin
Gilles
G
Gunn-Moore
Frank
F
Denisenko-Nehrbass
Natalia
N
Guennoc
Anne-Marie
AM
Girault
Jean-Antoine
JA
Brophy
Peter J
PJ
Lubetzki
Catherine
C
D000818:Animals; D001369:Axons / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000378:metabolism; D016466:CHO Cells; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D018920:Coculture Techniques; D058966:Contactins; D006224:Cricetinae; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008954:Models, Biological; D009413:Nerve Fibers, Myelinated / Q000378:metabolism; D009414:Nerve Growth Factors / Q000737:chemistry / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D014162:Transfection
D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal; C491322:Cntnap1 protein, mouse; C105177:Cntnap1 protein, rat; D058966:Contactins; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D009414:Nerve Growth Factors; D009479:Neuropeptides; C504594:Nfasc protein, rat; D020033:Protein Isoforms; D011956:Receptors, Cell Surface