Differential expression of proteoglycans at central and peripheral nodes of Ranvier.
The nodes of Ranvier are regularly spaced gaps between myelin sheaths that are markedly enriched in voltage-gated sodium channels and associated proteins. Myelinating glia play a key role in promoting node formation, although the requisite glial signals remain poorly understood. In this study, we have examined the expression of glial proteoglycans in the peripheral and central nodes. We report that the heparan sulfate proteoglycan, syndecan-3, becomes highly enriched with PNS node formation; its ligand, collagen V, is also concentrated at the PNS nodes and at lower levels along the abaxonal membrane. The V1 isoform of versican, a chondroitin sulfate proteoglycan, is also present in the nodal gap. By contrast, CNS nodes are enriched in versican isoform V2, but not syndecan-3. We have examined the molecular composition of the PNS nodes in syndecan-3 knockout mice. Nodal components are normally expressed in mice deficient in syndecan-3, suggesting that it has a nonessential role in the organization of nodes in the adult. These results indicate that the molecular composition and extracellular environment of the PNS and CNS nodes of Ranvier are significantly distinct.
Melendez-Vasquez
Carmen
C
Department of Cell Biology, New York University School of Medicine, New York, New York 10016, USA.
Carey
David J
DJ
Zanazzi
George
G
Reizes
Ofer
O
Maurel
Patrice
P
Salzer
James L
JL
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D002490:Central Nervous System / Q000378:metabolism* / Q000648:ultrastructure; D024062:Collagen Type V / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism; D017933:Peripheral Nervous System / Q000378:metabolism* / Q000648:ultrastructure; D020033:Protein Isoforms / Q000378:metabolism; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism*; D011901:Ranvier's Nodes / Q000378:metabolism* / Q000648:ultrastructure; D012583:Schwann Cells / Q000378:metabolism; D053670:Syndecan-3; D053675:Versicans
D002352:Carrier Proteins; D024062:Collagen Type V; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D011509:Proteoglycans; C508302:Sdc3 protein, mouse; D053670:Syndecan-3; C508323:Vcan protein, mouse; D053675:Versicans