The present address of Dr. B. Kosaras is New England Regional Primate Research Center, Harvard Medical School, 1 Pine Hill Drive, Southborough, MA 01772, U.S.A.
Protein and Lipid Composition of Radial Component-Enriched CNS Myelin
Article first published online: 28 JUN 2008
Journal of Neurochemistry
Volume 62, Issue 3, pages 1203–1213, March 1994
How to Cite
Karthigasan, J., Kosaras, B., Nguyen, J. and Kirschner, D. A. (1994), Protein and Lipid Composition of Radial Component-Enriched CNS Myelin. Journal of Neurochemistry, 62: 1203–1213. doi: 10.1046/j.1471-4159.1994.62031203.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Recieved December 16, 1992; revised August 6, 1993; accepted August 10, 1993.
- Membrane junctions;
- Myelin proteins;
- Cyto-skeletal protein;
- Proteolipid protein;
- Triton X-100;
- Electron microscopy
Abstract: The radial component is a junctional complex that is believed to stabilize the apposition of myelin membranes in the internode of CNS myelin. Based on our previous finding that the radial component of compact myelin retains its structure in tissue treated with the detergent Triton X-100, we have attempted to isolate the junctional complex from spinal cord myelin treated with this detergent. Using 0.5% Triton X-100, our procedures yielded a fraction of isolated myelin that was enriched in well-preserved radial component. This fraction that contained morphologically well-defined radial component was examined by sodium dodecyl sulfate-polyacrylamide gel electropho-resis and immunoblotting, and TLC, and was found to be significantly and consistently enriched in the 21.5-kDa and 17-kDa isoforms of myelin basic protein, and in cerebro-sides, hydroxy sulfatide, and sphingomyelin. In addition, the myelin-associated enzyme 2′,3′-cyclic nucleotide 3′-phosphodiesterase, tubulin, and actin tended to be resistant to Triton extraction. The fraction of isolated myelin that contained radial component was deficient in proteolipid protein and DM-20, the 18.5-and 14-kDa isoforms of myelin basic proteins, and in the major phospholipids, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylserine. Our data indicate that the radial component can be isolated and that certain myelin and cytoskeletal proteins and lipids are closely associated with it.