Nfasc155H and MAG are Specifically Susceptible to Detergent Extraction in the Absence of the Myelin Sphingolipid Sulfatide
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Mice incapable of synthesizing the myelin lipid sulfatide form paranodes that deteriorate with age. Similar instability also occurs in mice that lack contactin, contactin-associated protein or neurofascin155 (Nfasc155), the proteins that cluster in the paranode and form the junctional complex that mediates myelin-axon adhesion. In contrast to these proteins, sulfatide has not been shown to be enriched in the paranode nor has a sulfatide paranodal binding partner been identified; thus, it remains unclear how the absence of sulfatide results in compromised paranode integrity. Using an in situ extraction procedure, it has been reported that the absence of the myelin sphingolipids, galactocerebroside and sulfatide, increased the susceptibility of Nfasc155 to detergent extraction. Here, employing a similar approach, we demonstrate that in the presence of galactocerebroside but in the absence of sulfatide Nfasc155 is susceptible to detergent extraction. Furthermore, we use this in situ approach to show that stable association of myelin-associated glycoprotein (MAG) with the myelin membrane is sulfatide dependent while the membrane associations of myelin/oligodendrocyte glycoprotein, myelin basic protein and cyclic nucleotide phosphodiesterase are sulfatide independent. These findings indicate that myelin proteins maintain their membrane associations by different mechanisms. Moreover, the myelin proteins that cluster in the paranode and require sulfatide mediate myelin-axon adhesion. Additionally, the apparent dependency on sulfatide for maintaining Nfasc155 and MAG associations is intriguing since the fatty acid composition of sulfatide is altered and paranodal ultrastructure is compromised in multiple sclerosis. Thus, our findings present a potential link between sulfatide perturbation and myelin deterioration in multiple sclerosis.
KeywordsSulfatide Neurofascin Membrane rafts Myelin
The authors wish to thank Drs. Manzoor Bhat, Peter Brophy, and Matt Rasband for their generous gifts of antibodies. This work was funded by a grant from the National Institute of Health-National Institute of Neurologic Disease and Stroke (R03 NS066186 (JLD)). All microscopy was performed at the VCU Department of Anatomy and Neurobiology Microscopy Facility, supported, in part, with funding from an National Institute of Health Center core grant (5P30NS047463).
Conflict of interest
The authors report no conflict of interests.
- 11.Pillai AM, Thaxton C, Pribisko AL, Cheng JG, Dupree JL, Bhat MA (2009) Spatiotemporal ablation of myelinating glia-specific neurofascin (Nfasc NF155) in mice reveals gradual loss of paranodal axoglial junctions and concomitant disorganization of axonal domains. J Neurosci Res 87(8):1773–1793PubMedCrossRefGoogle Scholar
- 14.Ishibashi T, Dupree JL, Ikenaka K, Hirahara Y, Honke K, Peles E, Popko B, Suzuki K, Nishino H, Baba H (2002) A myelin galactolipid, sulfatide, is essential for maintenance of ion channels on myelinated axon but not essential for initial cluster formation. J Neurosci 22(15):6507–6514PubMedGoogle Scholar
- 18.Taylor CM, Marta CB, Bansal R, Pfeiffer S (2003) The transport, assembly, and function of myelin lipids. In: Lazzarini R (ed) Myelin biology and disorders. Elsevier Academic Press, New York, pp 57–88Google Scholar
- 20.Maggio B, Borioli GA, Del Boca M, De Tullio L, Fanani ML, Oliveira RG, Rosetti CM, Wilke N (2007) Composition-driven surface domain structuring mediated by sphingolipids and membrane-active proteins: above the nano- but under the micro-scale: mesoscopic biochemical/structural cross-talk in biomembranes. Cell Biochem Biophys 50(2):79–109PubMedCrossRefGoogle Scholar
- 34.Shepherd MN, Pomicter AD, Velazco CS, Henderson SC, Dupree JL (2012) Paranodal reorganization results in the depletion of transverse bands in the aged central nervous system. Neurobiol Aging 33(1):203.e13–203.e24Google Scholar
- 38.Abramoff MD, Magalhaes PJ, Ram SJ (2004) Image processing with ImageJ. Biophot Internat 11(7):36–42Google Scholar
- 43.Marta CB, Taylor CM, Coetzee T, Kim T, Winkler S, Bansal R, Pfeiffer SE (2003) Antibody cross-linking of myelin oligodendrocyte glycoprotein leads to its rapid repartitioning into detergent-insoluble fractions, and altered protein phosphorylation and cell morphology. J Neurosci 23(13):5461–5471PubMedGoogle Scholar
- 55.Erb M, Flueck B, Kern F, Erne B, Steck AJ, Schaeren-Wiemers N (2006) Unraveling the differential expression of the two isoforms of myelin-associated glycoprotein in a mouse expressing GFP-tagged S-MAG specifically regulated and targeted into the different myelin compartments. Mol Cell Neurosci 31:613–627PubMedCrossRefGoogle Scholar
- 64.Esposito C, Scrima M, Carotenuto A, Tedeschi A, Rovero P, D’Errico G, Malfitano AM, Bifulco M, D’Ursi AM (2008) Structures and micelle locations of the nonlipidated and lipidated C-terminal membrane anchor of 2’,3’-cyclic nucleotide-3’-phosphodiesterase. Biochemistry 47(1):308–319PubMedCrossRefGoogle Scholar