Sphingomyelin modulates the transbilayer distribution of galactosylceramide in phospholipid membranes

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Mattjus P, Malewicz B, Valiyaveettil JT, Baumann WJ, Bittman R, Brown RE
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Publication year: 2002
Journal: Journal of Biological Chemistry
Journal acronym: J BIOL CHEM
Volume number: 277
Issue number: 22
Start page: 19476
End page: 19481
Number of pages: 6
ISSN: 0021-9258
eISSN: 1083-351X


Abstract

The interrelationships among sphingolipid structure, membrane curvature, and glycosphingolipid transmembrane distribution remain poorly defined despite the emerging importance of sphingolipids in curved regions and vesicle buds of biomembranes. Here, we describe a novel approach to investigate the transmembrane distribution of galactosylceramide in phospholipid small unilamellar vesicles by C-13 NMR spectroscopy. Quantitation of the transbilayer distribution of [6-C-13]galactosylceramide (99.8% isotopic enrichment) was achieved by exposure of vesicles to the paramagnetic ion, Mn2+. The data show that [6-13C]galactosylceramide prefers (70%) the inner leaflet of phosphatidylcholine vesicles. Increasing the sphingomyelin content of the 1-palmitoyl-2-oleoyl-phosphatidylcholine vesicles shifted galactosylceramide from the inner to the outer leaflet. The amount of galactosylceramide localized in the inner leaflet decreased from 70% in pure 1-palmitoyl-2-oleoyl-phosphatidylcholine vesicles to only 40% in 1-palmitoyl-2-oleoyl-phosphatidylcholine/sphingomyelin (1:2) vesicles. The present study demonstrates that sphingomyelin can dramatically alter the transbilayer distribution of a monohexosylceramide, such as galactosylceramide, in 1-palmitoyl-2-oleoyl-phosphatidylcholine/sphingomyelin vesicles. The results suggest that sphingolipid-sphingolipid interactions that occur even in the absence of cholesterol play a role in controlling the transmembrane distributions of cerebrosides.

Last updated on 2019-20-10 at 04:33