title: Chemical mapping of ceramide distribution in sphingomyelin-rich domains in monolayers.
abstract: The incorporation of ceramide in phase-separated monolayers of ternary lipid mixtures has been studied by a combination of atomic force microscopy (AFM), fluorescence, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Replacement of a fraction of the sphingomyelin by ceramide in DOPC/SM/cholesterol monolayers leads to changes in the SM-cholesterol-rich liquid-ordered domains. AFM shows the formation of heterogeneous domains with small raised islands that are assigned to a ceramide-rich gel phase. ToF-SIMS provides conclusive evidence for the localization of SM and ceramide in ordered domains and shows that ceramide is heterogeneously distributed in small islands throughout the domains. The results indicate the utility of combining AFM and ToF-SIMS for understanding compositions of phase-separated membranes.
authors.affiliation: Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada.
authors.forename: Jesse
authors.initials: J
authors.lastname: Popov
authors.forename: Dusan
authors.initials: D
authors.lastname: Vobornik
authors.forename: Oana
authors.initials: O
authors.lastname: Coban
authors.forename: Eleonora
authors.initials: E
authors.lastname: Keating
authors.forename: David
authors.initials: D
authors.lastname: Miller
authors.forename: James
authors.initials: J
authors.lastname: Francis
authors.forename: Nils O
authors.initials: NO
authors.lastname: Petersen
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Johnston
mesh_terms: D002518:Ceramides / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D010316:Particle Size; D013050:Spectrometry, Fluorescence; D018629:Spectrometry, Mass, Secondary Ion; D013109:Sphingomyelins / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D002518:Ceramides; D008567:Membranes, Artificial; D013109:Sphingomyelins