title: Sphingolipid domains in the plasma membranes of fibroblasts are not enriched with cholesterol.
abstract: The plasma membranes of mammalian cells are widely expected to contain domains that are enriched with cholesterol and sphingolipids. In this work, we have used high-resolution secondary ion mass spectrometry to directly map the distributions of isotope-labeled cholesterol and sphingolipids in the plasma membranes of intact fibroblast cells. Although acute cholesterol depletion reduced sphingolipid domain abundance, cholesterol was evenly distributed throughout the plasma membrane and was not enriched within the sphingolipid domains. Thus, we rule out favorable cholesterol-sphingolipid interactions as dictating plasma membrane organization in fibroblast cells. Because the sphingolipid domains are disrupted by drugs that depolymerize the cells actin cytoskeleton, cholesterol must instead affect the sphingolipid organization via an indirect mechanism that involves the cytoskeleton.
authors.affiliation: Departments of Chemistry, Urbana, Illinois 61801.
authors.forename: Jessica F
authors.initials: JF
authors.lastname: Frisz
authors.affiliation: Departments of Chemistry, Urbana, Illinois 61801.
authors.forename: Haley A
authors.initials: HA
authors.lastname: Klitzing
authors.affiliation: Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801.
authors.forename: Kaiyan
authors.initials: K
authors.lastname: Lou
authors.affiliation: Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94551.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Hutcheon
authors.affiliation: Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94551.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Weber
authors.affiliation: Program in Physical Biology, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Joshua
authors.initials: J
authors.lastname: Zimmerberg
authors.affiliation: Departments of Chemistry, Urbana, Illinois 61801; Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801. Electronic address: mlkraft@illinois.edu.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Kraft
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells; D013107:Sphingolipids / Q000378:metabolism*
chemical_list: D013107:Sphingolipids; D002784:Cholesterol
keywords: Cholesterol; Isotopic Tracers; Lipid Raft; Mass Spectrometry (MS); Membrane Structure; Plasma Membrane; Sphingolipid