title: Depletion of phytosterols from the plant plasma membrane provides evidence for disruption of lipid rafts.
abstract: Involvement of sterols in membrane structural properties has been extensively studied in model systems but rarely assessed in natural membranes and never investigated for the plant plasma membrane (PM). Here, we address the question of the role of phytosterols in the organization of the plant PM. The sterol composition of tobacco BY-2 cell PM was determined by gas chromatography. The cyclic oligosaccharide methyl-beta-cyclodextrin, commonly used in animal cells to decrease cholesterol levels, caused a drastic reduction (50%) in the PM total free sterol content of the plant material, without modification in amounts of steryl-conjugates. Fluorescence spectroscopy experiments using DPH, TMA-DPH, Laurdan, and di-4-ANEPPDHQ indicated that such a depletion in sterol content increased lipid acyl chain disorder and reduced the overall liquid-phase heterogeneity in correlation with the disruption of phytosterol-rich domains. Methyl-beta-cyclodextrin also prevented isolation of a PM fraction resistant to solubilization by nonionic detergents, previously characterized in tobacco, and induced redistribution of the proteic marker of this fraction, NtrbohD, within the membrane. Altogether, our results support the role of phytosterols in the lateral structuring of the PM of higher plant cells and suggest that they are key compounds for the formation of plant PM microdomains.
authors.affiliation: Laboratoire Plantes-Microbe-Environnement, UMR INRA 1088/CNRS 5184/Université de Bourgogne, 17 rue Sully, BP 86510, 21065 Dijon cedex, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Roche
authors.forename: Patricia
authors.initials: P
authors.lastname: Gerbeau-Pissot
authors.forename: Blandine
authors.initials: B
authors.lastname: Buhot
authors.forename: Dominique
authors.initials: D
authors.lastname: Thomas
authors.forename: Laurent
authors.initials: L
authors.lastname: Bonneau
authors.forename: Joseph
authors.initials: J
authors.lastname: Gresti
authors.forename: Sébastien
authors.initials: S
authors.lastname: Mongrand
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Perrier-Cornet
authors.forename: Françoise
authors.initials: F
authors.lastname: Simon-Plas
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism*; D010840:Phytosterols / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods; D014026:Nicotiana / Q000737:chemistry / Q000378:metabolism*; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D010840:Phytosterols; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin