title: Tocopherol cyclase (VTE1) localization and vitamin E accumulation in chloroplast plastoglobule lipoprotein particles.
abstract: Chloroplasts contain lipoprotein particles termed plastoglobules. Plastoglobules are generally believed to have little function beyond lipid storage. Here we report on the identification of plastoglobule proteins using mass spectrometry methods in Arabidopsis thaliana. We demonstrate specific plastoglobule association of members of the plastid lipid-associated proteins/fibrillin family as well as known metabolic enzymes, including the tocopherol cyclase (VTE1), a key enzyme of tocopherol (vitamin E) synthesis. Moreover, comparative analysis of chloroplast membrane fractions shows that plastoglobules are a site of vitamin E accumulation in chloroplasts. Thus, in addition to their lipid storage function, we propose that plastoglobules are metabolically active, taking part in tocopherol synthesis and likely other pathways.
authors.affiliation: Institute of Botany, University of Neuchâtel, Emile Argand 11, CH-2007 Neuchâtel, Switzerland.
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Vidi
authors.forename: Marion
authors.initials: M
authors.lastname: Kanwischer
authors.forename: Sacha
authors.initials: S
authors.lastname: Baginsky
authors.forename: Jotham R
authors.initials: JR
authors.lastname: Austin
authors.forename: Gabor
authors.initials: G
authors.lastname: Csucs
authors.forename: Peter
authors.initials: P
authors.lastname: Dörmann
authors.forename: Felix
authors.initials: F
authors.lastname: Kessler
authors.forename: Claire
authors.initials: C
authors.lastname: Bréhélin
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000378:metabolism; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D019751:Intramolecular Transferases / Q000096:biosynthesis*; D008074:Lipoproteins / Q000737:chemistry* / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D013058:Mass Spectrometry; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D010940:Plant Proteins / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism; D024505:Tocopherols / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D018076:DNA, Complementary; D005227:Fatty Acids; D008074:Lipoproteins; D008164:Luminescent Proteins; D010940:Plant Proteins; C054562:yellow fluorescent protein, Bacteria; D014810:Vitamin E; D049452:Green Fluorescent Proteins; D005634:Fructose-Bisphosphate Aldolase; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase; D019751:Intramolecular Transferases; C103397:tocopherol cyclase; D024505:Tocopherols