title: Structural and biochemical properties of lipid particles from the yeast Saccharomyces cerevisiae.
abstract: The two most prominent neutral lipids of the yeast Saccharomyces cerevisiae, triacylglycerols (TAG) and steryl esters (SE), are synthesized by the two TAG synthases Dga1p and Lro1p and the two SE synthases Are1p and Are2p. In this study, we made use of a set of triple mutants with only one of these acyltransferases active to elucidate the contribution of each single enzyme to lipid particle (LP)/droplet formation. Depending on the remaining acyltransferases, LP from triple mutants contained only TAG or SE, respectively, with specific patterns of fatty acids and sterols. Biophysical investigations, however, revealed that individual neutral lipids strongly affected the internal structure of LP. SE form several ordered shells below the surface phospholipid monolayer of LP, whereas TAG are more or less randomly packed in the center of the LP. We propose that this structural arrangement of neutral lipids in LP may be important for their physiological role especially with respect to mobilization of TAG and SE reserves.
authors.affiliation: Institute of Biochemistry, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria.
authors.forename: Tibor
authors.initials: T
authors.lastname: Czabany
authors.forename: Andrea
authors.initials: A
authors.lastname: Wagner
authors.forename: Dagmar
authors.initials: D
authors.lastname: Zweytick
authors.forename: Karl
authors.initials: K
authors.lastname: Lohner
authors.forename: Erich
authors.initials: E
authors.lastname: Leitner
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ingolic
authors.forename: Günther
authors.initials: G
authors.lastname: Daum
mesh_terms: D000217:Acyltransferases / Q000378:metabolism; D002152:Calorimetry, Differential Scanning; D015536:Down-Regulation; D005227:Fatty Acids / Q000737:chemistry; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005838:Genotype; D008055:Lipids / Q000737:chemistry*; D008954:Models, Biological; D009154:Mutation; D010316:Particle Size; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology; D013261:Sterols / Q000378:metabolism; D013347:Subcellular Fractions
chemical_list: D005227:Fatty Acids; D008055:Lipids; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D000217:Acyltransferases