title: Function and localization of the Arabidopsis thaliana diacylglycerol acyltransferase DGAT2 expressed in yeast.
abstract: Diacylglycerol acyltransferases (DGATs) catalyze the final and only committed step of triacylglycerol synthesis. DGAT activity is rate limiting for triacylglycerol accumulation in mammals, plants and microbes. DGATs belong to three different evolutionary classes. In Arabidopsis thaliana, DGAT1, encoded by At2g19450, is the major DGAT enzyme involved in triacylglycerol accumulation in seeds. Until recently, the function of DGAT2 (At3g51520) has remained elusive. Previous attempts to characterize its enzymatic function by heterologous expression in yeast were unsuccessful. In the present report we demonstrate that expression of a codon-optimized version of the DGAT2 gene is able to restore neutral lipid accumulation in the Saccharomyces cerevisiae mutant strain (H1246), which is defective in triacylglycerol biosynthesis. Heterologous expression of codon-optimized DGAT2 and DGAT1 induced the biogenesis of subcellular lipid droplets containing triacylglycerols and squalene. Both DGAT proteins were found to be associated with these lipid droplets. The fatty acid composition was affected by the nature of the acyltransferase expressed. DGAT2 preferentially incorporated C16:1 fatty acids whereas DGAT1 displayed preference for C16:0, strongly suggesting that these enzymes have contrasting substrate specificities.
authors.affiliation: INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Aymé
authors.affiliation: INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Baud
authors.affiliation: INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Dubreucq
authors.affiliation: ITERG, Pessac, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Joffre
authors.affiliation: INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Chardot
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D003062:Codon / Q000235:genetics; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D042541:Intracellular Space / Q000378:metabolism; D066292:Lipid Droplets / Q000378:metabolism; D009154:Mutation; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D014280:Triglycerides / Q000096:biosynthesis
chemical_list: D029681:Arabidopsis Proteins; D003062:Codon; D014280:Triglycerides; C578613:DGAT2 protein, Arabidopsis; D051048:Diacylglycerol O-Acyltransferase