PMID:16920778

Citation	Shockey, JM, Gidda, SK, Chapital, DC, Kuan, JC, Dhanoa, PK, Bland, JM, Rothstein, SJ, Mullen, RT and Dyer, JM (2006) Tung tree DGAT1 and DGAT2 have nonredundant functions in triacylglycerol biosynthesis and are localized to different subdomains of the endoplasmic reticulum. Plant Cell 18:2294-313
Abstract	Seeds of the tung tree (Vernicia fordii) produce large quantities of triacylglycerols (TAGs) containing approximately 80% eleostearic acid, an unusual conjugated fatty acid. We present a comparative analysis of the genetic, functional, and cellular properties of tung type 1 and type 2 diacylglycerol acyltransferases (DGAT1 and DGAT2), two unrelated enzymes that catalyze the committed step in TAG biosynthesis. We show that both enzymes are encoded by single genes and that DGAT1 is expressed at similar levels in various organs, whereas DGAT2 is strongly induced in developing seeds at the onset of oil biosynthesis. Expression of DGAT1 and DGAT2 in yeast produced different types and proportions of TAGs containing eleostearic acid, with DGAT2 possessing an enhanced propensity for the synthesis of trieleostearin, the main component of tung oil. Both DGAT1 and DGAT2 are located in distinct, dynamic regions of the endoplasmic reticulum (ER), and surprisingly, these regions do not overlap. Furthermore, although both DGAT1 and DGAT2 contain a similar C-terminal pentapeptide ER retrieval motif, this motif alone is not sufficient for their localization to specific regions of the ER. These data suggest that DGAT1 and DGAT2 have nonredundant functions in plants and that the production of storage oils, including those containing unusual fatty acids, occurs in distinct ER subdomains.
Links	PubMed PMC1560902 Online version:10.1105/tpc.106.043695
Keywords	Amino Acid Motifs; Amino Acid Sequence; Diacylglycerol O-Acyltransferase/analysis; Diacylglycerol O-Acyltransferase/chemistry; Diacylglycerol O-Acyltransferase/physiology; Endoplasmic Reticulum/enzymology; Euphorbiaceae/enzymology; Euphorbiaceae/genetics; Flowers/enzymology; Flowers/genetics; Linolenic Acids/metabolism; Molecular Sequence Data; Multigene Family; Phylogeny; Plant Leaves/enzymology; Plant Leaves/genetics; Plant Oils/chemistry; Plants, Genetically Modified/cytology; Plants, Genetically Modified/metabolism; Plants, Genetically Modified/ultrastructure; Protein Transport/genetics; Seeds/enzymology; Seeds/genetics; Sequence Alignment; Substrate Specificity; Tobacco/cytology; Tobacco/genetics; Triglycerides/biosynthesis
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
VERFO:Q0QJI1	part_of	GO:0005783: endoplasmic reticulum	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
VERFO:Q0QJI1		GO:0005783: endoplasmic reticulum	ECO:0000314:		C		Figure 5	complete CACAO 8359
VERFO:Q0QJH9	part_of	GO:0005783: endoplasmic reticulum	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
VERFO:Q0QJH9		GO:0005783: endoplasmic reticulum	ECO:0000314:		C		Figure 5	complete CACAO 8360

References

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