Identification and characterization of DGA2, an acyltransferase of the DGAT1 acyl-CoA:diacylglycerol acyltransferase family in the oleaginous yeast Yarrowia lipolytica. New insights into the storage lipid metabolism of oleaginous yeasts

Triacylglycerols (TAG) and steryl esters (SE) are the principal storage lipids in all eukaryotic cells. In yeasts, these storage lipids accumulate within special organelles known as lipid bodies (LB). In the lipid accumulation-oriented metabolism of the oleaginous yeast Yarrowia lipolytica, storage lipids are mostly found in the form of TAG, and only small amounts of SE accumulate. We report here the identification of a new DAG acyltransferase gene, DGA2, homologous to the ARE genes of Saccharomyces cerevisiae. This gene encodes a member of the type 1 acyl-CoA:diacylglycerol acyltransferase family (DGAT1), which has not previously been identified in yeasts, but is commonly found in mammals and plants. Unlike the Are proteins in S. cerevisiae, Dga2p makes a major contribution to TAG synthesis via an acyl-CoA-dependent mechanism and is not involved in SE synthesis. This enzyme appears to affect the size and morphology of LB, suggesting a direct role of storage lipid proteins in LB formation. We report that the Are1p of Y. lipolytica was essential for sterol esterification, as deletion of the encoding gene (ARE1) completely abolished SE synthesis. Unlike its homologs in yeasts, YlARE1 has no DAG acyltransferase activity. We also reconsider the role and function of all four acyltransferase enzymes involved in the final step of neutral lipid synthesis in this oleaginous yeast

Mastering pox genotype for fatty acid transport and accumulation in the yeast Yarrowia lipolytica

Poster *INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA) Diffusion du document : INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA)International audienc

Dégradation des lipides et obésité chez la levure Yarrowia lipolytica

Poster *INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA) Diffusion du document : INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA)National audienc

Dégradation des lipides et obésité chez la levure Yarrowia lipolytica

Poster *INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA) Diffusion du document : INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA)National audienc

Mastering pox genotype for fatty acid transport and accumulation in the yeast Yarrowia lipolytica

Poster *INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA) Diffusion du document : INRA Laboratoire de chimie biologique 78850 Thiverval-Grignon (FRA)International audienc

Evidence that Mono-ADP-Ribosylation of CtBP1/BARS Regulates Lipid Storage

Mono-ADP-ribosylation is emerging as an important posttranslational modification that modulates a variety of cell signaling pathways. Here, we present evidence that mono-ADP-ribosylation of the transcriptional corepressor C terminal binding protein, brefeldin A (BFA)-induced ADP-ribosylated substrate (CtBP1/BARS) regulates neutral lipid storage in droplets that are surrounded by a monolayer of phospholipid and associated proteins. CtBP1/BARS is an NAD-binding protein that becomes ribosylated when cells are exposed to BFA. Both endogenous lipid droplets and droplets enlarged by oleate treatment are lost after 12-h exposure to BFA. Lipid loss requires new protein synthesis, and it is blocked by multiple ribosylation inhibitors, but it is not stimulated by disruption of the Golgi apparatus or the endoplasmic reticulum unfolded protein response. Small interfering RNA knockdown of CtBP1/BARS mimics the effect of BFA, and mouse embryonic fibroblasts derived from embryos that are deficient in CtBP1/BARS seem to be defective in lipid accumulation. We conclude that mono-ADP-ribosylation of CtBP1/BARS inactivates its repressor function, which leads to the activation of genes that regulate neutral lipid storage