title: Regulation of lipid droplet size and phospholipid composition by stearoyl-CoA desaturase.
abstract: Fatty acid desaturation regulates membrane function and fat storage in animals. To determine the contribution of stearoyl-CoA desaturase (SCD) activity on fat storage and development in the nematode Caenorhabditis elegans, we analyzed the lipid composition and lipid droplet size in the fat-6;fat-7 desaturase mutants independently and in combination with mutants disrupted in conserved lipid metabolic pathways. C. elegans with impaired SCD activity displayed both reduced fat stores and decreased lipid droplet size. Mutants in the daf-2 (insulin-like growth factor receptor), rsks-1 (homolog of p70S6 kinase, an effector of the target of rapamycin signaling pathway), and daf-7 (transforming growth factor β) displayed high fat stores, the opposite of the low fat observed in the fat-6;fat-7 desaturase mutants. The metabolic mutants in combination with fat-6;fat-7 displayed low fat stores, with the exception of the daf-2;fat-6;fat-7 triple mutants, which had increased de novo fatty acid synthesis and wild-type levels of fat stores. Notably, SCD activity is required for the formation of large-sized lipid droplets in all mutant backgrounds, as well as for normal ratios of phosphatidylcholine (PC) to phosphatidylethanolamine (PE). These studies reveal previously uncharacterized roles for SCD in the regulation of lipid droplet size and membrane phospholipid composition.
authors.affiliation: School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA.
authors.forename: Xun
authors.initials: X
authors.lastname: Shi
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Xiaoju
authors.initials: X
authors.lastname: Zou
authors.forename: Joel
authors.initials: J
authors.lastname: Greggain
authors.forename: Steven V
authors.initials: SV
authors.lastname: Rødkær
authors.forename: Nils J
authors.initials: NJ
authors.lastname: Færgeman
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Watts
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004041:Dietary Fats / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis; D009154:Mutation; D019301:Oleic Acid / Q000494:pharmacology; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism*; D013230:Stearoyl-CoA Desaturase / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D019301:Oleic Acid; D013230:Stearoyl-CoA Desaturase
keywords: Caenorahbditis elegans; fatty acid oxidation; fatty acid synthesis; oleic acid; phosphatidylcholine; phosphatidylethanolamine