title: Metabolic interactions between the Lands cycle and the Kennedy pathway of glycerolipid synthesis in Arabidopsis developing seeds.
abstract: It has been widely accepted that the primary function of the Lands cycle is to provide a route for acyl remodeling to modify fatty acid (FA) composition of phospholipids derived from the Kennedy pathway. Lysophosphatidylcholine acyltransferase (LPCAT) is an evolutionarily conserved key enzyme in the Lands cycle. In this study, we provide direct evidence that the Arabidopsis thaliana LPCATs, LPCAT1 and LPCAT2, participate in the Lands cycle in developing seeds. In spite of a substantially reduced initial rate of nascent FA incorporation into phosphatidylcholine (PC), the PC level in the double mutant lpcat1 lpcat2-2 remained unchanged. LPCAT deficiency triggered a compensatory response of de novo PC synthesis and a concomitant acceleration of PC turnover that were attributable at least in part to PC deacylation. Acyl-CoA profile analysis revealed complicated metabolic alterations rather than merely reduced acyl group shuffling from PC in the mutant. Shifts in FA stereo-specific distribution in triacylglycerol of the mutant seed suggested a preferential retention of saturated acyl chains at the stereospecific numbering (sn)-1 position from PC and likely a channeling of lysophosphatidic acid, derived from PC, into the Kennedy pathway. Our study thus illustrates an intricate relationship between the Lands cycle and the Kennedy pathway.
authors.affiliation: National Research Council Canada, Saskatoon, Saskatchewan S7N 0W9, Canada.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.forename: Wenyun
authors.initials: W
authors.lastname: Shen
authors.forename: Michael
authors.initials: M
authors.lastname: Kazachkov
authors.forename: Guanqun
authors.initials: G
authors.lastname: Chen
authors.forename: Qilin
authors.initials: Q
authors.lastname: Chen
authors.forename: Anders S
authors.initials: AS
authors.lastname: Carlsson
authors.forename: Sten
authors.initials: S
authors.lastname: Stymne
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Weselake
authors.forename: Jitao
authors.initials: J
authors.lastname: Zou
mesh_terms: D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D000214:Acyl Coenzyme A / Q000378:metabolism; D000215:Acylation; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D005227:Fatty Acids / Q000378:metabolism; D035264:Flowers / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D006017:Glycolipids / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010713:Phosphatidylcholines / Q000378:metabolism*; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D012639:Seeds / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D013379:Substrate Specificity; D014280:Triglycerides / Q000378:metabolism
chemical_list: D000214:Acyl Coenzyme A; D005227:Fatty Acids; D006017:Glycolipids; D010713:Phosphatidylcholines; D014280:Triglycerides; D008243:1-Acylglycerophosphocholine O-Acyltransferase