title: Four Acyltransferases Uniquely Contribute to Phospholipid Heterogeneity inSaccharomyces cerevisiae.
abstract: Diverse acyl-CoA species and acyltransferase isoenzymes are components of a complex system that synthesizes glycerophospholipids and triacylglycerols.Saccharomyces cerevisiaehas four main acyl-CoA species, two main glycerol-3-phosphate 1-O-acyltransferases (Gat1p, Gat2p), and two main 1-acylglycerol-3-phosphateO-acyltransferases (Lpt1p, Slc1p). The in vivo contribution of these isoenzymes to phospholipid heterogeneity was determined using haploids with compound mutations:gat1Δlpt1Δ, gat2Δlpt1Δ, gat1Δslc1Δ, andgat2Δslc1Δ. All mutations mildly reduced [3H]palmitic acid incorporation into phospholipids relative to triacylglycerol. Electrospray ionization tandem mass spectrometry identified few differences from wild type ingat1Δlpt1Δ, dramatic differences ingat2Δslc1Δ, and intermediate changes ingat2Δlpt1Δandgat1Δslc1Δ. Yeast expressing Gat1p and Lpt1p had phospholipids enriched with acyl chains that were unsaturated, 18 carbons long, and paired for length. These alterations prevented growth at 18.5°C and in 10% ethanol. Therefore, Gat2p and Slc1p dictate phospholipid acyl chain composition in rich media at 30°C. Slc1p selectively pairs acyl chains of different lengths.
authors.affiliation: Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Oelkers
authors.affiliation: Department of Mathematics and Statistics, University of Michigan-Dearborn, Dearborn, MI, USA.
authors.forename: Keshav
authors.initials: K
authors.lastname: Pokhrel
keywords: 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT, LPAT); glycerol-3-phosphate 1-O-acyltransferase (GPAT); lipidomics; membranes; tandem mass spectrometry