title: Characterization of a lysophospholipid acyltransferase involved in membrane remodeling in Candida albicans.
abstract: Phospholipid remodeling involves phospholipase activity to remove acyl chains and acyltransferases to replace acyl chains. We here describe the characterization of a lysophospholipid acyltransferase in the opportunistic fungal pathogen, Candida albicans. Expression of this gene, C.a. LPT1, complemented the lysophospholipid acyltransferase defect in Saccharomyces cerevisiae strains lacking the homologous LPT1 gene. In vitro, lysophospholipid acyltransferase activity in these strains showed acyl-CoA substrate specificity, as measured by apparent Vmax/Km ratios, to be linolenoyl-CoA>oleoyl-CoA>linoleoyl-CoA>stearoyl-CoA. To address the physiological importance of C.a. LPT1, homozygous deletion strains were generated. Lysophospholipid acyltransferase activity with amine containing lysophospholipids was dramatically reduced while lysophosphatidylinositol and lysophosphatidic acid esterification was not significantly lowered. However, C.a. LPT1 over-expression yielded an increased amount of lysophosphatidic acyltransferase activity, suggesting a role in de novo phospholipid synthesis. LPT1 deletion strains showed slightly slowed growth in standard liquid media but no phenotype in media containing three antifungals that target sterols. To assess the role of C.a. Lpt1 in phospholipid remodeling, an in vivo, pulse-chase assay utilizing polysorbitan palmitate and mass spectrometry was developed. Cellular phospholipid composition became atypical with the provision of palmitate and gradually returned to the typical distribution when palmitate was removed. Deletion of C.a. LPT1 showed a modest yet significant effect on remodeling under these conditions.
authors.affiliation: University of Michigan - Dearborn, Department of Natural Sciences, 4901 Evergreen Rd., Dearborn, MI 48128, USA. Electronic address: ayyash@umich.edu.
authors.forename: Mariam
authors.initials: M
authors.lastname: Ayyash
authors.affiliation: University of Michigan - Dearborn, Department of Natural Sciences, 4901 Evergreen Rd., Dearborn, MI 48128, USA. Electronic address: aalgahmi@umich.edu.
authors.forename: Amal
authors.initials: A
authors.lastname: Algahmi
authors.affiliation: University of Michigan - Dearborn, Department of Mathematics, 4901 Evergreen Rd., Dearborn, MI 48128, USA. Electronic address: jgillesp@umich.edu.
authors.forename: John
authors.initials: J
authors.lastname: Gillespie
authors.affiliation: University of Michigan - Dearborn, Department of Natural Sciences, 4901 Evergreen Rd., Dearborn, MI 48128, USA. Electronic address: poelkers@umich.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Oelkers
mesh_terms: D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000378:metabolism; D002176:Candida albicans / Q000201:enzymology*; D002462:Cell Membrane / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008246:Lysophospholipids / Q000096:biosynthesis / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D000214:Acyl Coenzyme A; D008246:Lysophospholipids; D029701:Saccharomyces cerevisiae Proteins; C025449:lysophosphatidylinositol; C017585:oleoyl-coenzyme A; C017725:stearoyl-coenzyme A; C026562:linoleoyl-coenzyme A; D008243:1-Acylglycerophosphocholine O-Acyltransferase; C525807:ALE1 protein, S cerevisiae
keywords: Candida albicans; Lysophospholipid acyltransferase; Mass spectrometry; Phospholipid remodeling