Publications

• Lysophospholipid acyltransferases and arachidonate recycling in human neutrophils.

  Gijon M.A., Riekhof W.R., Zarini S., Murphy R.C., Voelker D.R.

  The cycle of deacylation and reacylation of phospholipids plays a critical role in regulating availability of arachidonic acid for eicosanoid production. The major yeast lysophospholipid acyltransferase, Ale1p, is related to mammalian membrane-bound O-acyltransferase (MBOAT) proteins. We expressed ... >> More

  The cycle of deacylation and reacylation of phospholipids plays a critical role in regulating availability of arachidonic acid for eicosanoid production. The major yeast lysophospholipid acyltransferase, Ale1p, is related to mammalian membrane-bound O-acyltransferase (MBOAT) proteins. We expressed four human MBOATs in yeast strains lacking Ale1p and studied their acyl-CoA and lysophospholipid specificities using novel mass spectrometry-based enzyme assays. MBOAT1 is a lysophosphatidylserine (lyso-PS) acyltransferase with preference for oleoyl-CoA. MBOAT2 also prefers oleoyl-CoA, using lysophosphatidic acid and lysophosphatidylethanolamine as acyl acceptors. MBOAT5 prefers lysophosphatidylcholine and lyso-PS to incorporate linoleoyl and arachidonoyl chains. MBOAT7 is a lysophosphatidylinositol acyltransferase with remarkable specificity for arachidonoyl-CoA. MBOAT5 and MBOAT7 are particularly susceptible to inhibition by thimerosal. Human neutrophils express mRNA for these four enzymes, and neutrophil microsomes incorporate arachidonoyl chains into phosphatidylinositol, phosphatidylcholine, PS, and phosphatidylethanolamine in a thimerosal-sensitive manner. These results strongly implicate MBOAT5 and MBOAT7 in arachidonate recycling, thus regulating free arachidonic acid levels and leukotriene synthesis in neutrophils. << Less

  J. Biol. Chem. 283:30235-30245(2008) [PubMed] [EuropePMC]

  This publication is cited by 26 other entries.

• Identification of a novel lysophospholipid acyltransferase in Saccharomyces cerevisiae.

  Jain S., Stanford N., Bhagwat N., Seiler B., Costanzo M., Boone C., Oelkers P.

  The incorporation of unsaturated acyl chains into phospholipids during de novo synthesis is primarily mediated by the 1-acyl-sn-glycerol-3-phosphate acyltransferase reaction. In Saccharomyces cerevisiae, Slc1 has been shown to mediate this reaction, but distinct activity remains after its removal ... >> More

  The incorporation of unsaturated acyl chains into phospholipids during de novo synthesis is primarily mediated by the 1-acyl-sn-glycerol-3-phosphate acyltransferase reaction. In Saccharomyces cerevisiae, Slc1 has been shown to mediate this reaction, but distinct activity remains after its removal from the genome. To identify the enzyme that mediates the remaining activity, we performed synthetic genetic array analysis using a slc1Delta strain. One of the genes identified by the screen, LPT1, was found to encode for an acyltransferase that uses a variety of lysophospholipid species, including 1-acyl-sn-glycerol-3-phosphate. Deletion of LPT1 had a minimal effect on 1-acyl-sn-glycerol-3-phosphate acyltransferase activity, but overexpression increased activity 7-fold. Deletion of LPT1 abrogated the esterification of other lysophospholipids, and overexpression increased lysophosphatidylcholine acyltransferase activity 7-fold. The majority of this activity co-purified with microsomes. To test the putative role for this enzyme in selectively incorporating unsaturated acyl chains into phospholipids in vitro, substrate concentration series experiments were performed with the four acyl-CoA species commonly found in yeast. Although the saturated palmitoyl-CoA and stearoyl-CoA showed a lower apparent Km, the monounsaturated palmitoleoyl-CoA and oleoyl-CoA showed a higher apparent Vmax. Arachidonyl-CoA, although not abundant in yeast, also had a high apparent Vmax. Pulse-labeling of lpt1Delta strains showed a 30% reduction in [3H]oleate incorporation into phosphatidylcholine only. Therefore, Lpt1p, a member of the membrane-bound o-acyltransferase gene family, seems to work in conjunction with Slc1 to mediate the incorporation of unsaturated acyl chains into the sn-2 position of phospholipids. << Less

  J. Biol. Chem. 282:30562-30569(2007) [PubMed] [EuropePMC]

  This publication is cited by 7 other entries.

• Drosophila lysophospholipid acyltransferases are specifically required for germ cell development.

  Steinhauer J., Gijon M.A., Riekhof W.R., Voelker D.R., Murphy R.C., Treisman J.E.

  Enzymes of the membrane-bound O-acyltransferase (MBOAT) family add fatty acyl chains to a diverse range of protein and lipid substrates. A chromosomal translocation disrupting human MBOAT1 results in a novel syndrome characterized by male sterility and brachydactyly. We have found that the Drosoph ... >> More

  Enzymes of the membrane-bound O-acyltransferase (MBOAT) family add fatty acyl chains to a diverse range of protein and lipid substrates. A chromosomal translocation disrupting human MBOAT1 results in a novel syndrome characterized by male sterility and brachydactyly. We have found that the Drosophila homologues of MBOAT1, Oysgedart (Oys), Nessy (Nes), and Farjavit (Frj), are lysophospholipid acyltransferases. When expressed in yeast, these MBOATs esterify specific lysophospholipids preferentially with unsaturated fatty acids. Generating null mutations for each gene allowed us to identify redundant functions for Oys and Nes in two distinct aspects of Drosophila germ cell development. Embryos lacking both oys and nes show defects in the ability of germ cells to migrate into the mesoderm, a process guided by lipid signals. In addition, oys nes double mutant adult males are sterile due to specific defects in spermatid individualization. oys nes mutant testes, as well as single, double, and triple mutant whole adult animals, show an increase in the saturated fatty acid content of several phospholipid species. Our findings suggest that lysophospholipid acyltransferase activity is essential for germline development and could provide a mechanistic explanation for the etiology of the human MBOAT1 mutation. << Less

  Mol. Biol. Cell 20:5224-5235(2009) [PubMed] [EuropePMC]

  This publication is cited by 16 other entries.