The initial step of glycerolipid metabolism in Leishmania major promastigotes involves a single glycerol-3-phosphate acyltransferase enzyme important for the synthesis of triacylglycerol but not essential for virulence

Mol Microbiol. 2005 May;56(3):800-10. doi: 10.1111/j.1365-2958.2005.04579.x.

Abstract

The synthesis of the major phospholipids, including those that play an essential role in Leishmania virulence, initiates with the acylation of glycerol-3-phosphate and dihydroxyacetonephosphate at the sn-1 position by glycerol-3-phosphate and dihydroxyacetonephosphate acyltransferases respectively. In this study, we show that Leishmania major promastigotes express a single glycerol-3-phosphate acyltransferase activity important for triacylglycerol synthesis but not essential for virulence. The encoding gene, LmGAT, expressed in yeast results in full complementation of the lethality of a mutant, gat1Deltagat2Delta, lacking glycerol-3-phosphate activity. Biochemical analyses revealed that LmGAT is a low-affinity glycerol-3-phosphate acyltransferase and exhibits higher specific activity with unsaturated long fatty acyl-CoA donors. A L. major null mutant, Deltalmgat/Deltalmgat, was created and a thorough analysis of its lipid composition was performed. Deletion of LmGAT resulted in a complete loss of Leishmania glycerol-3-phosphate acyltransferase activity and a major reduction in triacylglycerol synthesis. Consistent with the specificity of LmGAT for glycerol-3-phosphate but not dihydroxyacetonephosphate, Deltalmgat/Deltalmgat mutant expressed normal levels of the ether-lipid derivatives and virulence factors, lipophosphoglycan and GPI-anchored proteins, gp63, and its virulence was not affected in mice.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Dihydroxyacetone Phosphate / metabolism
  • Genes, Protozoan
  • Glycerides / metabolism*
  • Glycerol-3-Phosphate O-Acyltransferase / genetics
  • Glycerol-3-Phosphate O-Acyltransferase / metabolism*
  • Glycerophosphates / metabolism
  • Glycosphingolipids / metabolism
  • Kinetics
  • Leishmania major / metabolism*
  • Leishmania major / pathogenicity*
  • Leishmania major / physiology
  • Leishmaniasis, Cutaneous / parasitology
  • Metalloendopeptidases / metabolism
  • Mice
  • Molecular Sequence Data
  • Mutation
  • Substrate Specificity
  • Triglycerides / biosynthesis*
  • Virulence / physiology

Substances

  • Glycerides
  • Glycerophosphates
  • Glycosphingolipids
  • Triglycerides
  • lipophosphonoglycan
  • Dihydroxyacetone Phosphate
  • alpha-glycerophosphoric acid
  • Glycerol-3-Phosphate O-Acyltransferase
  • Metalloendopeptidases
  • glycoprotein gp63, Leishmania