Molecular characterization of a lysophosphatidylcholine acyltransferase gene belonging to the MBOAT family in Ricinus communis L

Lipids. 2013 Jul;48(7):663-74. doi: 10.1007/s11745-013-3797-z. Epub 2013 May 23.

Abstract

Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT, EC 2.3.1.23) catalyzes acylation of lysophosphatidylcholine (lysoPtdCho) to produce phosphatidylcholine (PtdCho), the main phospholipid in cellular membranes. This reaction is a key component of the acyl-editing process, involving recycling of the fatty acids (FA) mainly at the sn-2 position of PtdCho. Growing evidences indicate that the LPCAT reaction controls the direct entry of newly synthesized FA into PtdCho and, at least in some plant species, it has an important impact on the synthesis and composition of triacylglycerols. Here we describe the molecular characterization of the single LPCAT gene found in the genome of Ricinus communis (RcLPCAT) that is homologous to LPCAT genes of the MBOAT family previously described in Arabidopsis and Brassica. RcLPCAT is ubiquitously expressed in all organs of the castor plant. Biochemical properties have been studied by heterologous expression of RcLPCAT in the ale1 yeast mutant, defective in lysophospholipid acyltransferase activity. RcLPCAT preferentially acylates lysoPtdCho against other lysophospholipids (lysoPL) and does not discriminates the acyl chain in the acceptor, displaying a strong activity with alkyl lysoPL. Regarding the acyl-CoA donor, RcLPCAT uses monounsaturated fatty acid thioesters, such as oleoyl-CoA (18:1-CoA), as preferred donors, while it has a low activity with saturated fatty acids and shows a poor utilization of ricinoleoyl-CoA (18:1-OH-CoA). These characteristics are discussed in terms of a possible role of RcLPCAT in regulating the entry of FA into PtdCho and the exclusion from the membranes of the hydroxylated FA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Acylglycerophosphocholine O-Acyltransferase / classification
  • 1-Acylglycerophosphocholine O-Acyltransferase / genetics*
  • 1-Acylglycerophosphocholine O-Acyltransferase / metabolism
  • Acyl Coenzyme A / metabolism
  • Amino Acid Sequence
  • Arabidopsis / enzymology
  • Arabidopsis / genetics
  • Brassica / enzymology
  • Brassica / genetics
  • Enzyme Assays
  • Fatty Acids / metabolism
  • Kinetics
  • Lysophosphatidylcholines / metabolism*
  • Molecular Sequence Data
  • Phosphatidylcholines / metabolism*
  • Phylogeny
  • Plant Proteins / classification
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Recombinant Proteins / classification
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Ricinus communis / chemistry*
  • Ricinus communis / enzymology
  • Ricinus communis / genetics
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Sequence Homology, Amino Acid
  • Substrate Specificity

Substances

  • Acyl Coenzyme A
  • Fatty Acids
  • Lysophosphatidylcholines
  • Phosphatidylcholines
  • Plant Proteins
  • Recombinant Proteins
  • oleoyl-coenzyme A
  • 1-Acylglycerophosphocholine O-Acyltransferase