Mammalian acyl-CoA:lysophosphatidylcholine acyltransferase enzymes

Abstract

The mammalian RBC lacks de novo lipid synthesis but maintains its membrane composition by rapid turnover of acyl moieties at the sn-2 position of phospholipids. Plasma-derived fatty acids are esterified to acyl-CoA by acyl-CoA synthetases and transferred to lysophospholipids by acyl-CoA:lysophospholipid acyltransferases. We report the characterization of three lysophosphatidylcholine (lysoPC) acyltransferases (LPCATs), products of the AYTL1, -2, and -3 genes. These proteins are three members of a LPCAT family, of which all three genes are expressed in an erythroleukemic cell line. Aytl2 mRNA was detected in mouse reticulocytes, and the presence of the product of the human ortholog was confirmed in adult human RBCs. The three murine Aytl proteins generated phosphatidylcholine from long-chain acyl-CoA and lysoPC when expressed in Escherichia coli membranes. Spliced variants of Aytl1, affecting a conserved catalytic motif, were identified. Calcium and magnesium modulated LPCAT activity of both Aytl1 and -2 proteins that exhibit EF-hand motifs at the C terminus. Characterization of the product of the Aytl2 gene as the phosphatidylcholine reacylating enzyme in RBCs represents the identification of a plasma membrane lysophospholipid acyltransferase and establishes the function of a LPCAT protein.phosphatidylcholine ͉ RBC ͉ AYTL2

Metabolic Interactions between the Lands Cycle and the Kennedy Pathway of Glycerolipid Synthesis in Arabidopsis Developing Seeds

“…Despite recent progress on the molecular cloning of its biochemical components (Benghezal et al, 2007;Chen et al, 2007;Jain et al, 2007Jain et al, , 2009Tamaki et al, 2007;Hishikawa et al, 2008;Soupene et al, 2008;Ståhl et al, 2008;Zhao et al, 2008;Kazachkov et al, 2008), the metabolic significance of LPCAT in acyl lipid metabolism remains to be fully explored. LPCAT1 and LPCAT2 were the only two genes from Arabidopsis capable of complementing the yeast lca1D mutant in a functional screening (Zheng et al, 2012).…”

Acyl-CoA:Lysophospholipid Acyltransferases

“…Because the enzyme is expressed mainly in the brain, it was suggested that LPEAT2 is an important enzyme for the biogenesis of brain PE. In addition, it has been reported that AGPAT7 (LPEAT2) has LPCAT activity in red blood cells, although its activity is relatively weak (43).…”

Characterization of human lysophospholipid acyltransferase 3

“…As previously described ( 24 ), qualitative identification of individual PL molecular species was based on their calculated theoretical monoisotopic mass values and subsequent species utilized is 1-alkyl lysoPC and 1-alkenyl lysoPC, indicating the likely importance of this enzyme in platelet activating factor (PAF) synthesis. A third mouse paralog can also esterify lysoPC with a preference for palmitoyl-CoA ( 11 ).…”