| 研究実績の概要 |
N-Acyl-phosphatidylethanolamines (NAPEs) are known to be precursors of bioactive N-acylethanolamines (NAEs). In mammals, NAPEs are produced by N-acyltransferases, which transfer an acyl chain from a glycerophospholipid (like phosphatidylcholine (PC)) to the amino group of phosphatidylethanolamine (PE). Recently, the e isoform of cytosolic phospholipase A2 (cPLA2e) was found to be Ca2+-dependent N-acyltransferase. However, it was less understood which types of phospholipids serve as substrates in living cells. In this study, we established a human embryonic kidney 293 cell line, in which doxycycline potently induces human cPLA2e-expression, and used these cells to investigate endogenous substrates and products of cPLA2e with liquid chromatography-tandem mass spectrometry. When treated with doxycycline and Ca2+ ionophore, the cells produced massive amounts of various species of diacyl- and alkenylacyl-types of NAPEs as well as NAEs. Moreover, the levels of various PEs and PCs decreased, while those of lysoPE and lysoPC increased. These results suggested that cPLAe Ca2+-dependently produces NAPEs by utilizing endogenous PEs as acyl acceptors and PCs as well as PEs as acyl donors.
|
