| First Author | Hussain Z | Year | 2018 |
| Journal | Biochim Biophys Acta | Volume | 1863 |
| Issue | 5 | Pages | 493-502 |
| PubMed ID | 29447909 | Mgi Jnum | J:262289 |
| Mgi Id | MGI:6161105 | Doi | 10.1016/j.bbalip.2018.02.002 |
| Citation | Hussain Z, et al. (2018) Phosphatidylserine-stimulated production of N-acyl-phosphatidylethanolamines by Ca(2+)-dependent N-acyltransferase. Biochim Biophys Acta 1863(5):493-502 |
| abstractText | N-acyl-phosphatidylethanolamine (NAPE) is known to be a precursor for various bioactive N-acylethanolamines including the endocannabinoid anandamide. NAPE is produced in mammals through the transfer of an acyl chain from certain glycerophospholipids to phosphatidylethanolamine (PE) by Ca(2+)-dependent or -independent N-acyltransferases. The epsilon isoform of mouse cytosolic phospholipase A2 (cPLA2epsilon) was recently identified as a Ca(2+)-dependent N-acyltransferase (Ca-NAT). In the present study, we first showed that two isoforms of human cPLA2epsilon function as Ca-NAT. We next purified both mouse recombinant cPLA2epsilon and its two human orthologues to examine their catalytic properties. The enzyme absolutely required Ca(2+) for its activity and the activity was enhanced by phosphatidylserine (PS). PS enhanced the activity 25-fold in the presence of 1mM CaCl2 and lowered the EC50 value of Ca(2+) >8-fold. Using a PS probe, we showed that cPLA2epsilon largely co-localizes with PS in plasma membrane and organelles involved in the endocytic pathway, further supporting the interaction of cPLA2epsilon with PS in living cells. Finally, we found that the Ca(2+)-ionophore ionomycin increased [(14)C]NAPE levels >10-fold in [(14)C]ethanolamine-labeled cPLA2epsilon-expressing cells while phospholipase A/acyltransferase-1, acting as a Ca(2+)-independent N-acyltransferase, was insensitive to ionomycin for full activity. In conclusion, PS potently stimulated the Ca(2+)-dependent activity and human cPLA2epsilon isoforms also functioned as Ca-NAT. |
