Phospholipase A and acyltransferase 4

Exhibits both phospholipase A1/2 and acyltransferase activities. Shows phospholipase A1 (PLA1) and A2 (PLA2), catalyzing the calcium-independent release of fatty acids from the sn-1 or sn-2 position of glycerophospholipids. For most substrates, PLA1 activity is much higher than PLA2 activity. Shows O-acyltransferase activity, catalyzing the transfer of a fatty acyl group from glycerophospholipid to the hydroxyl group of lysophospholipid. Shows N-acyltransferase activity, catalyzing the calcium-independent transfer of a fatty acyl group at the sn-1 position of phosphatidylcholine (PC) and other glycerophospholipids to the primary amine of phosphatidylethanolamine (PE), forming N-acylphosphatidylethanolamine (NAPE), which serves as precursor for N-acylethanolamines (NAEs). Promotes keratinocyte differentiation via activation of TGM1.