title: Novel reactions in acyl editing of phosphatidylcholine by lysophosphatidylcholine transacylase (LPCT) and acyl-CoA:glycerophosphocholine acyltransferase (GPCAT) activities in microsomal preparations of plant tissues.
abstract: Plants have lysophosphatidylcholine transacylase (LPCT) and acyl-CoA:glycerophosphocholine acyltransferase (GPCAT) activities. The combined action of LPCT and GPCAT provides a novel route of PC re-synthesis after its deacylation. Phosphatidylcholine (PC) is the major lipid in eukaryotic membranes and has a central role in overall plant lipid metabolism. It is also the site of production of polyunsaturated fatty acids in plants. The recently discovered acyl-CoA:glycerophosphocholine acyltransferase (GPCAT) activity in yeast provides a novel route of re-synthesising PC via lysophosphatidylcholine (LPC) after its deacylation. This route does not require the degradation of the glycerophosphocholine (GPC) into free choline, the activation of choline to CDP-choline, nor the utilization of CDP-choline by the CDP-choline:diacylglycerol cholinephosphotransferase. We show here that GPCAT activities also are present in membrane preparations from developing oil seeds of safflower and other species as well as in membrane preparations of roots and leaves of Arabidopsis, indicating that GPCAT activity plays a ubiquitous role in plant lipid metabolism. The last step in formation of GPC, the substrate for GPCAT, is the deacylation of LPC. Microsomal membranes of developing safflower seeds utilized LPC in LPC:LPC transacylation reactions (LPCT activities) creating PC and GPC. The results demonstrate that safflower membranes have LPCT and GPCAT activities that represent novel reactions for PC acyl editing. The physiological relevance of these reactions probably has to await identification of the enzymes catalysing these reactions.
authors.affiliation: Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden, ida.lager@slu.se.
authors.forename: Ida
authors.initials: I
authors.lastname: Lager
authors.forename: Bartosz
authors.initials: B
authors.lastname: Glab
authors.forename: Lovisa
authors.initials: L
authors.lastname: Eriksson
authors.forename: Guanqun
authors.initials: G
authors.lastname: Chen
authors.forename: Antoni
authors.initials: A
authors.lastname: Banas
authors.forename: Sten
authors.initials: S
authors.lastname: Stymne
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D008244:Lysophosphatidylcholines / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*
chemical_list: D008244:Lysophosphatidylcholines; D010940:Plant Proteins; D000217:Acyltransferases