title: Plant acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs) have different specificities in their forward and reverse reactions.
abstract: Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) enzymes have central roles in acyl editing of phosphatidylcholine (PC). Plant LPCAT genes were expressed in yeast and characterized biochemically in microsomal preparations of the cells. Specificities for different acyl-CoAs were similar for seven LPCATs from five different species, including species accumulating hydroxylated acyl groups in their seed oil, with a preference for C18-unsaturated acyl-CoA and low activity with palmitoyl-CoA and ricinoleoyl (12-hydroxyoctadec-9-enoyl)-CoA. We showed that Arabidopsis LPCAT1 and LPCAT2 enzymes catalyzed the acylation and de-acylation of both sn positions of PC, with a preference for the sn-2 position. When acyl specificities of the Arabidopsis LPCATs were measured in the reverse reaction, sn-2-bound oleoyl, linoleoyl, and linolenoyl groups from PC were transferred to acyl-CoA to a similar extent. However, a ricinoleoyl group at the sn-2-position of PC was removed 4-6-fold faster than an oleoyl group in the reverse reaction, despite poor utilization in the forward reaction. The data presented, taken together with earlier published reports on in vivo lipid metabolism, support the hypothesis that plant LPCAT enzymes play an important role in regulating the acyl-CoA composition in plant cells by transferring polyunsaturated and hydroxy fatty acids produced on PC directly to the acyl-CoA pool for further metabolism or catabolism.
authors.affiliation: From the Department of Plant Breeding, Swedish University of Agricultural Sciences, S-230 53 Alnarp, Sweden.
authors.forename: Ida
authors.initials: I
authors.lastname: Lager
authors.forename: Jenny Lindberg
authors.initials: JL
authors.lastname: Yilmaz
authors.forename: Xue-Rong
authors.initials: XR
authors.lastname: Zhou
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Jasieniecka
authors.forename: Michael
authors.initials: M
authors.lastname: Kazachkov
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Jitao
authors.initials: J
authors.lastname: Zou
authors.forename: Randall
authors.initials: R
authors.lastname: Weselake
authors.forename: Mark A
authors.initials: MA
authors.lastname: Smith
authors.forename: Shen
authors.initials: S
authors.lastname: Bayon
authors.forename: John M
authors.initials: JM
authors.lastname: Dyer
authors.forename: Jay M
authors.initials: JM
authors.lastname: Shockey
authors.forename: Ernst
authors.initials: E
authors.lastname: Heinz
authors.forename: Allan
authors.initials: A
authors.lastname: Green
authors.forename: Antoni
authors.initials: A
authors.lastname: Banas
authors.forename: Sten
authors.initials: S
authors.lastname: Stymne
mesh_terms: D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000215:Acylation; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002384:Catalysis; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D013045:Species Specificity
chemical_list: D000214:Acyl Coenzyme A; D029681:Arabidopsis Proteins; D005231:Fatty Acids, Unsaturated; D008243:1-Acylglycerophosphocholine O-Acyltransferase
keywords: Arabidopsis; Enzyme; Enzymes; Lipid Metabolism; Lysophosphatidylcholine Acyltransferases; Phosphatidylcholine; Phosphatidylcholine Metabolism; Plant Biochemistry; Plant Lipid Biochemistry