title: Malonylation of Glucosylated N-Lauroylethanolamine: A NEW PATHWAY THAT DETERMINES N-ACYLETHANOLAMINE METABOLIC FATE IN PLANTS.
abstract: N-Acylethanolamines (NAEs) are bioactive fatty acid derivatives present in trace amounts in many eukaryotes. Although NAEs have signaling and physiological roles in animals, little is known about their metabolic fate in plants. Our previous microarray analyses showed that inhibition of Arabidopsis thaliana seedling growth by exogenous N-lauroylethanolamine (NAE 12:0) was accompanied by the differential expression of multiple genes encoding small molecule-modifying enzymes. We focused on the gene At5g39050, which encodes a phenolic glucoside malonyltransferase 1 (PMAT1), to better understand the biological significance of NAE 12:0-induced gene expression changes. PMAT1 expression was induced 3-5-fold by exogenous NAE 12:0. PMAT1 knockouts (pmat1) had reduced sensitivity to the growth-inhibitory effects of NAE 12:0 compared with wild type leading to the hypothesis that PMAT1 might be a previously uncharacterized regulator of NAE metabolism in plants. To test this hypothesis, metabolic profiling of wild-type and pmat1 seedlings treated with NAE 12:0 was conducted. Wild-type seedlings treated with NAE 12:0 accumulated glucosylated and malonylated forms of this NAE species, and structures were confirmed using nuclear magnetic resonance (NMR) spectroscopy. By contrast, only the peak corresponding to NAE 12:0-glucoside was detected in pmat1 Recombinant PMAT1 catalyzed the reaction converting NAE 12:0-glucoside to NAE 12:0-mono- or -dimalonylglucosides providing direct evidence that this enzyme is involved in NAE 12:0-glucose malonylation. Taken together, our results indicate that glucosylation of NAE 12:0 by a yet to be determined glucosyltransferase and its subsequent malonylation by PMAT1 could represent a mechanism for modulating the biological activities of NAEs in plants.
authors.affiliation: From the Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401.
authors.forename: Bibi Rafeiza
authors.initials: BR
authors.lastname: Khan
authors.affiliation: the Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Wherritt
authors.affiliation: From the Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401.
authors.forename: David
authors.initials: D
authors.lastname: Huhman
authors.affiliation: the Bond Life Sciences Center, Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, and.
authors.forename: Lloyd W
authors.identifier: 0000-0002-4086-663X
authors.initials: LW
authors.lastname: Sumner
authors.affiliation: the Division of Biochemistry and Molecular Biology, Department of Biological Sciences, University of North Texas, Denton, Texas 76203-5220.
authors.forename: Kent D
authors.identifier: 0000-0003-0489-3072
authors.initials: KD
authors.lastname: Chapman
authors.affiliation: From the Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401, eblancaflor@noble.org.
authors.forename: Elison B
authors.identifier: 0000-0001-6115-9670
authors.initials: EB
authors.lastname: Blancaflor
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004983:Ethanolamines / Q000378:metabolism*; D005960:Glucosides / Q000378:metabolism*; D007850:Lauric Acids / Q000378:metabolism*; D008314:Malonates / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D004983:Ethanolamines; D005960:Glucosides; D007850:Lauric Acids; D008314:Malonates; C022203:N-acylethanolamines; C090359:N-lauroylethanolamine; C030290:malonic acid; D000581:Amidohydrolases
keywords: Arabidopsis thaliana; glycosylation; lipid metabolism; metabolomics; nuclear magnetic resonance (NMR)