A Multigene Family of Lysophosphatidic Acid Acyltransferases of Arabidopsis Thaliana

Maisonneuve, Sylvie; Guyot, Romain; Delseny, Michel; Roscoe, Thomas

doi:10.1007/978-94-017-0159-4_42

Cited by 5 publications

(4 citation statements)

References 5 publications

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“…Also, a thorough search of the Arabidopsis database for genes that might encode LPAATs has not been described. A short report mentions 10 unspecified putative LPAAT genes in Arabidopsis (Maisonneuve et al, 2003). A Web site for Arabidopsis genes involved in lipid metabolism (Beisson et al, 2003; http://www.…”

Section: Arabidopsis Has Five Genes That Could Encode Lpaatsmentioning

confidence: 99%

Plastid Lysophosphatidyl Acyltransferase Is Essential for Embryo Development in Arabidopsis

2004

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Lysophosphatidyl acyltransferase (LPAAT) is a pivotal enzyme controlling the metabolic flow of lysophosphatidic acid into different phosphatidic acids in diverse tissues. A search of the Arabidopsis genome database revealed five genes that could encode LPAAT-like proteins. We identified one of them, LPAAT1, to be the lone gene that encodes the plastid LPAAT. LPAAT1 could functionally complement a bacterial mutant that has defective LPAAT. Bacteria transformed with LPAAT1 produced LPAAT that had in vitro enzyme activity much higher on 16:0-coenzyme A than on 18:1-coenzyme A in the presence of 18:1-lysophosphatidic acid. LPAAT1 transcript was present in diverse organs, with the highest level in green leaves. A mutant having a T-DNA inserted into LPAAT1 was identified. The heterozygous mutant has no overt phenotype, and its leaf acyl composition is similar to that of the wild type. Selfing of a heterozygous mutant produced normal-sized and shrunken seeds in the Mendelian ratio of 3:1, and the shrunken seeds could not germinate. The shrunken seeds apparently were homozygous of the T-DNA-inserted LPAAT1, and development of the embryo within them was arrested at the hearttorpedo stage. This embryo lethality could be rescued by transformation of the heterozygous mutant with a 35S:LPAAT1 construct. The current findings of embryo death in the homozygous knockout mutant of the plastid LPAAT contrasts with earlier findings of a normal phenotype in the homozygous mutant deficient of the plastid glycerol-3-phosphate acyltransferase; both mutations block the synthesis of plastid phosphatidic acid. Reasons for the discrepancy between the contrasting phenotypes of the two mutants are discussed.Glycerolipids are the most abundant lipids in higher plants (Somerville et al., 2000;Voelker and Kinney, 2001). They are synthesized in two subcellular compartments, which are denoted as the prokaryotic and eukaryotic systems. In the prokaryotic system of the plastids, glycerol-3-phosphate (GP) is acylated sequentially with acyl acyl-carrier protein (ACP) to lysophosphatidic acid (LPA) and phosphatidic acid (PA), which are catalyzed by GP acyltransferase (AT; EC 2.3.1.15) and lysophosphatidyl AT (LPAAT; EC 2.3.1.51), respectively. The PA is converted to different glyco-and sulfo-lipids for membrane synthesis within the plastids. In the eukaryotic system of mainly the endoplasmic reticulum (ER), GP is acylated sequentially with acyl-CoA to LPA and PA, which are also catalyzed by glycerol-3-phosphate acyltransferase (GPAT) and LPAAT, respectively. The PA is converted to phospholipids for incorporation into the ER membranes, which will eventually be distributed throughout the cell to become membranes of different eukaryotic cell components. Some of the cytoplasm-synthesized glycerolipids are channeled to the plastids to be converted to glycol-and sulfo-lipids. In maturing seeds, the cytoplasmsynthesized PA is also converted to triacylglycerols (TAGs) for storage. The prokaryotic and eukaryotic glycerolipid syntheses are similar in the two-en...

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Section: Arabidopsis Has Five Genes That Could Encode Lpaatsmentioning

confidence: 99%

Plastid Lysophosphatidyl Acyltransferase Is Essential for Embryo Development in Arabidopsis

2004

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“…Polyamines stabilize the membrane by bridging and shielding the charged membrane. (4) The existence of isozymes-in Arabidopsis thaliana, putative members of the LPA acyltransferase multigene family were identified (Maisonneuve et al 2003) and one of them was shown to encode a plastid LPA acyltransferase (Kim and Huang 2004). Castor bean may possess an isozyme that is dependent on polyamines.…”

Section: Discussionmentioning

confidence: 98%

Polyamines are essential for the synthesis of 2-ricinoleoyl phosphatidic acid in developing seeds of castor

Tomosugi

Ichihara

Saito

2005

Planta

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The major fatty acid component of castor (Ricinus communis L.) oil is ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid), and unsaturated hydroxy acid accounts for >85% of the total fatty acids in triacylglycerol (TAG). TAG had a higher ricinoleate content at position 2 than at positions 1 and 3. Although lysophosphatidic acid (LPA) acyltransferase (EC 2.3.1.51), which catalyzes acylation of LPA at position 2, was expected to utilize ricinoleoyl-CoA preferentially over other fatty acyl-CoAs, no activity was found for ricinoleoyl-CoA in vitro at concentrations at which other unsaturated acyl-CoAs were incorporated rapidly. However, activity for ricinoleoyl-CoA appeared with addition of polyamines (putrescine, spermidine, and spermine), while polyamines decreased the rates of incorporation of other acyl-CoAs into position 2. The order of effect of polyamines on LPA acyltransferase activity was spermine > spermidine >> putrescine. At concentrations of spermine and spermidine of >0.1 mM, ricinoleoyl-CoA served as an effective substrate for LPA acyltransferase reaction. The concentrations of spermine and spermidine in the developing seeds were estimated at approximately 0.09 and approximately 0.63 mM, respectively. These stimulatory effects for incorporation of ricinoleate were specific to polyamines, but basic amino acids were ineffective as cations. In contrast, in microsomes from safflower seeds that do not contain ricinoleic acid, spermine and spermidine stimulated the LPA acyltransferase reaction for all acyl-CoAs tested, including ricinoleoyl-CoA. Although the fatty acid composition of TAG depends on both acyl-CoA composition in the cell and substrate specificity of acyltransferases, castor bean polyamines are crucial for incorporation of ricinoleate into position 2 of LPA. Polyamines are essential for synthesis of 2-ricinoleoyl phosphatidic acid in developing castor seeds.

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“…The sequences from several plant LPATs indicated that this enzyme possessed 4 transmembrane domains that anchored it very strongly in the ER membranes [61]. The carboxyl and amino terminals were orientated to the cytosol, as was the catalytic center where the acylation reaction takes place.…”

Section: Lysophosphatidic Acid:acyl-coa Acyltransferasementioning

confidence: 99%

Biochemistry of high stearic sunflower, a new source of saturated fats

Salas

Martı́nez-Force

Harwood

et al. 2014

Progress in Lipid Research

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Fats based on stearic acid could be a healthy alternative to existing oils especially hydrogenated fractions oils or palm, but only a few non-tropical species produce oils with these characteristics. In this regard, newly developed high stearic oilseed crops could be a future source of healthy fats and hard stocks rich in stearic and oleic fatty acids. These oil crops have been obtained either by breeding and mutagenesis or by suppression of desaturases using RNA interference. The present review depicts the molecular and biochemical bases for the accumulation of stearic acid in sunflower.Moreover, aspects limiting the accumulation of stearate in the seeds of this species are reviewed. This included data obtained of the characterization of genes and enzymes related to fatty acid biosynthesis and triacylglycerol assembly. Future improvements and uses of these oils are also discussed.

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A Multigene Family of Lysophosphatidic Acid Acyltransferases of Arabidopsis Thaliana

Cited by 5 publications

References 5 publications

Plastid Lysophosphatidyl Acyltransferase Is Essential for Embryo Development in Arabidopsis

Plastid Lysophosphatidyl Acyltransferase Is Essential for Embryo Development in Arabidopsis

Polyamines are essential for the synthesis of 2-ricinoleoyl phosphatidic acid in developing seeds of castor

Biochemistry of high stearic sunflower, a new source of saturated fats

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