Enzymes of triacylglycerol synthesis and their regulation

Coleman, Rosalind A.; Lee, Douglas P.

doi:10.1016/s0163-7827(03)00051-1

Cited by 838 publications

(769 citation statements)

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“…In mammals and bacteria, motif 2 normally contains the sequence FXXR, and the invariant arginine is essential for the activity of human tafazzin, human dihydroxyacetonephosphate acyltransferase and E. coli PlsB, probably because it interacts with the phosphate portion of the glycerolphosphate substrates of these enzymes [1]. Motif 3 usually contains the consensus sequence FXEGXRXR in which the glutamic acid, glycine, and the first arginine are essential for activity [1,15]. In GPAT2, however, the usual motif 2 and 3 sequences differ markedly from GPAT1 and are similar, instead, to sequences in several chloroplast GPATs (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…This reaction is catalyzed by glycerol-3-phosphate acyltransferase (GPAT 1 ; EC 3.1.3.9) which exhibits the lowest specific activity of all enzymes in the glycerol-3-phosphate pathway, suggesting that it is the rate limiting step [1].…”

Section: Introductionmentioning

confidence: 99%

“…Microsomal GPAT activity does not appear to be regulated in liver. In contrast, the mitochondrial isoform (GPAT1) 2 that has been purified [5] and cloned [6,7], is highly regulated by insulin and SREBP1c under conditions in which fatty acid and triacylglycerol synthesis are enhanced [1]. GPAT1, which comprises 30−50% of total GPAT activity in rodent liver is NEM-resistant.…”

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confidence: 99%

“…A search of the mouse and human databases with a sequence encompassing the GPAT1 active site region [8] identified a putative glycerolipid acyltransferase with significant homology to GPAT1 and a similar molecular mass. Here we report the cloning and expression of GPAT2 and demonstrate that overexpression of GPAT2 in Cos-7 cells increases [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]oleate incorporation into triacylglycerol.…”

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Cloning and functional characterization of a novel mitochondrial N-ethylmaleimide-sensitive glycerol-3-phosphate acyltransferase (GPAT2)

Wang

Lee²,

Gong³

et al. 2007

Archives of Biochemistry and Biophysics

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Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the initial and rate-limiting step in glycerolipid synthesis. Several mammalian GPAT activities have been recognized, including Nethylmaleimide (NEM)-sensitive isoforms in microsomes and mitochondria and an NEM-resistant form in mitochondrial outer membrane (GPAT1). We have now cloned a second mitochondrial isoform, GPAT2 from mouse testis. The open reading frame encodes a protein of 798 amino acids with a calculated mass of 88.8 kDa and 27% amino acid identity to GPAT1. Testis mRNA expression was 50-fold higher than in liver or brown adipose tissue, but the specific activity of NEM-sensitive GPAT in testis mitochondria was similar to that in liver. When Cos-7 cells were transiently transfected with GPAT2, NEM-sensitive GPAT activity increased 30%. Confocal microscopy confirmed a mitochondrial location. Incubation of GPAT2-transfected Cos-7 cells with trace (3 μM; 0.25μCi) [1-14 C]oleate for 6 h increased incorporation of [ 14 C]oleate into TAG 84%. In contrast, incorporation into phospholipid species was lower than in control cells. Although a polyclonal antibody raised against full-length GPAT1 detected an ∼89 kDa band in liver and testis from GPAT1 null mice and both 89 and 80 kDa bands in BAT from the knockout animals, the GPAT2 protein expressed in Cos-7 cells was only 80 kDa. In vitro translation showed a single product of 89 kDa. Unlike GPAT1, GPAT2 mRNA abundance in liver was not altered by fasting or refeeding. GPAT2 is likely to have a specialized function in testis.The synthesis of triacylglycerol and all glycerophospholipids begins with the acylation of glycerol-3-phosphate with long-chain fatty acyl-CoA to produce 1-acylglycerol-3-phosphate. This reaction is catalyzed by glycerol-3-phosphate acyltransferase (GPAT 1 ; EC 3.1.3.9) which exhibits the lowest specific activity of all enzymes in the glycerol-3-phosphate pathway, suggesting that it is the rate limiting step [1].Three mammalian GPAT activities have been differentiated based on their subcellular location and biochemical properties [2,3]. GPAT activity is present in microsomal and mitochondrial Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. fractions. In most tissues, 90% of the activity is attributed to a microsomal GPAT which is sensitive to inactivation by sulfhydryl reagents such as NEM. Microsomal GPAT3, prominent in adipose tissue, has been cloned [4]. Microsomal GPAT activity does not appear to be regulated in liver. In contrast, the mitochondrial isoform (GPAT1) 2 that has been purified [5] and cloned [6,7], is highly regulated by i...

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Cloning and functional characterization of a novel mitochondrial N-ethylmaleimide-sensitive glycerol-3-phosphate acyltransferase (GPAT2)

Wang

Lee²,

Gong³

et al. 2007

Archives of Biochemistry and Biophysics

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“…6,7 TG is synthesized by a number of enzymes. 8 Acyl-CoA: diacylglycerol acyltransferase (DGAT) 9 is the final enzyme to synthesize TG, and only a few DGAT inhibitors have been reported by several groups, including ours. [10][11][12][13][14] We established a high content assay to observe the TG biosynthetic pathway using Chinese hamster ovary (CHO) K1 cells.…”

Section: Introductionmentioning

confidence: 86%

New isochaetochromin, an inhibitor of triacylglycerol synthesis in mammalian cells, produced by Penicillium sp. FKI-4942: I. Taxonomy, fermentation, isolation and biological properties

et al. 2011

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A new bis-naphtho-c-pyrone isomer named isochaetochromin A 1 was isolated along with known isochaetochromins B 1 and B 2 from the culture broth of Penicillium sp. FKI-4942 by solvent extraction, silica gel column chromatography and HPLC. Among them, isochaetochromin B 1 showed the most potent inhibitory activity of triacylglycerol synthesis with an IC 50 value of 5.6 lM, followed by isochaetochromins B 2 (IC 50 , 11 lM) and A 1 (33 lM).

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