Identification and Characterization of a Gene Encoding Human LPGAT1, an Endoplasmic Reticulum-associated Lysophosphatidylglycerol Acyltransferase

Yang, Yanzhu; Cao, Jingsong; Shi, Yuguang

doi:10.1074/jbc.m406710200

Cited by 94 publications

(108 citation statements)

References 52 publications

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“…Using the 798 GPAT2 amino acid sequence, the Blast alignment of GPAT1 and GPAT2 showed an amino acid sequence identity of 27% with GPAT1 and, in the active site region from amino acid 153 to 372, an amino acid identity of 24.5%. The active site region contained recognizable motifs 1 and 4 that had been identified in E. coli PlsB [8,14] and mouse GPAT1 [15], and that are present in dihydroxyacetonephosphate acyltransferase [1], lysocardiolipin acyltransferase [16], and lysophosphatidylglycerol acyltransferase [17]. Motifs 2 and 3, however, differed in GPAT2.…”

Section: Identification Of the Gpat2 Sequencementioning

confidence: 99%

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: Identification Of the Gpat2 Sequencementioning

confidence: 99%

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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“…Whereas the recombinant LPAAT␣ was shown to use various fatty acyl-CoAs as acyl donors, no lysophospholipid other than LPA was found to serve as an acceptor. Several LPLATs, including LPAAT␣ and ␤, lyso-PG acyltransferase (LPGAT), and lyso-CL acyltransferase (ALCAT), have been cloned in the last decade, and putative LPAATs (␥, ␦, , , and ) and tafazzin have been reported (12)(13)(14)(15)(16)(17)(18)(19). Recently, our group identified two lyso-PC acyltansferases (LPCATs) functioning in the remodeling pathway, designated LPCAT1 and lyso-PAF acetyltransferase (LysoPAFAT)/LPCAT2, which are mainly expressed in lung and inflammatory cells, respectively (20,21).…”

mentioning

confidence: 99%

Discovery of a lysophospholipid acyltransferase family essential for membrane asymmetry and diversity

Hishikawa

Shindou²,

Kobayashi³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

291

282

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All organisms consist of cells that are enclosed by a cell membrane containing bipolar lipids and proteins. Glycerophospholipids are important not only as structural and functional components of cellular membrane but also as precursors of various lipid mediators. Polyunsaturated fatty acids comprising arachidonic acid or eicosapentaenoic acid are located at sn-2 position, but not at sn-1 position of glycerophospholipids in an asymmetrical manner. In addition to the asymmetry, the membrane diversity is important for membrane fluidity and curvature. To explain the asymmetrical distribution of fatty acids, the rapid turnover of sn-2 position was proposed in 1958 by Lands [Lands WE (1958) Metabolism of glycerolipides: A comparison of lecithin and triglyceride synthesis. J Biol Chem 231:883-888]. However, the molecular mechanisms and biological significance of the asymmetry remained unknown. Here, we describe a putative enzyme superfamily consisting mainly of three gene families, which catalyzes the transfer of acyl-CoAs to lysophospholipids to produce different classes of phospholipids. Among them, we characterized three important enzymes with different substrate specificities and tissue distributions; one, termed lysophosphatidylcholine acyltransferase-3 (a mammalian homologue of Drosophila nessy critical for embryogenesis), prefers arachidonoyl-CoA, and the other two enzymes incorporate oleoyl-CoAs to lysophosphatidylethanolamine and lysophosphatidylserine. Thus, we propose that the membrane diversity is produced by the concerted and overlapped reactions with multiple enzymes that recognize both the polar head group of glycerophospholipids and various acyl-CoAs. Our findings constitute a critical milestone for our understanding about how membrane diversity and asymmetry are established and their biological significance.glycerophospholipids ͉ Lands' cycle ͉ membrane remodeling ͉ phospholipase A 2 ͉ acyl-CoA

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“…Structural analysis of several glycerolipid acyltransferases from a variety of organisms has revealed a critical domain responsible for their catalytic activity (12). The critical amino acid motif of H(X) 4 D is present within this domain in all glycerolipid acyltransferases that have been studied to date (8)(9)(10)(11). To our knowledge, the cloning of any lysoPC acyltransferase has not been reported.…”

mentioning

confidence: 99%

“…Only a few glycerol lipid acyltransferases have been cloned and sequenced (7)(8)(9)(10)(11). Structural analysis of several glycerolipid acyltransferases from a variety of organisms has revealed a critical domain responsible for their catalytic activity (12).…”

mentioning

confidence: 99%

Identification and characterization of a lysophosphatidylcholine acyltransferase in alveolar type II cells

Chen

Hyatt

Mucenski

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

176

187

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Pulmonary surfactant is a complex of lipids and proteins produced and secreted by alveolar type II cells that provides the low surface tension at the air-liquid interface. The phospholipid most responsible for providing the low surface tension in the lung is dipalmitoylphosphatidylcholine. Dipalmitoylphosphatidylcholine is synthesized in large part by phosphatidylcholine (PC) remodeling, and a lysophosphatidylcholine (lysoPC) acyltransferase is thought to play a critical role in its synthesis. However, this acyltransferase has not yet been identified. We have cloned full-length rat and mouse cDNAs coding for a lysoPC acyltransferase (LPCAT). LPCAT encodes a 535-aa protein of Ϸ59 kDa that contains a transmembrane domain and a putative acyltransferase domain. When transfected into COS-7 cells and HEK293 cells, LPCAT significantly increased lysoPC acyltransferase activity. LPCAT preferred lysoPC as a substrate over lysoPA, lysoPI, lysoPS, lysoPE, or lysoPG and prefers palmitoyl-CoA to oleoyl-CoA as the acyl donor. This LPCAT was preferentially expressed in the lung, specifically within alveolar type II cells. Expression in the fetal lung and in rat type II cells correlated with the expression of the surfactant proteins. LPCAT expression in fetal lung explants was sensitive to dexamethasone and FGFs. KGF was a potent stimulator of LPCAT expression in cultured adult type II cells. We hypothesize that LPCAT plays a critical role in regulating surfactant phospholipid biosynthesis and suggest that understanding the regulation of LPCAT will offer important insight into surfactant phospholipid biosynthesis.biochemistry ͉ lung ͉ surfactant ͉ phosphatidylcholine

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Identification and Characterization of a Gene Encoding Human LPGAT1, an Endoplasmic Reticulum-associated Lysophosphatidylglycerol Acyltransferase

Cited by 94 publications

References 52 publications

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

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

Discovery of a lysophospholipid acyltransferase family essential for membrane asymmetry and diversity

Identification and characterization of a lysophosphatidylcholine acyltransferase in alveolar type II cells

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