1
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Kim S, Lee KR, Suh MC. Ectopic Expression of Perilla frutescens WRI1 Enhanced Storage Oil Accumulation in Nicotiana benthamiana Leaves. PLANTS (BASEL, SWITZERLAND) 2023; 12:1081. [PMID: 36903941 PMCID: PMC10005204 DOI: 10.3390/plants12051081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/14/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Vegetable oils are indispensable in human and animal diets and have been widely used for the production of detergents, lubricants, cosmetics, and biofuels. The seeds of an allotetraploid Perilla frutescens contain approximately 35 to 40% oils with high levels of polyunsaturated fatty acids (PUFAs). WRINKELD1 (WRI1) encoding an AP2/ERF-type transcription factor is known to upregulate the expression of genes involved in glycolysis and fatty acid biosynthesis and TAG assembly. In this study, two WRI1 isoforms, PfWRI1A, and PfWRI1B were isolated from Perilla and predominantly expressed in developing Perilla seeds. The fluorescent signals from PfWRI1A:eYFP and PfWRI1B:eYFP driven by the CaMV 35S promoter were detected in the nucleus of the Nicotiana benthamiana leaf epidermis. Ectopic expression of each of PfWRI1A and PfWRI1B increased the levels of TAG by approximately 2.9- and 2.7-fold in N. benthamiana leaves and particularly, the enhanced levels (mol%) of C18:2, and C18:3 in the TAGs were prominent with the concomitant reduction in the amounts of saturated fatty acids. The expression levels of NbPl-PKβ1, NbKAS1, and NbFATA, which were known to be target genes of WRI1, significantly increased in tobacco leaves overexpressing PfWRI1A or PfWRI1B. Therefore, newly characterized PfWRI1A and PfWRI1B can be potentially useful for the enhanced accumulation of storage oils with increased PUFAs in oilseed crops.
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Affiliation(s)
- Semi Kim
- Department of Life Science, Sogang University, Seoul 04107, Republic of Korea
| | - Kyeong-Ryeol Lee
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju 54875, Republic of Korea
| | - Mi Chung Suh
- Department of Life Science, Sogang University, Seoul 04107, Republic of Korea
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2
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Shen Y, Shen Y, Liu Y, Bai Y, Liang M, Zhang X, Chen Z. Characterization and functional analysis of AhGPAT9 gene involved in lipid synthesis in peanut ( Arachis hypogaea L.). FRONTIERS IN PLANT SCIENCE 2023; 14:1144306. [PMID: 36844041 PMCID: PMC9950565 DOI: 10.3389/fpls.2023.1144306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
GPAT enzymes (glycerol-3-phosphate 1-O-acyltransferase, EC 2.3.1.15) catalyze the initial and rate-limiting step of plant glycerolipid biosynthesis for membrane homeostasis and lipid accumulation, yet little research has been done on peanuts. By reverse genetics and bioinformatics analyses, we have characterized an AhGPAT9 isozyme, of which the homologous product is isolated from cultivated peanut. QRT-PCR assay revealed a spatio-temporal expression pattern that the transcripts of AhGPAT9 accumulating in various peanut tissues are highly expressed during seed development, followed by leaves. Green fluorescent protein tagging of AhGPAT9 confirmed its subcellular accumulation in the endoplasmic reticulum. Compared with the wild type control, overexpressed AhGPAT9 delayed the bolting stage of transgenic Arabidopsis, reduced the number of siliques, and increased the seed weight as well as seed area, suggesting the possibility of participating in plant growth and development. Meanwhile, the mean seed oil content from five overexpression lines increased by about 18.73%. The two lines with the largest increases in seed oil content showed a decrease in palmitic acid (C16:0) and eicosenic acid (C20:1) by 17.35% and 8.33%, respectively, and an increase in linolenic acid (C18:3) and eicosatrienoic acid (C20:3) by 14.91% and 15.94%, respectively. In addition, overexpressed AhGPAT9 had no significant effect on leaf lipid content of transgenic plants. Taken together, these results suggest that AhGPAT9 is critical for the biosynthesis of storage lipids, which contributes to the goal of modifying peanut seeds for improved oil content and fatty acid composition.
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Affiliation(s)
- Yue Shen
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yi Shen
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yonghui Liu
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yang Bai
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing, China
| | - Man Liang
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xuyao Zhang
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Zhide Chen
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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3
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Rangan P, Maurya R, Singh S. Can omic tools help generate alternative newer sources of edible seed oil? PLANT DIRECT 2022; 6:e399. [PMID: 35774621 PMCID: PMC9219012 DOI: 10.1002/pld3.399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/04/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
There are three pathways for triacylglycerol (TAG) biosynthesis: De novo TAG biosynthesis, phosphatidylcholine-derived biosynthesis, and cytosolic TAG biosynthesis. Variability in fatty acid composition is mainly associated with phosphatidylcholine-derived TAG pathway. Mobilization of TAG-formed through cytosolic pathway into lipid droplets is yet unknown. There are multiple regulatory checkpoints starting from acetyl-CoA carboxylase to the lipid droplet biogenesis in TAG biosynthesis. Although a primary metabolism, only a few species synthesize oil in seeds for storage, and less than 10 species are commercially exploited. To meet out the growing demand for oil, diversifying into newer sources is the only choice left. The present review highlights the potential strategies targeting species like Azadirachta, Callophyllum, Madhuca, Moringa, Pongamia, Ricinus, and Simarouba, which are not being used for eating but are otherwise high yielding (ranging from 1.5 to 20 tons per hectare) with seeds having a high oil content (40-60%). Additionally, understanding the toxin biosynthesis in Ricinus and Simarouba would be useful in developing toxin-free oil plants. Realization of the importance of cell cultures as "oil factories" is not too far into the future and would soon be a commercially viable option for producing oils in vitro, round the clock.
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Affiliation(s)
- Parimalan Rangan
- Division of Genomic ResourcesICAR‐National Bureau of Plant Genetic ResourcesNew Delhi‐12India
| | - Rasna Maurya
- Division of Genomic ResourcesICAR‐National Bureau of Plant Genetic ResourcesNew Delhi‐12India
| | - Shivani Singh
- Division of Genomic ResourcesICAR‐National Bureau of Plant Genetic ResourcesNew Delhi‐12India
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4
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Aymé L, Arragain S, Canonge M, Baud S, Touati N, Bimai O, Jagic F, Louis-Mondésir C, Briozzo P, Fontecave M, Chardot T. Arabidopsis thaliana DGAT3 is a [2Fe-2S] protein involved in TAG biosynthesis. Sci Rep 2018; 8:17254. [PMID: 30467384 PMCID: PMC6250708 DOI: 10.1038/s41598-018-35545-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 10/30/2018] [Indexed: 11/09/2022] Open
Abstract
Acyl-CoA:diacylglycerol acyltransferases 3 (DGAT3) are described as plant cytosolic enzymes synthesizing triacylglycerol. Their protein sequences exhibit a thioredoxin-like ferredoxin domain typical of a class of ferredoxins harboring a [2Fe-2S] cluster. The Arabidopsis thaliana DGAT3 (AtDGAT3; At1g48300) protein is detected in germinating seeds. The recombinant purified protein produced from Escherichia coli, although very unstable, exhibits DGAT activity in vitro. A shorter protein version devoid of its N-terminal putative chloroplast transit peptide, Δ46AtDGAT3, was more stable in vitro, allowing biochemical and spectroscopic characterization. The results obtained demonstrate the presence of a [2Fe-2S] cluster in the protein. To date, AtDGAT3 is the first metalloprotein described as a DGAT.
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Affiliation(s)
- Laure Aymé
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Simon Arragain
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Paris 6, 11 Place Marcelin Berthelot, 75231, Paris, CEDEX 05, France
| | - Michel Canonge
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Sébastien Baud
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Nadia Touati
- Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), F-75005, Paris, France
| | - Ornella Bimai
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Paris 6, 11 Place Marcelin Berthelot, 75231, Paris, CEDEX 05, France
| | - Franjo Jagic
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Christelle Louis-Mondésir
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Pierre Briozzo
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Paris 6, 11 Place Marcelin Berthelot, 75231, Paris, CEDEX 05, France.
| | - Thierry Chardot
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France.
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5
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Xu Y, Caldo KMP, Pal-Nath D, Ozga J, Lemieux MJ, Weselake RJ, Chen G. Properties and Biotechnological Applications of Acyl-CoA:diacylglycerol Acyltransferase and Phospholipid:diacylglycerol Acyltransferase from Terrestrial Plants and Microalgae. Lipids 2018; 53:663-688. [PMID: 30252128 DOI: 10.1002/lipd.12081] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 12/14/2022]
Abstract
Triacylglycerol (TAG) is the major storage lipid in most terrestrial plants and microalgae, and has great nutritional and industrial value. Since the demand for vegetable oil is consistently increasing, numerous studies have been focused on improving the TAG content and modifying the fatty-acid compositions of plant seed oils. In addition, there is a strong research interest in establishing plant vegetative tissues and microalgae as platforms for lipid production. In higher plants and microalgae, TAG biosynthesis occurs via acyl-CoA-dependent or acyl-CoA-independent pathways. Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step in the acyl-CoA-dependent biosynthesis of TAG, which appears to represent a bottleneck in oil accumulation in some oilseed species. Membrane-bound and soluble forms of DGAT have been identified with very different amino-acid sequences and biochemical properties. Alternatively, TAG can be formed through acyl-CoA-independent pathways via the catalytic action of membrane-bound phospholipid:diacylglycerol acyltransferase (PDAT). As the enzymes catalyzing the terminal steps of TAG formation, DGAT and PDAT play crucial roles in determining the flux of carbon into seed TAG and thus have been considered as the key targets for engineering oil production. Here, we summarize the most recent knowledge on DGAT and PDAT in higher plants and microalgae, with the emphasis on their physiological roles, structural features, and regulation. The development of various metabolic engineering strategies to enhance the TAG content and alter the fatty-acid composition of TAG is also discussed.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biochemistry, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2H7, Canada
| | - Dipasmita Pal-Nath
- French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Jocelyn Ozga
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2H7, Canada
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
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6
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Venkateshwari V, Vijayakumar A, Vijayakumar AK, Reddy LPA, Srinivasan M, Rajasekharan R. Leaf lipidome and transcriptome profiling of Portulaca oleracea: characterization of lysophosphatidylcholine acyltransferase. PLANTA 2018; 248:347-367. [PMID: 29736624 DOI: 10.1007/s00425-018-2908-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
Portulaca leaves serve as an alternative bioresource for edible PUFAs. Transcriptome data provide information to explore Portulaca as a model system for galactolipids, leaf lipid metabolism, and PUFA-rich designer lipids. Poly-unsaturated fatty acids (PUFAs) are gaining importance due to their innumerable health benefits, and hence, understanding their biosynthesis in plants has attained prominence in recent years. The most common source of PUFAs is of marine origin. Although reports have identified Portulaca oleracea (purslane) as a leaf source of omega-3 fatty acids in the form of alpha-linolenic acid (ALA), the mechanism of ALA accumulation and its distribution into various lipids has not been elucidated. Here, we present the lipid profiles of leaves and seeds of several accessions of P. oleracea. Among the nineteen distinct accessions, the RR04 accession has the highest amount of ALA and is primarily associated with galactolipids. In addition, we report the transcriptome of RR04, and we have mapped the potential genes involved in lipid metabolism. Phosphatidylcholine (PC) is the major site of acyl editing, which is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT), an integral membrane protein that plays a major role in supplying oleate to the PC pool for further unsaturation. Our investigations using mass spectrometric analysis of leaf microsomal fractions identified LPCAT as part of a membrane protein complex. Both native and recombinant LPCAT showed strong acyltransferase activity with various acyl-CoA substrates. Altogether, the results suggest that ALA-rich glycerolipid biosynthetic machinery is highly active in nutritionally important Portulaca leaves. Furthermore, lipidome, transcriptome, and mass spectrometric analyses of RR04 provide novel information for exploring Portulaca as a potential resource and a model system for studying leaf lipid metabolism.
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Affiliation(s)
- Varadarajan Venkateshwari
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Anitha Vijayakumar
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
| | - Arun Kumar Vijayakumar
- Food Safety and Analytical Quality Control Department, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
| | - L Prasanna Anjaneya Reddy
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
| | - Malathi Srinivasan
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Ram Rajasekharan
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India.
- Academy of Scientific and Innovative Research, New Delhi, India.
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7
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Selvaraju K, Gowsalya R, Vijayakumar R, Nachiappan V. MGL2/YMR210w encodes a monoacylglycerol lipase in Saccharomyces cerevisiae. FEBS Lett 2016; 590:1174-86. [PMID: 26991558 DOI: 10.1002/1873-3468.12136] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 02/27/2016] [Accepted: 03/10/2016] [Indexed: 11/10/2022]
Abstract
In silico analysis of the uncharacterized open reading frame YMR210w in Saccharomyces cerevisiae revealed that it possesses both an α/β hydrolase domain (ABHD) and a typical lipase (GXSXG) motif. The purified protein displayed monoacylglycerol (MAG) lipase activity and preferred palmitoyl-MAG. Overexpression of YMR210w in the known MAG lipase mutant yju3Δ clearly revealed that the protein had MAG lipase activity, hence we named the ORF MGL2. Overexpression of YMR210w decreased the cellular triacylglycerol levels. Analysis of the overexpressed strains showed reduction in the lipid droplets number and size. Phenotype studies revealed that the double deletion yju3Δmgl2Δ displayed a growth defect that was partially restored by MGL2 overexpression.
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Affiliation(s)
- Kandasamy Selvaraju
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Ramachandran Gowsalya
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Rajendran Vijayakumar
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Vasanthi Nachiappan
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
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8
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Arroyo-Caro JM, Mañas-Fernández A, Alonso DL, García-Maroto F. Type I Diacylglycerol Acyltransferase (MtDGAT1) from Macadamia tetraphylla: Cloning, Characterization, and Impact of Its Heterologous Expression on Triacylglycerol Composition in Yeast. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:277-285. [PMID: 26666454 DOI: 10.1021/acs.jafc.5b04805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Acyltransferase enzymes have been reported as useful biotechnological tools in order to increase oil yield and modify fatty acid composition. Macadamia species are able to accumulate unusually high levels of palmitoleic acid that besides oleic acid amounts to over 80% of monounsaturated fatty acids in the seed oil. In this work, a gene encoding a type 1 acyl-CoA:diacylglycerol acyltransferase (DGAT1) was cloned from M. tetraphylla. DGAT activity of the protein encoded by MtDGAT1 was confirmed by heterologous expression in a yeast mutant. Fatty acid composition of triacylglycerols synthesized by MtDGAT1 was compared to that of DGAT1 enzymes from Arabidopsis and Echium, with the results suggesting a substrate preference for monounsaturated over polyunsaturated fatty acids. Characteristics of MtDGAT1 may contribute to biochemical mechanisms determining the particular fatty acid composition of Macadamia oil and also indicate the possibility of using this enzyme in biotechnological approaches where a reduction of polyunsaturated fatty acids in the oil is desired.
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Affiliation(s)
- José María Arroyo-Caro
- Grupo de "Biotecnología de Productos Naturales" (BIO-279), Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Campus Internacional de Excelencia Agroalimentario (CeiA3), Universidad de Almería , 04120 Almería, Spain
| | - Aurora Mañas-Fernández
- Grupo de "Biotecnología de Productos Naturales" (BIO-279), Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Campus Internacional de Excelencia Agroalimentario (CeiA3), Universidad de Almería , 04120 Almería, Spain
| | - Diego López Alonso
- Grupo de "Biotecnología de Productos Naturales" (BIO-279), Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Campus Internacional de Excelencia Agroalimentario (CeiA3), Universidad de Almería , 04120 Almería, Spain
| | - Federico García-Maroto
- Grupo de "Biotecnología de Productos Naturales" (BIO-279), Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Campus Internacional de Excelencia Agroalimentario (CeiA3), Universidad de Almería , 04120 Almería, Spain
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9
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Responses to phosphate deprivation in yeast cells. Curr Genet 2015; 62:301-7. [PMID: 26615590 DOI: 10.1007/s00294-015-0544-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 01/10/2023]
Abstract
Inorganic phosphate is an essential nutrient because it is required for the biosynthesis of nucleotides, phospholipids and metabolites in energy metabolism. During phosphate starvation, phosphatases play a major role in phosphate acquisition by hydrolyzing phosphorylated macromolecules. In Saccharomyces cerevisiae, PHM8 (YER037W), a lysophosphatidic acid phosphatase, plays an important role in phosphate acquisition by hydrolyzing lysophosphatidic acid and nucleotide monophosphate that results in accumulation of triacylglycerol and nucleotides under phosphate limiting conditions. Under phosphate limiting conditions, it is transcriptionally regulated by Pho4p, a phosphate-responsive transcription factor. In this review, we focus on triacylglycerol metabolism in transcription factors deletion mutants involved in phosphate metabolism and propose a link between phosphate and triacylglycerol metabolism. Deletion of these transcription factors results in an increase in triacylglycerol level. Based on these observations, we suggest that PHM8 is responsible for the increase in triacylglycerol in phosphate metabolising gene deletion mutants.
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10
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Haslam RP, Ruiz-Lopez N, Eastmond P, Moloney M, Sayanova O, Napier JA. The modification of plant oil composition via metabolic engineering--better nutrition by design. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:157-68. [PMID: 23066823 DOI: 10.1111/pbi.12012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 09/19/2012] [Accepted: 09/20/2012] [Indexed: 05/08/2023]
Abstract
This article will focus on the modification of plant seed oils to enhance their nutritional composition. Such modifications will include C18 Δ6-desaturated fatty acids such as γ-linolenic and stearidonic acid, omega-6 long-chain polyunsaturated fatty acids such as arachidonic acid, as well as the omega-3 long-chain polyunsaturated fatty acids (often named 'fish oils') such as eicosapentaenoic acid and docosahexaenoic acid. We will consider how new technologies (such as synthetic biology, next-generation sequencing and lipidomics) can help speed up and direct the development of desired traits in transgenic oilseeds. We will also discuss how manipulating triacylglycerol structure can further enhance the nutritional value of 'designer' oils. We will also consider how advances in model systems have translated into crops and the potential end-users for such novel oils (e.g. aquaculture, animal feed, human nutrition).
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Affiliation(s)
- Richard P Haslam
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts, UK
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11
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Chen JE, Smith AG. A look at diacylglycerol acyltransferases (DGATs) in algae. J Biotechnol 2012; 162:28-39. [PMID: 22750092 DOI: 10.1016/j.jbiotec.2012.05.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 05/17/2012] [Accepted: 05/30/2012] [Indexed: 12/20/2022]
Abstract
Triacylglycerols (TAGs) from algae are considered to be a potentially viable source of biodiesel and thereby renewable energy, but at the moment very little is known about the biosynthetic pathway in these organisms. Here we compare what is currently known in eukaryotic algal species, in particular the characteristics of algal diacylglycerol acyltransferase (DGAT), the last enzyme of de novo TAG biosynthesis. Several studies in plants and mammals have shown that there are two DGAT isoforms, DGAT1 and DGAT2, which catalyse the same reaction but have no clear sequence similarities. Instead, they have differences in functionality and spatial and temporal expression patterns. Bioinformatic searches of sequenced algal genomes reveal that most algae have multiple copies of putative DGAT2s, whereas other eukaryotes have single genes. Investigating whether these putative isoforms are indeed functional and whether they confer significantly different phenotypes to algal cells will be vital for future efforts to genetically modify algae for biofuel production.
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Affiliation(s)
- Jit Ern Chen
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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12
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Vijayaraj P, Jashal CB, Vijayakumar A, Rani SH, Venkata Rao D, Rajasekharan R. A bifunctional enzyme that has both monoacylglycerol acyltransferase and acyl hydrolase activities. PLANT PHYSIOLOGY 2012; 160:667-83. [PMID: 22915575 PMCID: PMC3461547 DOI: 10.1104/pp.112.202135] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 08/16/2012] [Indexed: 05/23/2023]
Abstract
Monoacylglycerol acyltransferase (MGAT) catalyzes the synthesis of diacylglycerol, the precursor of triacylglycerol biosynthesis and an important signaling molecule. Here, we describe the isolation and characterization of the peanut (Arachis hypogaea) MGAT gene. The soluble enzyme utilizes invariant histidine-62 and aspartate-67 residues of the acyltransferase motif for its MGAT activity. A sequence analysis revealed the presence of a hydrolase (GXSXG) motif, and enzyme assays revealed the presence of monoacylglycerol (MAG) and lysophosphatidylcholine (LPC) hydrolytic activities, indicating the bifunctional nature of the enzyme. The overexpression of the MGAT gene in yeast (Saccharomyces cerevisiae) caused an increase in triacylglycerol accumulation. Similar to the peanut MGAT, the Arabidopsis (Arabidopsis thaliana) homolog (At1g52760) also exhibited both acyltransferase and hydrolase activities. Interestingly, the yeast homolog lacks the conserved HX(4)D motif, and it is deficient in the acyltransferase function but exhibits MAG and LPC hydrolase activities. This study demonstrates the presence of a soluble MGAT/hydrolase in plants. The predicted three-dimensional homology modeling and substrate docking suggested the presence of two separate substrate (MAG and LPC)-binding sites in a single polypeptide. Our study describes a soluble bifunctional enzyme that has both MGAT and hydrolase functions.
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13
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Hernández ML, Whitehead L, He Z, Gazda V, Gilday A, Kozhevnikova E, Vaistij FE, Larson TR, Graham IA. A cytosolic acyltransferase contributes to triacylglycerol synthesis in sucrose-rescued Arabidopsis seed oil catabolism mutants. PLANT PHYSIOLOGY 2012; 160:215-25. [PMID: 22760209 PMCID: PMC3440200 DOI: 10.1104/pp.112.201541] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 07/02/2012] [Indexed: 05/19/2023]
Abstract
Triacylglycerol (TAG) levels and oil bodies persist in sucrose (Suc)-rescued Arabidopsis (Arabidopsis thaliana) seedlings disrupted in seed oil catabolism. This study set out to establish if TAG levels persist as a metabolically inert pool when downstream catabolism is disrupted, or if other mechanisms, such as fatty acid (FA) recycling into TAG are operating. We show that TAG composition changes significantly in Suc-rescued seedlings compared with that found in dry seeds, with 18:2 and 18:3 accumulating. However, 20:1 FA is not efficiently recycled back into TAG in young seedlings, instead partitioning into the membrane lipid fraction and diacylglycerol. In the lipolysis mutant sugar dependent1and the β-oxidation double mutant acx1acx2 (for acyl-Coenzyme A oxidase), levels of TAG actually increased in seedlings growing on Suc. We performed a transcriptomic study and identified up-regulation of an acyltransferase gene, DIACYLGLYCEROL ACYLTRANSFERASE3 (DGAT3), with homology to a peanut (Arachis hypogaea) cytosolic acyltransferase. The acyl-Coenzyme A substrate for this acyltransferase accumulates in mutants that are blocked in oil breakdown postlipolysis. Transient expression in Nicotiana benthamiana confirmed involvement in TAG synthesis and specificity toward 18:3 and 18:2 FAs. Double-mutant analysis with the peroxisomal ATP-binding cassette transporter mutant peroxisomal ABC transporter1 indicated involvement of DGAT3 in the partitioning of 18:3 into TAG in mutant seedlings growing on Suc. Fusion of the DGAT3 protein with green fluorescent protein confirmed localization to the cytosol of N. benthamiana. This work has demonstrated active recycling of 18:2 and 18:3 FAs into TAG when seed oil breakdown is blocked in a process involving a soluble cytosolic acyltransferase.
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Affiliation(s)
| | | | - Zhesi He
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Valeria Gazda
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Alison Gilday
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Ekaterina Kozhevnikova
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Fabián E. Vaistij
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Tony R. Larson
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Ian A. Graham
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
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14
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Liu Q, Siloto RMP, Lehner R, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: molecular biology, biochemistry and biotechnology. Prog Lipid Res 2012; 51:350-77. [PMID: 22705711 DOI: 10.1016/j.plipres.2012.06.001] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Triacylglycerol (TG) is a storage lipid which serves as an energy reservoir and a source of signalling molecules and substrates for membrane biogenesis. TG is essential for many physiological processes and its metabolism is widely conserved in nature. Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the final step in the sn-glycerol-3-phosphate pathway leading to TG. DGAT activity resides mainly in two distinct membrane bound polypeptides, known as DGAT1 and DGAT2 which have been identified in numerous organisms. In addition, a few other enzymes also hold DGAT activity, including the DGAT-related acyl-CoA:monoacylglycerol acyltransferases (MGAT). Progress on understanding structure/function in DGATs has been limited by the lack of detailed three-dimensional structural information due to the hydrophobic properties of theses enzymes and difficulties associated with purification. This review examines several aspects of DGAT and MGAT genes and enzymes, including current knowledge on their gene structure, expression pattern, biochemical properties, membrane topology, functional motifs and subcellular localization. Recent progress in probing structural and functional aspects of DGAT1 and DGAT2, using a combination of molecular and biochemical techniques, is emphasized. Biotechnological applications involving DGAT enzymes ranging from obesity therapeutics to oilseed engineering are also discussed.
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Affiliation(s)
- Qin Liu
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6H 2P5.
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15
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Petrie JR, Vanhercke T, Shrestha P, El Tahchy A, White A, Zhou XR, Liu Q, Mansour MP, Nichols PD, Singh SP. Recruiting a new substrate for triacylglycerol synthesis in plants: the monoacylglycerol acyltransferase pathway. PLoS One 2012; 7:e35214. [PMID: 22523576 PMCID: PMC3327653 DOI: 10.1371/journal.pone.0035214] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Accepted: 03/12/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Monoacylglycerol acyltransferases (MGATs) are predominantly associated with lipid absorption and resynthesis in the animal intestine where they catalyse the first step in the monoacylglycerol (MAG) pathway by acylating MAG to form diacylglycerol (DAG). Typical plant triacylglycerol (TAG) biosynthesis routes such as the Kennedy pathway do not include an MGAT step. Rather, DAG and TAG are synthesised de novo from glycerol-3-phosphate (G-3-P) by a series of three subsequent acylation reactions although a complex interplay with membrane lipids exists. METHODOLOGY/PRINCIPAL FINDINGS We demonstrate that heterologous expression of a mouse MGAT acyltransferase in Nicotiana benthamiana significantly increases TAG accumulation in vegetative tissues despite the low levels of endogenous MAG substrate available. In addition, DAG produced by this acyltransferase can serve as a substrate for both native and coexpressed diacylglycerol acyltransferases (DGAT). Finally, we show that the Arabidopsis thaliana GPAT4 acyltransferase can produce MAG in Saccharomyces cerevisiae using oleoyl-CoA as the acyl-donor. CONCLUSIONS/SIGNIFICANCE This study demonstrates the concept of a new method of increasing oil content in vegetative tissues by using MAG as a substrate for TAG biosynthesis. Based on in vitro yeast assays and expression results in N. benthamiana, we propose that co-expression of a MAG synthesising enzyme such as A. thaliana GPAT4 and a MGAT or bifunctional M/DGAT can result in DAG and TAG synthesis from G-3-P via a route that is independent and complementary to the endogenous Kennedy pathway and other TAG synthesis routes.
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Affiliation(s)
- James R. Petrie
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
| | | | - Pushkar Shrestha
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
| | - Anna El Tahchy
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
| | - Adam White
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
| | | | - Qing Liu
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
| | - Maged P. Mansour
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
- CSIRO Marine and Atmospheric Research, Hobart, TAS, Australia
| | - Peter D. Nichols
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
- CSIRO Marine and Atmospheric Research, Hobart, TAS, Australia
| | - Surinder P. Singh
- CSIRO Food Futures National Research Flagship, Canberra, ACT, Australia
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16
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Parthibane V, Rajakumari S, Venkateshwari V, Iyappan R, Rajasekharan R. Oleosin is bifunctional enzyme that has both monoacylglycerol acyltransferase and phospholipase activities. J Biol Chem 2011; 287:1946-54. [PMID: 22128159 DOI: 10.1074/jbc.m111.309955] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In plants, fatty oils are generally stored in spherical intracellular organelles referred to as oleosomes that are covered by proteins such as oleosin. Seeds with high oil content have more oleosin than those with low oil content. However, the exact role of oleosin in oil accumulation is thus far unclear. Here, we report the isolation of a catalytically active 14 S multiprotein complex capable of acylating monoacylglycerol from the microsomal membranes of developing peanut cotyledons. Microsomal membranes from immature peanut seeds were solubilized using 8 m urea and 10 mm CHAPS. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 27 proteins in the 14 S complex. The major proteins present in the 14 S complex are conarachin, the major allergen Ara h 1, and other seed storage proteins. We identified oleosin 3 as a part of the 14 S complex, which is capable of acylating monoacylglycerol. The recombinant OLE3 microsomes from Saccharomyces cerevisiae have been shown to have both a monoacylglycerol acyltransferase and a phospholipase A(2) activity. Overexpression of the oleosin 3 (OLE3) gene in S. cerevisiae resulted in an increased accumulation of diacylglycerols and triacylglycerols and decreased phospholipids. These findings provide a direct role for a structural protein (OLE3) in the biosynthesis and mobilization of plant oils.
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17
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Duclos RI, Johnston M, Vadivel SK, Makriyannis A, Glaser ST, Gatley SJ. A methodology for radiolabeling of the endocannabinoid 2-arachidonoylglycerol (2-AG). J Org Chem 2011; 76:2049-55. [PMID: 21370840 PMCID: PMC3064716 DOI: 10.1021/jo102277q] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The metabolic intermediate and endocannabinoid signaling lipid 2-arachidonoylglycerol (2-AG) has not been readily labeled, primarily because of its instability toward rearrangement. We now detail a synthetic method that easily gives tritiated 2-AG from [5,6,8,9,11,12,14,15-(3)H(N)]arachidonic acid in two steps. We utilized a short chain 1,3-diacylglycerol and proceeded through the "structured lipid" [5'',6'',8'',9'',11'',12'',14'',15''-(3)H(N)]2-arachidonoyl-1,3-dibutyrylglycerol, a triacylglycerol that was conveniently deprotected in ethanol with acrylic beads containing Candida antarctica lipase B to give [5'',6'',8'',9'',11'',12'',14'',15''-(3)H(N)]2-arachidonoylglycerol ([(3)H]2-AG). The flash chromatographic separation necessary to isolate the labeled 2-acylglycerol [(3)H]2-AG resulted in only 4% of the rearrangement byproducts that have been a particular problem with previous methodologies. This reliable "kit" method to prepare the radiolabeled endocannabinoid as needed gave tritiated 2-arachidonoylglycerol [(3)H]2-AG with a specific activity of 200 Ci/mmol for enzyme assays, metabolic studies, and tissue imaging. It has been run on unlabeled materials on over 10 mg scales and should be generally applicable to other 2-acylglycerols.
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Affiliation(s)
- Richard I Duclos
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, USA.
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18
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Rani SH, Krishna THA, Saha S, Negi AS, Rajasekharan R. Defective in cuticular ridges (DCR) of Arabidopsis thaliana, a gene associated with surface cutin formation, encodes a soluble diacylglycerol acyltransferase. J Biol Chem 2010; 285:38337-47. [PMID: 20921218 PMCID: PMC2992267 DOI: 10.1074/jbc.m110.133116] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 10/01/2010] [Indexed: 11/06/2022] Open
Abstract
A key step in the triacylglycerol (TAG) biosynthetic pathway is the final acylation of diacylglycerol (DAG) by DAG acyltransferase. In silico analysis has revealed that the DCR (defective in cuticular ridges) (At5g23940) gene has a typical HX(4)D acyltransferase motif at the N-terminal end and a lipid binding motif VX(2)GF at the middle of the sequence. To understand the biochemical function, the gene was overexpressed in Escherichia coli, and the purified recombinant protein was found to acylate DAG specifically in an acyl-CoA-dependent manner. Overexpression of At5g23940 in a Saccharomyces cerevisiae quadruple mutant deficient in DAG acyltransferases resulted in TAG accumulation. At5g23940 rescued the growth of this quadruple mutant in the oleate-containing medium, whereas empty vector control did not. Lipid particles were localized in the cytosol of At5g23940-transformed quadruple mutant cells, as observed by oil red O staining. There was an incorporation of 16-hydroxyhexadecanoic acid into TAG in At5g23940-transformed cells of quadruple mutant. Here we report a soluble acyl-CoA-dependent DAG acyltransferase from Arabidopsis thaliana. Taken together, these data suggest that a broad specific DAG acyltransferase may be involved in the cutin as well as in the TAG biosynthesis by supplying hydroxy fatty acid.
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Affiliation(s)
- Sapa Hima Rani
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India and
| | - T. H. Anantha Krishna
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India and
| | - Saikat Saha
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India and
| | - Arvind Singh Negi
- the Central Institute of Medicinal and Aromatic Plants, Council of Scientific and Industrial Research, Lucknow 220015, India
| | - Ram Rajasekharan
- the Central Institute of Medicinal and Aromatic Plants, Council of Scientific and Industrial Research, Lucknow 220015, India
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19
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Functional characterization of lysophosphatidic acid phosphatase from Arabidopsis thaliana. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:455-61. [DOI: 10.1016/j.bbalip.2009.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 12/13/2009] [Accepted: 12/15/2009] [Indexed: 11/18/2022]
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20
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Hiramine Y, Emoto H, Takasuga S, Hiramatsu R. Novel acyl-coenzyme A:monoacylglycerol acyltransferase plays an important role in hepatic triacylglycerol secretion. J Lipid Res 2009; 51:1424-31. [PMID: 20018982 DOI: 10.1194/jlr.m002584] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acyl-CoA:monoacylglycerol acyltransferase (MGAT) plays a predominant role in the resynthesis of triacylglycerol in the small intestine, but its contribution to triacylglycerol synthesis in other tissues, such as the liver, is not clear. In this study, we identified a novel MGAT gene, which is identical with lysophosphatidylglycerol acyltransferase1 (LPGAT1). Mouse LPGAT1 is expressed in a number of tissues and most highly expressed in the liver. Hepatic LPGAT1 expression in diabetic db/db mice is higher than that in the control db/m mouse, which is consistent with increased hepatic MGAT activity in db/db mouse. To elucidate the role of LPGAT1 gene in lipid metabolism in db/db mice, we constructed an adenovirus of short hairpin RNA (shRNA) targeting LPGAT1 to selectively knockdown LPGAT1 gene expression in the liver. Hepatic MGAT activity and LPGAT1 expression in db/db mice infected with LPGAT1 shRNA adenovirus were significantly lower than those in mice infected with the control virus. Notably, treatment with LPGAT1 shRNA adenovirus caused a marked reduction in serum triacylglycerol and cholesterol levels and a significant increase in hepatic cholesterol level. These findings indicate that LPGAT1, a newly identified MGAT enzyme, plays a significant role in hepatic triacylglycerol synthesis and secretion in db/db mice.
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21
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Ghosh AK, Chauhan N, Rajakumari S, Daum G, Rajasekharan R. At4g24160, a soluble acyl-coenzyme A-dependent lysophosphatidic acid acyltransferase. PLANT PHYSIOLOGY 2009; 151:869-81. [PMID: 19700561 PMCID: PMC2754629 DOI: 10.1104/pp.109.144261] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 08/17/2009] [Indexed: 05/19/2023]
Abstract
Human CGI-58 (for comparative gene identification-58) and YLR099c, encoding Ict1p in Saccharomyces cerevisiae, have recently been identified as acyl-CoA-dependent lysophosphatidic acid acyltransferases. Sequence database searches for CGI-58 like proteins in Arabidopsis (Arabidopsis thaliana) revealed 24 proteins with At4g24160, a member of the alpha/beta-hydrolase family of proteins being the closest homolog. At4g24160 contains three motifs that are conserved across the plant species: a GXSXG lipase motif, a HX(4)D acyltransferase motif, and V(X)(3)HGF, a probable lipid binding motif. Dendrogram analysis of yeast ICT1, CGI-58, and At4g24160 placed these three polypeptides in the same group. Here, we describe and characterize At4g24160 as, to our knowledge, the first soluble lysophosphatidic acid acyltransferase in plants. A lipidomics approach revealed that At4g24160 has additional triacylglycerol lipase and phosphatidylcholine hydrolyzing enzymatic activities. These data establish At4g24160, a protein with a previously unknown function, as an enzyme that might play a pivotal role in maintaining the lipid homeostasis in plants by regulating both phospholipid and neutral lipid levels.
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Affiliation(s)
- Ananda K Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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22
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Yu XH, Gou JY, Liu CJ. BAHD superfamily of acyl-CoA dependent acyltransferases in Populus and Arabidopsis: bioinformatics and gene expression. PLANT MOLECULAR BIOLOGY 2009; 70:421-42. [PMID: 19343509 DOI: 10.1007/s11103-009-9482-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Accepted: 03/12/2009] [Indexed: 05/04/2023]
Abstract
Plant acyl-CoA dependent acyltransferases constitute a large specific protein superfamily, named BAHD. Using the conserved sequence motifs of BAHD members, we searched the genome sequences of Populus and Arabidopsis, and identified, respectively, 94- and 61-putative genes. Subsequently, we analyzed the phylogeny, gene structure, and chromosomal distribution of BAHD members of both species; then, we profiled expression patterns of BAHD genes by "in silico" northern- and microarray-analyses based on public databases, and by RT-PCR. While our genomic- and bioinformatic- analyses provided full sets of BAHD superfamily genes, and cleaned up a few existing annotation errors, importantly it led to our recognizing several unique Arabidopsis BAHD genes that inversely overlapped with their neighboring genes on the genome, and disclosing a potential natural anti-sense regulation for gene expressions. Systemic gene-expression profiling of BAHD members revealed distinct tissue-specific/preferential expression patterns, indicating their diverse biological functions. Our study affords a strong knowledge base for understanding BAHD members' evolutionary relationships and gene functions implicated in plant growth, development and metabolism.
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Affiliation(s)
- Xiao-Hong Yu
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA
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23
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Fatty Acid Biosynthesis in Plants — Metabolic Pathways, Structure and Organization. LIPIDS IN PHOTOSYNTHESIS 2009. [DOI: 10.1007/978-90-481-2863-1_2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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24
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Ghosh AK, Ramakrishnan G, Chandramohan C, Rajasekharan R. CGI-58, the causative gene for Chanarin-Dorfman syndrome, mediates acylation of lysophosphatidic acid. J Biol Chem 2008; 283:24525-33. [PMID: 18606822 DOI: 10.1074/jbc.m801783200] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
cgi-58 (comparative gene identification-58) is a member of alpha/beta-hydrolase family of proteins. Mutations in CGI-58 are shown to be responsible for a rare genetic disorder known as Chanarin-Dorfman syndrome, characterized by an excessive accumulation of triacylglycerol in several tissues and ichthyosis. We have earlier reported that YLR099c encoding Ict1p in Saccharomyces cerevisiae can acylate lysophosphatidic acid to phosphatidic acid. Here we report that human CGI-58 is closely related to ICT1. To understand the biochemical function of cgi-58, the gene was overexpressed in Escherichia coli, and the purified recombinant protein was found to specifically acylate lysophosphatidic acid in an acyl-CoA-dependent manner. Overexpression of CGI-58 in S. cerevisiae showed an increase in the formation of phosphatidic acid resulting in an overall increase in the total phospholipids. However, the triacylglycerol level was found to be significantly reduced. In addition, the physiological significance of cgi-58 in mice white adipose tissue was studied. We found soluble lysophosphatidic acid acyltransferase activity in mouse white adipose tissue. Immunoblot analysis using anti-Ict1p antibodies followed by mass spectrometry of the immunocross-reactive protein in lipid droplets revealed its identity as cgi-58. These observations suggest the existence of an alternate cytosolic phosphatidic acid biosynthetic pathway in the white adipose tissue. Collectively, these results reveal the role of cgi-58 as an acyltransferase.
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Affiliation(s)
- Ananda K Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore 562, India
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25
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Saha S, Enugutti B, Rajakumari S, Rajasekharan R. Cytosolic triacylglycerol biosynthetic pathway in oilseeds. Molecular cloning and expression of peanut cytosolic diacylglycerol acyltransferase. PLANT PHYSIOLOGY 2006; 141:1533-43. [PMID: 16798944 PMCID: PMC1533943 DOI: 10.1104/pp.106.082198] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Triacylglycerols (TAGs) are the most important storage form of energy for eukaryotic cells. TAG biosynthetic activity was identified in the cytosolic fraction of developing peanut (Arachis hypogaea) cotyledons. This activity was NaF insensitive and acyl-coenzyme A (CoA) dependent. Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final step in TAG biosynthesis that acylates diacylglycerol to TAG. Soluble DGAT was identified from immature peanuts and purified by conventional column chromatographic procedures. The enzyme has a molecular mass of 41 +/- 1.0 kD. Based on the partial peptide sequence, a degenerate probe was used to obtain the full-length cDNA. The isolated gene shared less than 10% identity with the previously identified DGAT1 and 2 families, but has 13% identity with the bacterial bifunctional wax ester/DGAT. To differentiate the unrelated families, we designate the peanut gene as AhDGAT. Expression of peanut cDNA in Escherichia coli resulted in the formation of labeled TAG and wax ester from [14C]acetate. The recombinant E. coli showed high levels of DGAT activity but no wax ester synthase activity. TAGs were localized in transformed cells with Nile blue A and oil red O staining. The recombinant and native DGAT was specific for 1,2-diacylglycerol and did not utilize hexadecanol, glycerol-3-phosphate, monoacylglycerol, lysophosphatidic acid, and lysophosphatidylcholine. Oleoyl-CoA was the preferred acyl donor as compared to palmitoyl- and stearoyl-CoAs. These data suggest that the cytosol is one of the sites for TAG biosynthesis in oilseeds. The identified pathway may present opportunities of bioengineering oil-yielding plants for increased oil production.
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Affiliation(s)
- Saikat Saha
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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26
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Rajakumari S, Srinivasan M, Rajasekharan R. Spectrophotometric method for quantitative determination of nonionic, ionic and zwitterionic detergents. ACTA ACUST UNITED AC 2006; 68:133-7. [PMID: 16757032 DOI: 10.1016/j.jbbm.2006.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/30/2006] [Accepted: 04/15/2006] [Indexed: 10/24/2022]
Abstract
Detergents serve as means of solubilizing biological membranes and thus play an important role in purification and characterization of membrane proteins. We report here a simple method to estimate the amount of detergent bound to a protein or present in an aqueous solution. The method is based on the turbidity caused by the addition of a detergent to triolein. Detergent bound to an integral membrane protein, lysophosphatidic acid acyltransferase, was separated by native gel electrophoresis and the amount of detergent bound to the same was estimated. This method is applicable for Triton X-100, sodium dodecyl sulfate and zwitterionic detergent, and was validated in the presence of reagents commonly used in membrane protein solubilization and purification.
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Affiliation(s)
- Sona Rajakumari
- Lipid Laboratory, Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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27
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Clinical application of C18and C20chain length polyunsaturated fatty acids and their biotechnological production in plants. J AM OIL CHEM SOC 2006. [DOI: 10.1007/s11746-006-1191-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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28
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Hills MJ, Roscoe TJ. Synthesis of Structural and Storage Lipids by the ER. PLANT CELL MONOGRAPHS 2006. [DOI: 10.1007/7089_056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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29
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Stoll C, Lühs W, Zarhloul MK, Friedt W. Genetic modification of saturated fatty acids in oilseed rape (Brassica napus). EUR J LIPID SCI TECH 2005. [DOI: 10.1002/ejlt.200590021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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30
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Roscoe TJ. Identification of acyltransferases controlling triacylglycerol biosynthesis in oilseeds using a genomics-based approach. EUR J LIPID SCI TECH 2005. [DOI: 10.1002/ejlt.200590023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Drexler H, Spiekermann P, Meyer A, Domergue F, Zank T, Sperling P, Abbadi A, Heinz E. Metabolic engineering of fatty acids for breeding of new oilseed crops: strategies, problems and first results. JOURNAL OF PLANT PHYSIOLOGY 2003; 160:779-802. [PMID: 12940546 DOI: 10.1078/0176-1617-01025] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Affiliation(s)
- Hjördis Drexler
- Institut für Allgemeine Botanik, Universität Hamburg, Ohnhorststr. 18, D-22609 Hamburg, Germany
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32
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Abstract
In developing seeds of Perilla frutescens var. crispa, the triacylglycerol fraction was found to accumulate between 15 and 19 days after flowering. Of this, 65% of the total fatty acids was alpha-linolenic acid in the mature seeds, with the latter being esterified in comparable amounts at all positions (sn-1, 2 and 3) of the glycerol residue. It was also demonstrated that, 1-acylglycerol-3-phosphate acyltransferase, which catalyzes esterification at the sn-2 position of the glycerol backbone, showed low activities for alpha-linolenoyl-CoA as substrate. These findings suggest that the diacylglycerol precursor for triacylglycerol synthesis is not directly derived from phosphatidic acid through the glycerol phosphate pathway.
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Affiliation(s)
- Ken'ichi Ichihara
- Biological Chemistry, Faculty of Agriculture, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
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Rudrabhatla P, Rajasekharan R. Developmentally regulated dual-specificity kinase from peanut that is induced by abiotic stresses. PLANT PHYSIOLOGY 2002; 130:380-90. [PMID: 12226517 PMCID: PMC166570 DOI: 10.1104/pp.005173] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2002] [Revised: 04/17/2002] [Accepted: 04/26/2002] [Indexed: 05/20/2023]
Abstract
Tyrosine (Tyr) phosphorylation represents an important biochemical mechanism to regulate many cellular processes. No Tyr kinase has been cloned so far in plants. Dual-specificity kinases are reported in plants and the function of these kinases remains unknown. A 1.7-kb cDNA that encodes serine/threonine/Tyr (STY) kinase was isolated by screening peanut (Arachis hypogaea) expression library using the anti-phospho-Tyr antibody. The histidine-tagged recombinant kinase histidine-6-STY predominantly autophosphorylated on Tyr and phosphorylated the histone primarily on threonine. Genomic DNA gel-blot analysis revealed that STY kinase is a member of a small multigene family. The transcript of STY kinase is accumulated in the mid-maturation stage of seed development, suggesting a role in the signaling of storage of seed reserves. The STY kinase mRNA expression, as well as kinase activity, markedly increased in response to cold and salt treatments; however, no change in the protein level was observed, suggesting a posttranslational activation mechanism. The activation of the STY kinase is detected after 12 to 48 h of cold and salt treatments, which indicates that the kinase may not participate in the initial response to abiotic stresses, but may play a possible role in the adaptive process to adverse conditions. The transcript levels and kinase activity were unaltered with abscisic acid treatment, suggesting an abscisic acid-independent cold and salt signaling pathway. Here, we report the first identification of a non-MAP kinase cascade dual-specificity kinase involved in abiotic stress and seed development.
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MESH Headings
- Amino Acid Sequence
- Arachis/enzymology
- Arachis/genetics
- Arachis/growth & development
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Enzyme Activation/drug effects
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Molecular Sequence Data
- Phylogeny
- Protein Processing, Post-Translational/drug effects
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sodium Chloride/pharmacology
- Stress, Mechanical
- Substrate Specificity
- Temperature
- Transcriptional Activation/drug effects
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Affiliation(s)
- Parvathi Rudrabhatla
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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Gangar A, Raychaudhuri S, Rajasekharan R. Alteration in the cytosolic triacylglycerol biosynthetic machinery leads to decreased cell growth and triacylglycerol synthesis in oleaginous yeast. Biochem J 2002; 365:577-89. [PMID: 11972450 PMCID: PMC1222718 DOI: 10.1042/bj20011654] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2001] [Revised: 03/27/2002] [Accepted: 04/24/2002] [Indexed: 11/17/2022]
Abstract
Altered nutrient content (levels of glucose) caused a drastic reduction in cell growth and triacylglycerol (TAG) production in the wild-type (WT) Rhodotorula glutinis. This was due to the decreased level of synthesis of TAG biosynthetic enzymes, reflected by a reduction in enzyme activity. A similar observation was made in the case of non-lethal mutants of TAG-deficient oleaginous yeast, namely TAG1 and TAG2, which were generated by ethyl methane sulphonate mutagenesis. Metabolic labelling of TAG-deficient cells with [(14)C]acetate, [(32)P]orthophosphate and [(14)C]mevalonate showed a negligible TAG formation with minimal alterations in phospholipid and sterol compositions. Assays on the activities of cytosolic TAG biosynthetic enzymes revealed that lysophosphatidic acid and diacylglycerol acyltransferases (ATs) were defective in TAG1 and TAG2 respectively. The activity of membrane-bound isoforms of TAG biosynthetic enzymes remains unaltered in the mutants. Analysis of cytosolic TAG biosynthetic enzymes by immunoblotting and immunoprecipitation indicated that the defective ATs were a part of the TAG biosynthetic multienzyme complex. Quantitatively, the cytosolic lysophosphatidic acid-AT was comparable between TAG1 and the WT. However, diacylglycerol-AT was relatively less in TAG2 than the WT. These results demonstrated that either by decreasing the nutrient content or mutating the enzymes of the soluble TAG biosynthetic pathway, TAG production was decreased with concomitant reduction in the cell growth.
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Affiliation(s)
- Akanksha Gangar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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Yen CLE, Stone SJ, Cases S, Zhou P, Farese RV. Identification of a gene encoding MGAT1, a monoacylglycerol acyltransferase. Proc Natl Acad Sci U S A 2002; 99:8512-7. [PMID: 12077311 PMCID: PMC124292 DOI: 10.1073/pnas.132274899] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acyl-CoA:monoacylglycerol acyltransferase (MGAT) catalyzes the synthesis of diacylglycerol, the precursor of physiologically important lipids such as triacylglycerol and phospholipids. In the intestine, MGAT plays a major role in the absorption of dietary fat because resynthesis of triacylglycerol is required for the assembly of lipoproteins that transport absorbed fat to other tissues. MGAT activity has also been reported in mammalian liver and white adipose tissue. However, MGAT has never been purified to homogeneity from mammalian tissues, and its gene has not been cloned. We identified a gene that encodes an MGAT (MGAT1) in mice. This gene has sequence homology with members of a recently identified diacylglycerol acyltransferase gene family. Expression of the MGAT1 cDNA in insect cells markedly increased MGAT activity in cell membranes. In addition, MGAT activity was proportional to the level of MGAT1 protein expressed, and the amount of diacylglycerol produced depended on the concentration of either of its substrates, oleoyl-CoA or monooleoylglycerol. In mice, MGAT1 expression and MGAT activity were detected in the stomach, kidney, white and brown adipose tissue, and liver. However, MGAT1 was not expressed in the small intestine, implying the existence of a second MGAT gene. The identification of the MGAT1 gene should greatly facilitate research on the identification of the intestinal MGAT gene and on the function of MGAT enzymes in mammalian glycerolipid metabolism.
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Affiliation(s)
- Chi-Liang Eric Yen
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94141-1900, USA
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Shekar S, Tumaney AW, Rao TJVS, Rajasekharan R. Isolation of lysophosphatidic acid phosphatase from developing peanut cotyledons. PLANT PHYSIOLOGY 2002; 128:988-96. [PMID: 11891254 PMCID: PMC152211 DOI: 10.1104/pp.010654] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2001] [Revised: 09/17/2001] [Accepted: 11/19/2001] [Indexed: 05/20/2023]
Abstract
The soluble fraction of immature peanut (Arachis hypogaea) was capable of dephosphorylating [(3)H]lysophosphatidic acid (LPA) to generate monoacylglycerol (MAG). The enzyme responsible for the generation of MAG, LPA phosphatase, has been identified in plants and purified by successive chromatography separations on octyl-Sepharose, Blue Sepharose, Superdex-75, and heparin-agarose to apparent homogeneity from developing peanuts. This enzyme was purified 5,048-fold to a final specific activity of 858 nmol min(-1) mg(-1). The enzyme has a native molecular mass of approximately 39 kD determined by gel filtration and migrates as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a subunit molecular mass of 39 +/- 1.5 kD. The K(m) values for oleoyl-, stearoyl-, and palmitoyl-sn-glycerol-3-phosphate were determined to be 28.6, 39.3, and 47.9 microM, respectively. The LPA phosphatase was specific to LPA and did not utilize any other substrate such as glycerol-3-phosphate, phosphatidic acid, or p-nitrophenylphosphate. The enzyme activity was stimulated by the low concentrations of detergents such as Triton X-100 and octylglucoside. Cations had no effect on the enzyme activity. Fatty acids, sphingosine, and sphingomyelin at low concentrations stimulated the enzyme activity. The identification of LPA phosphatase in plants demonstrates the existence of MAG biosynthetic machinery in plants.
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Affiliation(s)
- Sunil Shekar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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