1
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Blank HM, Griffith WP, Polymenis M. Targeting APEX2 to the mRNA encoding fatty acid synthase β in yeast identifies interacting proteins that control its abundance in the cell cycle. Mol Biol Cell 2023; 34:br20. [PMID: 37792491 PMCID: PMC10848943 DOI: 10.1091/mbc.e23-05-0166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 10/06/2023] Open
Abstract
Profiling the repertoire of proteins associated with a given mRNA during the cell cycle is unstudied. Furthermore, it is easier to ask and answer what mRNAs a specific protein might bind to than the other way around. Here, we implemented an RNA-centric proximity labeling technology at different points in the cell cycle in highly synchronous yeast cultures. To understand how the abundance of FAS1, encoding fatty acid synthase, peaks late in the cell cycle, we identified proteins that interact with the FAS1 transcript in a cell cycle-dependent manner. We used dCas13d-APEX2 fusions to target FAS1 and label nearby proteins, which were then identified by mass spectrometry. The glycolytic enzyme Tdh3p, a known RNA-binding protein, interacted with the FAS1 mRNA, and it was necessary for the periodic abundance of Fas1p in the cell cycle. These results point to unexpected connections between major metabolic pathways. They also underscore the role of mRNA-protein interactions for gene expression during cell division.
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Affiliation(s)
- Heidi M. Blank
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Wendell P. Griffith
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249
| | - Michael Polymenis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
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2
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Zhang Y, Su M, Chen Y, Wang Z, Nielsen J, Liu Z. Engineering yeast mitochondrial metabolism for 3-hydroxypropionate production. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:64. [PMID: 37031180 PMCID: PMC10082987 DOI: 10.1186/s13068-023-02309-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 03/24/2023] [Indexed: 04/10/2023]
Abstract
BACKGROUND With unique physiochemical environments in subcellular organelles, there has been growing interest in harnessing yeast organelles for bioproduct synthesis. Among these organelles, the yeast mitochondrion has been found to be an attractive compartment for production of terpenoids and branched-chain alcohols, which could be credited to the abundant supply of acetyl-CoA, ATP and cofactors. In this study we explored the mitochondrial potential for production of 3-hydroxypropionate (3-HP) and performed the cofactor engineering and flux control at the acetyl-CoA node to maximize 3-HP synthesis. RESULTS Metabolic modeling suggested that the mitochondrion serves as a more suitable compartment for 3-HP synthesis via the malonyl-CoA pathway than the cytosol, due to the opportunity to obtain a higher maximum yield and a lower oxygen consumption. With the malonyl-CoA reductase (MCR) targeted into the mitochondria, the 3-HP production increased to 0.27 g/L compared with 0.09 g/L with MCR expressed in the cytosol. With enhanced expression of dissected MCR enzymes, the titer reached to 4.42 g/L, comparable to the highest titer achieved in the cytosol so far. Then, the mitochondrial NADPH supply was optimized by overexpressing POS5 and IDP1, which resulted in an increase in the 3-HP titer to 5.11 g/L. Furthermore, with induced expression of an ACC1 mutant in the mitochondria, the final 3-HP production reached 6.16 g/L in shake flask fermentations. The constructed strain was then evaluated in fed-batch fermentations, and produced 71.09 g/L 3-HP with a productivity of 0.71 g/L/h and a yield on glucose of 0.23 g/g. CONCLUSIONS In this study, the yeast mitochondrion is reported as an attractive compartment for 3-HP production. The final 3-HP titer of 71.09 g/L with a productivity of 0.71 g/L/h was achieved in fed-batch fermentations, representing the highest titer reported for Saccharomyces cerevisiae so far, that demonstrated the potential of recruiting the yeast mitochondria for further development of cell factories.
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Affiliation(s)
- Yiming Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Mo Su
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yu Chen
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Zheng Wang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Jens Nielsen
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
- BioInnovation Institute, Ole Maaløes Vej 3, DK2200, Copenhagen, Denmark
| | - Zihe Liu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
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3
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Pham T, Walden E, Huard S, Pezacki J, Fullerton MD, Baetz K. Fine tuning Acetyl-CoA Carboxylase 1 activity through localization: Functional genomics reveal a role for the lysine acetyltransferase NuA4 and sphingolipid metabolism in regulating Acc1 activity and localization. Genetics 2022; 221:6591204. [PMID: 35608294 PMCID: PMC9339284 DOI: 10.1093/genetics/iyac086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022] Open
Abstract
Acetyl-CoA Carboxylase 1 catalyzes the conversion of acetyl-CoA to malonyl-CoA, the committed step of de novo fatty acid synthesis. As a master regulator of lipid synthesis, acetyl-CoA carboxylase 1 has been proposed to be a therapeutic target for numerous metabolic diseases. We have shown that acetyl-CoA carboxylase 1 activity is reduced in the absence of the lysine acetyltransferase NuA4 in Saccharomyces cerevisiae. This change in acetyl-CoA carboxylase 1 activity is correlated with a change in localization. In wild-type cells, acetyl-CoA carboxylase 1 is localized throughout the cytoplasm in small punctate and rod-like structures. However, in NuA4 mutants, acetyl-CoA carboxylase 1 localization becomes diffuse. To uncover mechanisms regulating acetyl-CoA carboxylase 1 localization, we performed a microscopy screen to identify other deletion mutants that impact acetyl-CoA carboxylase 1 localization and then measured acetyl-CoA carboxylase 1 activity in these mutants through chemical genetics and biochemical assays. Three phenotypes were identified. Mutants with hyper-active acetyl-CoA carboxylase 1 form 1 or 2 rod-like structures centrally within the cytoplasm, mutants with mid-low acetyl-CoA carboxylase 1 activity displayed diffuse acetyl-CoA carboxylase 1, while the mutants with the lowest acetyl-CoA carboxylase 1 activity (hypomorphs) formed thick rod-like acetyl-CoA carboxylase 1 structures at the periphery of the cell. All the acetyl-CoA carboxylase 1 hypomorphic mutants were implicated in sphingolipid metabolism or very long-chain fatty acid elongation and in common, their deletion causes an accumulation of palmitoyl-CoA. Through exogenous lipid treatments, enzyme inhibitors, and genetics, we determined that increasing palmitoyl-CoA levels inhibits acetyl-CoA carboxylase 1 activity and remodels acetyl-CoA carboxylase 1 localization. Together this study suggests yeast cells have developed a dynamic feed-back mechanism in which downstream products of acetyl-CoA carboxylase 1 can fine-tune the rate of fatty acid synthesis.
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Affiliation(s)
- Trang Pham
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, K1H 8M5 Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5 Canada
| | - Elizabeth Walden
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, K1H 8M5 Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5 Canada
| | - Sylvain Huard
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, K1H 8M5 Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5 Canada
| | - John Pezacki
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, K1H 8M5 Canada.,Department of Chemistry and Biomolecular Sciences, Faculty of Science, University of Ottawa, Ottawa K1N6N5 Canada
| | - Morgan D Fullerton
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5 Canada
| | - Kristin Baetz
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, K1H 8M5 Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5 Canada.,Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary T2N 1N4, Canada
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4
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Maitra N, Hammer S, Kjerfve C, Bankaitis VA, Polymenis M. Translational control of lipogenesis links protein synthesis and phosphoinositide signaling with nuclear division in Saccharomyces cerevisiae. Genetics 2022; 220:iyab171. [PMID: 34849864 PMCID: PMC8733439 DOI: 10.1093/genetics/iyab171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 09/23/2021] [Indexed: 12/21/2022] Open
Abstract
Continuously dividing cells coordinate their growth and division. How fast cells grow in mass determines how fast they will multiply. Yet, there are few, if any, examples of a metabolic pathway that actively drives a cell cycle event instead of just being required for it. Here, we show that translational upregulation of lipogenic enzymes in Saccharomyces cerevisiae increased the abundance of lipids and promoted nuclear elongation and division. Derepressing translation of acetyl-CoA carboxylase and fatty acid synthase also suppressed cell cycle-related phenotypes, including delayed nuclear division, associated with Sec14p phosphatidylinositol transfer protein deficiencies, and the irregular nuclear morphologies of mutants defective in phosphatidylinositol 4-OH kinase activities. Our results show that increased lipogenesis drives a critical cell cycle landmark and report a phosphoinositide signaling axis in control of nuclear division. The broad conservation of these lipid metabolic and signaling pathways raises the possibility these activities similarly govern nuclear division in other eukaryotes.
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Affiliation(s)
- Nairita Maitra
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Staci Hammer
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Clara Kjerfve
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Vytas A Bankaitis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843, USA
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - Michael Polymenis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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5
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Pereira H, Azevedo F, Domingues L, Johansson B. Expression of Yarrowia lipolytica acetyl-CoA carboxylase in Saccharomyces cerevisiae and its effect on in-vivo accumulation of Malonyl-CoA. Comput Struct Biotechnol J 2022; 20:779-787. [PMID: 36284710 PMCID: PMC9582701 DOI: 10.1016/j.csbj.2022.01.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 12/18/2022] Open
Abstract
Novel S. cerevisiae strain with tetracycline repressible ACC1 promoter. Functional expression of Y. lipolytica ACC1 in S. cerevisiae. Higher malonyl-CoA concentration achieved with Y. lipolytica ACC1 gene. S. cerevisiae Acc1p seems to interact with the heterologous Y. lipolytica Acc1p.
Malonyl-CoA is an energy-rich molecule formed by the ATP-dependent carboxylation of acetyl coenzyme A catalyzed by acetyl-CoA carboxylase. This molecule is an important precursor for many biotechnologically interesting compounds such as flavonoids, polyketides, and fatty acids. The yeast Saccharomyces cerevisiae remains one of the preferred cell factories, but has a limited capacity to produce malonyl-CoA compared to oleaginous organisms. We developed a new S. cerevisiae strain with a conditional allele of ACC1, the essential acetyl-CoA carboxylase (ACC) gene, as a tool to test heterologous genes for complementation. Yarrowia lipolytica is an oleaginous yeast with a higher capacity for lipid production than S. cerevisiae, possibly due to a higher capacity to produce malonyl-CoA. Measuring relative intracellular malonyl-CoA levels with an in-vivo biosensor confirmed that expression of Y. lipolytica ACC in S. cerevisiae leads to a higher accumulation of malonyl-CoA compared with overexpression of the native gene from an otherwise identical vector. The higher accumulation was generally accompanied by a decreased growth rate. Concomitant expression of both the homologous and heterologous ACC1 genes eliminated the growth defect, with a marginal reduction of malonyl-CoA accumulation.
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Affiliation(s)
- Humberto Pereira
- CBMA - Center of Molecular and Environmental Biology Engineering
| | - Flávio Azevedo
- CBMA - Center of Molecular and Environmental Biology Engineering
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga, 4710-057, Portugal
| | - Björn Johansson
- CBMA - Center of Molecular and Environmental Biology Engineering
- Corresponding author.
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6
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Wang J, Ledesma-Amaro R, Wei Y, Ji B, Ji XJ. Metabolic engineering for increased lipid accumulation in Yarrowia lipolytica - A Review. BIORESOURCE TECHNOLOGY 2020; 313:123707. [PMID: 32595069 DOI: 10.1016/j.biortech.2020.123707] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Current energy security and climate change policies encourage the development and utilization of bioenergy. Oleaginous yeasts provide a particularly attractive platform for the sustainable production of biofuels and industrial chemicals due to their ability to accumulate high amounts of lipids. In particular, microbial lipids in the form of triacylglycerides (TAGs) produced from renewable feedstocks have attracted considerable attention because they can be directly used in the production of biodiesel and oleochemicals analogous to petrochemicals. As an oleaginous yeast that is generally regarded as safe, Yarrowia lipolytica has been extensively studied, with large amounts of data on its lipid metabolism, genetic tools, and genome sequencing and annotation. In this review, we highlight the newest strategies for increasing lipid accumulation using metabolic engineering and summarize the research advances on the overaccumulation of lipids in Y. lipolytica. Finally, perspectives for future engineering approaches are proposed.
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Affiliation(s)
- Jinpeng Wang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Yongjun Wei
- School of Pharmaceutical Sciences, Key Laboratory of State Ministry of Education, Key Laboratory of Henan Province for Drug Quality Control and Evaluation, Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, 100 Kexue Avenue, Zhengzhou 450001, People's Republic of China
| | - Boyang Ji
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Xiao-Jun Ji
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China.
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7
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Disruption in phosphate transport affects membrane lipid and lipid droplet homeostasis in Saccharomyces cerevisiae. J Bioenerg Biomembr 2020; 52:215-227. [PMID: 32462239 DOI: 10.1007/s10863-020-09837-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 05/19/2020] [Indexed: 10/24/2022]
Abstract
Phosphate plays a crucial role in phospholipid metabolism and it is transported by the phosphate (Pi) transporters. Phospholipids are building blocks of the cell membrane, and essential for cell growth; however, the role of phosphate transporters in lipid metabolism remains elusive. The present study shows that the deletion of Pi transporters exhibited an increase in both phospholipid and neutral lipid levels when compared to wild type. The mRNA expressions of genes involved in phospholipid synthesis (CKI1, EKI1, CHO2, and OPI3) were increased due to de-repression of the transcription factors (INO2 and INO4). Neutral lipid levels (triacylglycerol and sterol ester) and their synthesizing genes (LRO1, ARE2, ACC1, and FAS1) were also increased, resulting in lipid droplet accumulation in Pi transporter mutants. Interestingly, phospholipase (PLC1) and histone acetyltransferase genes (ESA1, EAF1, YNG1, YNG2, and GCN5) were also found to be significantly increased, leading to dysregulation of lipid levels in Pi transporter mutants. In summary, our results suggest that the Pi transporters are involved in lipid droplet and membrane lipid homeostasis.
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8
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Qiu Y, Hassaninasab A, Han GS, Carman GM. Phosphorylation of Dgk1 Diacylglycerol Kinase by Casein Kinase II Regulates Phosphatidic Acid Production in Saccharomyces cerevisiae. J Biol Chem 2016; 291:26455-26467. [PMID: 27834677 DOI: 10.1074/jbc.m116.763839] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/08/2016] [Indexed: 11/06/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, Dgk1 diacylglycerol (DAG) kinase catalyzes the CTP-dependent phosphorylation of DAG to form phosphatidic acid (PA). The enzyme in conjunction with Pah1 PA phosphatase controls the levels of PA and DAG for the synthesis of triacylglycerol and membrane phospholipids, the growth of the nuclear/endoplasmic reticulum membrane, and the formation of lipid droplets. Little is known about how DAG kinase activity is regulated by posttranslational modification. In this work, we examined the phosphorylation of Dgk1 DAG kinase by casein kinase II (CKII). When phosphate groups were globally reduced using nonspecific alkaline phosphatase, Triton X-100-solubilized membranes from DGK1-overexpressing cells showed a 7.7-fold reduction in DAG kinase activity; the reduced enzyme activity could be increased 5.5-fold by treatment with CKII. Dgk1(1-77) expressed heterologously in Escherichia coli was phosphorylated by CKII on a serine residue, and its phosphorylation was dependent on time as well as on the concentrations of CKII, ATP, and Dgk1(1-77). We used site-specific mutagenesis, coupled with phosphorylation analysis and phosphopeptide mapping, to identify Ser-45 and Ser-46 of Dgk1 as the CKII target sites, with Ser-46 being the major phosphorylation site. In vivo, the S46A and S45A/S46A mutations of Dgk1 abolished the stationary phase-dependent stimulation of DAG kinase activity. In addition, the phosphorylation-deficient mutations decreased Dgk1 function in PA production and in eliciting pah1Δ phenotypes, such as the expansion of the nuclear/endoplasmic reticulum membrane, reduced lipid droplet formation, and temperature sensitivity. This work demonstrates that the CKII-mediated phosphorylation of Dgk1 regulates its function in the production of PA.
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Affiliation(s)
- Yixuan Qiu
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Azam Hassaninasab
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
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9
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Chen L, Lee J, Ning Chen W. The use of metabolic engineering to produce fatty acid-derived biofuel and chemicals in Saccharomyces cerevisiae: a review. AIMS BIOENGINEERING 2016. [DOI: 10.3934/bioeng.2016.4.468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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10
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Nguyen NTT, Saguez C, Conesa C, Lefebvre O, Acker J. Identification of proteins associated with RNA polymerase III using a modified tandem chromatin affinity purification. Gene 2015; 556:51-60. [DOI: 10.1016/j.gene.2014.07.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 07/25/2014] [Accepted: 07/29/2014] [Indexed: 01/12/2023]
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11
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Krivoruchko A, Zhang Y, Siewers V, Chen Y, Nielsen J. Microbial acetyl-CoA metabolism and metabolic engineering. Metab Eng 2014; 28:28-42. [PMID: 25485951 DOI: 10.1016/j.ymben.2014.11.009] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 12/23/2022]
Abstract
Recent concerns over the sustainability of petrochemical-based processes for production of desired chemicals have fueled research into alternative modes of production. Metabolic engineering of microbial cell factories such as Saccharomyces cerevisiae and Escherichia coli offers a sustainable and flexible alternative for the production of various molecules. Acetyl-CoA is a key molecule in microbial central carbon metabolism and is involved in a variety of cellular processes. In addition, it functions as a precursor for many molecules of biotechnological relevance. Therefore, much interest exists in engineering the metabolism around the acetyl-CoA pools in cells in order to increase product titers. Here we provide an overview of the acetyl-CoA metabolism in eukaryotic and prokaryotic microbes (with a focus on S. cerevisiae and E. coli), with an emphasis on reactions involved in the production and consumption of acetyl-CoA. In addition, we review various strategies that have been used to increase acetyl-CoA production in these microbes.
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Affiliation(s)
- Anastasia Krivoruchko
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Yiming Zhang
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Verena Siewers
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Yun Chen
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
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12
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Hofbauer HF, Schopf FH, Schleifer H, Knittelfelder OL, Pieber B, Rechberger GN, Wolinski H, Gaspar ML, Kappe CO, Stadlmann J, Mechtler K, Zenz A, Lohner K, Tehlivets O, Henry SA, Kohlwein SD. Regulation of gene expression through a transcriptional repressor that senses acyl-chain length in membrane phospholipids. Dev Cell 2014; 29:729-39. [PMID: 24960695 PMCID: PMC4070385 DOI: 10.1016/j.devcel.2014.04.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/01/2014] [Accepted: 04/22/2014] [Indexed: 12/20/2022]
Abstract
Membrane phospholipids typically contain fatty acids (FAs) of 16 and 18 carbon atoms. This particular chain length is evolutionarily highly conserved and presumably provides maximum stability and dynamic properties to biological membranes in response to nutritional or environmental cues. Here, we show that the relative proportion of C16 versus C18 FAs is regulated by the activity of acetyl-CoA carboxylase (Acc1), the first and rate-limiting enzyme of FA de novo synthesis. Acc1 activity is attenuated by AMPK/Snf1-dependent phosphorylation, which is required to maintain an appropriate acyl-chain length distribution. Moreover, we find that the transcriptional repressor Opi1 preferentially binds to C16 over C18 phosphatidic acid (PA) species: thus, C16-chain containing PA sequesters Opi1 more effectively to the ER, enabling AMPK/Snf1 control of PA acyl-chain length to determine the degree of derepression of Opi1 target genes. These findings reveal an unexpected regulatory link between the major energy-sensing kinase, membrane lipid composition, and transcription. AMPK/Snf1 inhibition of acetyl-CoA carboxylase controls fatty acyl-chain length Opi1 repressor preferentially binds to C16 rather than C18 acyl-chains in PA Acyl-chain length tunes Opi1 sequestration to the ER and target gene derepression AMPK/Snf1 thus uses its effect on acyl-chain length to control Opi1 target genes
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Affiliation(s)
- Harald F Hofbauer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Florian H Schopf
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Hannes Schleifer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Oskar L Knittelfelder
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Bartholomäus Pieber
- Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Gerald N Rechberger
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Maria L Gaspar
- Department of Molecular Biology and Genetics, 249 Biotechnology Building, Cornell University, Ithaca, NY 14853-2703, USA
| | - C Oliver Kappe
- Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Johannes Stadlmann
- Protein Chemistry Facility, Institute of Molecular Pathology (IMP), Doktor-Bohr-Gasse 7, 1030 Vienna, Austria
| | - Karl Mechtler
- Protein Chemistry Facility, IMBA Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Doktor-Bohr-Gasse 3, 1030 Vienna, Austria
| | - Alexandra Zenz
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Oksana Tehlivets
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Susan A Henry
- Department of Molecular Biology and Genetics, 249 Biotechnology Building, Cornell University, Ithaca, NY 14853-2703, USA
| | - Sepp D Kohlwein
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria.
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13
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Liu Y, Xie L, Gong G, Zhang W, Zhu B, Hu Y. De novo comparative transcriptome analysis of Acremonium chrysogenum: high-yield and wild-type strains of cephalosporin C producer. PLoS One 2014; 9:e104542. [PMID: 25118715 PMCID: PMC4131913 DOI: 10.1371/journal.pone.0104542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/09/2014] [Indexed: 11/19/2022] Open
Abstract
β-lactam antibiotics are widely used in clinic. Filamentous fungus Acremonium chrysogenum is an important industrial fungus for the production of CPC, one of the major precursors of β-lactam antibiotics. Although its fermentation yield has been bred significantly over the past decades, little is known regarding molecular changes between the industrial strain and the wild type strain. This limits the possibility to improve CPC production further by molecular breeding. Comparative transcriptome is a powerful tool to understand the molecular mechanisms of CPC industrial high yield producer compared to wild type. A total of 57 million clean sequencing reads with an average length of 100 bp were generated from Illumina sequencing platform. 22,878 sequences were assembled. Among the assembled unigenes, 9502 were annotated and 1989 annotated sequences were assigned to 121 pathways by searching against the Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) database. Furthermore, we compared the transcriptome differences between a high-yield and a wild-type strain during fermentation. A total of 4329 unigenes with significantly different transcription level were identified, among which 1737 were up-regulated and 2592 were down-regulated. 24 pathways were subsequently determined which involve glycerolipid metabolism, galactose metabolism, and pyrimidine metabolism. We also examined the transcription levels of 18 identified genes, including 11 up-regulated genes and 7 down-regulated genes using reverse transcription quantitative -PCR (RT-qPCR). The results of RT-qPCR were consistent with the Illumina sequencing. In this study, the Illumina sequencing provides the most comprehensive sequences for gene expression profile of Acremonium chrysogenum and allows de novo transcriptome assembly while lacking genome information. Comparative analysis of RNA-seq data reveals the complexity of the transcriptome in the fermentation of different yield strains. This is an important public information platform which could be used to accelerate the research to improve CPC production in Acremonium chrysogenum.
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Affiliation(s)
- Yan Liu
- China State Institute of Pharmaceutical Industry, Zhangjiang Institute, Shanghai, China
- Shanghai Institute of Pharmaceutical Industry, Shanghai, China
| | - Liping Xie
- China State Institute of Pharmaceutical Industry, Zhangjiang Institute, Shanghai, China
- Shanghai Institute of Pharmaceutical Industry, Shanghai, China
| | - Guihua Gong
- China State Institute of Pharmaceutical Industry, Zhangjiang Institute, Shanghai, China
- Shanghai Institute of Pharmaceutical Industry, Shanghai, China
| | - Wei Zhang
- China State Institute of Pharmaceutical Industry, Zhangjiang Institute, Shanghai, China
- Shanghai Institute of Pharmaceutical Industry, Shanghai, China
| | - Baoquan Zhu
- China State Institute of Pharmaceutical Industry, Zhangjiang Institute, Shanghai, China
- * E-mail: (YH); (BZ)
| | - Youjia Hu
- China State Institute of Pharmaceutical Industry, Zhangjiang Institute, Shanghai, China
- Shanghai Institute of Pharmaceutical Industry, Shanghai, China
- * E-mail: (YH); (BZ)
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14
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Qiu Y, Fakas S, Han GS, Barbosa AD, Siniossoglou S, Carman GM. Transcription factor Reb1p regulates DGK1-encoded diacylglycerol kinase and lipid metabolism in Saccharomyces cerevisiae. J Biol Chem 2013; 288:29124-33. [PMID: 23970552 PMCID: PMC3790011 DOI: 10.1074/jbc.m113.507392] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, the DGK1-encoded diacylglycerol kinase catalyzes the CTP-dependent phosphorylation of diacylglycerol to form phosphatidate. This enzyme, in conjunction with PAH1-encoded phosphatidate phosphatase, controls the levels of phosphatidate and diacylglycerol for phospholipid synthesis, membrane growth, and lipid droplet formation. In this work, we showed that a functional level of diacylglycerol kinase is regulated by the Reb1p transcription factor. In the electrophoretic mobility shift assay, purified recombinant Reb1p was shown to specifically bind its consensus recognition sequence (CGGGTAA, -166 to -160) in the DGK1 promoter. Analysis of cells expressing the PDGK1-lacZ reporter gene showed that mutations (GT→TG) in the Reb1p-binding sequence caused an 8.6-fold reduction in β-galactosidase activity. The expression of DGK1(reb1), a DGK1 allele containing the Reb1p-binding site mutation, was greatly lower than that of the wild type allele, as indicated by analyses of DGK1 mRNA, Dgk1p, and diacylglycerol kinase activity. In the presence of cerulenin, an inhibitor of de novo fatty acid synthesis, the dgk1Δ mutant expressing DGK1(reb1) exhibited a significant defect in growth as well as in the synthesis of phospholipids from triacylglycerol mobilization. Unlike DGK1, the DGK1(reb1) expressed in the dgk1Δ pah1Δ mutant did not result in the nuclear/endoplasmic reticulum membrane expansion, which occurs in cells lacking phosphatidate phosphatase activity. Taken together, these results indicate that the Reb1p-mediated regulation of diacylglycerol kinase plays a major role in its in vivo functions in lipid metabolism.
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Affiliation(s)
- Yixuan Qiu
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
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15
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Runguphan W, Keasling JD. Metabolic engineering of Saccharomyces cerevisiae for production of fatty acid-derived biofuels and chemicals. Metab Eng 2013; 21:103-13. [PMID: 23899824 DOI: 10.1016/j.ymben.2013.07.003] [Citation(s) in RCA: 265] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 06/28/2013] [Accepted: 07/11/2013] [Indexed: 10/26/2022]
Abstract
As the serious effects of global climate change become apparent and access to fossil fuels becomes more limited, metabolic engineers and synthetic biologists are looking towards greener sources for transportation fuels. In recent years, microbial production of high-energy fuels by economically efficient bioprocesses has emerged as an attractive alternative to the traditional production of transportation fuels. Here, we engineered the budding yeast Saccharomyces cerevisiae to produce fatty acid-derived biofuels and chemicals from simple sugars. Specifically, we overexpressed all three fatty acid biosynthesis genes, namely acetyl-CoA carboxylase (ACC1), fatty acid synthase 1 (FAS1) and fatty acid synthase 2 (FAS2), in S. cerevisiae. When coupled to triacylglycerol (TAG) production, the engineered strain accumulated lipid to more than 17% of its dry cell weight, a four-fold improvement over the control strain. Understanding that TAG cannot be used directly as fuels, we also engineered S. cerevisiae to produce drop-in fuels and chemicals. Altering the terminal "converting enzyme" in the engineered strain led to the production of free fatty acids at a titer of approximately 400 mg/L, fatty alcohols at approximately 100mg/L and fatty acid ethyl esters (biodiesel) at approximately 5 mg/L directly from simple sugars. We envision that our approach will provide a scalable, controllable and economic route to this important class of chemicals.
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Affiliation(s)
- Weerawat Runguphan
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Jay D Keasling
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Departments of Chemical and Biomolecular Engineering and Bioengineering, University of California, Berkeley, Berkeley, CA 94720, United States.
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16
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Lipid droplets and peroxisomes: key players in cellular lipid homeostasis or a matter of fat--store 'em up or burn 'em down. Genetics 2013; 193:1-50. [PMID: 23275493 PMCID: PMC3527239 DOI: 10.1534/genetics.112.143362] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Lipid droplets (LDs) and peroxisomes are central players in cellular lipid homeostasis: some of their main functions are to control the metabolic flux and availability of fatty acids (LDs and peroxisomes) as well as of sterols (LDs). Both fatty acids and sterols serve multiple functions in the cell—as membrane stabilizers affecting membrane fluidity, as crucial structural elements of membrane-forming phospholipids and sphingolipids, as protein modifiers and signaling molecules, and last but not least, as a rich carbon and energy source. In addition, peroxisomes harbor enzymes of the malic acid shunt, which is indispensable to regenerate oxaloacetate for gluconeogenesis, thus allowing yeast cells to generate sugars from fatty acids or nonfermentable carbon sources. Therefore, failure of LD and peroxisome biogenesis and function are likely to lead to deregulated lipid fluxes and disrupted energy homeostasis with detrimental consequences for the cell. These pathological consequences of LD and peroxisome failure have indeed sparked great biomedical interest in understanding the biogenesis of these organelles, their functional roles in lipid homeostasis, interaction with cellular metabolism and other organelles, as well as their regulation, turnover, and inheritance. These questions are particularly burning in view of the pandemic development of lipid-associated disorders worldwide.
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17
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Abstract
Due to its genetic tractability and increasing wealth of accessible data, the yeast Saccharomyces cerevisiae is a model system of choice for the study of the genetics, biochemistry, and cell biology of eukaryotic lipid metabolism. Glycerolipids (e.g., phospholipids and triacylglycerol) and their precursors are synthesized and metabolized by enzymes associated with the cytosol and membranous organelles, including endoplasmic reticulum, mitochondria, and lipid droplets. Genetic and biochemical analyses have revealed that glycerolipids play important roles in cell signaling, membrane trafficking, and anchoring of membrane proteins in addition to membrane structure. The expression of glycerolipid enzymes is controlled by a variety of conditions including growth stage and nutrient availability. Much of this regulation occurs at the transcriptional level and involves the Ino2–Ino4 activation complex and the Opi1 repressor, which interacts with Ino2 to attenuate transcriptional activation of UASINO-containing glycerolipid biosynthetic genes. Cellular levels of phosphatidic acid, precursor to all membrane phospholipids and the storage lipid triacylglycerol, regulates transcription of UASINO-containing genes by tethering Opi1 to the nuclear/endoplasmic reticulum membrane and controlling its translocation into the nucleus, a mechanism largely controlled by inositol availability. The transcriptional activator Zap1 controls the expression of some phospholipid synthesis genes in response to zinc availability. Regulatory mechanisms also include control of catalytic activity of glycerolipid enzymes by water-soluble precursors, products and lipids, and covalent modification of phosphorylation, while in vivo function of some enzymes is governed by their subcellular location. Genome-wide genetic analysis indicates coordinate regulation between glycerolipid metabolism and a broad spectrum of metabolic pathways.
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18
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Abstract
Lipids from microalgae have become an important commodity in the last 20 years, biodiesel and supplementing human diets with ω-3 fatty acids are just two of the many applications. Acetyl-CoA carboxylase (ACCase) is a key enzyme in the lipid synthesis pathway. In general, ACCases consist of four functional domains: the biotin carboxylase (BC), the biotin carboxyl binding protein (BCCP), and α-and β-carboxyltransferases (α-and β-CT). In algae, like in plants, lipid synthesis is another function of the chloroplast. Despite being well researched in plants and animals, there is a distinct lack of information about this enzyme in the taxonomically diverse algae. In plastid-containing organisms, ACCases are present in the cytosol and the plastid (chloroplasts) and two different forms exist, the heteromeric (prokaryotic) and homomeric (eukaryotic) form. Despite recognition of the existence of the two ACCase forms, generalized published statements still list the heteromeric form as the one present in algal plastids. In this study, the authors show this is not the case for all algae. The presence of heteromeric or homomeric ACCase is dependent on the origin of plastid. The authors used ACCase amino acid sequence comparisons to show that green (Chlorophyta) and red (Rhodophyta) algae, with the exception of the green algal class Prasinophyceae, contain heteromeric ACCase in their plastids, which are of primary symbiotic origin and surrounded by two envelope membranes. In contrast, algal plastids surrounded by three to four membranes were derived through secondary endosymbiosis (Heterokontophyta and Haptophyta), as well as apicoplast containing Apicomplexa, contain homomeric ACCase in their plastids. Distinctive differences in the substrate binding regions of heteromeric and homomeric α-CT and β-CT were discovered, which can be used to distinguish between the two ACCase types. Furthermore, the acetyl-CoA binding region of homomeric α-CT can be used to distinguish between cytosolic and plastidial ACCase. The information provided here will be of fundamental importance in ACCase expression and activity research to unravel impacts of environmental and physicochemical parameters on lipid content and productivity.
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Affiliation(s)
- Roger Huerlimann
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia
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19
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Laliotis GP, Bizelis I, Rogdakis E. Comparative Approach of the de novo Fatty Acid Synthesis (Lipogenesis) between Ruminant and Non Ruminant Mammalian Species: From Biochemical Level to the Main Regulatory Lipogenic Genes. Curr Genomics 2011; 11:168-83. [PMID: 21037855 PMCID: PMC2878982 DOI: 10.2174/138920210791110960] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 01/03/2010] [Accepted: 01/10/2010] [Indexed: 11/24/2022] Open
Abstract
Over the second half of 20th century much research on lipogenesis has been conducted, especially focused on increasing the production efficiency and improving the quality of animal derived products. However, many diferences are observed in the physiology of lipogenesis between species. Recently, many studies have also elucidated the involvement of numerous genes in this procedure, highlighting diferences not only at physiology but also at the molecular level. The main scope of this review is to point out the major differences between ruminant and non ruminant species, that are observed in key regulatory genes involved in lipogenesis. Human is used as a central reference and according to the findinggs, main differences are analysed. These findings could serve not only as basis for understanding the main physiology of lipogenesis and further basic research, but also as a basis for any animal scientist to develop new concepts and methods for use in improving animal production and modern genetic improvement.
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Affiliation(s)
- G P Laliotis
- Department of Animal Science, Laboratory of Animal Breeding and Husbandry, Agricultural University of Athens, Iera Odos 75,118 55 Athens, Greece
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20
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Beopoulos A, Cescut J, Haddouche R, Uribelarrea JL, Molina-Jouve C, Nicaud JM. Yarrowia lipolytica as a model for bio-oil production. Prog Lipid Res 2009; 48:375-87. [PMID: 19720081 DOI: 10.1016/j.plipres.2009.08.005] [Citation(s) in RCA: 424] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 08/18/2009] [Accepted: 08/20/2009] [Indexed: 01/13/2023]
Abstract
The yeast Yarrowialipolytica has developed very efficient mechanisms for breaking down and using hydrophobic substrates. It is considered an oleaginous yeast, based on its ability to accumulate large amounts of lipids. Completion of the sequencing of the Y.lipolytica genome and the existence of suitable tools for genetic manipulation have made it possible to use the metabolic function of this species for biotechnological applications. In this review, we describe the coordinated pathways of lipid metabolism, storage and mobilization in this yeast, focusing in particular on the roles and regulation of the various enzymes and organelles involved in these processes. The physiological responses of Y.lipolytica to hydrophobic substrates include surface-mediated and direct interfacial transport processes, the production of biosurfactants, hydrophobization of the cytoplasmic membrane and the formation of protrusions. We also discuss culture conditions, including the mode of culture control and the culture medium, as these conditions can be modified to enhance the accumulation of lipids with a specific composition and to identify links between various biological processes occurring in the cells of this yeast. Examples are presented demonstrating the potential use of Y.lipolytica in fatty-acid bioconversion, substrate valorization and single-cell oil production. Finally, this review also discusses recent progress in our understanding of the metabolic fate of hydrophobic compounds within the cell: their terminal oxidation, further degradation or accumulation in the form of intracellular lipid bodies.
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Affiliation(s)
- Athanasios Beopoulos
- Microbiology and Molecular Genetic Laboratory, CNRS UMR2585, INRA UMR1238, AgroParisTech, INRA centre de Versailles-Grignon BP 01, F-78850 Thiverval-Grignon, France
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21
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Tehlivets O, Scheuringer K, Kohlwein SD. Fatty acid synthesis and elongation in yeast. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:255-70. [PMID: 16950653 DOI: 10.1016/j.bbalip.2006.07.004] [Citation(s) in RCA: 298] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 07/14/2006] [Accepted: 07/17/2006] [Indexed: 12/30/2022]
Abstract
Fatty acids are essential compounds in the cell. Since the yeast Saccharomyces cerevisiae does not feed typically on fatty acids, cellular function and growth relies on endogenous synthesis. Since all cellular organelles are involved in--or dependent on--fatty acid synthesis, multiple levels of control may exist to ensure proper fatty acid composition and homeostasis. In this review, we summarize what is currently known about enzymes involved in cellular fatty acid synthesis and elongation, and discuss potential links between fatty acid metabolism, physiology and cellular regulation.
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Affiliation(s)
- Oksana Tehlivets
- Institute of Molecular Biosciences, University of Graz, A8010 Graz, Austria
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22
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Jesch SA, Liu P, Zhao X, Wells MT, Henry SA. Multiple endoplasmic reticulum-to-nucleus signaling pathways coordinate phospholipid metabolism with gene expression by distinct mechanisms. J Biol Chem 2006; 281:24070-83. [PMID: 16777852 DOI: 10.1074/jbc.m604541200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In many organisms the coordinated synthesis of membrane lipids is controlled by feedback systems that regulate the transcription of target genes. However, a complete description of the transcriptional changes that accompany the remodeling of membrane phospholipids has not been reported. To identify metabolic signaling networks that coordinate phospholipid metabolism with gene expression, we profiled the sequential and temporal changes in genome-wide expression that accompany alterations in phospholipid metabolism induced by inositol supplementation in yeast. This analysis identified six distinct expression responses, which included phospholipid biosynthetic genes regulated by Opi1p, endoplasmic reticulum (ER) luminal protein folding chaperone and oxidoreductase genes regulated by the unfolded protein response pathway, lipid-remodeling genes regulated by Mga2p, as well as genes involved in ribosome biogenesis, cytosolic stress response, and purine and amino acid metabolism. We also report that the unfolded protein response pathway is rapidly inactivated by inositol supplementation and demonstrate that the response of the unfolded protein response pathway to inositol is separable from the response mediated by Opi1p. These data indicate that altering phospholipid metabolism produces signals that are relayed through numerous distinct ER-to-nucleus signaling pathways and, thereby, produce an integrated transcriptional response. We propose that these signals are generated in the ER by increased flux through the pathway of phosphatidylinositol synthesis.
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Affiliation(s)
- Stephen A Jesch
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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23
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Abstract
Fatty acids and sterols are vital components of all eukaryotic cells. Both are used as building blocks for numerous cellular processes such as membrane biosynthesis or hormone production (sterols). Furthermore, these compounds elicit a variety of effects intracellularly as they can act as signalling molecules and regulate gene expression. The metabolism of fatty acids and sterols represents a very intricate network of pathways that are regulated in a precise manner in order to maintain lipid homoeostasis within a cell. Using the budding yeast Saccharomyces cerevisiae as a model system, we touch upon some of the aspects of achieving and maintaining this lipid homoeostasis.
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24
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Abu-Elheiga L, Matzuk MM, Kordari P, Oh W, Shaikenov T, Gu Z, Wakil SJ. Mutant mice lacking acetyl-CoA carboxylase 1 are embryonically lethal. Proc Natl Acad Sci U S A 2005; 102:12011-6. [PMID: 16103361 PMCID: PMC1189351 DOI: 10.1073/pnas.0505714102] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Acetyl-CoA carboxylases (ACC1 and ACC2) catalyze the carboxylation of acetyl-CoA to form malonyl-CoA, an intermediate metabolite that plays a pivotal role in the regulation of fatty acid metabolism. We previously reported that ACC2 null mice are viable, and that ACC2 plays an important role in the regulation of fatty acid oxidation through the inhibition of carnitine palmitoyltransferase I, a mitochondrial component of the fatty-acyl shuttle system. Herein, we used gene targeting to knock out the ACC1 gene. The heterozygous mutant mice (Acc1(+/-)) had normal fertility and lifespans and maintained a similar body weight to that of their wild-type cohorts. The mRNA level of ACC1 in the tissues of Acc1(+/-) mice was half that of the wild type; however, the protein level of ACC1 and the total malonyl-CoA level were similar. In addition, there was no difference in the acetate incorporation into fatty acids nor in the fatty acid oxidation between the hepatocytes of Acc1(+/-) mice and those of the wild type. In contrast to Acc2(-/-) mice, Acc1(-/-) mice were not detected after mating. Timed pregnancies of heterozygotes revealed that Acc(-/-) embryos are already undeveloped at embryonic day (E)7.5, they die by E8.5, and are completely resorbed at E11.5. Our previous results of the ACC2 knockout mice and current studies of ACC1 knockout mice further confirm our hypotheses that malonyl-CoA exists in two independent pools, and that ACC1 and ACC2 have distinct roles in fatty acid metabolism.
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Affiliation(s)
- Lutfi Abu-Elheiga
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Barber MC, Price NT, Travers MT. Structure and regulation of acetyl-CoA carboxylase genes of metazoa. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:1-28. [PMID: 15749055 DOI: 10.1016/j.bbalip.2004.12.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 11/02/2004] [Accepted: 12/01/2004] [Indexed: 11/16/2022]
Abstract
Acetyl-CoA carboxylase (ACC) plays a fundamental role in fatty acid metabolism. The reaction product, malonyl-CoA, is both an intermediate in the de novo synthesis of long-chain fatty acids and also a substrate for distinct fatty acyl-CoA elongation enzymes. In metazoans, which have evolved energy storage tissues to fuel locomotion and to survive periods of starvation, energy charge sensing at the level of the individual cell plays a role in fuel selection and metabolic orchestration between tissues. In mammals, and probably other metazoans, ACC forms a component of an energy sensor with malonyl-CoA, acting as a signal to reciprocally control the mitochondrial transport step of long-chain fatty acid oxidation through the inhibition of carnitine palmitoyltransferase I (CPT I). To reflect this pivotal role in cell function, ACC is subject to complex regulation. Higher metazoan evolution is associated with the duplication of an ancestral ACC gene, and with organismal complexity, there is an increasing diversity of transcripts from the ACC paraloges with the potential for the existence of several isozymes. This review focuses on the structure of ACC genes and the putative individual roles of their gene products in fatty acid metabolism, taking an evolutionary viewpoint provided by data in genome databases.
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Affiliation(s)
- Michael C Barber
- Hannah Research Institute, Ayr, KA6 5HL, Scotland, United Kingdom.
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26
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Wan H, Sjölinder M, Schairer HU, Leclerque A. A new dominant selection marker for transformation of Pichia pastoris to soraphen A resistance. J Microbiol Methods 2004; 57:33-9. [PMID: 15003686 DOI: 10.1016/j.mimet.2003.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 11/17/2003] [Accepted: 11/18/2003] [Indexed: 11/30/2022]
Abstract
Despite the considerable progress molecular genetics of filamentous fungi has made during the past decade, there is still an urgent need for efficiently working selectable markers for fungal transformation. Using Pichia pastoris as a host, we describe the development of a new dominant selectable marker of prokaryotic origin. This system, termed sor(R), is based upon the resistance of the bacterial enzyme acetyl-CoA carboxylase (ACCase) to the macrocyclic polyketide soraphen A, a potent inhibitor of fungal ACCase produced by the myxobacterium Sorangium cellulosum. In this study, we firstly demonstrate that the integration of a single sor(R) cassette into the P. pastoris genome confers resistance to elevated concentrations of soraphen A. Furthermore, it has been shown that the versatility of this marker can be considerably increased by splitting the sor(R) cassette, especially when successive transformations are performed on the same strain. As pronounced sensitivity to soraphen A is the rule among filamentous fungi, we expect the sor(R) marker to be a widely applicable tool for fungal transformation.
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Affiliation(s)
- Hong Wan
- Molecular Biology Center of University Heidelberg (ZMBH) Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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27
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Hoja U, Marthol S, Hofmann J, Stegner S, Schulz R, Meier S, Greiner E, Schweizer E. HFA1 encoding an organelle-specific acetyl-CoA carboxylase controls mitochondrial fatty acid synthesis in Saccharomyces cerevisiae. J Biol Chem 2004; 279:21779-86. [PMID: 14761959 DOI: 10.1074/jbc.m401071200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae gene, HFA1, encodes a >250-kDa protein, which is required for mitochondrial function. Hfa1p exhibits 72% overall sequence similarity (54% identity) to ACC1-encoded yeast cytoplasmic acetyl-CoA carboxylase. Nevertheless, HFA1 and ACC1 functions are not overlapping because mutants of the two genes have different phenotypes and do not complement each other. Whereas ACC1 is involved in cytoplasmic fatty acid synthesis, the phenotype of hfa1Delta disruptants resembles that of mitochondrial fatty-acid synthase mutants. They fail to grow on lactate or glycerol, and the mitochondrial cofactor, lipoic acid, is reduced to <10% of its normal cellular concentration. Other than Acc1p, the N-terminal sequence of Hfa1p comprises a canonical mitochondrial targeting signal together with a matrix protease cleavage site. Accordingly, the HFA1-encoded protein was specifically assigned by Western blotting of appropriate cell fractions to the mitochondrial compartment. Removal of the mitochondrial targeting sequence abolished the competence of HFA1 DNA to complement hfal null mutants. Conversely and in contrast to the intact HFA1 sequence, the signal sequence-free HFA1 gene complemented the mutational loss of cytoplasmic acetyl-CoA carboxylase. Expression of HFA1 under the control of the ACC1 promoter restored cellular ACC activity in ACC1-defective yeast mutants to wild type levels. From this finding, it is concluded that HFA1 encodes a specific mitochondrial acetyl-CoA carboxylase providing malonyl-CoA for intraorganellar fatty acid and, in particular, lipoic acid synthesis.
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Affiliation(s)
- Ursula Hoja
- Lehrstuhl für Biochemie der Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
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28
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Harwood HJ, Petras SF, Shelly LD, Zaccaro LM, Perry DA, Makowski MR, Hargrove DM, Martin KA, Tracey WR, Chapman JG, Magee WP, Dalvie DK, Soliman VF, Martin WH, Mularski CJ, Eisenbeis SA. Isozyme-nonselective N-substituted bipiperidylcarboxamide acetyl-CoA carboxylase inhibitors reduce tissue malonyl-CoA concentrations, inhibit fatty acid synthesis, and increase fatty acid oxidation in cultured cells and in experimental animals. J Biol Chem 2003; 278:37099-111. [PMID: 12842871 DOI: 10.1074/jbc.m304481200] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inhibition of acetyl-CoA carboxylase (ACC), with its resultant inhibition of fatty acid synthesis and stimulation of fatty acid oxidation, has the potential to favorably affect the multitude of cardiovascular risk factors associated with the metabolic syndrome. To achieve maximal effectiveness, an ACC inhibitor should inhibit both the lipogenic tissue isozyme (ACC1) and the oxidative tissue isozyme (ACC2). Herein, we describe the biochemical and acute physiological properties of CP-610431, an isozyme-nonselective ACC inhibitor identified through high throughput inhibition screening, and CP-640186, an analog with improved metabolic stability. CP-610431 inhibited ACC1 and ACC2 with IC50s of approximately 50 nm. Inhibition was reversible, uncompetitive with respect to ATP, and non-competitive with respect to bicarbonate, acetyl-CoA, and citrate, indicating interaction with the enzymatic carboxyl transfer reaction. CP-610431 also inhibited fatty acid synthesis, triglyceride (TG) synthesis, TG secretion, and apolipoprotein B secretion in HepG2 cells (ACC1) with EC50s of 1.6, 1.8, 3.0, and 5.7 microm, without affecting either cholesterol synthesis or apolipoprotein CIII secretion. CP-640186, also inhibited both isozymes with IC50sof approximately 55 nm but was 2-3 times more potent than CP-610431 in inhibiting HepG2 cell fatty acid and TG synthesis. CP-640186 also stimulated fatty acid oxidation in C2C12 cells (ACC2) and in rat epitrochlearis muscle strips with EC50s of 57 nm and 1.3 microm. In rats, CP-640186 lowered hepatic, soleus muscle, quadriceps muscle, and cardiac muscle malonyl-CoA with ED50s of 55, 6, 15, and 8 mg/kg. Consequently, CP-640186 inhibited fatty acid synthesis in rats, CD1 mice, and ob/ob mice with ED50s of 13, 11, and 4 mg/kg, and stimulated rat whole body fatty acid oxidation with an ED50 of approximately 30 mg/kg. Taken together, These observations indicate that isozyme-nonselective ACC inhibition has the potential to favorably affect risk factors associated with the metabolic syndrome.
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Affiliation(s)
- H James Harwood
- Department of Cardiovascular and Metabolic Diseases, Pfizer Global Research and Development, Groton Laboratories, Pfizer Inc., Groton, Connecticut 06340, USA.
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29
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Abstract
Biotin-containing proteins are found in all forms of life, and they catalyze carboxylation, decarboxylation, or transcarboxylation reactions that are central to metabolism. In plants, five biotin-containing proteins have been characterized. Of these, four are catalysts, namely the two structurally distinct acetyl-CoA carboxylases (heteromeric and homomeric), 3-methylcrotonyl-CoA carboxylase and geranoyl-CoA carboxylase. In addition, plants contain a noncatalytic biotin protein that accumulates in seeds and is thought to play a role in storing biotin. Acetyl-CoA carboxylases generate two pools of malonyl-CoA, one in plastids that is the precursor for de novo fatty acid biosynthesis and the other in the cytosol that is the precursor for fatty acid elongation and a large number of secondary metabolites. 3-Methylcrotonyl-CoA carboxylase catalyzes a reaction in the mitochondrial pathway for leucine catabolism. The exact metabolic function of geranoyl-CoA carboxylase is as yet unknown, but it may be involved in isoprenoid metabolism. This minireview summarizes the recent developments in our understanding of the structure, regulation, and metabolic functions of these proteins in plants.
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Al-Feel W, DeMar JC, Wakil SJ. A Saccharomyces cerevisiae mutant strain defective in acetyl-CoA carboxylase arrests at the G2/M phase of the cell cycle. Proc Natl Acad Sci U S A 2003; 100:3095-100. [PMID: 12626751 PMCID: PMC152252 DOI: 10.1073/pnas.0538069100] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
To elucidate the essential functions of acetyl-CoA carboxylase (ACC1FAS3) in Saccharomyces cerevisiae, a temperature-sensitive mutant (acc1(ts)) was constructed. When the acc1(ts) cells were synchronized in G(1) phase with alpha-factor at the permissive temperature of 24 degrees C and then released from the blockade and incubated at the restrictive temperature of 37 degrees C, 95% of the cell population became arrested at the G(2)M phase of the cell cycle despite the presence of fatty acids (C(14)-C(26)) in the medium. These cells developed large undivided nuclei, and the spindles of the arrested mutant cells were short. Shifting the G(2) arrested cells back to the permissive temperature resulted in a reversal of the cell-cycle arrest, with cells initiating mitosis. However, after 3 h of incubation at 37 degrees C, G(2) arrested mutant cells lost viability and displayed a uniquely altered nuclear envelope. Using [1-(14)C]acetate as a precursor for fatty acids synthesis, we identified the phospholipids and sphingolipids derived from acc1(ts) cells and wild-type cells at 24 degrees C and 37 degrees C, respectively. The levels of inositol-ceramides [IPC, MIPC, and M(IP)(2)C] and very long-chain fatty acids C(24) and C(26) declined sharply in the G(2)M arrested cells because of ACC inactivation. Shifting the acc1(ts) cells to 24 degrees C after 2 h of incubation at 37 degrees C resulted in reactivation of the ACC and elevation of the ceramides and very long-chain fatty acid syntheses with normal cell-cycle progression. In contrast, synthesis of wild-type inositol-ceramides, C(24) and C(26), fatty acids were elevated on incubation at 37 degrees C and declined when the cells shifted to the permissive temperature of 24 degrees C.
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Affiliation(s)
- Walid Al-Feel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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31
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Chuakrut S, Arai H, Ishii M, Igarashi Y. Characterization of a bifunctional archaeal acyl coenzyme A carboxylase. J Bacteriol 2003; 185:938-47. [PMID: 12533469 PMCID: PMC142822 DOI: 10.1128/jb.185.3.938-947.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acyl coenzyme A carboxylase (acyl-CoA carboxylase) was purified from Acidianus brierleyi. The purified enzyme showed a unique subunit structure (three subunits with apparent molecular masses of 62, 59, and 20 kDa) and a molecular mass of approximately 540 kDa, indicating an alpha(4)beta(4)gamma(4) subunit structure. The optimum temperature for the enzyme was 60 to 70 degrees C, and the optimum pH was around 6.4 to 6.9. Interestingly, the purified enzyme also had propionyl-CoA carboxylase activity. The apparent K(m) for acetyl-CoA was 0.17 +/- 0.03 mM, with a V(max) of 43.3 +/- 2.8 U mg(-1), and the K(m) for propionyl-CoA was 0.10 +/- 0.008 mM, with a V(max) of 40.8 +/- 1.0 U mg(-1). This result showed that A. brierleyi acyl-CoA carboxylase is a bifunctional enzyme in the modified 3-hydroxypropionate cycle. Both enzymatic activities were inhibited by malonyl-CoA, methymalonyl-CoA, succinyl-CoA, or CoA but not by palmitoyl-CoA. The gene encoding acyl-CoA carboxylase was cloned and characterized. Homology searches of the deduced amino acid sequences of the 62-, 59-, and 20-kDa subunits indicated the presence of functional domains for carboxyltransferase, biotin carboxylase, and biotin carboxyl carrier protein, respectively. Amino acid sequence alignment of acetyl-CoA carboxylases revealed that archaeal acyl-CoA carboxylases are closer to those of Bacteria than to those of Eucarya. The substrate-binding motifs of the enzymes are highly conserved among the three domains. The ATP-binding residues were found in the biotin carboxylase subunit, whereas the conserved biotin-binding site was located on the biotin carboxyl carrier protein. The acyl-CoA-binding site and the carboxybiotin-binding site were found in the carboxyltransferase subunit.
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Affiliation(s)
- Songkran Chuakrut
- Laboratory of Applied Microbiology, Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8567, Japan
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32
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Abstract
Long-chain fatty acids are a vital metabolic energy source and are building blocks of membrane lipids. The yeast Saccharomyces cerevisiae is a valuable model system for elucidation of gene-function relationships in such eukaryotic processes as fatty acid metabolism. Yeast degrades fatty acids only in the peroxisome, and recently, genes encoding core and auxiliary enzymes of peroxisomal beta-oxidation have been identified. Mechanisms involved in fatty acid induction of gene expression have been described, and novel fatty acid-responsive genes have been discovered via yeast genome analysis. In addition, a number of genes essential for synthesis of the variety of fatty acids in yeast have been cloned. Advances in understanding such processes in S. cerevisiae will provide helpful insights to functional genomics approaches in more complex organisms.
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Affiliation(s)
- P J Trotter
- The Division of Nutritional Sciences and the Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
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33
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Abstract
Biotin is an essential cofactor for a small number of enzymes involved mainly in the transfer of CO2 during HCO-3-dependent carboxylation reactions. This review highlights progress in plant biotin research by focusing on the four major areas of recent investigation: the structure, enzymology, and localization of two important biotinylated proteins (methylcrotonoyl-CoA carboxylase involved in the catabolism of leucine and noncyclic isoprenoids; acetyl-CoA carboxylase isoforms involved in a number of biosynthetic pathways); the biosynthesis of biotin; the biotinylation of biotin-dependent carboxylases, including the characterization of biotin holocarboxylase synthetase isoforms; and the detailed characterization of a novel, seed-specific biotinylated protein. A central challenge for plant biotin research is to determine in molecular terms how plant cells regulate the flow of biotin to sustain the biotinylation of biotin-dependent carboxylases during biosynthetic reactions.
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Affiliation(s)
- Claude Alban
- Laboratoire Mixte CNRS/Aventis (UMR 1932), Aventis CropScience, Lyon, France; e-mail:
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34
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Schneiter R, Guerra CE, Lampl M, Tatzer V, Zellnig G, Klein HL, Kohlwein SD. A novel cold-sensitive allele of the rate-limiting enzyme of fatty acid synthesis, acetyl coenzyme A carboxylase, affects the morphology of the yeast vacuole through acylation of Vac8p. Mol Cell Biol 2000; 20:2984-95. [PMID: 10757783 PMCID: PMC85561 DOI: 10.1128/mcb.20.9.2984-2995.2000] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The yeast vacuole functions both as a degradative organelle and as a storage depot for small molecules and ions. Vacuoles are dynamic reticular structures that appear to alternately fuse and fragment as a function of growth stage and environment. Vac8p, an armadillo repeat-containing protein, has previously been shown to function both in vacuolar inheritance and in protein targeting from the cytoplasm to the vacuole. Both myristoylation and palmitoylation of Vac8p are required for its efficient localization to the vacuolar membrane (Y.-X. Wang, N. L. Catlett, and L. S. Weisman, J. Cell Biol. 140:1063-1074, 1998). We report that mutants with conditional defects in the rate-limiting enzyme of fatty acid synthesis, acetyl coenzyme A carboxylase (ACC1), display unusually multilobed vacuoles, similar to those observed in vac8 mutant cells. This vacuolar phenotype of acc1 mutant cells was shown biochemically to be accompanied by a reduced acylation of Vac8p which was alleviated by fatty acid supplementation. Consistent with the proposed defect of acc1 mutant cells in acylation of Vac8p, vacuolar membrane localization of Vac8p was impaired upon shifting acc1 mutant cells to nonpermissive condition. The function of Vac8p in protein targeting, on the other hand, was not affected under these conditions. These observations link fatty acid synthesis and availability to direct morphological alterations of an organellar membrane.
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Affiliation(s)
- R Schneiter
- SFB Biomembrane Research Center, Institut für Biochemie und Lebensmittelchemie, Technische Universität Graz, A-8010 Graz, Austria.
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35
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Ke J, Wen TN, Nikolau BJ, Wurtele ES. Coordinate regulation of the nuclear and plastidic genes coding for the subunits of the heteromeric acetyl-coenzyme A carboxylase. PLANT PHYSIOLOGY 2000; 122:1057-71. [PMID: 10759501 PMCID: PMC58940 DOI: 10.1104/pp.122.4.1057] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/1999] [Accepted: 12/17/1999] [Indexed: 05/20/2023]
Abstract
Plastidic acetyl-coenzyme A (CoA) carboxylase (ACCase) catalyzes the first committed reaction of de novo fatty acid biosynthesis. This heteromeric enzyme is composed of one plastid-coded subunit (beta-carboxyltransferase) and three nuclear-coded subunits (biotin carboxy-carrier, biotin carboxylase, and alpha-carboxyltransferase). We report the primary structure of the Arabidopsis alpha-carboxyltransferase and beta-carboxyltransferase subunits deduced from nucleotide sequences of the respective genes and/or cDNA. Co-immunoprecipitation experiments confirm that the alpha-carboxyltransferase and beta-carboxyltransferase subunits are physically associated. The plant alpha-carboxyltransferases have gained a C-terminal domain relative to eubacteria, possibly via the evolutionary acquisition of a single exon. This C-terminal domain is divergent among plants and may have a structural function rather than being essential for catalysis. The four ACCase subunit mRNAs accumulate to the highest levels in tissues and cells that are actively synthesizing fatty acids, which are used either for membrane biogenesis in rapidly growing tissues or for oil accumulation in developing embryos. Development coordinately affects changes in the accumulation of the ACCase subunit mRNAs so that these four mRNAs maintain a constant molar stoichiometric ratio. These data indicate that the long-term, developmentally regulated expression of the heteromeric ACCase is in part controlled by a mechanism(s) that coordinately affects the steady-state concentrations of each subunit mRNA.
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Affiliation(s)
- J Ke
- Department of Botany, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA
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36
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Abstract
Pyruvate carboxylase (PC; EC 6.4.1.1), a member of the biotin-dependent enzyme family, catalyses the ATP-dependent carboxylation of pyruvate to oxaloacetate. PC has been found in a wide variety of prokaryotes and eukaryotes. In mammals, PC plays a crucial role in gluconeogenesis and lipogenesis, in the biosynthesis of neurotransmitter substances, and in glucose-induced insulin secretion by pancreatic islets. The reaction catalysed by PC and the physical properties of the enzyme have been studied extensively. Although no high-resolution three-dimensional structure has yet been determined by X-ray crystallography, structural studies of PC have been conducted by electron microscopy, by limited proteolysis, and by cloning and sequencing of genes and cDNA encoding the enzyme. Most well characterized forms of active PC consist of four identical subunits arranged in a tetrahedron-like structure. Each subunit contains three functional domains: the biotin carboxylation domain, the transcarboxylation domain and the biotin carboxyl carrier domain. Different physiological conditions, including diabetes, hyperthyroidism, genetic obesity and postnatal development, increase the level of PC expression through transcriptional and translational mechanisms, whereas insulin inhibits PC expression. Glucocorticoids, glucagon and catecholamines cause an increase in PC activity or in the rate of pyruvate carboxylation in the short term. Molecular defects of PC in humans have recently been associated with four point mutations within the structural region of the PC gene, namely Val145-->Ala, Arg451-->Cys, Ala610-->Thr and Met743-->Thr.
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Affiliation(s)
- S Jitrapakdee
- Department of Biochemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
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37
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Schneiter R, Guerra CE, Lampl M, Gogg G, Kohlwein SD, Klein HL. The Saccharomyces cerevisiae hyperrecombination mutant hpr1Delta is synthetically lethal with two conditional alleles of the acetyl coenzyme A carboxylase gene and causes a defect in nuclear export of polyadenylated RNA. Mol Cell Biol 1999; 19:3415-22. [PMID: 10207065 PMCID: PMC84134 DOI: 10.1128/mcb.19.5.3415] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In a screen for mutants that display synthetic lethal interaction with hpr1Delta, a hyperrecombination mutant of Saccharomyces cerevisiae, we have isolated a novel cold-sensitive allele of the acetyl coenzyme A (CoA) carboxylase gene, acc1(cs), encoding the rate-limiting enzyme of fatty acid synthesis. The synthetic lethal phenotype of the acc1(cs) hpr1Delta double mutant was only partially complemented by exogenous fatty acids. hpr1Delta was also synthetically lethal with a previously isolated, temperature-sensitive allele of ACC1, mtr7 (mRNA transport), indicating that the lethality of the acc1(cs) hpr1Delta double mutant was not allele specific. The basis for the interaction between conditional acc1 alleles and hpr1Delta was investigated in more detail. In the hpr1Delta mutant background, acetyl-CoA carboxylase enzyme activity was reduced about 15-fold and steady-state levels of biotinylated Acc1p and ACC1 mRNA were reduced 2-fold. The reduced Acc1p activity in hpr1Delta cells, however, did not result in an altered lipid or fatty acid composition of the mutant membranes but rendered cells hypersensitive to soraphen A, an inhibitor of Acc1p. Similar to mtr7, hpr1Delta and acc1(cs) mutant cells displayed a defect in nuclear export of polyadenylated RNA. Oversized transcripts were detected in hpr1Delta, and rRNA processing was disturbed, but pre-mRNA splicing appeared wild type. Surprisingly, the transport defect of hpr1Delta and acc1(cs) mutant cells was accompanied by an altered ring-shaped structure of the nucleolus. These observations suggest that the basis for the synthetic lethal interaction between hpr1Delta and acc1 may lie in a functional overlap of the two mutations in nuclear poly(A)+ RNA production and export that results in an altered structure of the nucleolus.
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Affiliation(s)
- R Schneiter
- Institut für Biochemie und Lebensmittelchemie, Technische Universität Graz, A-8010 Graz, Austria
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38
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Reverdatto S, Beilinson V, Nielsen NC. A multisubunit acetyl coenzyme A carboxylase from soybean. PLANT PHYSIOLOGY 1999; 119:961-78. [PMID: 10069834 PMCID: PMC32110 DOI: 10.1104/pp.119.3.961] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/1998] [Accepted: 11/11/1998] [Indexed: 05/18/2023]
Abstract
A multisubunit form of acetyl coenzyme A (CoA) carboxylase (ACCase) from soybean (Glycine max) was characterized. The enzyme catalyzes the formation of malonyl CoA from acetyl CoA, a rate-limiting step in fatty acid biosynthesis. The four known components that constitute plastid ACCase are biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), and the alpha- and beta-subunits of carboxyltransferase (alpha- and beta-CT). At least three different cDNAs were isolated from germinating soybean seeds that encode BC, two that encode BCCP, and four that encode alpha-CT. Whereas BC, BCCP, and alpha-CT are products of nuclear genes, the DNA that encodes soybean beta-CT is located in chloroplasts. Translation products from cDNAs for BC, BCCP, and alpha-CT were imported into isolated pea (Pisum sativum) chloroplasts and became integrated into ACCase. Edman microsequence analysis of the subunits after import permitted the identification of the amino-terminal sequence of the mature protein after removal of the transit sequences. Antibodies specific for each of the chloroplast ACCase subunits were generated against products from the cDNAs expressed in bacteria. The antibodies permitted components of ACCase to be followed during fractionation of the chloroplast stroma. Even in the presence of 0.5 M KCl, a complex that contained BC plus BCCP emerged from Sephacryl 400 with an apparent molecular mass greater than about 800 kD. A second complex, which contained alpha- and beta-CT, was also recovered from the column, and it had an apparent molecular mass of greater than about 600 kD. By mixing the two complexes together at appropriate ratios, ACCase enzymatic activity was restored. Even higher ACCase activities were recovered by mixing complexes from pea and soybean. The results demonstrate that the active form of ACCase can be reassembled and that it could form a high-molecular-mass complex.
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Affiliation(s)
- S Reverdatto
- United States Department of Agriculture, Agricultural Research Service, Purdue University, West Lafayette, Indiana 47907-1150, USA
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39
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40
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Abstract
The yeast Saccharomyces cerevisiae is a powerful experimental system to study biochemical, cell biological and molecular biological aspects of lipid synthesis. Most but not all genes encoding enzymes involved in fatty acid, phospholipid, sterol or sphingolipid biosynthesis of this unicellular eukaryote have been cloned, and many gene products have been functionally characterized. Less information is available about genes and gene products governing the transport of lipids between organelles and within membranes, turnover and degradation of complex lipids, regulation of lipid biosynthesis, and linkage of lipid metabolism to other cellular processes. Here we summarize current knowledge about lipid biosynthetic pathways in S. cerevisiae and describe the characteristic features of the gene products involved. We focus on recent discoveries in these fields and address questions on the regulation of lipid synthesis, subcellular localization of lipid biosynthetic steps, cross-talk between organelles during lipid synthesis and subcellular distribution of lipids. Finally, we discuss distinct functions of certain key lipids and their possible roles in cellular processes.
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Affiliation(s)
- G Daum
- Institut für Biochemie und Lebensmittelchemie, Technische Universität, Petersgasse, Graz, Austria.
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41
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Henry SA, Patton-Vogt JL. Genetic regulation of phospholipid metabolism: yeast as a model eukaryote. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1998; 61:133-79. [PMID: 9752720 DOI: 10.1016/s0079-6603(08)60826-0] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Baker's yeast, Saccharomyces cerevisiae, is an excellent and an increasingly important model for the study of fundamental questions in eukaryotic cell biology and genetic regulation. The fission yeast, Schizosaccharomyces pombe, although not as intensively studied as S. cerevisiae, also has many advantages as a model system. In this review, we discuss progress over the past several decades in biochemical and molecular genetic studies of the regulation of phospholipid metabolism in these two organisms and higher eukaryotes. In S. cerevisiae, following the recent completion of the yeast genome project, a very high percentage of the gene-enzyme relationships in phospholipid metabolism have been assigned and the remaining assignments are expected to be completed rapidly. Complex transcriptional regulation, sensitive to the availability of phospholipid precusors, as well as growth phase, coordinates the expression of the structural genes encoding these enzymes in S. cerevisiae. In this article, this regulation is described, the mechanism by which the cell senses the ongoing metabolic activity in the pathways for phospholipid biosynthesis is discussed, and a model is presented. Recent information relating to the role of phosphatidylcholine turnover in S. cerevisiae and its relationship to the secretory pathway, as well as to the regulation of phospholipid metabolism, is also presented. Similarities in the role of phospholipase D-mediated phosphatidylcholine turnover in the secretory process in yeast and mammals lend further credence to yeast as a model system.
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Affiliation(s)
- S A Henry
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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42
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Sun J, Ke J, Johnson JL, Nikolau BJ, Wurtele ES. Biochemical and molecular biological characterization of CAC2, the Arabidopsis thaliana gene coding for the biotin carboxylase subunit of the plastidic acetyl-coenzyme A carboxylase. PLANT PHYSIOLOGY 1997; 115:1371-83. [PMID: 9414551 PMCID: PMC158602 DOI: 10.1104/pp.115.4.1371] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The biotin carboxylase subunit of the heteromeric chloroplastic acetyl-coenzyme A carboxylase (ACCase) of Arabidopsis thaliana is coded by a single gene (CAC2), which is interrupted by 15 introns. The cDNA encodes a deduced protein of 537 amino acids with an apparent N-terminal chloroplast-targeting transit peptide. Antibodies generated to a glutathione S-transferase-CAC2 fusion protein react solely with a 51-kD polypeptide of Arabidopsis; these antibodies also inhibit ACCase activity in extracts of Arabidopsis. The entire CAC2 cDNA sequence was expressed in Escherichia coli and the resulting recombinant biotin carboxylase was enzymatically active in carboxylating free biotin. The catalytic properties of the recombinant biotin carboxylase indicate that the activity of the heteromeric ACCase may be regulated by light-/dark-induced changes in stromal pH. The CAC2 gene is maximally expressed in organs and tissues that are actively synthesizing fatty acids for membrane lipids or oil deposition. The observed expression pattern of CAC2 mirrors that previously reported for the CAC1 gene (J.-K. Choi, F. Yu, E.S. Wurtele, B.J. Nikolau [1995] Plant Physiol 109: 619-625; J. Ke, J.-K. Choi, M. Smith, H.T. Horner, B.J. Nikolau, E.S. Wurtele [1997] Plant Physiol 113: 357-365), which codes for the biotin carboxyl carrier subunit of the heteromeric ACCase. This coordination is probably partially established by coordinate transcription of the two genes. This hypothesis is consistent with the finding that the CAC2 and CAC1 gene promoters share a common set of sequence motifs that may be important in guiding the transcription of these genes.
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Affiliation(s)
- J Sun
- Department of Botany, Iowa State University, Ames 50011-1020, USA
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Abu-Elheiga L, Almarza-Ortega DB, Baldini A, Wakil SJ. Human acetyl-CoA carboxylase 2. Molecular cloning, characterization, chromosomal mapping, and evidence for two isoforms. J Biol Chem 1997; 272:10669-77. [PMID: 9099716 DOI: 10.1074/jbc.272.16.10669] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
cDNA encoding the 280-kDa acetyl-CoA carboxylase 2 (ACC2) isoform was isolated from human liver using the polymerase chain reaction. Sequencing the cDNA revealed an open reading frame of 7,449 base pairs (bp) that encode 2,483 amino acids (Mr 279,380). Using 5-kilobase pair cDNA clones as probes, we localized the gene encoding the 280-kDa human carboxylase to chromosome 12q23. When the cDNA of ACC2 was compared with that of ACC1, the nucleotide sequences and the predicted amino acid sequences had about 60 and 80% identity, respectively. Ser77 and Ser79, which were found to be critical for the phosphorylation and subsequent inactivation of rat ACC1 (Ser78 and Ser80 of human ACC1), are conserved in ACC2 and are represented as Ser219 and Ser221, respectively. On the other hand, Ser1200, which is also a phosphorylation site in rat ACC1 (Ser1201 of human ACC1), is not conserved in ACC2. The homology between the amino acid sequences of the two human carboxylases, however, is primarily found downstream of residues Ser78 and Ser81 in human ACC1 and their equivalents, that is Ser219 and Ser221 in ACC2, suggesting that the sequence of the first 218 amino acids at the N terminus of ACC2 represents a unique peptide that accounts, in part, for the variance between the two carboxylases. Using a cDNA probe (400 bp) that encodes the N-terminal amino acid residues of ACC2 in Northern blot analyses of different human and mouse tissues showed that ACC2 is predominantly expressed in liver, heart, and the skeletal muscles. Polyclonal antibodies raised against the N-terminal peptide (amino acid residues 1-220) reacted specifically and equally with human and rat ACC2 carboxylases, confirming the uniqueness of this N-terminal peptide and its conservation in animal ACC2. In addition, we present evidence for the presence of an isoform of ACC2 (Mr 270,000) in human liver that differs from the 280-kDa ACC2 by the absence of 303 nucleotides that encode 101 amino acids in the region between Arg1114 and Asp1215. The regulation and physiological significance of the two ACC2 isoforms remain to be determined.
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Affiliation(s)
- L Abu-Elheiga
- Verna and Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030, USA
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44
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Schulte W, Töpfer R, Stracke R, Schell J, Martini N. Multi-functional acetyl-CoA carboxylase from Brassica napus is encoded by a multi-gene family: indication for plastidic localization of at least one isoform. Proc Natl Acad Sci U S A 1997; 94:3465-70. [PMID: 9096417 PMCID: PMC20393 DOI: 10.1073/pnas.94.7.3465] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Three genes coding for different multifunctional acetyl-CoA carboxylase (ACCase; EC 6.4.1.2) isoenzymes from Brassica napus were isolated and divided into two major classes according to structural features in their 5' regions: class I comprises two genes with an additional coding exon of approximately 300 bp at the 5' end, and class II is represented by one gene carrying an intron of 586 bp in its 5' untranslated region. Fusion of the peptide sequence encoded by the additional first exon of a class I ACCase gene to the jellyfish Aequorea victoria green fluorescent protein (GFP) and transient expression in tobacco protoplasts targeted GFP to the chloroplasts. In contrast to the deduced primary structure of the biotin carboxylase domain encoded by the class I gene, the corresponding amino acid sequence of the class II ACCase shows higher identity with that of the Arabidopsis ACCase, both lacking a transit peptide. The Arabidopsis ACCase has been proposed to be a cytosolic isoenzyme. These observations indicate that the two classes of ACCase genes encode plastidic and cytosolic isoforms of multi-functional, eukaryotic type, respectively, and that B. napus contains at least one multi-functional ACCase besides the multi-subunit, prokaryotic type located in plastids. Southern blot analysis of genomic DNA from B. napus, Brassica rapa, and Brassica oleracea, the ancestors of amphidiploid rapeseed, using a fragment of a multi-functional ACCase gene as a probe revealed that ACCase is encoded by a multi-gene family of at least five members.
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Affiliation(s)
- W Schulte
- Max-Planck-Institut für Zuchtungsforschung, Cologne, Germany
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45
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Carreras CW, Pieper R, Khosla C. The chemistry and biology of fatty acid, polyketide, and nonribosomal peptide biosynthesis. Top Curr Chem (Cham) 1997. [DOI: 10.1007/bfb0119235] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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46
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Schneiter R, Hitomi M, Ivessa AS, Fasch EV, Kohlwein SD, Tartakoff AM. A yeast acetyl coenzyme A carboxylase mutant links very-long-chain fatty acid synthesis to the structure and function of the nuclear membrane-pore complex. Mol Cell Biol 1996; 16:7161-72. [PMID: 8943372 PMCID: PMC231720 DOI: 10.1128/mcb.16.12.7161] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The conditional mRNA transport mutant of Saccharomyces cerevisiae, acc1-7-1 (mtr7-1), displays a unique alteration of the nuclear envelope. Unlike nucleoporin mutants and other RNA transport mutants, the intermembrane space expands, protuberances extend from the inner membrane into the intermembrane space, and vesicles accumulate in the intermembrane space. MTR7 is the same gene as ACC1, encoding acetyl coenzyme A (CoA) carboxylase (Acc1p), the rate-limiting enzyme of de novo fatty acid synthesis. Genetic and biochemical analyses of fatty acid synthesis mutants and acc1-7-1 indicate that the continued synthesis of malonyl-CoA, the enzymatic product of acetyl-CoA carboxylase, is required for an essential pathway which is independent from de novo synthesis of fatty acids. We provide evidence that synthesis of very-long-chain fatty acids (C26 atoms) is inhibited in acc1-7-1, suggesting that very-long-chain fatty acid synthesis is required to maintain a functional nuclear envelope.
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Affiliation(s)
- R Schneiter
- Institut für Biochemie und Lebensmittelchemie, Technische UniversitätGraz, Austria
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47
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Saitoh S, Takahashi K, Nabeshima K, Yamashita Y, Nakaseko Y, Hirata A, Yanagida M. Aberrant mitosis in fission yeast mutants defective in fatty acid synthetase and acetyl CoA carboxylase. J Cell Biol 1996; 134:949-61. [PMID: 8769419 PMCID: PMC2120970 DOI: 10.1083/jcb.134.4.949] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Two fission yeast temperature-sensitive mutants, cut6 and lsd1, show a defect in nuclear division. The daughter nuclei differ dramatically in size (the phenotype designated lsd, large and small daughter). Fluorescence in situ hybridization (FISH) revealed that sister chromatids were separated in the lsd cells, but appeared highly compact in one of the two daughter nuclei. EM showed asymmetric nuclear elongation followed by unequal separation of nonchromosomal nuclear structures in these mutant nuclei. The small nuclei lacked electron-dense nuclear materials and contained highly compacted chromatin. The cut6+ and lsd1+ genes are essential for viability and encode, respectively, acetyl CoA carboxylase and fatty acid synthetase, the key enzymes for fatty acid synthesis. Gene disruption of lsd1+ led to the lsd phenotype. Palmitate in medium fully suppressed the phenotypes of lsd1. Cerulenin, an inhibitor for fatty acid synthesis, produced the lsd phenotype in wild type. The drug caused cell inviability during mitosis but not during the G2-arrest induced by the cdc25 mutation. A reduced level of fatty acid thus led to impaired separation of non-chromosomal nuclear components. We propose that fatty acid is directly or indirectly required for separating the mother nucleus into two equal daughters.
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Affiliation(s)
- S Saitoh
- Department of Biophysics, Faculty of Science, Kyoto University, Japan
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Elborough KM, Winz R, Deka RK, Markham JE, White AJ, Rawsthorne S, Slabas AR. Biotin carboxyl carrier protein and carboxyltransferase subunits of the multi-subunit form of acetyl-CoA carboxylase from Brassica napus: cloning and analysis of expression during oilseed rape embryogenesis. Biochem J 1996; 315 ( Pt 1):103-12. [PMID: 8670092 PMCID: PMC1217156 DOI: 10.1042/bj3150103] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In the oilseed rape Brassica napus there are two forms of acetyl-CoA carboxylase (ACCase). As in other dicotyledonous plants there is a type I ACCase, the single polypeptide 220 kDa form, and a type II multi-subunit complex analogous to that of Escherichia coli and Anabaena. This paper describes the cloning and characterization of a plant biotin carboxyl carrier protein (BCCP) from the type II ACCase complex that shows 61% identity/79% similarity with Anabaena BCCP at the amino acid level. Six classes of nuclear encoded oilseed rape BCCP cDNA were clones, two of which contained the entire coding region. The BCCP sequences allowed the assignment of function to two previously unassigned Arabidopsis expressed sequence tag (EST) sequences. We also report the cloning of a second type II ACCase component from oilseed rape, the beta-carboxyltransferase subunit (betaCT), which is chloroplast-encoded. Northern analysis showed that although the relative levels of BCCP and betaCT mRNA differed between different oilseed rape tissues, their temporal patterns of expression were identical during embryo development. At the protein level, expression of BCCP during embryo development was studied by Western blotting, using affinity-purified anti-biotin polyclonal sera. With this technique a 35 kDa protein thought to be BCCP was shown to reside within the chloroplast. This analysis also permitted us to view the differential expression of several unidentified biotinylated proteins during embryogenesis.
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Affiliation(s)
- K M Elborough
- Lipid Molecular Biology Group, Biological Sciences Department, University of Durham, U.K
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Podkowinski J, Sroga GE, Haselkorn R, Gornicki P. Structure of a gene encoding a cytosolic acetyl-CoA carboxylase of hexaploid wheat. Proc Natl Acad Sci U S A 1996; 93:1870-4. [PMID: 8700851 PMCID: PMC39874 DOI: 10.1073/pnas.93.5.1870] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
An entire gene encoding wheat (var. Hard Red Winter Tam 107) acetyl-CoA carboxylase [ACCase; acetyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] has been cloned and sequenced. Comparison of the 12-kb genomic sequence with the 7.4-kb cDNA sequence reported previously revealed 29 introns. Within the coding region, the exon sequence is 98% identical to the known wheat cDNA sequence. A second ACCase gene was identified by sequencing fragments of genomic clones that include the first two exons and the first intron. Additional transcripts were detected by 5' and 3' RACE analysis (rapid amplification of cDNA ends). One set of transcripts had a 5' end sequence identical to the cDNA found previously and another set was identical to the gene reported here. The 3' RACE clones fall into four distinguishable sequence sets, bringing the number of ACCase sequences to six. None of these cDNA or genomic clones encodes a chloroplast targeting signal. Identification of six different sequences suggests that either the cytosolic ACCase genes are duplicated in the three chromosome sets in hexaploid wheat or that each of the six alleles of the cytosolic ACCase gene has a readily distinguishable DNA sequence.
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Affiliation(s)
- J Podkowinski
- Department of Molecular Genetics and Cell Biology, University of Chicago, IL 60637, USA
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50
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Greenberg ML, Lopes JM. Genetic regulation of phospholipid biosynthesis in Saccharomyces cerevisiae. Microbiol Rev 1996; 60:1-20. [PMID: 8852893 PMCID: PMC239415 DOI: 10.1128/mr.60.1.1-20.1996] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- M L Greenberg
- Department of Molecular and Cellular Biochemistry and Program in Molecular Biology, Loyola University of Chicago, Maywood, Illinois 60153, USA
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