1
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Wang Y, Wakelam MJO, Bankaitis VA, McDermott MI. The wide world of non-mammalian phospholipase D enzymes. Adv Biol Regul 2024; 91:101000. [PMID: 38081756 DOI: 10.1016/j.jbior.2023.101000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 02/25/2024]
Abstract
Phospholipase D (PLD) hydrolyses phosphatidylcholine (PtdCho) to produce free choline and the critically important lipid signaling molecule phosphatidic acid (PtdOH). Since the initial discovery of PLD activities in plants and bacteria, PLDs have been identified in a diverse range of organisms spanning the taxa. While widespread interest in these proteins grew following the discovery of mammalian isoforms, research into the PLDs of non-mammalian organisms has revealed a fascinating array of functions ranging from roles in microbial pathogenesis, to the stress responses of plants and the developmental patterning of flies. Furthermore, studies in non-mammalian model systems have aided our understanding of the entire PLD superfamily, with translational relevance to human biology and health. Increasingly, the promise for utilization of non-mammalian PLDs in biotechnology is also being recognized, with widespread potential applications ranging from roles in lipid synthesis, to their exploitation for agricultural and pharmaceutical applications.
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Affiliation(s)
- Y Wang
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Microbiology, University of Washington, Seattle, WA98109, USA
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX, 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - M I McDermott
- Department of Cell Biology & Genetics, Texas A&M Health Science Center, College Station, TX, 77843, USA.
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2
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Jog R, Han GS, Carman GM. The Saccharomyces cerevisiae Spo7 basic tail is required for Nem1-Spo7/Pah1 phosphatase cascade function in lipid synthesis. J Biol Chem 2024; 300:105587. [PMID: 38141768 PMCID: PMC10820825 DOI: 10.1016/j.jbc.2023.105587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 12/25/2023] Open
Abstract
The Saccharomyces cerevisiae Nem1-Spo7 protein phosphatase complex dephosphorylates and thereby activates Pah1 at the nuclear/endoplasmic reticulum membrane. Pah1, a phosphatidate phosphatase catalyzing the dephosphorylation of phosphatidate to produce diacylglycerol, is one of the most highly regulated enzymes in lipid metabolism. The diacylglycerol produced in the lipid phosphatase reaction is utilized for the synthesis of triacylglycerol that is stored in lipid droplets. Disruptions of the Nem1-Spo7/Pah1 phosphatase cascade cause a plethora of physiological defects. Spo7, the regulatory subunit of the Nem1-Spo7 complex, is required for the Nem1 catalytic function and interacts with the acidic tail of Pah1. Spo7 contains three conserved homology regions (CR1-3) that are important for the interaction with Nem1, but its region for the interaction with Pah1 is unknown. Here, by deletion and site-specific mutational analyses of Spo7, we revealed that the C-terminal basic tail (residues 240-259) containing five arginine and two lysine residues is important for the Nem1-Spo7 complex-mediated dephosphorylation of Pah1 and its cellular function (triacylglycerol synthesis, lipid droplet formation, maintenance of nuclear/endoplasmic reticulum membrane morphology, and cell growth at elevated temperatures). The glutaraldehyde cross-linking analysis of synthetic peptides indicated that the Spo7 basic tail interacts with the Pah1 acidic tail. This work advances our understanding of the Spo7 function and the Nem1-Spo7/Pah1 phosphatase cascade in yeast lipid synthesis.
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Affiliation(s)
- Ruta Jog
- 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, USA
| | - Gil-Soo Han
- 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, USA
| | - George M Carman
- 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, USA.
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3
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Nenadic A, Zaman MF, Johansen J, Volpiana MW, Beh CT. Increased Phospholipid Flux Bypasses Overlapping Essential Requirements for the Yeast Sac1p Phosphoinositide Phosphatase and ER-PM Membrane Contact Sites. J Biol Chem 2023; 299:105092. [PMID: 37507017 PMCID: PMC10470028 DOI: 10.1016/j.jbc.2023.105092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
In budding yeast cells, much of the inner surface of the plasma membrane (PM) is covered with the endoplasmic reticulum (ER). This association is mediated by seven ER membrane proteins that confer cortical ER-PM association at membrane contact sites (MCSs). Several of these membrane "tether" proteins are known to physically interact with the phosphoinositide phosphatase Sac1p. However, it is unclear how or if these interactions are necessary for their interdependent functions. We find that SAC1 inactivation in cells lacking the homologous synaptojanin-like genes INP52 and INP53 results in a significant increase in cortical ER-PM MCSs. We show in sac1Δ, sac1tsinp52Δ inp53Δ, or Δ-super-tether (Δ-s-tether) cells lacking all seven ER-PM tethering genes that phospholipid biosynthesis is disrupted and phosphoinositide distribution is altered. Furthermore, SAC1 deletion in Δ-s-tether cells results in lethality, indicating a functional overlap between SAC1 and ER-PM tethering genes. Transcriptomic profiling indicates that SAC1 inactivation in either Δ-s-tether or inp52Δ inp53Δ cells induces an ER membrane stress response and elicits phosphoinositide-dependent changes in expression of autophagy genes. In addition, by isolating high-copy suppressors that rescue sac1Δ Δ-s-tether lethality, we find that key phospholipid biosynthesis genes bypass the overlapping function of SAC1 and ER-PM tethers and that overexpression of the phosphatidylserine/phosphatidylinositol-4-phosphate transfer protein Osh6 also provides limited suppression. Combined with lipidomic analysis and determinations of intracellular phospholipid distributions, these results suggest that Sac1p and ER phospholipid flux controls lipid distribution to drive Osh6p-dependent phosphatidylserine/phosphatidylinositol-4-phosphate counter-exchange at ER-PM MCSs.
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Affiliation(s)
- Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Jesper Johansen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Matthew W Volpiana
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada.
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4
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Joshi A, Richard TH, Gohil VM. Mitochondrial phospholipid metabolism in health and disease. J Cell Sci 2023; 136:jcs260857. [PMID: 37655851 PMCID: PMC10482392 DOI: 10.1242/jcs.260857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
Abstract
Studies of rare human genetic disorders of mitochondrial phospholipid metabolism have highlighted the crucial role that membrane phospholipids play in mitochondrial bioenergetics and human health. The phospholipid composition of mitochondrial membranes is highly conserved from yeast to humans, with each class of phospholipid performing a specific function in the assembly and activity of various mitochondrial membrane proteins, including the oxidative phosphorylation complexes. Recent studies have uncovered novel roles of cardiolipin and phosphatidylethanolamine, two crucial mitochondrial phospholipids, in organismal physiology. Studies on inter-organellar and intramitochondrial phospholipid transport have significantly advanced our understanding of the mechanisms that maintain mitochondrial phospholipid homeostasis. Here, we discuss these recent advances in the function and transport of mitochondrial phospholipids while describing their biochemical and biophysical properties and biosynthetic pathways. Additionally, we highlight the roles of mitochondrial phospholipids in human health by describing the various genetic diseases caused by disruptions in their biosynthesis and discuss advances in therapeutic strategies for Barth syndrome, the best-studied disorder of mitochondrial phospholipid metabolism.
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Affiliation(s)
- Alaumy Joshi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Travis H. Richard
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Vishal M. Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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5
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Korbecki J, Bosiacki M, Gutowska I, Chlubek D, Baranowska-Bosiacka I. Biosynthesis and Significance of Fatty Acids, Glycerophospholipids, and Triacylglycerol in the Processes of Glioblastoma Tumorigenesis. Cancers (Basel) 2023; 15:cancers15072183. [PMID: 37046844 PMCID: PMC10093493 DOI: 10.3390/cancers15072183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023] Open
Abstract
One area of glioblastoma research is the metabolism of tumor cells and detecting differences between tumor and healthy brain tissue metabolism. Here, we review differences in fatty acid metabolism, with a particular focus on the biosynthesis of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) by fatty acid synthase (FASN), elongases, and desaturases. We also describe the significance of individual fatty acids in glioblastoma tumorigenesis, as well as the importance of glycerophospholipid and triacylglycerol synthesis in this process. Specifically, we show the significance and function of various isoforms of glycerol-3-phosphate acyltransferases (GPAT), 1-acylglycerol-3-phosphate O-acyltransferases (AGPAT), lipins, as well as enzymes involved in the synthesis of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and cardiolipin (CL). This review also highlights the involvement of diacylglycerol O-acyltransferase (DGAT) in triacylglycerol biosynthesis. Due to significant gaps in knowledge, the GEPIA database was utilized to demonstrate the significance of individual enzymes in glioblastoma tumorigenesis. Finally, we also describe the significance of lipid droplets in glioblastoma and the impact of fatty acid synthesis, particularly docosahexaenoic acid (DHA), on cell membrane fluidity and signal transduction from the epidermal growth factor receptor (EGFR).
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Department of Anatomy and Histology, Collegium Medicum, University of Zielona Góra, Zyty 28 Str., 65-046 Zielona Góra, Poland
| | - Mateusz Bosiacki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Department of Functional Diagnostics and Physical Medicine, Faculty of Health Sciences, Pomeranian Medical University in Szczecin, Żołnierska 54 Str., 71-210 Szczecin, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
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6
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Kwiatek JM, Gutierrez B, Izgu EC, Han GS, Carman GM. Phosphatidic acid mediates the Nem1-Spo7/Pah1 phosphatase cascade in yeast lipid synthesis. J Lipid Res 2022; 63:100282. [DOI: 10.1016/j.jlr.2022.100282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 10/31/2022] Open
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7
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van Aalst AC, de Valk SC, van Gulik WM, Jansen ML, Pronk JT, Mans R. Pathway engineering strategies for improved product yield in yeast-based industrial ethanol production. Synth Syst Biotechnol 2022; 7:554-566. [PMID: 35128088 PMCID: PMC8792080 DOI: 10.1016/j.synbio.2021.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/16/2022] Open
Abstract
Product yield on carbohydrate feedstocks is a key performance indicator for industrial ethanol production with the yeast Saccharomyces cerevisiae. This paper reviews pathway engineering strategies for improving ethanol yield on glucose and/or sucrose in anaerobic cultures of this yeast by altering the ratio of ethanol production, yeast growth and glycerol formation. Particular attention is paid to strategies aimed at altering energy coupling of alcoholic fermentation and to strategies for altering redox-cofactor coupling in carbon and nitrogen metabolism that aim to reduce or eliminate the role of glycerol formation in anaerobic redox metabolism. In addition to providing an overview of scientific advances we discuss context dependency, theoretical impact and potential for industrial application of different proposed and developed strategies.
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Affiliation(s)
- Aafke C.A. van Aalst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Sophie C. de Valk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Walter M. van Gulik
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Mickel L.A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613, AX Delft, the Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
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8
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Dekker WJC, Jürgens H, Ortiz-Merino RA, Mooiman C, van den Berg R, Kaljouw A, Mans R, Pronk JT. OUP accepted manuscript. FEMS Yeast Res 2022; 22:6523363. [PMID: 35137036 PMCID: PMC8862043 DOI: 10.1093/femsyr/foac007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/26/2022] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
While thermotolerance is an attractive trait for yeasts used in industrial ethanol production, oxygen requirements of known thermotolerant species are incompatible with process requirements. Analysis of oxygen-sufficient and oxygen-limited chemostat cultures of the facultatively fermentative, thermotolerant species Ogataea parapolymorpha showed its minimum oxygen requirements to be an order of magnitude larger than those reported for the thermotolerant yeast Kluyveromyces marxianus. High oxygen requirements of O. parapolymorpha coincided with a near absence of glycerol, a key NADH/NAD+ redox-cofactor-balancing product in many other yeasts, in oxygen-limited cultures. Genome analysis indicated absence of orthologs of the Saccharomyces cerevisiae glycerol-3-phosphate-phosphatase genes GPP1 and GPP2. Co-feeding of acetoin, whose conversion to 2,3-butanediol enables reoxidation of cytosolic NADH, supported a 2.5-fold increase of the biomass concentration in oxygen-limited cultures. An O. parapolymorpha strain in which key genes involved in mitochondrial reoxidation of NADH were inactivated did produce glycerol, but transcriptome analysis did not reveal a clear candidate for a responsible phosphatase. Expression of S. cerevisiae GPD2, which encodes NAD+-dependent glycerol-3-phosphate dehydrogenase, and GPP1 supported increased glycerol production by oxygen-limited chemostat cultures of O. parapolymorpha. These results identify dependence on respiration for NADH reoxidation as a key contributor to unexpectedly high oxygen requirements of O. parapolymorpha.
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Affiliation(s)
- Wijbrand J C Dekker
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Hannes Jürgens
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Christiaan Mooiman
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Remon van den Berg
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Astrid Kaljouw
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Corresponding author: Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands. Tel: +31 15 2783214; E-mail:
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9
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Athenstaedt K. Phosphatidic acid biosynthesis in the model organism yeast Saccharomyces cerevisiae - a survey. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158907. [PMID: 33610760 PMCID: PMC7613133 DOI: 10.1016/j.bbalip.2021.158907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/04/2021] [Accepted: 02/11/2021] [Indexed: 01/07/2023]
Abstract
Phosphatidic acid biosynthesis represents the initial part of de novo formation of all glycerophospholipids (membrane lipids) as well as triacylglycerols (storage lipids), and is thus the centerpiece of glycerolipid metabolism. The universal route of phosphatidic acid biosynthesis starts from the precursor glycerol-3-phosphate and comprises two consecutive acylation reactions which are catalyzed by a glycerol-3-phosphate acyltransferase and a 1-acyl glycerol-3-phosphate acyltransferase. In addition, yeast and mammals harbor a set of enzymes which can synthesize phosphatidic acid from the precursor dihydroxyacetone phosphate. In the present review our current knowledge about enzymes contributing to phosphatidic acid biosynthesis in the invaluable model organism yeast, Saccharomyces cerevisiae, is summarized. A special focus is laid upon the regulation and the localization of these enzymes. Furthermore, research needs for a deeper insight into the high complexity of phosphatidic acid biosynthesis and consequently the entire lipid metabolic network is presented.
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Affiliation(s)
- Karin Athenstaedt
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/2, 8010 Graz, Austria.
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10
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Zaman MF, Nenadic A, Radojičić A, Rosado A, Beh CT. Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex. Front Cell Dev Biol 2020; 8:675. [PMID: 32793605 PMCID: PMC7387695 DOI: 10.3389/fcell.2020.00675] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/03/2020] [Indexed: 12/31/2022] Open
Abstract
Membrane contact sites between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM) provide a direct conduit for small molecule transfer and signaling between the two largest membranes of the cell. Contact is established through ER integral membrane proteins that physically tether the two membranes together, though the general mechanism is remarkably non-specific given the diversity of different tethering proteins. Primary tethers including VAMP-associated proteins (VAPs), Anoctamin/TMEM16/Ist2p homologs, and extended synaptotagmins (E-Syts), are largely conserved in most eukaryotes and are both necessary and sufficient for establishing ER-PM association. In addition, other species-specific ER-PM tether proteins impart unique functional attributes to both membranes at the cell cortex. This review distils recent functional and structural findings about conserved and species-specific tethers that form ER-PM contact sites, with an emphasis on their roles in the coordinate regulation of lipid metabolism, cellular structure, and responses to membrane stress.
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Affiliation(s)
- Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Ana Radojičić
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,The Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
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11
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McDermott MI, Wang Y, Wakelam MJO, Bankaitis VA. Mammalian phospholipase D: Function, and therapeutics. Prog Lipid Res 2019; 78:101018. [PMID: 31830503 DOI: 10.1016/j.plipres.2019.101018] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/08/2019] [Accepted: 10/14/2019] [Indexed: 01/23/2023]
Abstract
Despite being discovered over 60 years ago, the precise role of phospholipase D (PLD) is still being elucidated. PLD enzymes catalyze the hydrolysis of the phosphodiester bond of glycerophospholipids producing phosphatidic acid and the free headgroup. PLD family members are found in organisms ranging from viruses, and bacteria to plants, and mammals. They display a range of substrate specificities, are regulated by a diverse range of molecules, and have been implicated in a broad range of cellular processes including receptor signaling, cytoskeletal regulation and membrane trafficking. Recent technological advances including: the development of PLD knockout mice, isoform-specific antibodies, and specific inhibitors are finally permitting a thorough analysis of the in vivo role of mammalian PLDs. These studies are facilitating increased recognition of PLD's role in disease states including cancers and Alzheimer's disease, offering potential as a target for therapeutic intervention.
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Affiliation(s)
- M I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America.
| | - Y Wang
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, United States of America
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, United States of America; Department of Chemistry, Texas A&M University, College Station, Texas 77840, United States of America
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12
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Gouw AM, Margulis K, Liu NS, Raman SJ, Mancuso A, Toal GG, Tong L, Mosley A, Hsieh AL, Sullivan DK, Stine ZE, Altman BJ, Schulze A, Dang CV, Zare RN, Felsher DW. The MYC Oncogene Cooperates with Sterol-Regulated Element-Binding Protein to Regulate Lipogenesis Essential for Neoplastic Growth. Cell Metab 2019; 30:556-572.e5. [PMID: 31447321 PMCID: PMC6911354 DOI: 10.1016/j.cmet.2019.07.012] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 09/24/2018] [Accepted: 07/24/2019] [Indexed: 12/14/2022]
Abstract
Lipid metabolism is frequently perturbed in cancers, but the underlying mechanism is unclear. We present comprehensive evidence that oncogene MYC, in collaboration with transcription factor sterol-regulated element-binding protein (SREBP1), regulates lipogenesis to promote tumorigenesis. We used human and mouse tumor-derived cell lines, tumor xenografts, and four conditional transgenic mouse models of MYC-induced tumors to show that MYC regulates lipogenesis genes, enzymes, and metabolites. We found that MYC induces SREBP1, and they collaborate to activate fatty acid (FA) synthesis and drive FA chain elongation from glucose and glutamine. Further, by employing desorption electrospray ionization mass spectrometry imaging (DESI-MSI), we observed in vivo lipidomic changes upon MYC induction across different cancers, for example, a global increase in glycerophosphoglycerols. After inhibition of FA synthesis, tumorigenesis was blocked, and tumors regressed in both xenograft and primary transgenic mouse models, revealing the vulnerability of MYC-induced tumors to the inhibition of lipogenesis.
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Affiliation(s)
- Arvin M Gouw
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Natalie S Liu
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sudha J Raman
- Department of Biochemistry and Molecular Biology, Wurzburg University, Wurzburg, Germany
| | - Anthony Mancuso
- Department of Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Georgia G Toal
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ling Tong
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adriane Mosley
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Annie L Hsieh
- Department of Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Delaney K Sullivan
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zachary E Stine
- Department of Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brian J Altman
- Department of Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Almut Schulze
- Department of Biochemistry and Molecular Biology, Wurzburg University, Wurzburg, Germany
| | - Chi V Dang
- Department of Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Ludwig Institute for Cancer Research, New York, NY 10017, USA; The Wistar Institute, Philadelphia, PA 19104, USA.
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; Ludwig Institute for Cancer Research, New York, NY 10017, USA.
| | - Dean W Felsher
- Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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13
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Lipidomics Studies on Mitochondrial Damage of Saccharomyces cerevisiae Induced by Heavy Ion Beam Radiation. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2018. [DOI: 10.1016/s1872-2040(18)61123-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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14
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Zhang Z, He G, Han GS, Zhang J, Catanzaro N, Diaz A, Wu Z, Carman GM, Xie L, Wang X. Host Pah1p phosphatidate phosphatase limits viral replication by regulating phospholipid synthesis. PLoS Pathog 2018; 14:e1006988. [PMID: 29649282 PMCID: PMC5916857 DOI: 10.1371/journal.ppat.1006988] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/24/2018] [Accepted: 03/24/2018] [Indexed: 11/20/2022] Open
Abstract
Replication of positive-strand RNA viruses [(+)RNA viruses] takes place in membrane-bound viral replication complexes (VRCs). Formation of VRCs requires virus-mediated manipulation of cellular lipid synthesis. Here, we report significantly enhanced brome mosaic virus (BMV) replication and much improved cell growth in yeast cells lacking PAH1 (pah1Δ), the sole yeast ortholog of human LIPIN genes. PAH1 encodes Pah1p (phosphatidic acid phosphohydrolase), which converts phosphatidate (PA) to diacylglycerol that is subsequently used for the synthesis of the storage lipid triacylglycerol. Inactivation of Pah1p leads to altered lipid composition, including high levels of PA, total phospholipids, ergosterol ester, and free fatty acids, as well as expansion of the nuclear membrane. In pah1Δ cells, BMV replication protein 1a and double-stranded RNA localized to the extended nuclear membrane, there was a significant increase in the number of VRCs formed, and BMV genomic replication increased by 2-fold compared to wild-type cells. In another yeast mutant that lacks both PAH1 and DGK1 (encodes diacylglycerol kinase converting diacylglycerol to PA), which has a normal nuclear membrane but maintains similar lipid compositional changes as in pah1Δ cells, BMV replicated as efficiently as in pah1Δ cells, suggesting that the altered lipid composition was responsible for the enhanced BMV replication. We further showed that increased levels of total phospholipids play an important role because the enhanced BMV replication required active synthesis of phosphatidylcholine, the major membrane phospholipid. Moreover, overexpression of a phosphatidylcholine synthesis gene (CHO2) promoted BMV replication. Conversely, overexpression of PAH1 or plant PAH1 orthologs inhibited BMV replication in yeast or Nicotiana benthamiana plants. Competing with its host for limited resources, BMV inhibited host growth, which was markedly alleviated in pah1Δ cells. Our work suggests that Pah1p promotes storage lipid synthesis and thus represses phospholipid synthesis, which in turn restricts both viral replication and cell growth during viral infection.
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Affiliation(s)
- Zhenlu Zhang
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Guijuan He
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States of America
| | - Jiantao Zhang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Nicholas Catanzaro
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States of America
| | - Arturo Diaz
- Department of Biology, La Sierra University, Riverside, VA, United States of America
| | - Zujian Wu
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - George M. Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States of America
| | - Lianhui Xie
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - Xiaofeng Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
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15
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Klein I, Korber M, Athenstaedt K, Daum G. The impact of nonpolar lipids on the regulation of the steryl ester hydrolases Tgl1p and Yeh1p in the yeast Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1491-1501. [PMID: 28866104 DOI: 10.1016/j.bbalip.2017.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/14/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
Abstract
In the yeast Saccharomyces cerevisiae degradation of steryl esters is catalyzed by the steryl ester hydrolases Tgl1p, Yeh1p and Yeh2p. The two steryl ester hydrolases Tgl1p and Yeh1p localize to lipid droplets, a cell compartment storing steryl esters and triacylglycerols. In the present study we investigated regulatory aspects of these two hydrolytic enzymes, namely the gene expression level, protein amount, stability and enzyme activity of Tgl1p and Yeh1p in strains lacking both or only one of the two major nonpolar lipids, steryl esters and triacylglycerols. In a strain lacking both nonpolar lipids and consequently lipid droplets, Tgl1p as well as Yeh1p were present at low amount, became highly unstable compared to wild-type cells, and lost their enzymatic activity. Under these conditions both steryl ester hydrolases were retained in the endoplasmic reticulum. The lack of steryl esters alone was not sufficient to cause an altered intracellular localization of Tgl1p and Yeh1p. Surprisingly, the stability of Tgl1p and Yeh1p was markedly reduced in a strain lacking triacylglycerols, but their capacity to mobilize steryl esters remained unaffected. We also tested a possible cross-regulation of Tgl1p and Yeh1p by analyzing the behavior of each hydrolase in the absence of its counterpart steryl ester hydrolases. In summary, this study demonstrates a strong regulation of the two lipid droplet associated steryl ester hydrolases Tgl1p and Yeh1p due to the presence/absence of their host organelle.
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Affiliation(s)
- Isabella Klein
- Institute of Biochemistry, Graz University of Technology, NaWi Graz, Austria
| | - Martina Korber
- Institute of Biochemistry, Graz University of Technology, NaWi Graz, Austria
| | - Karin Athenstaedt
- Institute of Biochemistry, Graz University of Technology, NaWi Graz, Austria; Institute of Molecular Biosciences, University of Graz, NaWi Graz, Austria.
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, NaWi Graz, Austria.
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16
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Jain S, Dholakia H, Kirtley W, Oelkers P. Energy Storage in Yeast: Regulation and Competition with Ethanol Production. Curr Microbiol 2016; 73:851-858. [PMID: 27620384 DOI: 10.1007/s00284-016-1127-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
Abstract
Mechanisms that may regulate the storage of energy as triacylglycerol in Saccharomyces cerevisiae were examined. First, the kinetics of Dga1p, which mediates the majority of diacylglycerol esterification, the lone committed step in triacylglycerol synthesis, was measured in vitro. With an apparent K m of 17.0 μM, Dga1p has higher affinity for oleoyl-CoA than the only S. cerevisiae acyltransferase previously kinetically characterized, Lpt1p. Lpt1p is a 1-acylglycerol-3-phosphate O-acyltransferase that produces phosphatidate, a precursor to diacylglycerol. Therefore, limiting triacylglycerol synthesis to situations of elevated acyl-CoA concentration is unlikely. However, Dga1p's apparent V max of 5.8 nmol/min/mg was 20 times lower than Lpt1p's. This supports Dga1p being rate limiting for TAG synthesis. Dga1p activity was not activated or inhibited when seven different molecules (e.g., ATP) which reflect cellular energy status were provided at physiological concentrations. Thus, allosteric regulation was not found. Coordination between triacylglycerol and glycogen synthesis was also tested. Yeast genetically deficient in triacylglycerol synthesis did not store more energy in glycogen and vice versa. Lastly, we tested whether genetically limiting energy storage in triacylglycerol, glycogen, steryl esters, or combinations of these will increase ethanol production efficiency. In nutrient-rich media containing 5 % glucose, solely limiting glycogen synthesis had the greatest affect, increasing ethanol production efficiency by 12 %. Since limiting glycogen synthesis only had a modest effect on growth in media containing 10 % ethanol, such genetic manipulation may improve commercial ethanol production.
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Affiliation(s)
- Shilpa Jain
- Department of Bioscience and Biotechnology, Drexel University, 3245 Chestnut Street, Philadelphia, PA, 19104, USA.,Trac Services Ltd, Trevenson Road, TR153, Truro, Cornwall, UK
| | - Hemal Dholakia
- Department of Natural Sciences, University of Michigan-Dearborn, 4901 Evergreen Rd., Dearborn, MI, 48128, USA
| | - Winston Kirtley
- Department of Natural Sciences, University of Michigan-Dearborn, 4901 Evergreen Rd., Dearborn, MI, 48128, USA
| | - Peter Oelkers
- Department of Natural Sciences, University of Michigan-Dearborn, 4901 Evergreen Rd., Dearborn, MI, 48128, USA.
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17
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Petit J, Bres C, Mauxion JP, Tai FWJ, Martin LBB, Fich EA, Joubès J, Rose JKC, Domergue F, Rothan C. The Glycerol-3-Phosphate Acyltransferase GPAT6 from Tomato Plays a Central Role in Fruit Cutin Biosynthesis. PLANT PHYSIOLOGY 2016; 171:894-913. [PMID: 27208295 PMCID: PMC4902622 DOI: 10.1104/pp.16.00409] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 04/18/2016] [Indexed: 05/18/2023]
Abstract
The thick cuticle covering and embedding the epidermal cells of tomato (Solanum lycopersicum) fruit acts not only as a protective barrier against pathogens and water loss but also influences quality traits such as brightness and postharvest shelf-life. In a recent study, we screened a mutant collection of the miniature tomato cultivar Micro-Tom and isolated several glossy fruit mutants in which the abundance of cutin, the polyester component of the cuticle, was strongly reduced. We employed a newly developed mapping-by-sequencing strategy to identify the causal mutation underlying the cutin deficiency in a mutant thereafter named gpat6-a (for glycerol-3-phosphate acyltransferase6). To this end, a backcross population (BC1F2) segregating for the glossy trait was phenotyped. Individuals displaying either a wild-type or a glossy fruit trait were then pooled into bulked populations and submitted to whole-genome sequencing prior to mutation frequency analysis. This revealed that the causal point mutation in the gpat6-a mutant introduces a charged amino acid adjacent to the active site of a GPAT6 enzyme. We further showed that this mutation completely abolished the GPAT activity of the recombinant protein. The gpat6-a mutant showed perturbed pollen formation but, unlike a gpat6 mutant of Arabidopsis (Arabidopsis thaliana), was not male sterile. The most striking phenotype was observed in the mutant fruit, where cuticle thickness, composition, and properties were altered. RNA sequencing analysis highlighted the main processes and pathways that were affected by the mutation at the transcriptional level, which included those associated with lipid, secondary metabolite, and cell wall biosynthesis.
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Affiliation(s)
- Johann Petit
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Cécile Bres
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Jean-Philippe Mauxion
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Fabienne Wong Jun Tai
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Laetitia B B Martin
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Eric A Fich
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Jérôme Joubès
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Jocelyn K C Rose
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Frédéric Domergue
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
| | - Christophe Rothan
- Unité Mixte de Recherche 1332 BFP, Institut National de la Recherche Agronomique, Université de Bordeaux, F-33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., F.W.J.T., C.R.);Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853 (L.B.B.M., E.A.F., J.K.C.R.);Laboratoire de Biogénèse Membranaire, Université de Bordeaux, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.); andLaboratoire de Biogénèse Membranaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France (J.J., F.D.)
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18
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Klein I, Klug L, Schmidt C, Zandl M, Korber M, Daum G, Athenstaedt K. Regulation of the yeast triacylglycerol lipases Tgl4p and Tgl5p by the presence/absence of nonpolar lipids. Mol Biol Cell 2016; 27:2014-24. [PMID: 27170177 PMCID: PMC4927276 DOI: 10.1091/mbc.e15-09-0633] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 05/03/2016] [Indexed: 12/04/2022] Open
Abstract
Tgl4p and Tgl5p are two yeast lipid droplet proteins exhibiting triacylglycerol lipase and lysophospholipid acyltransferase activity. In the absence of lipid droplets, Tgl4p and Tgl5p are retained in the ER, where their properties change. Thus triacylglycerol substrate availability is an important regulator of Tgl4p and Tgl5p functionality. Tgl3p, Tgl4p, and Tgl5p are the major triacylglycerol lipases of the yeast Saccharomyces cerevisiae. Recently we demonstrated that properties of Tgl3p are regulated by the formation of nonpolar lipids. The present study extends these investigations to the two other yeast triacylglycerol lipases, Tgl4p and Tgl5p. We show that Tgl4p and Tgl5p, which are localized to lipid droplets in wild type, are partially retained in the endoplasmic reticulum in cells lacking triacylglycerols and localize exclusively to the endoplasmic reticulum in a mutant devoid of lipid droplets. In cells lacking steryl esters, the subcellular distribution of Tgl4p and Tgl5p is unaffected, but Tgl5p becomes unstable, whereas the stability of Tgl4p increases. In cells lacking nonpolar lipids, Tgl4p and Tgl5p lose their lipolytic activity but retain their side activity as lysophospholipid acyltransferases. To investigate the regulatory network of yeast triacylglycerol lipases in more detail, we also examined properties of Tgl3p, Tgl4p, and Tgl5p, respectively, in the absence of the other lipases. Surprisingly, lack of two lipases did not affect expression, localization, and stability of the remaining Tgl protein. These results suggest that Tgl3p, Tgl4p, and Tgl5p, although they exhibit similar functions, act as independent entities.
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Affiliation(s)
- Isabella Klein
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Lisa Klug
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Claudia Schmidt
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Martina Zandl
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Martina Korber
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Karin Athenstaedt
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
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19
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Li CS, Ren G, Yang BJ, Miklossy G, Turkson J, Fei P, Ding Y, Walker LA, Cao S. Meroterpenoids with Antiproliferative Activity from a Hawaiian-Plant Associated Fungus Peyronellaea coffeae-arabicae FT238. Org Lett 2016; 18:2335-8. [PMID: 27135759 DOI: 10.1021/acs.orglett.6b00685] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three unusual polyketide-sesquiterpene metabolites peyronellins A-C (1-3), along with the new epoxyphomalin analog 11-dehydroxy epoxyphomalin A (4), have been isolated from the endophytic fungus Peyronellaea coffeae-arabicae FT238, which was isolated from the native Hawaiian plant Pritchardia lowreyana. The structures of compounds 1-4 were characterized based on NMR and MS spectroscopic analysis. The absolute configuration (AC) of the compounds was determined by electronic circular dichroism (ECD). Compound 4 showed antiproliferative activity with an IC50 of 0.5 μM against OVCAR3, and it also strongly inhibited Stat3 at 5 μM.
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Affiliation(s)
- Chun-Shun Li
- Department of Pharmaceutical Sciences, Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo , 200 West Kawili Street, Hilo, Hawai'i 96720, United States.,Natural Products & Experimental Therapeutics, University of Hawaii Cancer Center , 701 Ilalo Street, Honolulu, Hawai'i 96813, United States
| | - Gang Ren
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, and Division of Pharmacology, Department of BioMolecular Sciences, School of Pharmacy, The University of Mississippi , University, Mississippi 38677, United States
| | - Bao-Jun Yang
- Natural Products & Experimental Therapeutics, University of Hawaii Cancer Center , 701 Ilalo Street, Honolulu, Hawai'i 96813, United States
| | - Gabriella Miklossy
- Natural Products & Experimental Therapeutics, University of Hawaii Cancer Center , 701 Ilalo Street, Honolulu, Hawai'i 96813, United States
| | - James Turkson
- Natural Products & Experimental Therapeutics, University of Hawaii Cancer Center , 701 Ilalo Street, Honolulu, Hawai'i 96813, United States
| | - Peiwen Fei
- Natural Products & Experimental Therapeutics, University of Hawaii Cancer Center , 701 Ilalo Street, Honolulu, Hawai'i 96813, United States
| | - Yuanqing Ding
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, and Division of Pharmacology, Department of BioMolecular Sciences, School of Pharmacy, The University of Mississippi , University, Mississippi 38677, United States
| | - Larry A Walker
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, and Division of Pharmacology, Department of BioMolecular Sciences, School of Pharmacy, The University of Mississippi , University, Mississippi 38677, United States
| | - Shugeng Cao
- Department of Pharmaceutical Sciences, Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo , 200 West Kawili Street, Hilo, Hawai'i 96720, United States.,Natural Products & Experimental Therapeutics, University of Hawaii Cancer Center , 701 Ilalo Street, Honolulu, Hawai'i 96813, United States
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20
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Smart HC, Mast FD, Chilije MFJ, Tavassoli M, Dacks JB, Zaremberg V. Phylogenetic analysis of glycerol 3-phosphate acyltransferases in opisthokonts reveals unexpected ancestral complexity and novel modern biosynthetic components. PLoS One 2014; 9:e110684. [PMID: 25340523 PMCID: PMC4207751 DOI: 10.1371/journal.pone.0110684] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 09/16/2014] [Indexed: 12/11/2022] Open
Abstract
Glycerolipid synthesis represents a central metabolic process of all forms of life. In the last decade multiple genes coding for enzymes responsible for the first step of the pathway, catalyzed by glycerol 3-phosphate acyltransferase (GPAT), have been described, and characterized primarily in model organisms like Saccharomyces cerevisiae and mice. Notoriously, the fungal enzymes share low sequence identity with their known animal counterparts, and the nature of their homology is unclear. Furthermore, two mitochondrial GPAT isoforms have been described in animal cells, while no such enzymes have been identified in Fungi. In order to determine if the yeast and mammalian GPATs are representative of the set of enzymes present in their respective groups, and to test the hypothesis that metazoan orthologues are indeed absent from the fungal clade, a comparative genomic and phylogenetic analysis was performed including organisms spanning the breadth of the Opisthokonta supergroup. Surprisingly, our study unveiled the presence of ‘fungal’ orthologs in the basal taxa of the holozoa and ‘animal’ orthologues in the basal holomycetes. This includes a novel clade of fungal homologues, with putative peroxisomal targeting signals, of the mitochondrial/peroxisomal acyltransferases in Metazoa, thus potentially representing an undescribed metabolic capacity in the Fungi. The overall distribution of GPAT homologues is suggestive of high relative complexity in the ancestors of the opisthokont clade, followed by loss and sculpting of the complement in the descendent lineages. Divergence from a general versatile metabolic model, present in ancestrally deduced GPAT complements, points to distinctive contributions of each GPAT isoform to lipid metabolism and homeostasis in contemporary organisms like humans and their fungal pathogens.
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Affiliation(s)
- Heather C. Smart
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Fred D. Mast
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Marjan Tavassoli
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Joel B. Dacks
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
- * E-mail: (JBD); (VZ)
| | - Vanina Zaremberg
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (JBD); (VZ)
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21
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Dittrich-Domergue F, Joubès J, Moreau P, Lessire R, Stymne S, Domergue F. The bifunctional protein TtFARAT from Tetrahymena thermophila catalyzes the formation of both precursors required to initiate ether lipid biosynthesis. J Biol Chem 2014; 289:21984-94. [PMID: 24917677 PMCID: PMC4139215 DOI: 10.1074/jbc.m114.579318] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/03/2014] [Indexed: 11/06/2022] Open
Abstract
The biosynthesis of ether lipids and wax esters requires as precursors fatty alcohols, which are synthesized by fatty acyl reductases (FARs). The presence of ether glycerolipids as well as branched wax esters has been reported in several free-living ciliate protozoa. In the genome of Tetrahymena thermophila, the only ORF sharing similarities with FARs is fused to an acyltransferase-like domain, whereas, in most other organisms, FARs are monofunctional proteins of similar size and domain structure. Here, we used heterologous expression in plant and yeast to functionally characterize the activities catalyzed by this protozoan protein. Transient expression in tobacco epidermis of a truncated form fused to the green fluorescence protein followed by confocal microscopy analysis suggested peroxisomal localization. In vivo approaches conducted in yeast indicated that the N-terminal FAR-like domain produced both 16:0 and 18:0 fatty alcohols, whereas the C-terminal acyltransferase-like domain was able to rescue the lethal phenotype of the yeast double mutant gat1Δ gat2Δ. Using in vitro approaches, we further demonstrated that this domain is a dihydroxyacetone phosphate acyltransferase that uses preferentially 16:0-coenzyme A as an acyl donor. Finally, coexpression in yeast with the alkyl-dihydroxyacetone phosphate synthase from T. thermophila resulted the detection of various glycerolipids with an ether bond, indicating reconstitution of the ether lipid biosynthetic pathway. Together, these results demonstrate that this FAR-like protein is peroxisomal and bifunctional, providing both substrates required by alkyl-dihydroxyacetone phosphate synthase to initiate ether lipid biosynthesis.
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Affiliation(s)
- Franziska Dittrich-Domergue
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - Jérôme Joubès
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - Patrick Moreau
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - René Lessire
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - Sten Stymne
- the Department of Plant Breeding, Swedish University of Agricultural Sciences, P.O.B. 101, 23053 Alnarp, Sweden
| | - Frédéric Domergue
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
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22
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Currie E, Guo X, Christiano R, Chitraju C, Kory N, Harrison K, Haas J, Walther TC, Farese RV. High confidence proteomic analysis of yeast LDs identifies additional droplet proteins and reveals connections to dolichol synthesis and sterol acetylation. J Lipid Res 2014; 55:1465-77. [PMID: 24868093 PMCID: PMC4076087 DOI: 10.1194/jlr.m050229] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Indexed: 01/29/2023] Open
Abstract
Accurate protein inventories are essential for understanding an organelle’s functions. The lipid droplet (LD) is a ubiquitous intracellular organelle with major functions in lipid storage and metabolism. LDs differ from other organelles because they are bounded by a surface monolayer, presenting unique features for protein targeting to LDs. Many proteins of varied functions have been found in purified LD fractions by proteomics. While these studies have become increasingly sensitive, it is often unclear which of the identified proteins are specific to LDs. Here we used protein correlation profiling to identify 35 proteins that specifically enrich with LD fractions of Saccharomyces cerevisiae. Of these candidates, 30 fluorophore-tagged proteins localize to LDs by microscopy, including six proteins, several with human orthologs linked to diseases, which we newly identify as LD proteins (Cab5, Rer2, Say1, Tsc10, YKL047W, and YPR147C). Two of these proteins, Say1, a sterol deacetylase, and Rer2, a cis-isoprenyl transferase, are enzymes involved in sterol and polyprenol metabolism, respectively, and we show their activities are present in LD fractions. Our results provide a highly specific list of yeast LD proteins and reveal that the vast majority of these proteins are involved in lipid metabolism.
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Affiliation(s)
- Erin Currie
- Department of Biochemistry and Biophysics University of California, San Francisco, CA 94158 Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Xiuling Guo
- Department of Cell Biology, Yale University, New Haven, CT 06520
| | | | | | - Nora Kory
- Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Kenneth Harrison
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Joel Haas
- Department of Biochemistry and Biophysics University of California, San Francisco, CA 94158 Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Tobias C Walther
- Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Robert V Farese
- Department of Biochemistry and Biophysics University of California, San Francisco, CA 94158 Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158 Department of Medicine, University of California, San Francisco, CA 94158
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23
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Koch B, Schmidt C, Daum G. Storage lipids of yeasts: a survey of nonpolar lipid metabolism in Saccharomyces cerevisiae, Pichia pastoris, and Yarrowia lipolytica. FEMS Microbiol Rev 2014; 38:892-915. [PMID: 24597968 DOI: 10.1111/1574-6976.12069] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/21/2014] [Accepted: 02/21/2014] [Indexed: 11/29/2022] Open
Abstract
Biosynthesis and storage of nonpolar lipids, such as triacylglycerols (TG) and steryl esters (SE), have gained much interest during the last decades because defects in these processes are related to severe human diseases. The baker's yeast Saccharomyces cerevisiae has become a valuable tool to study eukaryotic lipid metabolism because this single-cell microorganism harbors many enzymes and pathways with counterparts in mammalian cells. In this article, we will review aspects of TG and SE metabolism and turnover in the yeast that have been known for a long time and combine them with new perceptions of nonpolar lipid research. We will provide a detailed insight into the mechanisms of nonpolar lipid synthesis, storage, mobilization, and degradation in the yeast S. cerevisiae. The central role of lipid droplets (LD) in these processes will be addressed with emphasis on the prevailing view that this compartment is more than only a depot for TG and SE. Dynamic and interactive aspects of LD with other organelles will be discussed. Results obtained with S. cerevisiae will be complemented by recent investigations of nonpolar lipid research with Yarrowia lipolytica and Pichia pastoris. Altogether, this review article provides a comprehensive view of nonpolar lipid research in yeast.
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Affiliation(s)
- Barbara Koch
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
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24
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Glycerol-3-phosphate Acyltransferase contributes to triacylglycerol biosynthesis, lipid droplet formation, and host invasion in Metarhizium robertsii. Appl Environ Microbiol 2013; 79:7646-53. [PMID: 24077712 DOI: 10.1128/aem.02905-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Enzymes involved in the triacylglycerol (TAG) biosynthesis have been well studied in the model organisms of yeasts and animals. Among these, the isoforms of glycerol-3-phosphate acyltransferase (GPAT) redundantly catalyze the first and rate-limiting step in glycerolipid synthesis. Here, we report the functions of mrGAT, a GPAT ortholog, in an insect-pathogenic fungus, Metarhizium robertsii. Unlike in yeasts and animals, a single copy of the mrGAT gene is present in the fungal genome and the gene deletion mutant is viable. Compared to the wild type and the gene-rescued mutant, the ΔmrGAT mutant demonstrated reduced abilities to produce conidia and synthesize TAG, glycerol, and total lipids. More importantly, we found that mrGAT is localized to the endoplasmic reticulum and directly linked to the formation of lipid droplets (LDs) in fungal cells. Insect bioassay results showed that mrGAT is required for full fungal virulence by aiding fungal penetration of host cuticles. Data from this study not only advance our understanding of GPAT functions in fungi but also suggest that filamentous fungi such as M. robertsii can serve as a good model to elucidate the role of the glycerol phosphate pathway in fungal physiology, particularly to determine the mechanistic connection of GPAT to LD formation.
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25
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Hirasawa T, Ida Y, Furuasawa C, Shimizu H. Potential of a Saccharomyces cerevisiae recombinant strain lacking ethanol and glycerol biosynthesis pathways in efficient anaerobic bioproduction. Bioengineered 2013; 5:123-8. [PMID: 24247205 DOI: 10.4161/bioe.26569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Saccharomyces cerevisiae shows high growth activity under low pH conditions and can be used for producing acidic chemicals such as organic acids as well as fuel ethanol. However, ethanol can also be a problematic by-product in the production of chemicals except for ethanol. We have reported that a stable low-ethanol production phenotype was achieved by disrupting 6 NADH-dependent alcohol dehydrogenase genes of S. cerevisiae. Moreover, the genes encoding the NADH-dependent glycerol biosynthesis enzymes were further disrupted because the ADH-disrupted recombinant strain showed high glycerol production to maintain intracellular redox balance. The recombinant strain incapable producing ethanol and glycerol could have the potential to be a host for producing metabolite(s) whose biosynthesis is coupled with NADH oxidation. Indeed, we successfully achieved almost 100% yield for L-lactate production using this recombinant strain as a host. In addition, the potential of our constructed recombinant strain for efficient bioproduction, particularly under anaerobic conditions, is also discussed.
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Affiliation(s)
- Takashi Hirasawa
- Department of Bioengineering; Tokyo Institute of Technology; Kanagawa, Japan
| | - Yoshihiro Ida
- Department of Bioinformatic Engineering; Graduate School of Information Science and Technology; Osaka University; Osaka, Japan
| | | | - Hiroshi Shimizu
- Department of Bioinformatic Engineering; Graduate School of Information Science and Technology; Osaka University; Osaka, Japan
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26
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Horvath SE, Daum G. Lipids of mitochondria. Prog Lipid Res 2013; 52:590-614. [PMID: 24007978 DOI: 10.1016/j.plipres.2013.07.002] [Citation(s) in RCA: 591] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 07/31/2013] [Indexed: 01/06/2023]
Abstract
A unique organelle for studying membrane biochemistry is the mitochondrion whose functionality depends on a coordinated supply of proteins and lipids. Mitochondria are capable of synthesizing several lipids autonomously such as phosphatidylglycerol, cardiolipin and in part phosphatidylethanolamine, phosphatidic acid and CDP-diacylglycerol. Other mitochondrial membrane lipids such as phosphatidylcholine, phosphatidylserine, phosphatidylinositol, sterols and sphingolipids have to be imported. The mitochondrial lipid composition, the biosynthesis and the import of mitochondrial lipids as well as the regulation of these processes will be main issues of this review article. Furthermore, interactions of lipids and mitochondrial proteins which are highly important for various mitochondrial processes will be discussed. Malfunction or loss of enzymes involved in mitochondrial phospholipid biosynthesis lead to dysfunction of cell respiration, affect the assembly and stability of the mitochondrial protein import machinery and cause abnormal mitochondrial morphology or even lethality. Molecular aspects of these processes as well as diseases related to defects in the formation of mitochondrial membranes will be described.
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Affiliation(s)
- Susanne E Horvath
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
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27
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Li J, Dong Y, Lü X, Wang L, Peng W, Zhang XC, Rao Z. Crystal structures and biochemical studies of human lysophosphatidic acid phosphatase type 6. Protein Cell 2013; 4:548-61. [PMID: 23807634 DOI: 10.1007/s13238-013-3031-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/28/2013] [Indexed: 10/26/2022] Open
Abstract
Lysophosphatidic acid (LPA) is an important bioactive phospholipid involved in cell signaling through Gprotein-coupled receptors pathways. It is also involved in balancing the lipid composition inside the cell, and modulates the function of lipid rafts as an intermediate in phospholipid metabolism. Because of its involvement in these important processes, LPA degradation needs to be regulated as precisely as its production. Lysophosphatidic acid phosphatase type 6 (ACP6) is an LPA-specific acid phosphatase that hydrolyzes LPA to monoacylglycerol (MAG) and phosphate. Here, we report three crystal structures of human ACP6 in complex with malonate, L-(+)-tartrate and tris, respectively. Our analyses revealed that ACP6 possesses a highly conserved Rossmann-foldlike body domain as well as a less conserved cap domain. The vast hydrophobic substrate-binding pocket, which is located between those two domains, is suitable for accommodating LPA, and its shape is different from that of other histidine acid phosphatases, a fact that is consistent with the observed difference in substrate preferences. Our analysis of the binding of three molecules in the active site reveals the involvement of six conserved and crucial residues in binding of the LPA phosphate group and its catalysis. The structure also indicates a water-supplying channel for substrate hydrolysis. Our structural data are consistent with the fact that the enzyme is active as a monomer. In combination with additional mutagenesis and enzyme activity studies, our structural data provide important insights into substrate recognition and the mechanism for catalytic activity of ACP6.
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Affiliation(s)
- Jun Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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28
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Flis VV, Daum G. Lipid transport between the endoplasmic reticulum and mitochondria. Cold Spring Harb Perspect Biol 2013; 5:5/6/a013235. [PMID: 23732475 DOI: 10.1101/cshperspect.a013235] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mitochondria are partially autonomous organelles that depend on the import of certain proteins and lipids to maintain cell survival and membrane formation. Although phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine are synthesized by mitochondrial enzymes, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and sterols need to be imported from other organelles. The origin of most lipids imported into mitochondria is the endoplasmic reticulum, which requires interaction of these two subcellular compartments. Recently, protein complexes that are involved in membrane contact between endoplasmic reticulum and mitochondria were identified, but their role in lipid transport is still unclear. In the present review, we describe components involved in lipid translocation between the endoplasmic reticulum and mitochondria and discuss functional as well as regulatory aspects that are important for lipid homeostasis.
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Affiliation(s)
- Vid V Flis
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
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29
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Vijayaraj P, Jashal CB, Vijayakumar A, Rani SH, Venkata Rao D, Rajasekharan R. A bifunctional enzyme that has both monoacylglycerol acyltransferase and acyl hydrolase activities. PLANT PHYSIOLOGY 2012; 160:667-83. [PMID: 22915575 PMCID: PMC3461547 DOI: 10.1104/pp.112.202135] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 08/16/2012] [Indexed: 05/23/2023]
Abstract
Monoacylglycerol acyltransferase (MGAT) catalyzes the synthesis of diacylglycerol, the precursor of triacylglycerol biosynthesis and an important signaling molecule. Here, we describe the isolation and characterization of the peanut (Arachis hypogaea) MGAT gene. The soluble enzyme utilizes invariant histidine-62 and aspartate-67 residues of the acyltransferase motif for its MGAT activity. A sequence analysis revealed the presence of a hydrolase (GXSXG) motif, and enzyme assays revealed the presence of monoacylglycerol (MAG) and lysophosphatidylcholine (LPC) hydrolytic activities, indicating the bifunctional nature of the enzyme. The overexpression of the MGAT gene in yeast (Saccharomyces cerevisiae) caused an increase in triacylglycerol accumulation. Similar to the peanut MGAT, the Arabidopsis (Arabidopsis thaliana) homolog (At1g52760) also exhibited both acyltransferase and hydrolase activities. Interestingly, the yeast homolog lacks the conserved HX(4)D motif, and it is deficient in the acyltransferase function but exhibits MAG and LPC hydrolase activities. This study demonstrates the presence of a soluble MGAT/hydrolase in plants. The predicted three-dimensional homology modeling and substrate docking suggested the presence of two separate substrate (MAG and LPC)-binding sites in a single polypeptide. Our study describes a soluble bifunctional enzyme that has both MGAT and hydrolase functions.
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30
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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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31
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Rupwate SD, Rupwate PS, Rajasekharan R. Regulation of lipid biosynthesis by phosphatidylinositol-specific phospholipase C through the transcriptional repression of upstream activating sequence inositol containing genes. FEBS Lett 2012; 586:1555-60. [PMID: 22673525 DOI: 10.1016/j.febslet.2012.04.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 10/28/2022]
Abstract
The regulation of phospholipid biosynthesis in Saccharomyces cerevisiae through cis-acting upstream activating sequence inositol (UAS(ino)) and trans-acting elements, such as the INO2-INO4 complex and OPI1 by inositol supplementation in growth is thoroughly studied. In this study, we provide evidence for the regulation of lipid biosynthesis by phosphatidylinositol-specific phospholipase C (PLC) through UAS(ino) and the trans-acting elements. Gene expression analysis and radiolabelling experiments demonstrated that the overexpression of rice PLC in yeast cells altered phospholipid biosynthesis at the levels of transcriptional and enzyme activity. This is the first report implicating PLC in the direct regulation of lipid biosynthesis.
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Affiliation(s)
- Sunny D Rupwate
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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32
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Marr N, Foglia J, Terebiznik M, Athenstaedt K, Zaremberg V. Controlling lipid fluxes at glycerol-3-phosphate acyltransferase step in yeast: unique contribution of Gat1p to oleic acid-induced lipid particle formation. J Biol Chem 2012; 287:10251-10264. [PMID: 22267742 DOI: 10.1074/jbc.m111.314112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability to channel excess fatty acids into neutral lipids like triacylglycerol (TAG) is a critical strategy used by cells to maintain lipid homeostasis. Upon activation to acyl-CoA, fatty acids become readily available as substrates for acyltransferases involved in neutral lipid synthesis. Neutral lipids are then packed into organelles derived from the endoplasmic reticulum called lipid particles (LPs). The first acylation step in the de novo pathway for TAG synthesis is catalyzed by glycerol-3-phosphate acyltransferases (GPATs). Two isoforms, Gat1p/Gpt2p and Gat2p/Sct1p, are present in the yeast Saccharomyces cerevisiae. Previous evidence indicated that these enzymes contribute differentially to the synthesis of TAG in actively growing cells. In this work we studied the role of the yeast GPATs in the formation of LPs induced by a surplus of oleic acid. Yeast lacking Gat1p (but not Gat2p) were sensitive to oleate and failed to accumulate LPs induced by this unsaturated fatty acid. It is shown that oleate induces dephosphorylation of Gat1p as well as an increment in its levels. Most importantly, we identified novel Gat1p crescent structures that are formed in the presence of oleate. These structures are connected with the endoplasmic reticulum and are intimately associated with LPs. No such structures were observed for Gat2p. A crucial point of control of lipid fluxes at the GPAT step is proposed.
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Affiliation(s)
- Nancy Marr
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Julena Foglia
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Mauricio Terebiznik
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, Ontario M1C 1A4, Canada, and
| | - Karin Athenstaedt
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
| | - Vanina Zaremberg
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada,.
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33
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Bouillet L, Cardoso A, Perovano E, Pereira R, Ribeiro E, Trópia M, Fietto L, Tisi R, Martegani E, Castro I, Brandão R. The involvement of calcium carriers and of the vacuole in the glucose-induced calcium signaling and activation of the plasma membrane H+-ATPase in Saccharomyces cerevisiae cells. Cell Calcium 2012; 51:72-81. [DOI: 10.1016/j.ceca.2011.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Accepted: 10/31/2011] [Indexed: 11/30/2022]
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34
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Selvy PE, Lavieri RR, Lindsley CW, Brown HA. Phospholipase D: enzymology, functionality, and chemical modulation. Chem Rev 2011; 111:6064-119. [PMID: 21936578 PMCID: PMC3233269 DOI: 10.1021/cr200296t] [Citation(s) in RCA: 251] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Paige E Selvy
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37064, USA
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35
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Abstract
The yeast Saccharomyces cerevisiae, with its full complement of organelles, synthesizes membrane phospholipids by pathways that are generally common to those found in higher eukaryotes. Phospholipid synthesis in yeast is regulated in response to a variety of growth conditions (e.g., inositol supplementation, zinc depletion, and growth stage) by a coordination of genetic (e.g., transcriptional activation and repression) and biochemical (e.g., activity modulation and localization) mechanisms. Phosphatidate (PA), whose cellular levels are controlled by the activities of key phospholipid synthesis enzymes, plays a central role in the transcriptional regulation of phospholipid synthesis genes. In addition to the regulation of gene expression, phosphorylation of key phospholipid synthesis catalytic and regulatory proteins controls the metabolism of phospholipid precursors and products.
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Affiliation(s)
- George M Carman
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901, USA.
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36
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Shui G, Guan XL, Gopalakrishnan P, Xue Y, Goh JSY, Yang H, Wenk MR. Characterization of substrate preference for Slc1p and Cst26p in Saccharomyces cerevisiae using lipidomic approaches and an LPAAT activity assay. PLoS One 2010; 5:e11956. [PMID: 20694142 PMCID: PMC2915916 DOI: 10.1371/journal.pone.0011956] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/08/2010] [Indexed: 11/26/2022] Open
Abstract
Background Phosphatidic acid (PA) is a key regulated intermediate and precursor for de novo biosynthesis of all glycerophospholipids. PA can be synthesized through the acylation of lysophosphatidic acid (LPA) by 1-acyl-3-phosphate acyltransferase (also called lysophosphatidic acid acyltransferase, LPAAT). Recent findings have substantiated the essential roles of acyltransferases in various biological functions. Methodologies/Principal Findings We used a flow-injection-based lipidomic approach with ∼200 multiple reaction monitoring (MRM) transitions to pre-screen fatty acyl composition of phospholipids in the yeast Saccharomyces cerevisiae mutants. Dramatic changes were observed in fatty acyl composition in some yeast mutants including Slc1p, a well-characterized LPAAT, and Cst26p, a recently characterized phosphatidylinositol stearoyl incorporating 1 protein and putative LPAAT in S. cerevisiae. A comprehensive high-performance liquid chromatography–based multi-stage MRM approach (more than 500 MRM transitions) was developed and further applied to quantify individual phospholipids in both strains to confirm these changes. Our data suggest potential fatty acyl substrates as well as fatty acyls that compensate for defects in both Cst26p and Slc1p mutants. These results were consistent with those from a non-radioactive LPAAT enzymatic assay using C17-LPA and acyl-CoA donors as substrates. Conclusions We found that Slc1p utilized fatty acid (FA) 18:1 and FA 14:0 as substrates to synthesize corresponding PAs; moreover, it was probably the only acyltransferase responsible for acylation of saturated short-chain fatty acyls (12:0 and 10:0) in S. cerevisiae. We also identified FA 18:0, FA 16:0, FA 14:0 and exogenous FA 17:0 as preferred substrates for Cst26p because transformation with a GFP-tagged CST26 restored the phospholipid profile of a CST26 mutant. Our current findings expand the enzymes and existing scope of acyl-CoA donors for glycerophospholipid biosynthesis.
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Affiliation(s)
- Guanghou Shui
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
- Life Science Institute, National University of Singapore, Singapore, Singapore
- * E-mail: (GS); (MRW)
| | - Xue Li Guan
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | | | - Yangkui Xue
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Joyce Sze Yuin Goh
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Markus R. Wenk
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- * E-mail: (GS); (MRW)
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37
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A distinct type of glycerol-3-phosphate acyltransferase with sn-2 preference and phosphatase activity producing 2-monoacylglycerol. Proc Natl Acad Sci U S A 2010; 107:12040-5. [PMID: 20551224 DOI: 10.1073/pnas.0914149107] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The first step in assembly of membrane and storage glycerolipids is acylation of glycerol-3-phosphate (G3P). All previously characterized membrane-bound, eukaryotic G3P acyltransferases (GPATs) acylate the sn-1 position to produce lysophosphatidic acid (1-acyl-LPA). Cutin is a glycerolipid with omega-oxidized fatty acids and glycerol as integral components. It occurs as an extracellular polyester on the aerial surface of all plants, provides a barrier to pathogens and resistance to stress, and maintains organ identity. We have determined that Arabidopsis acyltransferases GPAT4 and GPAT6 required for cutin biosynthesis esterify acyl groups predominantly to the sn-2 position of G3P. In addition, these acyltransferases possess a phosphatase domain that results in sn-2 monoacylglycerol (2-MAG) rather than LPA as the major product. Such bifunctional activity has not been previously described in any organism. The possible roles of 2-MAGs as intermediates in cutin synthesis are discussed. GPAT5, which is essential for the accumulation of suberin aliphatics, also exhibits a strong preference for sn-2 acylation. However, phosphatase activity is absent and 2-acyl-LPA is the major product. Clearly, plant GPATs can catalyze more reactions than the sn-1 acylation by which they are currently categorized. Close homologs of GPAT4-6 are present in all land plants, but not in animals, fungi or microorganisms (including algae). Thus, these distinctive acyltransferases may have been important for evolution of extracellular glycerolipid polymers and adaptation of plants to a terrestrial environment. These results provide insight into the biosynthetic assembly of cutin and suberin, the two most abundant glycerolipid polymers in nature.
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Rajakumari S, Daum G. Janus-faced enzymes yeast Tgl3p and Tgl5p catalyze lipase and acyltransferase reactions. Mol Biol Cell 2009; 21:501-10. [PMID: 20016004 PMCID: PMC2820416 DOI: 10.1091/mbc.e09-09-0775] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The yeast triacylglycerol (TAG) lipases Tgl3p and Tgl5p not only contain a TAG lipase, but also an acyltransferase motif. We show that purified Tgl3p and Tgl5p indeed exhibit lysophospholipid acyltransferase activity. Both Tgl3p and Tgl5p affect the level of glycerophospholipids, and Tgl3p is also important for efficient sporulation of yeast. In the yeast, mobilization of triacylglycerols (TAGs) is facilitated by the three TAG lipases Tgl3p, Tgl4p, and Tgl5p. Motif search analysis, however, indicated that Tgl3p and Tgl5p do not only contain the TAG lipase motif GXSXG but also an H-(X)4-D acyltransferase motif. Interestingly, lipid analysis revealed that deletion of TGL3 resulted in a decrease and overexpression of TGL3 in an increase of glycerophospholipids. Similar results were obtained with TGL5. Therefore, we tested purified Tgl3p and Tgl5p for acyltransferase activity. Indeed, both enzymes not only exhibited lipase activity but also catalyzed acylation of lysophosphatidylethanolamine and lysophosphatidic acid, respectively. Experiments using variants of Tgl3p created by site-directed mutagenesis clearly demonstrated that the two enzymatic activities act independently of each other. We also showed that Tgl3p is important for efficient sporulation of yeast cells, but rather through its acyltransferase than lipase activity. In summary, our results demonstrate that yeast Tgl3p and Tgl5p play a dual role in lipid metabolism contributing to both anabolic and catabolic processes.
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Affiliation(s)
- Sona Rajakumari
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
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Elimination of glycerol production in anaerobic cultures of a Saccharomyces cerevisiae strain engineered to use acetic acid as an electron acceptor. Appl Environ Microbiol 2009; 76:190-5. [PMID: 19915031 DOI: 10.1128/aem.01772-09] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In anaerobic cultures of wild-type Saccharomyces cerevisiae, glycerol production is essential to reoxidize NADH produced in biosynthetic processes. Consequently, glycerol is a major by-product during anaerobic production of ethanol by S. cerevisiae, the single largest fermentation process in industrial biotechnology. The present study investigates the possibility of completely eliminating glycerol production by engineering S. cerevisiae such that it can reoxidize NADH by the reduction of acetic acid to ethanol via NADH-dependent reactions. Acetic acid is available at significant amounts in lignocellulosic hydrolysates of agricultural residues. Consistent with earlier studies, deletion of the two genes encoding NAD-dependent glycerol-3-phosphate dehydrogenase (GPD1 and GPD2) led to elimination of glycerol production and an inability to grow anaerobically. However, when the E. coli mhpF gene, encoding the acetylating NAD-dependent acetaldehyde dehydrogenase (EC 1.2.1.10; acetaldehyde+NAD++coenzyme A<-->acetyl coenzyme A+NADH+H+), was expressed in the gpd1Delta gpd2Delta strain, anaerobic growth was restored by supplementation with 2.0 g liter(-1) acetic acid. The stoichiometry of acetate consumption and growth was consistent with the complete replacement of glycerol formation by acetate reduction to ethanol as the mechanism for NADH reoxidation. This study provides a proof of principle for the potential of this metabolic engineering strategy to improve ethanol yields, eliminate glycerol production, and partially convert acetate, which is a well-known inhibitor of yeast performance in lignocellulosic hydrolysates, to ethanol. Further research should address the kinetic aspects of acetate reduction and the effect of the elimination of glycerol production on cellular robustness (e.g., osmotolerance).
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Gidda SK, Shockey JM, Rothstein SJ, Dyer JM, Mullen RT. Arabidopsis thaliana GPAT8 and GPAT9 are localized to the ER and possess distinct ER retrieval signals: functional divergence of the dilysine ER retrieval motif in plant cells. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:867-79. [PMID: 19539490 DOI: 10.1016/j.plaphy.2009.05.008] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 05/14/2009] [Accepted: 05/27/2009] [Indexed: 05/03/2023]
Abstract
Glycerol-3-phosphate acyltransferase (GPAT; EC 2.3.1.15) catalyzes the committed step in the production of glycerolipids, which are major components of cellular membranes, seed storage oils, and epicuticular wax coatings. While the biochemical activities of GPATs have been characterized in detail, the cellular features of these enzymes are only beginning to emerge. Here we characterized the phylogenetic relationships and cellular properties of two GPAT enzymes from the relatively large Arabidopsis thaliana GPAT family, including GPAT8, which is involved in cutin biosynthesis, and GPAT9, which is a new putative GPAT that has extensive homology with a GPAT from mammalian cells involved in storage oil formation and, thus, may have a similar role in plants. Immunofluorescence microscopy of transiently-expressed myc-epitope-tagged GPAT8 and GPAT9 revealed that both proteins were localized to the endoplasmic reticulum (ER), and differential permeabilization experiments indicated that their N- and C-termini were oriented towards the cytosol. However, these two proteins contained distinct types of ER retrieval signals, with GPAT8 possessing a divergent type of dilysine motif (-KK-COOH rather than the prototypic -KKXX-COOH or -KXKXX-COOH motif) and GPAT9 possessing a hydrophobic pentapeptide motif (-phi-X-X-K/R/D/E-phi-; where phi are large hydrophobic amino acid residues). Notably, the divergent dilysine motif in GPAT8 only functioned effectively when additional upstream residues were included to provide the proper protein context. Extensive mutational analyses of the divergent dilysine motif, based upon sequences present in the C-termini of other GPAT8s from various plant species, further expanded the functional definition of this molecular targeting signal, thereby providing insight to the targeting signals in other GPAT family members as well as other ER-resident membrane proteins within plant cells.
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Affiliation(s)
- Satinder K Gidda
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Glycerol-3-phosphate acyltransferases gat1p and gat2p are microsomal phosphoproteins with differential contributions to polarized cell growth. EUKARYOTIC CELL 2009; 8:1184-96. [PMID: 19525420 DOI: 10.1128/ec.00085-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the initial step in the synthesis of all glycerolipids. It is the committed and rate-limiting step and is redundant in Saccharomyces cerevisiae, mammals, and plants. GPAT controls the formation of lipid intermediates that serve not only as precursors of more-complex lipids but also as intracellular signaling molecules. Saccharomyces cerevisiae possesses two GPATs, encoded by the GAT1 and GAT2 genes. Metabolic analysis of yeast lacking either GAT1 or GAT2 indicated partitioning of the two main branches of phospholipid synthesis at the initial and rate-limiting GPAT step. We are particularly interested in identifying molecular determinants mediating lipid metabolic pathway partitioning; therefore, as a starting point, we have performed a detailed study of Gat1p and Gat2p cellular localization. We have compared Gat1p and Gat2p localization by fluorescence microscopy and subcellular fractionation using equilibrium density gradients. Our results indicate Gat1p and Gat2p overlap mostly in their localization and are in fact microsomal GPATs, localized to both perinuclear and cortical endoplasmic reticula in actively proliferating cells. A more detailed analysis suggests a differential enrichment of Gat1p and Gat2p in distinct ER fractions. Furthermore, overexpression of these enzymes in the absence of endogenous GPATs induces proliferation of distinct ER arrays, differentially affecting cortical ER morphology and polarized cell growth. In addition, our studies also uncovered a dynamic posttranslational regulation of Gat1p and Gat2p and a compensation mechanism through phosphorylation that responds to a cellular GPAT imbalance.
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Rajakumari S, Grillitsch K, Daum G. Synthesis and turnover of non-polar lipids in yeast. Prog Lipid Res 2008; 47:157-71. [DOI: 10.1016/j.plipres.2008.01.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 01/08/2008] [Accepted: 01/09/2008] [Indexed: 11/25/2022]
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Yang YL, Wang JH, Teng D, Zhang F. Preparation of high-purity fructo-oligosaccharides by Aspergillus japonicus beta-fructofuranosidase and successive cultivation with yeast. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:2805-2809. [PMID: 18333616 DOI: 10.1021/jf703586q] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The short-chain FOSs with high purity were prepared using a two-step strategy: Aspergillus japonicus extracellular beta-fructofuranosidase-catalyzed synthesis of FOSs followed by cultivation with Pichia pastoris (P. pastoris). The higher FOSs content was obtained after 8 h under the catalysis of beta-fructofuranosidase at pH 5.5 and 55 degrees C. Successive P. pastoris cultivation exhausts almost all monosugars in 12 h at 30 degrees C, which increases the purity of FOSs, and also recovers beta-fructofuranosidase activity by ceasing the inhibition of glucose from catalysis of the enzyme, yielding more FOSs. Finally, the FOSs purity was increased from 56.55 to 84.45% (26.47% 1-kestose and 57.98% nystose).
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Affiliation(s)
- Ya-Lin Yang
- Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, 12 Zhongguancun Nandajie Street, Beijing 100081, People's Republic of China
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The yeast acylglycerol acyltransferase LCA1 is a key component of Lands cycle for phosphatidylcholine turnover. FEBS Lett 2007; 581:5511-6. [DOI: 10.1016/j.febslet.2007.10.061] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 10/28/2007] [Accepted: 10/31/2007] [Indexed: 11/23/2022]
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Alvarez-Vasquez F, Sims KJ, Voit EO, Hannun YA. Coordination of the dynamics of yeast sphingolipid metabolism during the diauxic shift. Theor Biol Med Model 2007; 4:42. [PMID: 17974024 PMCID: PMC2203994 DOI: 10.1186/1742-4682-4-42] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Accepted: 10/31/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The diauxic shift in yeast requires cells to coordinate a complicated response that involves numerous genes and metabolic processes. It is unknown whether responses of this type are mediated in vivo through changes in a few "key" genes and enzymes, which are mathematically characterized by high sensitivities, or whether they are based on many small changes in genes and enzymes that are not particularly sensitive. In contrast to global assessments of changes in gene or protein interaction networks, we study here control aspects of the diauxic shift by performing a detailed analysis of one specific pathway-sphingolipid metabolism-which is known to have signaling functions and is associated with a wide variety of stress responses. RESULTS The approach uses two components: publicly available sets of expression data of sphingolipid genes and a recently developed Generalized Mass Action (GMA) mathematical model of the sphingolipid pathway. In one line of exploration, we analyze the sensitivity of the model with respect to enzyme activities, and thus gene expression. Complementary to this approach, we convert the gene expression data into changes in enzyme activities and then predict metabolic consequences by means of the mathematical model. It was found that most of the sensitivities in the model are low in magnitude, but that some stand out as relatively high. This information was then deployed to test whether the cell uses a few of the very sensitive pathway steps to mount a response or whether the control is distributed throughout the pathway. Pilot experiments confirm qualitatively and in part quantitatively the predictions of a group of metabolite simulations. CONCLUSION The results indicate that yeast coordinates sphingolipid mediated changes during the diauxic shift through an array of small changes in many genes and enzymes, rather than relying on a strategy involving a few select genes with high sensitivity. This study also highlights a novel approach in coupling data mining with mathematical modeling in order to evaluate specific metabolic pathways.
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Affiliation(s)
- Fernando Alvarez-Vasquez
- Dept. of Biostatistics, Bioinformatics and Epidemiology. Medical University of South Carolina, Charleston, SC. USA.
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Souza CM, Pichler H. Lipid requirements for endocytosis in yeast. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:442-54. [PMID: 16997624 DOI: 10.1016/j.bbalip.2006.08.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 08/10/2006] [Accepted: 08/10/2006] [Indexed: 01/19/2023]
Abstract
Endocytosis is, besides secretion, the most prominent membrane transport pathway in eukaryotic cells. In membrane transport, defined areas of the donor membranes engulf solutes of the compartment they are bordering and bud off with the aid of coat proteins to form vesicles. These transport vehicles are guided along cytoskeletal paths, often matured and, finally, fuse to the acceptor membrane they are targeted to. Lipids and proteins are equally important components in membrane transport pathways. Not only are they the structural units of membranes and vesicles, but both classes of molecules also participate actively in membrane transport processes. Whereas proteins form the cytoskeleton and vesicle coats, confer signals and constitute attachment points for membrane-membrane interaction, lipids modulate the flexibility of bilayers, carry protein recognition sites and confer signals themselves. Over the last decade it has been realized that all classes of bilayer lipids, glycerophospholipids, sphingolipids and sterols, actively contribute to functional membrane transport, in particular to endocytosis. Thus, abnormal bilayer lipid metabolism leads to endocytic defects of different severity. Interestingly, there seems to be a great deal of interdependence and interaction among lipid classes. It will be a challenge to characterize this plenitude of interactions and find out about their impact on cellular processes.
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Athenstaedt K, Jolivet P, Boulard C, Zivy M, Negroni L, Nicaud JM, Chardot T. Lipid particle composition of the yeastYarrowia lipolytica depends on the carbon source. Proteomics 2006; 6:1450-9. [PMID: 16470660 DOI: 10.1002/pmic.200500339] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lipid particles (LP) of all types of cells are a depot of neutral lipids. The present investigation deals with the isolation of LP from the yeast Yarrowia lipolytica and the characterization of their lipid and protein composition. Properties of LP varied depending on the carbon source. LP from glucose-grown cells revealed a mean diameter of 650 nm with a hydrophobic core mainly formed of triacylglycerols (TAG) and a minor amount of steryl esters (SE). Oleic acid was the major fatty acid species esterified in LP. When cells were grown on oleic acid, LP size increased 3.8-fold, the particles exhibited a significantly lower ratio of TAG to SE, and the relative amount of oleic acid in LP lipids increased compared to cells grown on glucose. Analysis of LP proteins revealed an increasing number of polypeptides when cells were shifted from glucose- to oleic acid-containing medium. Twenty-one major LP proteins were identified under both growth conditions, and additional nine polypeptides were specific for growth on oleic acid. Identification of these proteins by MS and comparison of the deduced ORFs to those from Saccharomyces cerevisiae revealed that most proteins of Y. lipolytica LP are involved in lipid metabolism. LP proteins specific for growth on oleic acid are also enzymes involved in lipid metabolism, but some of them are also components of the intracellular traffic machinery. Thus, proteom analysis of LP proteins suggests involvement of this compartment in different cell biological processes.
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Zufferey R, Ben Mamoun C. Leishmania major expresses a single dihydroxyacetone phosphate acyltransferase localized in the glycosome, important for rapid growth and survival at high cell density and essential for virulence. J Biol Chem 2006; 281:7952-9. [PMID: 16423830 DOI: 10.1074/jbc.m512911200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite major advances in the understanding of pathogenesis of the human protozoan parasite Leishmania major, little is known about the enzymes and the primary precursors involved in the initial steps of synthesis of its major glycerolipids including those involved in virulence. We have previously demonstrated that the initial step of acylation of the precursor glycerol 3-phosphate is not essential for the synthesis of ester and ether phospholipids in this parasite. Here we show that Leishmania expresses a single acyltransferase with high specificity for the precursor dihydroxyacetone phosphate and shows the best activity in the presence of palmitoyl-CoA. We have identified and characterized the LmDAT gene encoding this activity. LmDAT complements the lethality resulting from the loss of both dihydroxyacetone phosphate and glycerol-3-phosphate acyltransferase activities in yeast. Recombinant LmDAT exhibits biochemical properties similar to those of the native enzyme of the promastigote stage parasites. We show that LmDAT is a glycosomal enzyme and its loss in a delta lmdat/delta lmdat null mutant results in complete abrogation of the parasite dihydroxyacetone phosphate acyltransferase activity. Furthermore, lack of LmDAT causes a major alteration in parasite division during the logarithmic phase of growth, an accelerated cell death during stationary phase, and loss of virulence. Together, our results demonstrate that LmDAT is the only dihydroxyacetone phosphate acyltransferase of the L. major localized in the peroxisome, important for growth and survival and essential for virulence.
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Affiliation(s)
- Rachel Zufferey
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301, USA
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Gardocki ME, Jani N, Lopes JM. Phosphatidylinositol biosynthesis: biochemistry and regulation. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1735:89-100. [PMID: 15967713 DOI: 10.1016/j.bbalip.2005.05.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 05/14/2005] [Accepted: 05/19/2005] [Indexed: 12/22/2022]
Abstract
Phosphatidylinositol (PI) is a ubiquitous membrane lipid in eukaryotes. It is becoming increasingly obvious that PI and its metabolites play a myriad of very diverse roles in eukaryotic cells. The Saccharomyces cerevisiae PIS1 gene is essential and encodes PI synthase, which is required for the synthesis of PI. Recently, PIS1 expression was found to be regulated in response to carbon source and oxygen availability. It is particularly significant that the promoter elements required for these responses are conserved evolutionarily throughout the Saccharomyces genus. In addition, several genome-wide strategies coupled with more traditional screens suggest that several other factors regulate PIS1 expression. The impact of regulating PIS1 expression on PI synthesis will be discussed along with the possible role(s) that this may have on diseases such as cancer.
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Affiliation(s)
- Mary E Gardocki
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit MI 48202, USA
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Liu HJ, Liu DH, Zhong JJ. Interesting physiological response of the osmophilic yeast Candida krusei to heat shock. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2004.04.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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