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Abstract
My career in research has flourished through hard work, supportive mentors, and outstanding mentees and collaborators. The Carman laboratory has contributed to the understanding of lipid metabolism through the isolation and characterization of key lipid biosynthetic enzymes as well as through the identification of the enzyme-encoding genes. Our findings from yeast have proven to be invaluable to understand regulatory mechanisms of human lipid metabolism. Several rewarding aspects of my career have been my service to the Journal of Biological Chemistry as an editorial board member and Associate Editor, the National Institutes of Health as a member of study sections, and national and international scientific meetings as an organizer. I advise early career scientists to not assume anything, acknowledge others’ accomplishments, and pay it forward.
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Affiliation(s)
- 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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2
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Shuai L, Li L, Sun J, Liao L, Duan Z, Li C, He X. Role of phospholipase C in banana in response to anthracnose infection. Food Sci Nutr 2020; 8:1038-1045. [PMID: 32148812 PMCID: PMC7020292 DOI: 10.1002/fsn3.1388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/27/2019] [Accepted: 12/09/2019] [Indexed: 12/25/2022] Open
Abstract
Phospholipase C (PLC) plays an important role in plant immunity, and anthracnose caused by the Colletotrichum species is a common postharvest disease of the banana fruit. This study aims to evaluate the role of PLC in anthrax resistance in banana. The experimental group of banana samples was treated with a banana anthracnose conidia suspension, and the control group was treated with distilled water. After inoculation, the groups were sprayed with ethephon, and indicators, such as hardness and conductivity changes; PLC activity, 1,2-diacylglycerol (DAG) and phosphatidic acid (PA)content; and MaPLC-1and MaPLC-2 expression levels, were assessed at 0, 3, 6, 9, 12, and 15 days. Moreover, the expression levels of MaPLC-1 and MaPLC-2 were detected in various tissues. The hardness of banana fruits in the experimental group decreased faster than that in the control group. Furthermore, the conductivity was higher in the experimental group than in the control group. Regarding PLC activity, DAG, and PA content, bananas in the experimental group showed higher activities than those in the control group. Moreover, relatively higher expression of PLC mRNA was detected in anthracnose-inoculated tissues. The evaluation of MaPLC-1 and MaPLC-2 expression levels showed that the mature peel had the highest MaPLC-1 expression level. However, the MaPLC-2 gene was expressed at relatively low levels in the fruit and at relatively high levels in the flower organs. PLC might play a role in fruit ripening in response to anthracnose resistance.
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Affiliation(s)
- Liang Shuai
- Guangxi Crop Genetic Improvement and Biotechnology Key LaboratoryGuangxi Academy of Agricultural SciencesNanningChina
- College of Food and Biological Engineering/Institute of Food Science and Engineering TechnologyHezhou UniversityHezhouGuangxiChina
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
| | - Li Li
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Jian Sun
- Guangxi Crop Genetic Improvement and Biotechnology Key LaboratoryGuangxi Academy of Agricultural SciencesNanningChina
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Lingyan Liao
- College of Food and Biological Engineering/Institute of Food Science and Engineering TechnologyHezhou UniversityHezhouGuangxiChina
| | - Zhenhua Duan
- College of Food and Biological Engineering/Institute of Food Science and Engineering TechnologyHezhou UniversityHezhouGuangxiChina
| | - Changbao Li
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Xuemei He
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
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Carman GM. Discoveries of the phosphatidate phosphatase genes in yeast published in the Journal of Biological Chemistry. J Biol Chem 2018; 294:1681-1689. [PMID: 30061152 DOI: 10.1074/jbc.tm118.004159] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
This JBC Review on the discoveries of yeast phosphatidate (PA) phosphatase genes is dedicated to Dr. Herbert Tabor, Editor-in-Chief of the Journal of Biological Chemistry (JBC) for 40 years, on the occasion of his 100th birthday. Here, I reflect on the discoveries of the APP1, DPP1, LPP1, and PAH1 genes encoding all the PA phosphatase enzymes in yeast. PA phosphatase catalyzes PA dephosphorylation to generate diacylglycerol; both substrate and product are key intermediates in the synthesis of membrane phospholipids and triacylglycerol. App1 and Pah1 are peripheral membrane proteins catalyzing an Mg2+-dependent reaction governed by the DXDX(T/V) phosphatase motif. Dpp1 and Lpp1 are integral membrane proteins that catalyze an Mg2+-independent reaction governed by the KX 6RP-PSGH-SRX 5HX 3D phosphatase motif. Pah1 is PA-specific and is the only PA phosphatase responsible for lipid synthesis at the nuclear/endoplasmic reticulum membrane. App1, Dpp1, and Lpp1, respectively, are localized to cortical actin patches and the vacuole and Golgi membranes; they utilize several lipid phosphate substrates, including PA, lyso-PA, and diacylglycerol pyrophosphate. App1 is postulated to be involved in endocytosis, whereas Dpp1 and Lpp1 may be involved in lipid signaling. Pah1 is the yeast lipin homolog of mice and humans. A host of cellular defects and lipid-based diseases associated with loss or overexpression of PA phosphatase in yeast, mice, and humans, highlights its importance to cell physiology.
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Affiliation(s)
- 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 08901.
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Astorquiza PL, Usorach J, Racagni G, Villasuso AL. Diacylglycerol pyrophosphate binds and inhibits the glyceraldehyde-3-phosphate dehydrogenase in barley aleurone. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 101:88-95. [PMID: 26866974 DOI: 10.1016/j.plaphy.2016.01.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/14/2016] [Accepted: 01/18/2016] [Indexed: 06/05/2023]
Abstract
The aleurona cell is a model that allows the study of the antagonistic effect of gibberellic acid (GA) and abscisic acid (ABA). Previous results of our laboratory demonstrated the involvement of phospholipids during the response to ABA and GA. ABA modulates the levels of diacylglycerol, phosphatidic acid and diacylglycerol pyrophosphate (DAG, PA, DGPP) through the activities of phosphatidate phosphatases, phospholipase D, diacylglycerol kinase and phosphatidate kinase (PAP, PLD, DGK and PAK). PA and DGPP are key phospholipids in the response to ABA, since both are capable of modifying the hydrolitic activity of the aleurona. Nevertheless, little is known about the mechanism of action of these phospholipids during the ABA signal. DGPP is an anionic phospholipid with a pyrophosphate group attached to diacylglycerol. The ionization of the pyrophosphate group may be important to allow electrostatic interactions between DGPP and proteins. To understand how DGPP mediates cell functions in barley aleurone, we used a DGPP affinity membrane assay to isolate DGPP-binding proteins from Hordeum vulgare, followed by mass spectrometric sequencing. A cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) was identified for being bound to DGPP. To validate our method, the relatively abundant GAPDH was characterized with respect to its lipid-binding properties, by fat western blot. GAPDH antibody interacts with proteins that only bind to DGPP and PA. We also observed that ABA treatment increased GAPDH abundance and enzyme activity. The presence of phospholipids during GAPDH reaction modulated the GAPDH activity in ABA treated aleurone. These data suggest that DGPP binds to GAPDH and this DGPP and GAPDH interaction provides new evidences in the study of DGPP-mediated ABA responses in barley aleurone.
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Affiliation(s)
- Paula Luján Astorquiza
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina
| | - Javier Usorach
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina
| | - Graciela Racagni
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina
| | - Ana Laura Villasuso
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina.
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Villasuso AL, Wilke N, Maggio B, Machado E. Zn(2+)-dependent surface behavior of diacylglycerol pyrophosphate and its mixtures with phosphatidic acid at different pHs. FRONTIERS IN PLANT SCIENCE 2014; 5:371. [PMID: 25120554 PMCID: PMC4114284 DOI: 10.3389/fpls.2014.00371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 07/11/2014] [Indexed: 06/03/2023]
Abstract
Diacylglycerol pyrophosphate (DGPP) is a minor lipid that attenuates the phosphatidic acid (PA) signal, and also DGPP itself would be a signaling lipid. Diacylglycerol pyrophosphate is an anionic phospholipid with a pyrophosphate group attached to diacylglycerol that was shown to respond to changes of pH, thus affecting the surface organization of DGPP and their interaction with PA. In this work, we have investigated how the presence of Zn(2+) modulates the surface organization of DGPP and its interaction with PA at acidic and basic pHs. Both lipids formed expanded monolayers at pHs 5 and 8. At pH 5, monolayers formed by DGPP became stiffer when Zn(2+)was added to the subphase, while the surface potential decreased. At this pH, Zn(2+) induced a phase transition from an expanded to a condensed-phase state in monolayers formed by PA. Conversely, at pH 8 the effects induced by the presence of Zn(2+) on the surface behaviors of the pure lipids were smaller. Thus, the interaction of the bivalent cation with both lipids was modulated by pH and by the ionization state of the polar head groups. Mixed monolayers of PA and DGPP showed a non-ideal behavior and were not affected by the presence of Zn(2+) at pH 8. This could be explained considering that when mixed, the lipids formed a closely packed monolayer that could not be further modified by the cation. Our results indicate that DGPP and PA exhibit expanded- and condensed-phase states depending on pH, on the proportion of each lipid in the film and on the presence of Zn(2+). This may have implications for a possible role of DGPP as a signaling lipid molecule.
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Affiliation(s)
- Ana L. Villasuso
- Departamento de Biología Molecular, FCEFQN, Universidad Nacional de Río CuartoRío Cuarto, Argentina
| | - Natalia Wilke
- Facultad de Ciencias Químicas, Departamento de Química Biológica-Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba, Ciudad UniversitariaCórdoba, Argentina
| | - Bruno Maggio
- Facultad de Ciencias Químicas, Departamento de Química Biológica-Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba, Ciudad UniversitariaCórdoba, Argentina
| | - Estela Machado
- Departamento de Biología Molecular, FCEFQN, Universidad Nacional de Río CuartoRío Cuarto, Argentina
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Abd-El-Haliem A, Meijer HJ, Tameling WI, Vossen JH, Joosten MH. Defense activation triggers differential expression of phospholipase-C (PLC) genes and elevated temperature induces phosphatidic acid (PA) accumulation in tomato. PLANT SIGNALING & BEHAVIOR 2012; 7:1073-8. [PMID: 22899083 PMCID: PMC3489630 DOI: 10.4161/psb.21030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recently, we provided the first genetic evidence for the requirement of tomato PLC4 and PLC6 genes in defense activation and disease resistance. The encoded enzymes were catalytically active as they were able to degrade phosphatidylinositol (PI), thereby producing diacylglycerol (DG). Here we report differential PLC gene expression following the initiation of defense signaling by the interaction between Cladosporium fulvum resistance (R) protein Cf-4 and its matching effector Avr4 in tomato hybrid seedlings that express both Cf-4 and Avr4. Furthermore, we observed that PLC3 and PLC6 gene expression is upregulated by elevated temperature in the control seedlings. This upregulation coincides with an increase in the levels of phosphatidic acid (PA) and a decrease in the levels of PI and phosphatidylinositol phosphate (PIP). The decrease in PI and PIP levels matches with the activation of PLC. In addition, the levels of the structural phospholipids phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) declined transiently during recovery after the exposure to elevated temperature., Further studies will be required to explain the mechanism causing the sustained accumulation of PA during recovery, combined with a reduction in the levels of structural phospholipids.
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Affiliation(s)
- Ahmed Abd-El-Haliem
- Laboratory of Phytopathology; Wageningen University; Wageningen, The Netherlands
| | - Harold J.G. Meijer
- Laboratory of Phytopathology; Wageningen University; Wageningen, The Netherlands
| | | | - Jack H. Vossen
- Plant Breeding; Wageningen University; Wageningen, The Netherlands
| | - Matthieu H.A.J. Joosten
- Laboratory of Phytopathology; Wageningen University; Wageningen, The Netherlands
- Correspondence to: Matthieu H.A.J. Joosten,
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Arisz SA, Munnik T. The salt stress-induced LPA response in Chlamydomonas is produced via PLA₂ hydrolysis of DGK-generated phosphatidic acid. J Lipid Res 2011; 52:2012-20. [PMID: 21900174 DOI: 10.1194/jlr.m016873] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The unicellular green alga Chlamydomonas has frequently been used as a eukaryotic model system to study intracellular phospholipid signaling pathways in response to environmental stresses. Earlier, we found that hypersalinity induced a rapid increase in the putative lipid second messenger, phosphatidic acid (PA), which was suggested to be generated via activation of a phospholipase D (PLD) pathway and the combined action of a phospholipase C/diacylglycerol kinase (PLC/DGK) pathway. Lysophosphatidic acid (LPA) was also increased and was suggested to reflect a phospholipase A₂ (PLA₂) activity based on pharmacological evidence. The question of PA's and LPA's origin is, however, more complicated, especially as both function as precursors in the biosynthesis of phospho- and galactolipids. To address this complexity, a combination of fatty acid-molecular species analysis and in vivo ³²P-radiolabeling was performed. Evidence is provided that LPA is formed from a distinct pool of PA characterized by a high α-linolenic acid (18:3n-3) content. This molecular species was highly enriched in the polyphosphoinositide fraction, which is the substrate for PLC to form diacylglycerol. Together with differential ³²P-radiolabeling studies and earlier PLD-transphosphatidylation and PLA₂-inhibitor assays, the data were consistent with the hypothesis that the salt-induced LPA response is primarily generated through PLA₂-mediated hydrolysis of DGK-generated PA and that PLD or de novo synthesis [via endoplasmic reticulum - or plastid-localized routes] is not a major contributor.
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Affiliation(s)
- Steven A Arisz
- Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
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The surface organization of diacylglycerol pyrophosphate and its interaction with phosphatidic acid at the air–water interface. Chem Phys Lipids 2010; 163:771-7. [DOI: 10.1016/j.chemphyslip.2010.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/10/2010] [Accepted: 09/03/2010] [Indexed: 11/18/2022]
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Leprince AS, Savouré A. [Lipid signaling pathways in plants and their roles in response to water constraints]. Biol Aujourdhui 2010; 204:11-19. [PMID: 20950571 DOI: 10.1051/jbio/2009045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Plants are sessile organisms that have developed the capacity to detect slight variations of their environment. They are able to perceive these environmental signals and to transduce them by signaling pathways in order to trigger adaptative responses. Lipid signaling elements play a central role in these pathways in plants. A key element is phosphatidic acid (PA), which can be produced by two pathways. In the first one, phospholipids are hydrolysed by phospholipase D (PLD) to release PA. In the second one, PA is produced through the activity of phospholipase C (PLC) to produce diacylglycerol (DAG) which is then phosphorylated by DAG kinase (DAGK). The amount of PA in the cell is regulated by PA kinase, which phosphorylates PA to produce diacylglycerolpyrophosphate (DGPP), considered as a second messenger as well. PLCs play a dual role in cell signaling by regulating the amount of intracellular Ca(2+), another essential second messenger. Phosphoinositides, such as PI3P, PI4P and PI(4,5)P(2), are substrates of PLCs and PLDs and are considered as second messengers also. In this review, we present recent data regarding the specific features of these lipid signaling pathways in plant compared with other eukaryotes.
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Affiliation(s)
- Anne-Sophie Leprince
- Laboratoire de Physiologie Cellulaire et Moléculaire des Plantes, UR5 UPMC, EAC7180 CNRS, Université Pierre et Marie Curie P6, 4 place Jussieu, case 156, Paris Cedex 05, France.
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França MGC, Matos AR, D'arcy-Lameta A, Passaquet C, Lichtlé C, Zuily-Fodil Y, Pham-Thi AT. Cloning and characterization of drought-stimulated phosphatidic acid phosphatase genes from Vigna unguiculata. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:1093-100. [PMID: 18755595 DOI: 10.1016/j.plaphy.2008.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 06/14/2008] [Accepted: 07/09/2008] [Indexed: 05/22/2023]
Abstract
Under environmental stresses, several lipolytic enzymes are known to be activated and to contribute to membrane lipid turnover and generation of second messengers. In animal cells, phosphatidic acid phosphatase (PAP, EC 3.1.3.4), which dephosphorylates phosphatidic acid generating diacylglycerol, is long known as an enzyme involved in lipid synthesis and cell signalling. However, knowledge on PAP in plants remains very limited. The aim of this work was to isolate and characterize PAP genes in the tropical legume Vigna unguiculata (cowpea), and to study their expression under different stress conditions. Two cDNAs designated as VuPAPalpha and VuPAPbeta were cloned from the leaves of cowpea. Both proteins share sequence homology to animal type 2 PAP, namely, the six transmembrane regions and the consensus sequences corresponding to the catalytic domain of the phosphatase family, like the recently described Arabidopsis LPP (Lipid Phosphate Phosphatase) proteins. The recombinant protein VuPAPalpha expressed in Escherichia coli cells was able to convert phosphatidic acid into diacylglycerol. Unlike VuPAPbeta, VuPAPalpha has an N-terminal transit peptide and was addressed to chloroplast in vitro. Both genes are expressed in several cowpea organs and their transcripts accumulate in leaves in response to water deficit, including progressive dehydration of whole plants and rapid desiccation of detached leaves. No changes in expression of both genes were observed after wounding or by treatment with jasmonic acid. Furthermore, the in silico analysis of VuPAPalpha promoter allowed the identification of several putative drought-related regulatory elements. The possible physiological role of the two cloned PAPs is discussed.
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Affiliation(s)
- Marcel Giovanni Costa França
- Departamento de Botânica, Universidade Federal de Minas Gerais, ICB, Av. Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil
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Zalejski C, Paradis S, Maldiney R, Habricot Y, Miginiac E, Rona JP, Jeannette E. Induction of abscisic acid-regulated gene expression by diacylglycerol pyrophosphate involves Ca2+ and anion currents in Arabidopsis suspension cells. PLANT PHYSIOLOGY 2006; 141:1555-62. [PMID: 16766676 PMCID: PMC1533963 DOI: 10.1104/pp.106.080218] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Diacylglycerol pyrophosphate (DGPP) was recently shown to be a possible intermediate in abscisic acid (ABA) signaling. In this study, reverse transcription-PCR of ABA up-regulated genes was used to evaluate the ability of DGPP to trigger gene expression in Arabidopsis (Arabidopsis thaliana) suspension cells. At5g06760, LTI30, RD29A, and RAB18 were stimulated by ABA and also specifically expressed in DGPP-treated cells. Use of the Ca2+ channel blockers fluspirilene and pimozide and the Ca2+ chelator EGTA showed that Ca2+ was required for ABA induction of DGPP formation. In addition, Ca2+ participated in DGPP induction of gene expression via stimulation of anion currents. Hence, a sequence of Ca2+, DGPP, and anion currents, constituting a core of early ABA-signaling events necessary for gene expression, is proposed.
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Affiliation(s)
- Christine Zalejski
- Université Pierre et Marie Curie-Paris 6 and Centre National de la Recherche Scientifique, FRE 2846, Physiologie Cellulaire et Moléculaire des Plantes, F-94200 Ivry-sur-Seine, France
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12
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Zalejski C, Zhang Z, Quettier AL, Maldiney R, Bonnet M, Brault M, Demandre C, Miginiac E, Rona JP, Sotta B, Jeannette E. Diacylglycerol pyrophosphate is a second messenger of abscisic acid signaling in Arabidopsis thaliana suspension cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 42:145-52. [PMID: 15807778 DOI: 10.1111/j.1365-313x.2005.02373.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In plants, the importance of phospholipid signaling in responses to environmental stresses is becoming well documented. The involvement of phospholipids in abscisic acid (ABA) responses is also established. In a previous study, we demonstrated that the stimulation of phospholipase D (PLD) activity and plasma membrane anion currents by ABA were both required for RAB18 expression in Arabidopsis thaliana suspension cells. In this study, we show that the total lipids extracted from ABA-treated cells mimic ABA in activating plasmalemma anion currents and induction of RAB18 expression. Moreover, ABA evokes within 5 min a transient 1.7-fold increase in phosphatidic acid (PA) followed by a sevenfold increase in diacylglycerol pyrophosphate (DGPP) at 20 min. PA activated plasmalemma anion currents but was incapable of triggering RAB18 expression. By contrast, DGPP mimicked ABA on anion currents and was also able to stimulate RAB18 expression. Here we show the role of DGPP as phospholipid second messenger in ABA signaling.
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Affiliation(s)
- Christine Zalejski
- Physiologie Cellulaire et Moléculaire des Plantes, Unité Mixte de Recherche 7632-Centre National de la Recherche Scientifique, case 156, Université Pierre et Marie Curie, Le Raphaël, 3 rue Galilée 94200 Ivry sur Seine, France
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den Hartog M, Verhoef N, Munnik T. Nod factor and elicitors activate different phospholipid signaling pathways in suspension-cultured alfalfa cells. PLANT PHYSIOLOGY 2003; 132:311-7. [PMID: 12746536 PMCID: PMC166976 DOI: 10.1104/pp.102.017954] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2002] [Revised: 01/09/2003] [Accepted: 02/04/2003] [Indexed: 05/18/2023]
Abstract
Lipo-chitooligosaccharides (Nod factors) are produced by symbiotic Rhizobium sp. bacteria to elicit Nod responses on their legume hosts. One of the earliest responses is the formation of phosphatidic acid (PA), a novel second messenger in plant cells. Remarkably, pathogens have also been reported to trigger the formation of PA in nonlegume plants. To investigate how host plants can distinguish between symbionts and pathogens, the effects of Nod factor and elicitors (chitotetraose and xylanase) on the formation of PA were investigated in suspension-cultured alfalfa (Medicago sativa) cells. Theoretically, PA can be synthesized via two signaling pathways, i.e. via phospholipase D (PLD) and via phospholipase C in combination with diacylglycerol (DAG) kinase. Therefore, a strategy involving differential radiolabeling with [(32)P]orthophosphate was used to determine the contribution of each pathway to PA formation. In support, PLD activity was specifically measured by using the ability of the enzyme to transfer the phosphatidyl group of its substrate to a primary alcohol. In practice, Nod factor, chitotetraose, and xylanase induced the formation of PA and its phosphorylated product DAG pyrophosphate within 2 min of treatment. However, whereas phospholipase C and DAG kinase were activated during treatment with all three different compounds, PLD was only activated by Nod factor. No evidence was obtained for the activation of phospholipase A(2).
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Affiliation(s)
- Martine den Hartog
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, Kruislaan 318, The Netherlands
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14
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Abstract
Phospholipids are emerging as novel second messengers in plant cells. They are rapidly formed in response to a variety of stimuli via the activation of lipid kinases or phospholipases. These lipid signals can activate enzymes or recruit proteins to membranes via distinct lipid-binding domains, where the local increase in concentration promotes interactions and downstream signaling. Here, the latest developments in phospholipid-based signaling are discussed, including the lipid kinases and phospholipases that are activated, the signals they produce, the domains that bind them, the downstream targets that contain them and the processes they control.
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Affiliation(s)
- Harold J G Meijer
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, NL-1098 SM Amsterdam, The Netherlands
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15
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Abstract
Phospholipid-derived molecules are emerging as novel second messengers in plant defence signalling. Recent research has begun to reveal the signals produced by the enzymes phospholipase C, phospholipase D and phospholipase A2 and their putative downstream targets. These include the activation of a MAP kinase cascade and triggering of an oxidative burst by phosphatidic acid; the regulation of ion channels and proton pumps by lysophospholipids and free fatty acids; and the conversion of free fatty acids into bioactive octadecanoids such as jasmonic acid.
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Affiliation(s)
- Ana M Laxalt
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, Kruislaan 318, NL-1098 SM, Amsterdam, The Netherlands
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16
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Bovet L, Müller MO, Siegenthaler PA. Three distinct lipid kinase activities are present in spinach chloroplast envelope membranes: phosphatidylinositol phosphorylation is sensitive to wortmannin and not dependent on chloroplast ATP. Biochem Biophys Res Commun 2001; 289:269-75. [PMID: 11708811 DOI: 10.1006/bbrc.2001.5969] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chloroplast envelope membranes display properties that are important in lipid synthesis, regulation of metabolites, and protein transport, as well as in signal transduction. The recent discovery showing that phosphorylation of lipids occurs in envelope membranes provides a new approach for understanding the role of chloroplast lipids in these processes. The present investigation shows that three major lipid kinase activities are at least present in envelope membranes. These activities greatly depend on external conditions, such as pH, ATP concentrations, temperature, and chloroplast ATP and wortmannin sensitivity. Two types of phosphorylated lipid couples displayed similar intrinsic responses toward these biochemical parameters, namely phosphatidic acid (PA) and its lysoderivative (LPA) and monogalactosyl-phosphate-diacylglycerol (MGpDG) and its lysoderivative (LMGpDG), but not phosphatidylinositol-monophosphate (PIP) and its lysoderivative (LPIP). Phosphorylation of phosphatidylinositol was not dependent on chloroplast ATP, but was sensitive toward wortmannin in intact chloroplasts and outer envelope membrane vesicles.
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Affiliation(s)
- L Bovet
- Laboratoire de Physiologie Végétale, Université de Neuchâtel, Rue Emile Argand 13, CH-2007 Neuchâtel, Switzerland.
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17
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Pierrugues O, Brutesco C, Oshiro J, Gouy M, Deveaux Y, Carman GM, Thuriaux P, Kazmaier M. Lipid phosphate phosphatases in Arabidopsis. Regulation of the AtLPP1 gene in response to stress. J Biol Chem 2001; 276:20300-8. [PMID: 11278556 DOI: 10.1074/jbc.m009726200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An Arabidopsis thaliana gene (AtLPP1) was isolated on the basis that it was transiently induced by ionizing radiation. The putative AtLPP1 gene product showed homology to the yeast and mammalian lipid phosphate phosphatase enzymes and possessed a phosphatase signature sequence motif. Heterologous expression and biochemical characterization of the AtLPP1 gene in yeast showed that it encoded an enzyme (AtLpp1p) that exhibited both diacylglycerol pyrophosphate phosphatase and phosphatidate phosphatase activities. Kinetic analysis indicated that diacylglycerol pyrophosphate was the preferred substrate for AtLpp1p in vitro. A second Arabidopsis gene (AtLPP2) was identified based on sequence homology to AtLPP1 that was also heterologously expressed in yeast. The AtLpp2p enzyme also utilized diacylglycerol pyrophosphate and phosphatidate but with no preference for either substrate. The AtLpp1p and AtLpp2p enzymes showed differences in their apparent affinities for diacylglycerol pyrophosphate and phosphatidate as well as other enzymological properties. Northern blot analyses showed that the AtLPP1 gene was preferentially expressed in leaves and roots, whereas the AtLPP2 gene was expressed in all tissues examined. AtLPP1, but not AtLPP2, was regulated in response to various stress conditions. The AtLPP1 gene was transiently induced by genotoxic stress (gamma ray or UV-B) and elicitor treatments with mastoparan and harpin. The regulation of the AtLPP1 gene in response to stress was consistent with the hypothesis that its encoded lipid phosphate phosphatase enzyme may attenuate the signaling functions of phosphatidate and/or diacylglycerol pyrophosphate that form in response to stress in plants.
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Affiliation(s)
- O Pierrugues
- CEA/Cadarache, DSV-DEVM Laboratoire de Radiobiologie Végétale, 13108 Saint Paul-lez-Durance, France
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18
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Abstract
Plants are continuously exposed to all kinds of water stress such as drought and salinity. In order to survive and adapt, they have developed survival strategies that have been well studied, but little is known about the early mechanisms by which the osmotic stress is perceived and transduced into these responses. During the last few years, however, a variety of reports suggest that specific lipid and MAPK pathways are involved. This review briefly summarises them and presents a model showing that osmotic stress is transmitted by multiple signalling pathways.
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Affiliation(s)
- T Munnik
- Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 318, NL-1098 SM, Amsterdam, The Netherlands.
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19
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Han GS, Johnston CN, Chen X, Athenstaedt K, Daum G, Carman GM. Regulation of the Saccharomyces cerevisiae DPP1-encoded diacylglycerol pyrophosphate phosphatase by zinc. J Biol Chem 2001; 276:10126-33. [PMID: 11139591 DOI: 10.1074/jbc.m011421200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The DPP1 gene, encoding diacylglycerol pyrophosphate (DGPP) phosphatase from Saccharomyces cerevisiae, has recently been identified as a zinc-regulated gene, and it contains a putative zinc-responsive element (UAS(ZRE)) in its promoter. In this work we examined the hypothesis that expression of DGPP phosphatase was regulated by zinc availability. The deprivation of zinc from the growth medium resulted in a time- and dose-dependent induction of beta-galactosidase activity driven by a P(DPP1)-lacZ reporter gene. This regulation was dependent on the UAS(ZRE) in the DPP1 promoter and was mediated by the Zap1p transcriptional activator. Induction of the DGPP phosphatase protein and activity by zinc deprivation was demonstrated by immunoblot analysis and measurement of the dephosphorylation of DGPP. The regulation pattern of DGPP phosphatase in mutants defective in plasma membrane (Zrt1p and Zrt2p) and vacuolar membrane (Zrt3p) zinc transporters indicated that enzyme expression was sensitive to the cytoplasmic levels of zinc. DGPP phosphatase activity was inhibited by zinc by a mechanism that involved formation of DGPP-zinc complexes. Studies with well characterized subcellular fractions and by indirect immunofluorescence microscopy revealed that the DGPP phosphatase enzyme was localized to the vacuolar membrane.
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Affiliation(s)
- G S Han
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick, New Jersey 08901, USA
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20
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van der Luit AH, Piatti T, van Doorn A, Musgrave A, Felix G, Boller T, Munnik T. Elicitation of suspension-cultured tomato cells triggers the formation of phosphatidic acid and diacylglycerol pyrophosphate. PLANT PHYSIOLOGY 2000; 123:1507-16. [PMID: 10938366 PMCID: PMC59106 DOI: 10.1104/pp.123.4.1507] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2000] [Accepted: 04/07/2000] [Indexed: 05/20/2023]
Abstract
Phosphatidic acid (PA) and its phosphorylated derivative diacylglycerol pyrophosphate (DGPP) are lipid molecules that have been implicated in plant cell signaling. In this study we report the rapid but transient accumulation of PA and DGPP in suspension-cultured tomato (Lycopersicon esculentum) cells treated with the general elicitors, N,N',N",N"'-tetraacetylchitotetraose, xylanase, and the flagellin-derived peptide flg22. To determine whether PA originated from the activation of phospholipase D or from the phosphorylation of diacylglycerol (DAG) by DAG kinase, a strategy involving differential radiolabeling with [(32)P]orthophosphate was used. DAG kinase was found to be the dominant producer of PA that was subsequently metabolized to DGPP. A minor but significant role for phospholipase D could only be detected when xylanase was used as elicitor. Since PA formation was correlated with the high turnover of polyphosphoinositides, we hypothesize that elicitor treatment activates phospholipase C to produce DAG, which in turn acts as substrate for DAG kinase. The potential roles of PA and DGPP in plant defense signaling are discussed.
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Affiliation(s)
- A H van der Luit
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, Kruislaan 318, NL-1098 SM Amsterdam, Netherlands
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21
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Balsinde J, Balboa MA, Dennis EA. Group IV cytosolic phospholipase A2 activation by diacylglycerol pyrophosphate in murine P388D1 macrophages. Ann N Y Acad Sci 2000; 905:11-5. [PMID: 10818437 DOI: 10.1111/j.1749-6632.2000.tb06533.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diacylglycerol pyrophosphate (DGPP) is a novel phospholipid identified in yeast, bacteria, and plants, but not yet in mammalian cells. Given its structural resemblance to other phospholipid-activating molecules, such as lysophosphatidate, phosphatidate, and diacylglycerol, it was questioned whether DGPP was capable of activating macrophages to release arachidonic acid (AA) metabolites such as the prostaglandins. It has been found that DGPP is able to potently stimulate prostaglandin production in the murine cell line P388D1 by a mechanism that involves activation of the cytosolic Group IV phospholipase A2 (cPLA2). Our results demonstrate that DGPP possesses macrophage-activating-factor properties and suggest a role for this novel compound in the inflammatory response.
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Affiliation(s)
- J Balsinde
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla 92093-0601, USA
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22
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Wang X. Multiple forms of phospholipase D in plants: the gene family, catalytic and regulatory properties, and cellular functions. Prog Lipid Res 2000; 39:109-49. [PMID: 10775762 DOI: 10.1016/s0163-7827(00)00002-3] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multiple Phospholipase D (PLD) genes have been identified in plants and encode isoforms with distinct regulatory and catalytic properties. Elucidation of the genetic and biochemical heterogeneity has provided important clues as to the regulation and function of this family of enzymes. Polyphosphoinositides, Ca(2+), and G-proteins are possible cellular regulators for PLD activation. PLD-mediated hydrolysis of membrane lipids increases in response to various stresses. Recent studies suggest that PLD plays a role in the signaling and production of hormones involved in plant stress responses.
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Affiliation(s)
- X Wang
- Department of Biochemistry, Kansas State University, Manhattan 66506, USA.
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23
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Furneisen JM, Carman GM. Enzymological properties of the LPP1-encoded lipid phosphatase from Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1484:71-82. [PMID: 10685032 DOI: 10.1016/s1388-1981(99)00202-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The product of the LPP1 gene in Saccharomyces cerevisiae is a membrane-associated enzyme that catalyzes the Mg(2+)-independent dephosphorylation of phosphatidate (PA), diacylglycerol pyrophosphate (DGPP), and lysophosphatidate (LPA). The LPP1-encoded lipid phosphatase was overexpressed 681-fold in Sf-9 insect cells and used to examine the enzymological properties of the enzyme using PA, DGPP, and LPA as substrates. The optimum pH values for PA phosphatase, DGPP phosphatase, and LPA phosphatase activities were 7. 5, 7.0, and 7.0, respectively. Divalent cations (Mn(2+), Co(2+), and Ca(2+)), NaF, heavy metals, propranolol, phenylglyoxal, and N-ethylmaleimide inhibited the PA phosphatase, DGPP phosphatase, and LPA phosphatase activities of the enzyme. The inhibitory effects of N-ethylmaleimide and phenylglyoxal on the LPP1-encoded enzyme were novel properties when compared with other Mg(2+)-independent lipid phosphate phosphatases from S. cerevisiae and mammalian cells. The LPP1-encoded enzyme exhibited saturation kinetics with respect to the surface concentrations of PA (K(m)=0.05 mol%), DGPP (K(m)=0.07 mol%), and LPA (K(m)=0.08 mol%). Based on specificity constants (V(max)/K(m)LPA (1.3 units/mg/mol%). DGPP (K(i)=0.12 mol%) was a competitive inhibitor with respect to PA, and PA (K(i)=0.12 mol%) was a competitive inhibitor with respect to DGPP. This suggested that the binding sites for these substrates were the same. The enzymological properties of the LPP1-encoded enzyme differed significantly from those of the S. cerevisiae DPP1-encoded lipid phosphatase, a related enzyme that also utilizes PA, DGPP, and LPA as substrates.
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Affiliation(s)
- J M Furneisen
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901, USA
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24
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Carman GM, Henry SA. Phospholipid biosynthesis in the yeast Saccharomyces cerevisiae and interrelationship with other metabolic processes. Prog Lipid Res 1999; 38:361-99. [PMID: 10793889 DOI: 10.1016/s0163-7827(99)00010-7] [Citation(s) in RCA: 250] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this review, we have discussed recent progress in the study of the regulation that controls phospholipid metabolism in S. cerevisiae. This regulation occurs on multiple levels and is tightly integrated with a large number of other cellular processes and related metabolic and signal transduction pathways. Progress in deciphering this complex regulation has been very rapid in the last few years, aided by the availability of the sequence of the entire Saccharomyces genome. The assignment of functions to the remaining unassigned open reading frames, as well as ascertainment of remaining gene-enzyme relationships in phospholipid biosynthesis in yeast, promises to provide detailed understanding of the genetic regulation of a crucial area of metabolism in a key eukaryotic model system. Since the processes of lipid metabolism, secretion, and signal transduction show fundamental similarities in all eukaryotes, the dissection of this regulation in yeast promises to have wide application to our understanding of metabolic control in all eukaryotes.
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Affiliation(s)
- G M Carman
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08901, USA.
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25
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Pappan K, Wang X. Molecular and biochemical properties and physiological roles of plant phospholipase D. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1439:151-66. [PMID: 10425392 DOI: 10.1016/s1388-1981(99)00091-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Recent advances have thrust the study of plant phospholipase D (PLD) into the molecular era. This review will highlight some of the recent progress made in elucidating the molecular and biochemical nature of plant PLDs as well as their roles in plant physiology.
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Affiliation(s)
- K Pappan
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
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26
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Balboa MA, Balsinde J, Dillon DA, Carman GM, Dennis EA. Proinflammatory macrophage-activating properties of the novel phospholipid diacylglycerol pyrophosphate. J Biol Chem 1999; 274:522-6. [PMID: 9867874 DOI: 10.1074/jbc.274.1.522] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have found that the novel phospholipid diacylglycerol pyrophosphate (DGPP), identified in bacteria, yeast, and plants, but not in mammalian cells, is able to potently activate macrophages for enhanced secretion of arachidonate metabolites, a key event in the immunoinflammatory response of leukocytes. Macrophage responses to DGPP are specific and are not mediated by its conversion into other putative lipid mediators such as phosphatidic acid, lysophosphatidic acid, or diacylglycerol. The responses to DGPP are compatible with a receptor-recognition event because they are blocked by suramin. Intracellular signaling initiated by DGPP includes phosphorylation and activation of the Group IV cytosolic phospholipase A2 and of the extracellular-signal regulated p42 mitogen-activated protein kinase (MAPK) and p44 MAPK, and membrane translocation of the protein kinase C isoenzymes alpha, epsilon, delta. These results establish DGPP as a novel macrophage-activating factor and suggest a potential role for this compound in triggering homeostatic cellular responses.
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Affiliation(s)
- M A Balboa
- Department of Chemistry and Biochemistry, School of Medicine and Revelle College, University of California at San Diego, La Jolla, California 92093-0601, USA
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27
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Marchesini N, Santander V, Machado-Domenech E. Diacylglycerol pyrophosphate: a novel metabolite in the Trypanosoma cruzi phosphatidic acid metabolism. FEBS Lett 1998; 436:377-81. [PMID: 9801152 DOI: 10.1016/s0014-5793(98)01169-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This work provides evidence that phosphatidic acid (PA) is metabolized to diacylglycerol pyrophosphate (DGPP) in Trypanosoma cruzi. Also the presence of the enzymatic activities involved in its regulation, phosphatidate kinase (PA-k) and phosphatidate phosphatase, is demonstrated. The increase of DGPP levels in T. cruzi epimastigotes or in its membrane fraction after exogenous PA addition or phospholipase (PLD) pre-treatment suggests that PA-k may be involved in the regulation of PA levels after its stimulation.
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Affiliation(s)
- N Marchesini
- Química Biológica, Facultad de Ciencias Exactas, Fisico-Químicas y Naturales, Universidad Nacional de Rio Cuarto, Córdoba, Argentina
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28
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Toke DA, Bennett WL, Dillon DA, Wu WI, Chen X, Ostrander DB, Oshiro J, Cremesti A, Voelker DR, Fischl AS, Carman GM. Isolation and characterization of the Saccharomyces cerevisiae DPP1 gene encoding diacylglycerol pyrophosphate phosphatase. J Biol Chem 1998; 273:3278-84. [PMID: 9452443 DOI: 10.1074/jbc.273.6.3278] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Diacylglycerol pyrophosphate (DGPP) is involved in a putative novel lipid signaling pathway. DGPP phosphatase (DGPP phosphohydrolase) is a membrane-associated 34-kDa enzyme from Saccharomyces cerevisiae which catalyzes the dephosphorylation of DGPP to yield phosphatidate (PA) and then catalyzes the dephosphorylation of PA to yield diacylglycerol. Amino acid sequence information derived from DGPP phosphatase was used to identify and isolate the DPP1 (diacylglycerol pyrophosphate phosphatase) gene encoding the enzyme. Multicopy plasmids containing the DPP1 gene directed a 10-fold overexpression of DGPP phosphatase activity in S. cerevisiae. The heterologous expression of the S. cerevisiae DPP1 gene in Sf-9 insect cells resulted in a 500-fold overexpression of DGPP phosphatase activity over that expressed in wild-type S. cerevisiae. DGPP phosphatase possesses a Mg2+-independent PA phosphatase activity, and its expression correlated with the overexpression of DGPP phosphatase activity in S. cerevisiae and in insect cells. DGPP phosphatase was predicted to be an integral membrane protein with six transmembrane-spanning domains. The enzyme contains a novel phosphatase sequence motif found in a superfamily of phosphatases. A dpp1Delta mutant was constructed by deletion of the chromosomal copy of the DPP1 gene. The dpp1Delta mutant was viable and did not exhibit any obvious growth defects. The mutant was devoid of DGPP phosphatase activity and accumulated (4-fold) DGPP. Analysis of the mutant showed that the DPP1 gene was not responsible for all of the Mg2+-independent PA phosphatase activity in S. cerevisiae.
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Affiliation(s)
- D A Toke
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick, New Jersey 08903, USA
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29
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Munnik T, Irvine RF, Musgrave A. Phospholipid signalling in plants. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1389:222-72. [PMID: 9512651 DOI: 10.1016/s0005-2760(97)00158-6] [Citation(s) in RCA: 257] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- T Munnik
- Institute for Molecular Cell Biology, BioCentrum Amsterdam, University of Amsterdam, The Netherlands.
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30
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Carman GM. Phosphatidate phosphatases and diacylglycerol pyrophosphate phosphatases in Saccharomyces cerevisiae and Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1348:45-55. [PMID: 9370315 DOI: 10.1016/s0005-2760(97)00095-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Phosphatidate phosphatase plays a major role in the synthesis of phospholipids and triacylglycerols in the yeast Saccharomyces cerevisiae. Membrane- and cytosolic-associated forms of the enzyme have been isolated and characterized. These enzymes are Mg2+-dependent and N-ethylmaleimide-sensitive. The expression of a membrane-associated form of phosphatidate phosphatase is regulated by growth phase and inositol supplementation, whereas enzyme activity is regulated by lipids, nucleotides, and by phosphorylation. Phosphatidate phosphatase is coordinately regulated with other phospholipid biosynthetic enzymes including phosphatidylserine synthase. Diacylglycerol pyrophosphate phosphatase is a novel enzyme of phospholipid metabolism which is present in S. cerevisiae, Escherichia coli, and mammalian cells. This enzyme possesses a phosphatidate phosphatase activity which is Mg2+-independent and N-ethylmaleimide-insensitive and is distinct from the Mg2+-dependent and N-ethylmaleimide-sensitive form of phosphatidate phosphatase. Genes encoding for diacylglycerol pyrophosphate phosphatase have been isolated from S. cerevisiae and E. coli. The deduced protein sequences of these genes show homology to the sequence of the mouse PAP2 (Mg2+-independent and N-ethylmaleimide-insensitive phosphatidate phosphatase) protein, especially in a novel phosphatase sequence motif. Rat liver PAP2 displays diacylglycerol pyrophosphate phosphatase activity.
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Affiliation(s)
- G M Carman
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903, USA.
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31
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Dillon DA, Chen X, Zeimetz GM, Wu WI, Waggoner DW, Dewald J, Brindley DN, Carman GM. Mammalian Mg2+-independent phosphatidate phosphatase (PAP2) displays diacylglycerol pyrophosphate phosphatase activity. J Biol Chem 1997; 272:10361-6. [PMID: 9099673 DOI: 10.1074/jbc.272.16.10361] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Recent studies indicate that the metabolism of diacylglycerol pyrophosphate (DGPP) is involved in a novel lipid signaling pathway. DGPP phosphatases (DGPP phosphohydrolase) from Saccharomyces cerevisiae and Escherichia coli catalyze the dephosphorylation of DGPP to yield phosphatidate (PA) and then catalyze the dephosphorylation of PA to yield diacylglycerol. We demonstrated that the Mg2+-independent form of PA phosphatase (PA phosphohydrolase, PAP2) purified from rat liver catalyzed the dephosphorylation of DGPP. This reaction was Mg2+-independent, insensitive to inhibition by N-ethylmaleimide and bromoenol lactone, and inhibited by Mn2+ ions. PAP2 exhibited a high affinity for DGPP (Km = 0.04 mol %). The specificity constant (Vmax/Km) for DGPP was 1. 3-fold higher than that of PA. DGPP inhibited the ability of PAP2 to dephosphorylate PA, and PA inhibited the dephosphorylation of DGPP. Like rat liver PAP2, the Mg2+-independent PA phosphatase activity of DGPP phosphatase purified from S. cerevisiae was inhibited by lyso-PA, sphingosine 1-phosphate, and ceramide 1-phosphate. Mouse PAP2 showed homology to DGPP phosphatases from S. cerevisiae and E. coli, especially in localized regions that constitute a novel phosphatase sequence motif. Collectively, our work indicated that rat liver PAP2 is a member of a phosphatase family that includes DGPP phosphatases from S. cerevisiae and E. coli. We propose a model in which the phosphatase activities of rat liver PAP2 and the DGPP phosphatase of S. cerevisiae regulate the cellular levels of DGPP, PA, and diacylglycerol.
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Affiliation(s)
- D A Dillon
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick, New Jersey 08903, USA
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32
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Dillon DA, Wu WI, Riedel B, Wissing JB, Dowhan W, Carman GM. The Escherichia coli pgpB gene encodes for a diacylglycerol pyrophosphate phosphatase activity. J Biol Chem 1996; 271:30548-53. [PMID: 8940025 DOI: 10.1074/jbc.271.48.30548] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We provided genetic and biochemical evidence that supported the conclusion that the product of pgpB gene of Escherichia coli exhibited diacylglycerol pyrophosphate (DGPP) phosphatase activity. DGPP phosphatase activity was absent in pgpB mutant cells and was expressed at high levels in cells carrying the wild-type pgpB gene on a runaway replication plasmid. The pgpB mutant has been primarily characterized by a defect in phosphatidate (PA) phosphatase activity and also exhibits defects in lyso-PA phosphatase and phosphatidylglycerophosphate phosphatase activities. The defective PA phosphatase in the pgpB mutant was shown to be a Mg2+-independent PA phosphatase activity of the DGPP phosphatase enzyme. We characterized DGPP phosphatase activity in membranes from cells overproducing the pgpB gene product. DGPP phosphatase catalyzed the dephosphorylation of the beta phosphate of DGPP to form PA followed by the dephosphorylation of PA to form diacylglycerol. The specificity constant (Vmax/Km) for DGPP was 9.3-fold greater than that for PA. The pH optimum for the DGPP phosphatase reaction was 6. 5. Activity was independent of a divalent cation requirement, was potently inhibited by Mn2+ ions, and was insensitive to inhibition by N-ethylmaleimide. Pure DGPP phosphatase from Saccharomyces cerevisiae was shown to be similar to the E. coli DGPP phosphatase in its ability to utilize lyso-PA and phosphatidylglycerophosphate as substrates in vitro.
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Affiliation(s)
- D A Dillon
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick, New Jersey 08903, USA.
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33
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Munnik T, de Vrije T, Irvine RF, Musgrave A. Identification of diacylglycerol pyrophosphate as a novel metabolic product of phosphatidic acid during G-protein activation in plants. J Biol Chem 1996; 271:15708-15. [PMID: 8663116 DOI: 10.1074/jbc.271.26.15708] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We provide evidence that phosphatidic acid (PtdOH) formed during signaling in plants is metabolized by a novel pathway. In much of this study, 32Pi-labeled Chlamydomonas cells were used, and signaling was activated by adding the G-protein activator mastoparan. Within seconds of activation, large amounts of [32P]PtdOH were formed, with peak production at about 4 min, when the level was 5-25-fold higher than the control. As the level of [32P]PtdOH subsequently decreased, an unknown phospholipid (PLX) increased in radiolabeling; before activation it was barely detectable. The chromatographic properties of PLX resembled those of lyso-PtdOH and CMP.PtdOH but on close inspection were found to be different. PLX was shown to be diacylglycerol pyrophosphate (DGPP), the product of a newly discovered enzyme, phosphatidate kinase, whose in vitro activity was described recently (Wissing, J. B., and Behrbohm, H. (1993) Plant Physiol. 102, 1243-1249). The identity of DGPP was established by co-chromatrography with a standard and by degradation analysis as follows: [32P]DGPP was deacylated, and the product (glycerolpyrophosphate, GroPP) was hydrolyzed by mild acid treatment or pyrophosphatase to produce GroP and Pi as the only radioactive products. Since DGPP is the pyrophosphate derivative of PtdOH and is formed as the concentration of PtdOH decreases, we assumed that PtdOH was converted in vivo to DGPP. This was confirmed by showing that during a short labeling protocol while the specific radioactivity of DGPP was increasing, the specific radioactivity of the 32Pi derived from DGPP as above was higher than that of [32P]GroP. DGPP was also formed in suspension cultures of tomato and potato cells, and its synthesis was activated by mastoparan. Moreover, it was also found in intact tissues of a number of higher plants, for example, carnation flower petals, vetch roots, leaves of fig-leaved goosefoot, and common persicaria and microspores of rape seed. Our results suggest that DGPP is a common but minor plant lipid that increases in concentration when signaling is activated. Possible functions of DGPP in phospholpase C and D signaling cascades are discussed.
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Affiliation(s)
- T Munnik
- Institute for Molecular Cell Biology, BioCentrum Amsterdam, University of Amsterdam, Kruislaan 318, NL-1098 SM, Amsterdam, The Netherlands
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Wu WI, Liu Y, Riedel B, Wissing JB, Fischl AS, Carman GM. Purification and characterization of diacylglycerol pyrophosphate phosphatase from Saccharomyces cerevisiae. J Biol Chem 1996; 271:1868-76. [PMID: 8567632 DOI: 10.1074/jbc.271.4.1868] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Diacylglycerol pyrophosphate (DGPP) phosphatase is a novel membrane-associated enzyme that catalyzes the dephosphorylation of the beta phosphate of DGPP to yield phosphatidate and Pi. DGPP phosphatase was purified 33,333-fold from Saccharomyces cerevisiae by a procedure that included Triton X-100 solubilization of microsomal membranes followed by chromatography with DE53, Affi-Gel Blue, hydroxylapatite, and Mono Q. The procedure resulted in the isolation of an apparent homogeneous protein with a subunit molecular mass of 34 kDa. DGPP phosphatase activity was associated with the 34-kDa protein. DGPP phosphatase had a broad pH optimum between 6.0 and 8.5 and was dependent on Triton X-100 for maximum activity. The enzyme was inhibited by divalent cations, NaF, and pyrophosphate and was relatively insensitive to thioreactive agents. The turnover number (molecular activity) for the enzyme was 5.8 x 10(3) min-1 at pH 6.5 and 30 degrees C. DGPP phosphatase exhibited typical saturation kinetics with respect to DGPP (Km = 0.55 mol %). The Km value for DGPP was 3-fold greater than its cellular concentration (0.18 mol %). DGPP phosphatase also catalyzed the dephosphorylation of phosphatidate, but this dephosphorylation was subsequent to the dephosphorylation of the beta phosphate of DGPP. The dependence of activity on phosphatidate (Km = 2.2 mol %) was cooperative (Hill number = 2.0). DGPP was the preferred substrate for the enzyme with a specificity constant (Vmax/Km) 10-fold greater than that for phosphatidate. In addition, DGPP potently inhibited (Ki = 0.35 mol %) the dephosphorylation of phosphatidate by a competitive mechanism whereas phosphatidate did not inhibit the dephosphorylation of DGPP. DGPP was neither a substrate nor an inhibitor of pure phosphatidate phosphatase from S. cerevisiae. DGPP was synthesized from phosphatidate via the phosphatidate kinase reaction.
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Affiliation(s)
- W I Wu
- Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903, USA
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