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Hartmann M, Gas-Pascual E, Hemmerlin A, Rohmer M, Bach TJ. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation. F1000Res 2015; 4:14. [PMID: 26309725 PMCID: PMC4536634 DOI: 10.12688/f1000research.5923.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/31/2015] [Indexed: 03/26/2024] Open
Abstract
In a preceding study we have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was there demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect this localization. Furthermore, in this initial study complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established now new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP). We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test system.
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Affiliation(s)
- Michael Hartmann
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Department Biologie, Institut für Molekulare Ökophysiologie der Pflanzen, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Elisabet Gas-Pascual
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Horticulture and Crop Science, Ohio State University, 208 Williams Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
| | - Andrea Hemmerlin
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS/Université de Strasbourg, Institut Le Bel, 4 rue Blaise Pascal, F-67070 Strasbourg, France
| | - Thomas J. Bach
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
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Hartmann M, Gas-Pascual E, Hemmerlin A, Rohmer M, Bach TJ. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation. F1000Res 2015; 4:14. [PMID: 26309725 PMCID: PMC4536634 DOI: 10.12688/f1000research.5923.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/09/2014] [Indexed: 11/20/2022] Open
Abstract
We have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect this localization. Furthermore, complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP). We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test system.
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Affiliation(s)
- Michael Hartmann
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Department Biologie, Institut für Molekulare Ökophysiologie der Pflanzen, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Elisabet Gas-Pascual
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Horticulture and Crop Science, Ohio State University, 208 Williams Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
| | - Andrea Hemmerlin
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS/Université de Strasbourg, Institut Le Bel, 4 rue Blaise Pascal, F-67070 Strasbourg, France
| | - Thomas J. Bach
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
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Liao P, Wang H, Hemmerlin A, Nagegowda DA, Bach TJ, Wang M, Chye ML. Past achievements, current status and future perspectives of studies on 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS) in the mevalonate (MVA) pathway. PLANT CELL REPORTS 2014; 33:1005-22. [PMID: 24682521 DOI: 10.1007/s00299-014-1592-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 02/24/2014] [Indexed: 05/09/2023]
Abstract
HMGS functions in phytosterol biosynthesis, development and stress responses. F-244 could specifically-inhibit HMGS in tobacco BY-2 cells and Brassica seedlings. An update on HMGS from higher plants is presented. 3-Hydroxy-3-methylglutaryl-coenzyme A synthase (HMGS) is the second enzyme in the mevalonate pathway of isoprenoid biosynthesis and catalyzes the condensation of acetoacetyl-CoA and acetyl-CoA to produce S-3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). Besides HMG-CoA reductase (HMGR), HMGS is another key enzyme in the regulation of cholesterol and ketone bodies in mammals. In plants, it plays an important role in phytosterol biosynthesis. Here, we summarize the past investigations on eukaryotic HMGS with particular focus on plant HMGS, its enzymatic properties, gene expression, protein structure, and its current status of research in China. An update of the findings on HMGS from animals (human, rat, avian) to plants (Brassica juncea, Hevea brasiliensis, Arabidopsis thaliana) will be discussed. Current studies on HMGS have been vastly promoted by developments in biochemistry and molecular biology. Nonetheless, several limitations have been encountered, thus some novel advances in HMGS-related research that have recently emerged will be touched on.
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Affiliation(s)
- Pan Liao
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China,
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Huchelmann A, Gastaldo C, Veinante M, Zeng Y, Heintz D, Tritsch D, Schaller H, Rohmer M, Bach TJ, Hemmerlin A. S-carvone suppresses cellulase-induced capsidiol production in Nicotiana tabacum by interfering with protein isoprenylation. PLANT PHYSIOLOGY 2014; 164:935-50. [PMID: 24367019 PMCID: PMC3912117 DOI: 10.1104/pp.113.232546] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 12/20/2013] [Indexed: 05/27/2023]
Abstract
S-Carvone has been described as a negative regulator of mevalonic acid (MVA) production by interfering with 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGR) activity, a key player in isoprenoid biosynthesis. The impact of this monoterpene on the production of capsidiol in Nicotiana tabacum, an assumed MVA-derived sesquiterpenoid phytoalexin produced in response to elicitation by cellulase, was investigated. As expected, capsidiol production, as well as early stages of elicitation such as hydrogen peroxide production or stimulation of 5-epi-aristolochene synthase activity, were repressed. Despite the lack of capsidiol synthesis, apparent HMGR activity was boosted. Feeding experiments using (1-13C)Glc followed by analysis of labeling patterns by 13C-NMR, confirmed an MVA-dependent biosynthesis; however, treatments with fosmidomycin, an inhibitor of the MVA-independent 2-C-methyl-D-erythritol 4-phosphate (MEP) isoprenoid pathway, unexpectedly down-regulated the biosynthesis of this sesquiterpene as well. We postulated that S-carvone does not directly inhibit the production of MVA by inactivating HMGR, but possibly targets an MEP-derived isoprenoid involved in the early steps of the elicitation process. A new model is proposed in which the monoterpene blocks an MEP pathway-dependent protein geranylgeranylation necessary for the signaling cascade. The production of capsidiol was inhibited when plants were treated with some inhibitors of protein prenylation or by further monoterpenes. Moreover, S-carvone hindered isoprenylation of a prenylable GFP indicator protein expressed in N. tabacum cell lines, which can be chemically complemented with geranylgeraniol. The model was further validated using N. tabacum cell extracts or recombinant N. tabacum protein prenyltransferases expressed in Escherichia coli. Our study endorsed a reevaluation of the effect of S-carvone on plant isoprenoid metabolism.
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Affiliation(s)
- Alexandre Huchelmann
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Clément Gastaldo
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Mickaël Veinante
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | | | - Dimitri Heintz
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Denis Tritsch
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Hubert Schaller
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Michel Rohmer
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Thomas J. Bach
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
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