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Goldston AM, Sharma AI, Paul KS, Engman DM. Acylation in trypanosomatids: an essential process and potential drug target. Trends Parasitol 2014; 30:350-60. [PMID: 24954795 DOI: 10.1016/j.pt.2014.05.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/06/2014] [Accepted: 05/06/2014] [Indexed: 12/11/2022]
Abstract
Fatty acylation--the addition of fatty acid moieties such as myristate and palmitate to proteins--is essential for the survival, growth, and infectivity of the trypanosomatids: Trypanosoma brucei, Trypanosoma cruzi, and Leishmania. Myristoylation and palmitoylation are critical for parasite growth, targeting and localization, and the intrinsic function of some proteins. The trypanosomatids possess a single N-myristoyltransferase (NMT) and multiple palmitoyl acyltransferases, and these enzymes and their protein targets are only now being characterized. Global inhibition of either process leads to cell death in trypanosomatids, and genetic ablation of NMT compromises virulence. Moreover, NMT inhibitors effectively cure T. brucei infection in rodents. Thus, protein acylation represents an attractive target for the development of new trypanocidal drugs.
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Affiliation(s)
- Amanda M Goldston
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Chicago, Illinois, USA
| | - Aabha I Sharma
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Chicago, Illinois, USA
| | - Kimberly S Paul
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, USA
| | - David M Engman
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Chicago, Illinois, USA.
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Running MP. The role of lipid post-translational modification in plant developmental processes. FRONTIERS IN PLANT SCIENCE 2014; 5:50. [PMID: 24600462 PMCID: PMC3927097 DOI: 10.3389/fpls.2014.00050] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 02/01/2014] [Indexed: 05/06/2023]
Abstract
Most eukaryotic proteins are post-translationally modified, and modification has profound effects on protein function. One key modification is the attachment of a lipid group to certain amino acids; this typically facilitates subcellular targeting (association with a membrane) and protein-protein interactions (by virtue of the large hydrophobic moiety). Most widely recognized are lipid modifications of proteins involved in developmental signaling, but proteins with structural roles are also lipid-modified. The three known types of intracellular protein lipid modifications are S-acylation, N-myristoylation, and prenylation. In plants, genetic analysis of the enzymes involved, along with molecular analysis of select target proteins, has recently shed light on the roles of lipid modification in key developmental processes, such as meristem function, flower development, polar cell elongation, cell differentiation, and hormone responses. In addition, while lipid post-translational mechanisms are generally conserved among eukaryotes, plants differ in the nature and function of target proteins, the effects of lipid modification on target proteins, and the roles of lipid modification in developmental processes.
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Affiliation(s)
- Mark P. Running
- *Correspondence: Mark P. Running, Department of Biology, University of Louisville, Louisville, KY 40292, USA e-mail:
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53
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Crozet P, Margalha L, Confraria A, Rodrigues A, Martinho C, Adamo M, Elias CA, Baena-González E. Mechanisms of regulation of SNF1/AMPK/SnRK1 protein kinases. FRONTIERS IN PLANT SCIENCE 2014; 5:190. [PMID: 24904600 PMCID: PMC4033248 DOI: 10.3389/fpls.2014.00190] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/22/2014] [Indexed: 05/17/2023]
Abstract
The SNF1 (sucrose non-fermenting 1)-related protein kinases 1 (SnRKs1) are the plant orthologs of the budding yeast SNF1 and mammalian AMPK (AMP-activated protein kinase). These evolutionarily conserved kinases are metabolic sensors that undergo activation in response to declining energy levels. Upon activation, SNF1/AMPK/SnRK1 kinases trigger a vast transcriptional and metabolic reprograming that restores energy homeostasis and promotes tolerance to adverse conditions, partly through an induction of catabolic processes and a general repression of anabolism. These kinases typically function as a heterotrimeric complex composed of two regulatory subunits, β and γ, and an α-catalytic subunit, which requires phosphorylation of a conserved activation loop residue for activity. Additionally, SNF1/AMPK/SnRK1 kinases are controlled by multiple mechanisms that have an impact on kinase activity, stability, and/or subcellular localization. Here we will review current knowledge on the regulation of SNF1/AMPK/SnRK1 by upstream components, post-translational modifications, various metabolites, hormones, and others, in an attempt to highlight both the commonalities of these essential eukaryotic kinases and the divergences that have evolved to cope with the particularities of each one of these systems.
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Affiliation(s)
| | | | | | - Américo Rodrigues
- Instituto Gulbenkian de CiênciaOeiras, Portugal
- Escola Superior de Turismo e Tecnologia do Mar de Peniche, Instituto Politécnico de LeiriaPeniche, Portugal
| | | | | | | | - Elena Baena-González
- Instituto Gulbenkian de CiênciaOeiras, Portugal
- *Correspondence: Elena Baena-González, Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal e-mail:
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54
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Traverso JA, Giglione C, Meinnel T. High-throughput profiling of N-myristoylation substrate specificity across species including pathogens. Proteomics 2013; 13:25-36. [PMID: 23165749 DOI: 10.1002/pmic.201200375] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 11/10/2022]
Abstract
One of the most critical modifications affecting the N-terminus of proteins is N-myristoylation. This irreversible modification affects the membrane-binding properties of crucial proteins involved in signal transduction cascades. This cotranslational modification, catalyzed by N-myristoyl transferase, occurs both in lower and higher eukaryotes and is a validated therapeutic target for several pathologies. However, this lipidation proves very difficult to be evidenced in vivo even with state-of-the-art proteomics approaches or bioinformatics tools. A large part of N-myristoylated proteins remains to be discovered and the rules of substrate specificity need to be established in each organism. Because the peptide substrate recognition occurs around the first eight residues, short peptides are used for modeling the reaction in vitro. Here, we provide a novel approach including a dedicated peptide array for high-throughput profiling protein N-myristoylation specificity. We show that myristoylation predictive tools need to be fine-tuned to organisms and that their poor accuracy should be significantly enhanced. This should lead to strongly improved knowledge of the number and function of myristoylated proteins occurring in any proteome.
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Affiliation(s)
- José A Traverso
- CNRS, Centre de Recherche de Gif, Institut des Sciences du Végétal, Gif-sur-Yvette, France
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55
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Lu SX, Hrabak EM. The myristoylated amino-terminus of an Arabidopsis calcium-dependent protein kinase mediates plasma membrane localization. PLANT MOLECULAR BIOLOGY 2013; 82:267-78. [PMID: 23609608 PMCID: PMC3668125 DOI: 10.1007/s11103-013-0061-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 04/15/2013] [Indexed: 05/21/2023]
Abstract
Calcium-dependent protein kinases (CDPK) are a major group of calcium-stimulated kinases found in plants and some protists. Many CDPKs are membrane-associated, presumably because of lipid modifications at their amino termini. We investigated the subcellular location and myristoylation of AtCPK5, a member of the Arabidopsis CDPK family. Most AtCPK5 was associated with the plasma membrane as demonstrated by two-phase fractionation of plant microsomes and by in vivo detection of AtCPK5-GFP fusion proteins. AtCPK5 was a substrate for plant N-myristoyltransferase and myristoylation was prevented by converting the glycine at the proposed site of myristate attachment to alanine (G2A). In transgenic plants, a G2A mutation completely abolished AtCPK5 membrane association, indicating that myristoylation was essential for membrane binding. The first sixteen amino acids of AtCPK5 were sufficient to direct plasma membrane localization. In addition, differentially phosphorylated forms of AtCPK5 were detected both in planta and after expression of AtCPK5 in a cell-free plant extract. Our results demonstrate that AtCPK5 is myristoylated at its amino terminus and that myristoylation is required for membrane binding.
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Affiliation(s)
- Sheen X. Lu
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824 USA
- Present Address: Department of Molecular, Cellular and Developmental Biology, University of California, Los Angeles, CA 09905 USA
| | - Estelle M. Hrabak
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824 USA
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56
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Renna L, Stefano G, Majeran W, Micalella C, Meinnel T, Giglione C, Brandizzi F. Golgi traffic and integrity depend on N-myristoyl transferase-1 in Arabidopsis. THE PLANT CELL 2013; 25:1756-73. [PMID: 23673980 PMCID: PMC3694704 DOI: 10.1105/tpc.113.111393] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
N-myristoylation is a crucial irreversible eukaryotic lipid modification allowing a key subset of proteins to be targeted at the periphery of specific membrane compartments. Eukaryotes have conserved N-myristoylation enzymes, involving one or two N-myristoyltransferases (NMT1 and NMT2), among which NMT1 is the major enzyme. In the postembryonic developmental stages, defects in NMT1 lead to aberrant cell polarity, flower differentiation, fruit maturation, and innate immunity; however, no specific NMT1 target responsible for such deficiencies has hitherto been identified. Using a confocal microscopy forward genetics screen for the identification of Arabidopsis thaliana secretory mutants, we isolated STINGY, a recessive mutant with defective Golgi traffic and integrity. We mapped STINGY to a substitution at position 160 of Arabidopsis NMT1 (NMT1A160T). In vitro kinetic studies with purified NMT1A160T enzyme revealed a significant reduction in its activity due to a remarkable decrease in affinity for both myristoyl-CoA and peptide substrates. We show here that this recessive mutation is responsible for the alteration of Golgi traffic and integrity by predominantly affecting the Golgi membrane/cytosol partitioning of ADP-ribosylation factor proteins. Our results provide important functional insight into N-myristoylation in plants by ascribing postembryonic functions of Arabidopsis NMT1 that involve regulation of the functional and morphological integrity of the plant endomembranes.
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Affiliation(s)
- Luciana Renna
- Michigan State University–Department of Energy Plant Research Lab, Michigan State University, East Lansing, Michigan 48824
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Giovanni Stefano
- Michigan State University–Department of Energy Plant Research Lab, Michigan State University, East Lansing, Michigan 48824
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Wojciech Majeran
- Centre National de la Recherche Scientifique, Campus de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Chiara Micalella
- Centre National de la Recherche Scientifique, Campus de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Thierry Meinnel
- Centre National de la Recherche Scientifique, Campus de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Carmela Giglione
- Centre National de la Recherche Scientifique, Campus de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Federica Brandizzi
- Michigan State University–Department of Energy Plant Research Lab, Michigan State University, East Lansing, Michigan 48824
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
- Address correspondence to
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57
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Traverso JA, Micalella C, Martinez A, Brown SC, Satiat-Jeunemaître B, Meinnel T, Giglione C. Roles of N-terminal fatty acid acylations in membrane compartment partitioning: Arabidopsis h-type thioredoxins as a case study. THE PLANT CELL 2013; 25:1056-77. [PMID: 23543785 PMCID: PMC3634677 DOI: 10.1105/tpc.112.106849] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/22/2013] [Accepted: 03/04/2013] [Indexed: 05/18/2023]
Abstract
N-terminal fatty acylations (N-myristoylation [MYR] and S-palmitoylation [PAL]) are crucial modifications affecting 2 to 4% of eukaryotic proteins. The role of these modifications is to target proteins to membranes. Predictive tools have revealed unexpected targets of these acylations in Arabidopsis thaliana and other plants. However, little is known about how N-terminal lipidation governs membrane compartmentalization of proteins in plants. We show here that h-type thioredoxins (h-TRXs) cluster in four evolutionary subgroups displaying strictly conserved N-terminal modifications. It was predicted that one subgroup undergoes only MYR and another undergoes both MYR and PAL. We used plant TRXs as a model protein family to explore the effect of MYR alone or MYR and PAL in the same family of proteins. We used a high-throughput biochemical strategy to assess MYR of specific TRXs. Moreover, various TRX-green fluorescent protein fusions revealed that MYR localized protein to the endomembrane system and that partitioning between this membrane compartment and the cytosol correlated with the catalytic efficiency of the N-myristoyltransferase acting at the N terminus of the TRXs. Generalization of these results was obtained using several randomly selected Arabidopsis proteins displaying a MYR site only. Finally, we demonstrated that a palmitoylatable Cys residue flanking the MYR site is crucial to localize proteins to micropatching zones of the plasma membrane.
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Affiliation(s)
- José A. Traverso
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
- Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, C/ Profesor Albareda 1, Granada, Spain
| | - Chiara Micalella
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Aude Martinez
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Spencer C. Brown
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Béatrice Satiat-Jeunemaître
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Thierry Meinnel
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
| | - Carmela Giglione
- Centre National de la Recherche Scientifique, Centre de Recherche de Gif, Institut des Sciences du Végétal, F-91198 Gif-sur-Yvette cedex, France
- Address correspondence to
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58
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O'Hara LE, Paul MJ, Wingler A. How do sugars regulate plant growth and development? New insight into the role of trehalose-6-phosphate. MOLECULAR PLANT 2013; 6:261-74. [PMID: 23100484 DOI: 10.1093/mp/sss120] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plant growth and development are tightly controlled in response to environmental conditions that influence the availability of photosynthetic carbon in the form of sucrose. Trehalose-6-phosphate (T6P), the precursor of trehalose in the biosynthetic pathway, is an important signaling metabolite that is involved in the regulation of plant growth and development in response to carbon availability. In addition to the plant's own pathway for trehalose synthesis, formation of T6P or trehalose by pathogens can result in the reprogramming of plant metabolism and development. Developmental processes that are regulated by T6P range from embryo development to leaf senescence. Some of these processes are regulated in interaction with phytohormones, such as auxin. A key interacting factor of T6P signaling in response to the environment is the protein kinase sucrose non-fermenting related kinase-1 (SnRK1), whose catalytic activity is inhibited by T6P. SnRK1 is most likely involved in the adjustment of metabolism and growth in response to starvation. The transcription factor bZIP11 has recently been identified as a new player in the T6P/SnRK1 regulatory pathway. By inhibiting SnRK1, T6P promotes biosynthetic reactions. This regulation has important consequences for crop production, for example, in the developing wheat grain and during the growth of potato tubers.
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Affiliation(s)
- Liam E O'Hara
- Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
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59
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Li ZY, Xu ZS, Chen Y, He GY, Yang GX, Chen M, Li LC, Ma YZ. A novel role for Arabidopsis CBL1 in affecting plant responses to glucose and gibberellin during germination and seedling development. PLoS One 2013; 8:e56412. [PMID: 23437128 PMCID: PMC3577912 DOI: 10.1371/journal.pone.0056412] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 01/09/2013] [Indexed: 01/28/2023] Open
Abstract
Glucose and phytohormones such as abscisic acid (ABA), ethylene, and gibberellin (GA) coordinately regulate germination and seedling development. However, there is still inadequate evidence to link their molecular roles in affecting plant responses. Calcium acts as a second messenger in a diverse range of signal transduction pathways. As calcium sensors unique to plants, calcineurin B-like (CBL) proteins are well known to modulate abiotic stress responses. In this study, it was found that CBL1 was induced by glucose in Arabidopsis. Loss-of-function mutant cbl1 exhibited hypersensitivity to glucose and paclobutrazol, a GA biosynthetic inhibitor. Several sugar-responsive and GA biosynthetic gene expressions were altered in the cbl1 mutant. CBL1 protein physically interacted with AKINβ1, the regulatory β subunit of the SnRK1 complex which has a central role in sugar signaling. Our results indicate a novel role for CBL1 in modulating responses to glucose and GA signals.
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Affiliation(s)
- Zhi-Yong Li
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing, China
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, Chinese National Center of Plant Gene Research (Wuhan) HUST Part, College of Life Science and Technology, Huazhong University of Science & Technology (HUST), Wuhan, China
| | - Zhao-Shi Xu
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing, China
- * E-mail: (Z-SX); (Y-ZM); (YC)
| | - Yang Chen
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing, China
- * E-mail: (Z-SX); (Y-ZM); (YC)
| | - Guang-Yuan He
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, Chinese National Center of Plant Gene Research (Wuhan) HUST Part, College of Life Science and Technology, Huazhong University of Science & Technology (HUST), Wuhan, China
| | - Guang-Xiao Yang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, Chinese National Center of Plant Gene Research (Wuhan) HUST Part, College of Life Science and Technology, Huazhong University of Science & Technology (HUST), Wuhan, China
| | - Ming Chen
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing, China
| | - Lian-Cheng Li
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing, China
| | - You-Zhi Ma
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing, China
- * E-mail: (Z-SX); (Y-ZM); (YC)
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60
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Nunes C, Primavesi LF, Patel MK, Martinez-Barajas E, Powers SJ, Sagar R, Fevereiro PS, Davis BG, Paul MJ. Inhibition of SnRK1 by metabolites: tissue-dependent effects and cooperative inhibition by glucose 1-phosphate in combination with trehalose 6-phosphate. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 63:89-98. [PMID: 23257075 DOI: 10.1016/j.plaphy.2012.11.011] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 11/15/2012] [Indexed: 05/02/2023]
Abstract
SnRK1 of the SNF1/AMPK group of protein kinases is an important regulatory protein kinase in plants. SnRK1 was recently shown as a target of the sugar signal, trehalose 6-phosphate (T6P). Glucose 6-phosphate (G6P) can also inhibit SnRK1 and given the similarity in structure to T6P, we sought to establish if each could impart distinct inhibition of SnRK1. Other central metabolites, glucose 1-phosphate (G1P), fructose 6-phosphate and UDP-glucose were also tested, and additionally ribose 5-phosphate (R5P), recently reported to inhibit SnRK1 strongly in wheat grain tissue. For the metabolites that inhibited SnRK1, kinetic models show that T6P, G1P and G6P each provide distinct regulation (50% inhibition of SnRK1 at 5.4 μM, 480 μM, >1 mM, respectively). Strikingly, G1P in combination with T6P inhibited SnRK1 synergistically. R5P, in contrast to the other inhibitors, inhibited SnRK1 in green tissues only. We show that this is due to consumption of ATP in the assay mediated by phosphoribulokinase during conversion of R5P to ribulose-1,5-bisphosphate. The accompanying loss of ATP limits the activity of SnRK1 giving rise to an apparent inhibition of SnRK1. Inhibition of SnRK1 by R5P in wheat grain preparations can be explained by the presence of green pericarp tissue; this exposes an important caveat in the assessment of potential protein kinase inhibitors. Data provide further insight into the regulation of SnRK1 by metabolites.
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Affiliation(s)
- Cátia Nunes
- Plant Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
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62
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Lange PF, Overall CM. Protein TAILS: when termini tell tales of proteolysis and function. Curr Opin Chem Biol 2013; 17:73-82. [DOI: 10.1016/j.cbpa.2012.11.025] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/17/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
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63
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Padovani D, Zeghouf M, Traverso JA, Giglione C, Cherfils J. High yield production of myristoylated Arf6 small GTPase by recombinant N-myristoyl transferase. Small GTPases 2013; 4:3-8. [PMID: 23319116 DOI: 10.4161/sgtp.22895] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Small GTP-binding proteins of the Arf family (Arf GTPases) interact with multiple cellular partners and with membranes to regulate intracellular traffic and organelle structure. Understanding the underlying molecular mechanisms requires in vitro biochemical assays to test for regulations and functions. Such assays should use proteins in their cellular form, which carry a myristoyl lipid attached in N-terminus. N-myristoylation of recombinant Arf GTPases can be achieved by co-expression in E. coli with a eukaryotic N-myristoyl transferase. However, purifying myristoylated Arf GTPases is difficult and has a poor overall yield. Here we show that human Arf6 can be N-myristoylated in vitro by recombinant N-myristoyl transferases from different eukaryotic species. The catalytic efficiency depended strongly on the guanine nucleotide state and was highest for Arf6-GTP. Large-scale production of highly pure N-myristoylated Arf6 could be achieved, which was fully functional for liposome-binding and EFA6-stimulated nucleotide exchange assays. This establishes in vitro myristoylation as a novel and simple method that could be used to produce other myristoylated Arf and Arf-like GTPases for biochemical assays.
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Affiliation(s)
- Dominique Padovani
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif (CNRS), Gif-sur-Yvette, France
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64
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Rampoldi F, Sandhoff R, Owen RW, Gröne HJ, Porubsky S. A new, robust, and nonradioactive approach for exploring N-myristoylation. J Lipid Res 2012; 53:2459-68. [PMID: 22829651 DOI: 10.1194/jlr.d026997] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myristoyl-CoA (CoA):protein N-myristoyltransferase (NMT) catalyzes protein modification through covalent attachment of a C14 fatty acid (myristic acid) to the N-terminal glycine of proteins, thus promoting protein-protein and protein-membrane interactions. NMT is essential for the viability of numerous human pathogens and is also up-regulated in several tumors. Here we describe a new, nonradioactive, ELISA-based method for measuring NMT activity. After the NMT-catalyzed reaction between a FLAG-tagged peptide and azido-dodecanoyl-CoA (analog of myristoyl-CoA), the resulting azido-dodecanoyl-peptide-FLAG was coupled to phosphine-biotin by Staudinger ligation, captured by plate-bound anti-FLAG antibodies and detected by streptavidin-peroxidase. The assay was validated with negative controls (including inhibitors), corroborated by HPLC analysis, and demonstrated to function with fresh or frozen tissues. Recombinant murine NMT1 and NMT2 were characterized using this new method. This versatile assay is applicable for exploring recombinant NMTs with regard to their activity, substrate specificity, and possible inhibitors as well as for measuring NMT-activity in tissues.
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Affiliation(s)
- Francesca Rampoldi
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany
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65
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Tsugama D, Liu S, Takano T. A putative myristoylated 2C-type protein phosphatase, PP2C74, interacts with SnRK1 in Arabidopsis. FEBS Lett 2012; 586:693-8. [PMID: 22449965 DOI: 10.1016/j.febslet.2012.02.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 02/10/2012] [Accepted: 02/12/2012] [Indexed: 11/24/2022]
Abstract
N-myristoylation is a lipid modification of many signaling proteins in which myristate is added to an N-terminal glycine residue. Here we show that PP2C74, a putative myristoylated 2C-type protein phosphatase (PP2C) in Arabidopsis, is transcribed in various tissues and has protein phosphatase activity. GFP-fused PP2C74 localized to the plasma membrane, but not when a glycine residue at position 2, which is the putative myristoylation site, was substituted with an alanine residue. Yeast two-hybrid analysis and GST pull-down analysis showed that PP2C74 interacts with AKIN10, the catalytic α subunit of the SnRK1 protein kinase complex, the β subunits of which are known targets of myristoylation.
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Affiliation(s)
- Daisuke Tsugama
- Asian Natural Environmental Science Center (ANESC), The University of Tokyo, Tokyo, Japan
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66
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Sequence characterization and expression pattern of BcMF21, a novel gene related to pollen development in Brassica campestris ssp. chinensis. Mol Biol Rep 2012; 39:7319-26. [PMID: 22311045 DOI: 10.1007/s11033-012-1563-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 01/25/2012] [Indexed: 01/11/2023]
Abstract
In this report a full length cDNA, Brassica campestris Male Fertile 21 (BcMF21) was successfully isolated from one of the cDNA-amplified fragment length polymorphism (cDNA-AFLP) transcript-derived fragments (TDFs), BBP10, that was found down-regulated in the flower buds of sterile plants in Brassica campestris L. ssp. chinensis Makino genic male sterile (GMS) AB line system (Bcajh 97-01A/B). BcMF21 protein structure analysis showed a signal peptide at the N-terminus; two protein kinase C phosphorylation sites, five N-myristoylation sites and one casein kinase II phosphorylation site. The promoter region of BcMF21, a 779 bp upstream of ATG was isolated by thermal asymmetric interlaced-PCR (TAIL-PCR). Bioinformatics analysis revealed that the promoter of BcMF21 contained several classical cis-acting elements and three pollen specific elements. Transient expression analysis showed that the promoter could drive green fluorescence protein (GFP) expression. Quantitative reverse transcript-PCR analysis revealed that BcMF21 was specifically expressed in flower buds. The transcript level of BcMF21 was much lower in the sterile flower buds than in the fertile flower buds in 'Bcajh 97-01A/B' system. In situ hybridization further showed that BcMF21 was only expressed in the tetrads and the microspores at the tetrad stage and the uninucleate stage. In addition, phylogenetic analysis demonstrated that the BcMF21 was relative conserved within family Crucifereae and might be originated from the ancestor diploid B. campestris within genus Brassica according to the Triangle of U theory.
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67
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Comparative proteomic analysis reveals the mechanisms governing cotton fiber differentiation and initiation. J Proteomics 2012; 75:845-56. [DOI: 10.1016/j.jprot.2011.09.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 09/24/2011] [Accepted: 09/28/2011] [Indexed: 12/26/2022]
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68
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Bitrián M, Roodbarkelari F, Horváth M, Koncz C. BAC-recombineering for studying plant gene regulation: developmental control and cellular localization of SnRK1 kinase subunits. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 65:829-42. [PMID: 21235649 DOI: 10.1111/j.1365-313x.2010.04462.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Recombineering, permitting precise modification of genes within bacterial artificial chromosomes (BACs) through homologous recombination mediated by lambda phage-encoded Red proteins, is a widely used powerful tool in mouse, Caenorhabditis and Drosophila genetics. As Agrobacterium-mediated transfer of large DNA inserts from binary BACs and TACs into plants occurs at low frequency, recombineering is so far seldom exploited in the analysis of plant gene functions. We have constructed binary plant transformation vectors, which are suitable for gap-repair cloning of genes from BACs using recombineering methods previously developed for other organisms. Here we show that recombineering facilitates PCR-based generation of precise translational fusions between coding sequences of fluorescent reporter and plant proteins using galK-based exchange recombination. The modified target genes alone or as part of a larger gene cluster can be transferred by high-frequency gap-repair into plant transformation vectors, stably maintained in Agrobacterium and transformed without alteration into plants. Versatile application of plant BAC-recombineering is illustrated by the analysis of developmental regulation and cellular localization of interacting AKIN10 catalytic and SNF4 activating subunits of Arabidopsis Snf1-related (SnRK1) protein kinase using in vivo imaging. To validate full functionality and in vivo interaction of tagged SnRK1 subunits, it is demonstrated that immunoprecipitated SNF4-YFP is bound to a kinase that phosphorylates SnRK1 candidate substrates, and that the GFP- and YFP-tagged kinase subunits co-immunoprecipitate with endogenous wild type AKIN10 and SNF4.
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Affiliation(s)
- Marta Bitrián
- Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
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69
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Stael S, Bayer RG, Mehlmer N, Teige M. Protein N-acylation overrides differing targeting signals. FEBS Lett 2011; 585:517-522. [PMID: 21219905 PMCID: PMC3971372 DOI: 10.1016/j.febslet.2011.01.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 12/30/2010] [Accepted: 01/04/2011] [Indexed: 11/15/2022]
Abstract
In a bioinformatics based screen for chloroplast-localized protein kinases we noticed that available protein targeting predictors falsely predicted chloroplast localization. This seems to be due to interference with N-terminal protein acylation, which is of particular importance for protein kinases. Their N-myristoylation was found to be highly overrepresented in the proteome, whereas myristoylation motifs are almost absent in known chloroplast proteins. However, only abolishing their myristoylation was not sufficient to target those kinases to chloroplasts and resulted in nuclear accumulation instead. In contrast, inhibition of N-myristoylation of a calcium-dependent protein kinase was sufficient to alter its localization from the plasma membrane to chloroplasts and chloroplast localization of ferredoxin-NADP+ reductase and Rubisco activase could be efficiently suppressed by artificial introduction of myristoylation and palmitoylation sites.
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Affiliation(s)
- Simon Stael
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna. Dr. Bohrgasse 9, A-1030 Vienna, Austria
| | - Roman G. Bayer
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna. Dr. Bohrgasse 9, A-1030 Vienna, Austria
| | | | - Markus Teige
- Department of Biochemistry and Cell Biology, MFPL, University of Vienna. Dr. Bohrgasse 9, A-1030 Vienna, Austria
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70
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Posttranslational Modifications of Plasma Membrane Proteins and Their Implications for Plant Growth and Development. THE PLANT PLASMA MEMBRANE 2011. [DOI: 10.1007/978-3-642-13431-9_5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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71
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Yamauchi S, Fusada N, Hayashi H, Utsumi T, Uozumi N, Endo Y, Tozawa Y. The consensus motif for N-myristoylation of plant proteins in a wheat germ cell-free translation system. FEBS J 2010; 277:3596-607. [DOI: 10.1111/j.1742-4658.2010.07768.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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72
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dit Frey NF, Muller P, Jammes F, Kizis D, Leung J, Perrot-Rechenmann C, Bianchi MW. The RNA binding protein Tudor-SN is essential for stress tolerance and stabilizes levels of stress-responsive mRNAs encoding secreted proteins in Arabidopsis. THE PLANT CELL 2010; 22:1575-91. [PMID: 20484005 PMCID: PMC2899877 DOI: 10.1105/tpc.109.070680] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 04/29/2010] [Accepted: 05/03/2010] [Indexed: 05/20/2023]
Abstract
Tudor-SN (TSN) copurifies with the RNA-induced silencing complex in animal cells where, among other functions, it is thought to act on mRNA stability via the degradation of specific dsRNA templates. In plants, TSN has been identified biochemically as a cytoskeleton-associated RNA binding activity. In eukaryotes, it has recently been identified as a conserved primary target of programmed cell death-associated proteolysis. We have investigated the physiological role of TSN by isolating null mutations for two homologous genes in Arabidopsis thaliana. The double mutant tsn1 tsn2 displays only mild growth phenotypes under nonstress conditions, but germination, growth, and survival are severely affected under high salinity stress. Either TSN1 or TSN2 alone can complement the double mutant, indicating their functional redundancy. TSN accumulates heterogeneously in the cytosol and relocates transiently to a diffuse pattern in response to salt stress. Unexpectedly, stress-regulated mRNAs encoding secreted proteins are significantly enriched among the transcripts that are underrepresented in tsn1 tsn2. Our data also reveal that TSN is important for RNA stability of its targets. These findings show that TSN is essential for stress tolerance in plants and implicate TSN in new, potentially conserved mechanisms acting on mRNAs entering the secretory pathway.
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Affiliation(s)
- Nicolas Frei dit Frey
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Philippe Muller
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Fabien Jammes
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
- Unité de Recherche en Génomique Végétale, Unité Mixte de Recherche, Institut National de la Recherche Agronomique 1165, Centre National de la Recherche Scientifique 8114, Université d'Evry Val d'Essonne, 91057 Evry cedex, France
| | - Dimosthenis Kizis
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Jeffrey Leung
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Catherine Perrot-Rechenmann
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Michele Wolfe Bianchi
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
- Faculté des Sciences et Technologie, Université Paris Est-Créteil, 94010 Créteil cedex, France
- Address correspondence to
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73
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Gagne JM, Clark SE. The Arabidopsis stem cell factor POLTERGEIST is membrane localized and phospholipid stimulated. THE PLANT CELL 2010; 22:729-43. [PMID: 20348433 PMCID: PMC2861466 DOI: 10.1105/tpc.109.068734] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 03/03/2010] [Accepted: 03/09/2010] [Indexed: 05/18/2023]
Abstract
Stem cell maintenance and differentiation are tightly regulated in multicellular organisms. In plants, proper control of the stem cell populations is critical for extensive postembryonic organogenesis. The Arabidopsis thaliana protein phosphatase type 2C proteins POLTERGEIST (POL) and PLL1 are essential for maintenance of both the root and shoot stem cells. Specifically, POL and PLL1 are required for proper specification of key asymmetric cell divisions during stem cell initiation and maintenance. POL and PLL1 are known to be integral components of the CLE/WOX signaling pathways, but the location and mechanisms by which POL and PLL1 are regulated within these pathways are unclear. Here, we show that POL and PLL1 are dual-acylated plasma membrane proteins whose membrane localization is required for proper function. Furthermore, this localization places POL and PLL1 in proximity of the upstream plasma membrane receptors that regulate their activity. Additionally, we find that POL and PLL1 directly bind to multiple lipids and that POL is catalytically activated by phosphatidylinositol (4) phosphate [PI(4)P] in vitro. Based on these results, we propose that the upstream receptors in the CLE/WOX signaling pathways may function to either limit PI(4)P availability or antagonize PI(4)P stimulation of POL/PLL1. Significantly, the findings presented here suggest that phospholipids play an important role in promoting stem cell specification.
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Affiliation(s)
| | - Steven E. Clark
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048
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74
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Frottin F, Espagne C, Traverso JA, Mauve C, Valot B, Lelarge-Trouverie C, Zivy M, Noctor G, Meinnel T, Giglione C. Cotranslational proteolysis dominates glutathione homeostasis to support proper growth and development. THE PLANT CELL 2009; 21:3296-314. [PMID: 19855051 PMCID: PMC2782297 DOI: 10.1105/tpc.109.069757] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/17/2009] [Accepted: 10/05/2009] [Indexed: 05/18/2023]
Abstract
The earliest proteolytic event affecting most proteins is the excision of the initiating Met (NME). This is an essential and ubiquitous cotranslational process tightly regulated in all eukaryotes. Currently, the effects of NME on unknown complex cellular networks and the ways in which its inhibition leads to developmental defects and cell growth arrest remain poorly understood. Here, we provide insight into the earliest molecular mechanisms associated with the inhibition of the NME process in Arabidopsis thaliana. We demonstrate that the developmental defects induced by NME inhibition are caused by an increase in cellular proteolytic activity, primarily induced by an increase in the number of proteins targeted for rapid degradation. This deregulation drives, through the increase of the free amino acids pool, a perturbation of the glutathione homeostasis, which corresponds to the earliest limiting, reversible step promoting the phenotype. We demonstrate that these effects are universally conserved and that the reestablishment of the appropriate glutathione status restores growth and proper development in various organisms. Finally, we describe a novel integrated model in which NME, protein N-alpha-acylation, proteolysis, and glutathione homeostasis operate in a sequentially regulated mechanism that directs both growth and development.
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Affiliation(s)
- Frédéric Frottin
- Centre National de la Recherche Scientifique, Institut des Sciences du Végétal, Unité Propre de Recherche2355, Protein Maturation, Cell Fate, and Therapeutics, F-91198 Gif-sur-Yvette cedex, France
| | - Christelle Espagne
- Centre National de la Recherche Scientifique, Institut des Sciences du Végétal, Unité Propre de Recherche2355, Protein Maturation, Cell Fate, and Therapeutics, F-91198 Gif-sur-Yvette cedex, France
| | - José A. Traverso
- Centre National de la Recherche Scientifique, Institut des Sciences du Végétal, Unité Propre de Recherche2355, Protein Maturation, Cell Fate, and Therapeutics, F-91198 Gif-sur-Yvette cedex, France
| | - Caroline Mauve
- Université Paris-Sud, Institut Fédératif de Recherche87, Institut de Biotechnologie des Plantes, Plateforme Métabolisme-Métabolome, F-91405 Orsay, France
- Centre National de la Recherche Scientifique, Institut Fédératif de Recherche87, Institut de Biotechnologie des Plantes, Plateforme Métabolisme-Métabolome, Unité Mixte de Recherche 8618, F-91405 Orsay, France
| | - Benoît Valot
- Université Paris-Sud, Plateforme de Protéomique, Institut Fédératif de Recherche87, Centre National de la Recherche Scientifique/Université Paris-Sud/Institut National de la Recherche Agronomique, F-91190 Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique, Plateforme de Protéomique, Institut Fédératif de Recherche87, F-91190 Gif-sur-Yvette, France
- Institut National de la Recherche Agronomique, Plateforme de Protéomique, Institut Fédératif de Recherche87, F-91190 Gif-sur-Yvette, France
| | - Caroline Lelarge-Trouverie
- Université Paris-Sud, Institut Fédératif de Recherche87, Institut de Biotechnologie des Plantes, Plateforme Métabolisme-Métabolome, F-91405 Orsay, France
- Centre National de la Recherche Scientifique, Institut Fédératif de Recherche87, Institut de Biotechnologie des Plantes, Plateforme Métabolisme-Métabolome, Unité Mixte de Recherche 8618, F-91405 Orsay, France
| | - Michel Zivy
- Université Paris-Sud, Plateforme de Protéomique, Institut Fédératif de Recherche87, Centre National de la Recherche Scientifique/Université Paris-Sud/Institut National de la Recherche Agronomique, F-91190 Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique, Plateforme de Protéomique, Institut Fédératif de Recherche87, F-91190 Gif-sur-Yvette, France
- Institut National de la Recherche Agronomique, Plateforme de Protéomique, Institut Fédératif de Recherche87, F-91190 Gif-sur-Yvette, France
| | - Graham Noctor
- Université Paris-Sud, Institut Fédératif de Recherche87, Institut de Biotechnologie des Plantes, Plateforme Métabolisme-Métabolome, F-91405 Orsay, France
- Centre National de la Recherche Scientifique, Institut Fédératif de Recherche87, Institut de Biotechnologie des Plantes, Plateforme Métabolisme-Métabolome, Unité Mixte de Recherche 8618, F-91405 Orsay, France
| | - Thierry Meinnel
- Centre National de la Recherche Scientifique, Institut des Sciences du Végétal, Unité Propre de Recherche2355, Protein Maturation, Cell Fate, and Therapeutics, F-91198 Gif-sur-Yvette cedex, France
| | - Carmela Giglione
- Centre National de la Recherche Scientifique, Institut des Sciences du Végétal, Unité Propre de Recherche2355, Protein Maturation, Cell Fate, and Therapeutics, F-91198 Gif-sur-Yvette cedex, France
- Address correspondence to
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75
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Jossier M, Bouly JP, Meimoun P, Arjmand A, Lessard P, Hawley S, Grahame Hardie D, Thomas M. SnRK1 (SNF1-related kinase 1) has a central role in sugar and ABA signalling in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 59:316-28. [PMID: 19302419 DOI: 10.1111/j.1365-313x.2009.03871.x] [Citation(s) in RCA: 216] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The proteins kinases SNF1/AMPK/SnRK1 are a subfamily of serine/threonine kinases that act as metabolite sensors to constantly adapt metabolism to the supply of, and demand for, energy. In the yeast Saccharomyces cerevisiae, the SNF1 complex is a central component of the regulatory response to glucose starvation. AMP activated protein kinase (AMPK) the mammalian homologue of SNF1, plays a central role in the regulation of energy homeostasis at the cellular as well as the whole-body levels. In Arabidopsis thaliana, SnRK1.1 and SnRK1.2 have recently been described as central integrators of a transcription network for stress and energy signalling. In this study, biochemical analysis established SnRK1.1 as the major SnRK1 isoform both in isolated cells and leaves. In order to elucidate the function of SnRK1.1 in Arabidopsis thaliana, transgenic plants over-expressing SnRK1.1 were produced. Genetic, biochemical, physiological and molecular analyses of these plants revealed that SnRK1.1 is implicated in sugar and ABA signalling pathways. Modifications of the starch and soluble sugar content were observed in the 35S:SnRK1.1 transgenic lines. Our studies also revealed modifications of the activity of essential enzymes such as nitrate reductase or ADP-glucose pyrophosphorylase, and of the expression of several sugar-regulated genes, confirming the central role of the protein kinase SnRK1 in the regulation of metabolism.
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Affiliation(s)
- Mathieu Jossier
- Université Paris-Sud XI, Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR CNRS 8618), Bâtiment 630, Orsay Cedex, France
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76
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Zhang Y, Primavesi LF, Jhurreea D, Andralojc PJ, Mitchell RAC, Powers SJ, Schluepmann H, Delatte T, Wingler A, Paul MJ. Inhibition of SNF1-related protein kinase1 activity and regulation of metabolic pathways by trehalose-6-phosphate. PLANT PHYSIOLOGY 2009; 149:1860-71. [PMID: 19193861 PMCID: PMC2663748 DOI: 10.1104/pp.108.133934] [Citation(s) in RCA: 381] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 02/03/2009] [Indexed: 05/17/2023]
Abstract
Trehalose-6-phosphate (T6P) is a proposed signaling molecule in plants, yet how it signals was not clear. Here, we provide evidence that T6P functions as an inhibitor of SNF1-related protein kinase1 (SnRK1; AKIN10/AKIN11) of the SNF1-related group of protein kinases. T6P, but not other sugars and sugar phosphates, inhibited SnRK1 in Arabidopsis (Arabidopsis thaliana) seedling extracts strongly (50%) at low concentrations (1-20 microM). Inhibition was noncompetitive with respect to ATP. In immunoprecipitation studies using antibodies to AKIN10 and AKIN11, SnRK1 catalytic activity and T6P inhibition were physically separable, with T6P inhibition of SnRK1 dependent on an intermediary factor. In subsequent analysis, T6P inhibited SnRK1 in extracts of all tissues analyzed except those of mature leaves, which did not contain the intermediary factor. To assess the impact of T6P inhibition of SnRK1 in vivo, gene expression was determined in seedlings expressing Escherichia coli otsA encoding T6P synthase to elevate T6P or otsB encoding T6P phosphatase to decrease T6P. SnRK1 target genes showed opposite regulation, consistent with the regulation of SnRK1 by T6P in vivo. Analysis of microarray data showed up-regulation by T6P of genes involved in biosynthetic reactions, such as genes for amino acid, protein, and nucleotide synthesis, the tricarboxylic acid cycle, and mitochondrial electron transport, which are normally down-regulated by SnRK1. In contrast, genes involved in photosynthesis and degradation processes, which are normally up-regulated by SnRK1, were down-regulated by T6P. These experiments provide strong evidence that T6P inhibits SnRK1 to activate biosynthetic processes in growing tissues.
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Affiliation(s)
- Yuhua Zhang
- Plant Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
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77
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Ananieva EA, Gillaspy GE, Ely A, Burnette RN, Erickson FL. Interaction of the WD40 domain of a myoinositol polyphosphate 5-phosphatase with SnRK1 links inositol, sugar, and stress signaling. PLANT PHYSIOLOGY 2008; 148:1868-82. [PMID: 18931139 PMCID: PMC2593651 DOI: 10.1104/pp.108.130575] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 10/14/2008] [Indexed: 05/17/2023]
Abstract
In plants, myoinositol signaling pathways have been associated with several stress, developmental, and physiological processes, but the regulation of these pathways is largely unknown. In our efforts to better understand myoinositol signaling pathways in plants, we have found that the WD40 repeat region of a myoinositol polyphosphate 5-phosphatase (5PTase13; At1g05630) interacts with the sucrose nonfermenting-1-related kinase (SnRK1.1) in the yeast two-hybrid system and in vitro. Plant SnRK1 proteins (also known as AKIN10/11) have been described as central integrators of sugar, metabolic, stress, and developmental signals. Using mutants defective in 5PTase13, we show that 5PTase13 can act as a regulator of SnRK1 activity and that regulation differs with different nutrient availability. Specifically, we show that under low-nutrient or -sugar conditions, 5PTase13 acts as a positive regulator of SnRK1 activity. In contrast, under severe starvation conditions, 5PTase13 acts as a negative regulator of SnRK1 activity. To delineate the regulatory interaction that occurs between 5PTase13 and SnRK1.1, we used a cell-free degradation assay and found that 5PTase13 is required to reduce the amount of SnRK1.1 targeted for proteasomal destruction under low-nutrient conditions. This regulation most likely involves a 5PTase13-SnRK1.1 interaction within the nucleus, as a 5PTase13:green fluorescent protein was localized to the nucleus. We also show that a loss of function in 5PTase13 leads to nutrient level-dependent reduction of root growth, along with abscisic acid (ABA) and sugar insensitivity. 5ptase13 mutants accumulate less inositol 1,4,5-trisphosphate in response to sugar stress and have alterations in ABA-regulated gene expression, both of which are consistent with the known role of inositol 1,4,5-trisphosphate in ABA-mediated signaling. We propose that by forming a protein complex with SnRK1.1 protein, 5PTase13 plays a regulatory role linking inositol, sugar, and stress signaling.
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Affiliation(s)
- Elitsa A Ananieva
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
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78
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Polge C, Jossier M, Crozet P, Gissot L, Thomas M. Beta-subunits of the SnRK1 complexes share a common ancestral function together with expression and function specificities; physical interaction with nitrate reductase specifically occurs via AKINbeta1-subunit. PLANT PHYSIOLOGY 2008; 148:1570-82. [PMID: 18768910 PMCID: PMC2577271 DOI: 10.1104/pp.108.123026] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 08/11/2008] [Indexed: 05/19/2023]
Abstract
The SNF1/AMPK/SnRK1 kinases are evolutionary conserved kinases involved in yeast, mammals, and plants in the control of energy balance. These heterotrimeric enzymes are composed of one alpha-type catalytic subunit and two gamma- and beta-type regulatory subunits. In yeast it has been proposed that the beta-type subunits regulate both the localization of the kinase complexes within the cell and the interaction of the kinases with their targets. In this work, we demonstrate that the three beta-type subunits of Arabidopsis (Arabidopsis thaliana; AKINbeta1, AKINbeta2, and AKINbeta3) restore the growth phenotype of the yeast sip1Deltasip2Deltagal83Delta triple mutant, thus suggesting the conservation of an ancestral function. Expression analyses, using AKINbeta promoterbeta-glucuronidase transgenic lines, reveal different and specific patterns of expression for each subunit according to organs, developmental stages, and environmental conditions. Finally, our results show that the beta-type subunits are involved in the specificity of interaction of the kinase with the cytosolic nitrate reductase. Together with previous cell-free phosphorylation data, they strongly support the proposal that nitrate reductase is a real target of SnRK1 in the physiological context. Altogether our data suggest the conservation of ancestral basic function(s) together with specialized functions for each beta-type subunit in plants.
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Affiliation(s)
- Cécile Polge
- Laboratoire Signalisation et Régulation Coordonnée du Métabolisme Carboné et Azoté, Institut de Biotechnologie des Plantes (UMR8618), Université Paris-Sud, F-91405 Orsay cedex, France
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79
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Martinez A, Traverso JA, Valot B, Ferro M, Espagne C, Ephritikhine G, Zivy M, Giglione C, Meinnel T. Extent of N-terminal modifications in cytosolic proteins from eukaryotes. Proteomics 2008; 8:2809-31. [PMID: 18655050 DOI: 10.1002/pmic.200701191] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Most proteins in all organisms undergo crucial N-terminal modifications involving N-terminal methionine excision, N-alpha-acetylation or N-myristoylation (N-Myr), or S-palmitoylation. We investigated the occurrence of these poorly annotated but essential modifications in proteomes, focusing on eukaryotes. Experimental data for the N-terminal sequences of animal, fungi, and archaeal proteins, were used to build dedicated predictive modules in a new software. In vitro N-Myr experiments were performed with both plant and animal N-myristoyltransferases, for accurate prediction of the modification. N-terminal modifications from the fully sequenced genome of Arabidopsis thaliana were determined by MS. We identified 105 new modified protein N-termini, which were used to check the accuracy of predictive data. An accuracy of more than 95% was achieved, demonstrating (i) overall conservation of the specificity of the modification machinery in higher eukaryotes and (ii) robustness of the prediction tool. Predictions were made for various proteomes. Proteins that had undergone both N-terminal methionine (Met) cleavage and N-acetylation were found to be strongly overrepresented among the most abundant proteins, in contrast to those retaining their genuine unblocked Met. Here we propose that the nature of the second residue of an ORF is a key marker of the abundance of the mature protein in eukaryotes.
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Affiliation(s)
- Aude Martinez
- Institut des Sciences du Végétal, UPR2355, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
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Traverso JA, Meinnel T, Giglione C. Expanded impact of protein N-myristoylation in plants. PLANT SIGNALING & BEHAVIOR 2008; 3:501-2. [PMID: 19704499 PMCID: PMC2634443 DOI: 10.4161/psb.3.7.6039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 04/04/2008] [Indexed: 05/05/2023]
Abstract
N-MYR controls the function of the plant protein complex SnRK1, described as one of the most important plant regulatory protein in stress and energy signalling. In plant cells, N-MYR is involved in a significantly higher number of metabolic pathways than in yeast or human. Some N-myristoylated protein families are solely encountered in plant cells. This lipid modification could be involved in the control of the redox imbalances originating from different stresses in plants. This prevalence of N-MYR in such proteins is unique to the plant kingdom. We hypothesize that this expansion of the mechanism in plants improves the control of the damages induced by environmental changes.
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Affiliation(s)
- José A Traverso
- Protein Maturation and Cell Fate; ISV; UPR2355; Centre National de la Recherche Scientifique; France
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