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Zhang J, Zhao R, Yu C, Bryant CLN, Wu K, Liu Z, Ding Y, Zhao Y, Xue B, Pan ZQ, Li C, Huang L, Fang L. IKK-Mediated Regulation of the COP9 Signalosome via Phosphorylation of CSN5. J Proteome Res 2020; 19:1119-1130. [PMID: 31950832 DOI: 10.1021/acs.jproteome.9b00626] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The COP9 signalosome (CSN) is an evolutionarily conserved multisubunit protein complex, which controls protein degradation through deneddylation and inactivation of cullin-RING ubiquitin E3 ligases (CRLs). Recently, the CSN complex has been linked to the NF-κB signaling pathway due to its association with the IKK complex. However, how the CSN complex is regulated in this signaling pathway remains unclear. Here, we have carried out biochemical experiments and confirmed the interaction between the CSN and IKK complexes. In addition, we have determined that overexpression of IKKα or IKKβ leads to enhanced phosphorylation of CSN5, the catalytic subunit for CSN deneddylase activity. Mutational analyses have revealed that phosphorylation at serine 201 and threonine 205 of CSN5 impairs CSN-mediated deneddylation activity in vitro. Interestingly, TNF-α treatment not only enhances the interaction between CSN and IKK but also induces an IKK-dependent phosphorylation of CSN5 at serine 201, linking CSN to TNF-α signaling through IKK. Moreover, TNF-α treatment affects the CSN interaction network globally, especially the associations of CSN with the proteasome complex, eukaryotic translation initiation factor complex, and CRL components. Collectively, our results provide new insights into IKK-mediated regulation of CSN associated with the NF-κB signaling pathway.
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Affiliation(s)
- Jingzi Zhang
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China
| | - Ruoyu Zhao
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, California 92697, Unites States
| | - Christine L N Bryant
- Department of Physiology and Biophysics, University of California, Irvine, California 92697, Unites States
| | - Kenneth Wu
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, New York 10029, United States
| | - Zhihong Liu
- School of Life Science, Nanjing University, Nanjing 210023, China
| | - Yibing Ding
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China
| | - Yue Zhao
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China
| | - Bin Xue
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China
| | - Zhen-Qiang Pan
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, New York 10029, United States
| | - Chaojun Li
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, California 92697, Unites States
| | - Lei Fang
- Medical School and Model Animal Research Center of Nanjing University, Nanjing 210093, China.,Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing 210093, China
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Raabe K, Honys D, Michailidis C. The role of eukaryotic initiation factor 3 in plant translation regulation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 145:75-83. [PMID: 31665669 DOI: 10.1016/j.plaphy.2019.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/07/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Regulation of translation represents a critical step in the regulation of gene expression. In plants, the translation regulation plays an important role at all stages of development and, during stress responses, functions as a fast and flexible tool which not only modulates the global translation rate but also controls the production of specific proteins. Regulation of translation is mostly focused on the initiation phase. There, one of essential initiation factors is the large multisubunit protein complex of eukaryotic translation initiation factor 3 (eIF3). In all eukaryotes, the general eIF3 function is to scaffold the formation of the translation initiation complex and to enhance the accuracy of scanning mechanism for start codon selection. Over the past decades, additional eIF3 functions were described as necessary for development in various eukaryotic organisms, including plants. The importance of the eIF3 complex lies not only at the global level of initiation event, but also in the precise translation regulation of specific transcripts. This review gathers the available information on functions of the plant eIF3 complex.
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Affiliation(s)
- Karel Raabe
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - David Honys
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Christos Michailidis
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic.
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3
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Janiak A, Kwasniewski M, Sowa M, Gajek K, Żmuda K, Kościelniak J, Szarejko I. No Time to Waste: Transcriptome Study Reveals that Drought Tolerance in Barley May Be Attributed to Stressed-Like Expression Patterns that Exist before the Occurrence of Stress. FRONTIERS IN PLANT SCIENCE 2018; 8:2212. [PMID: 29375595 PMCID: PMC5767312 DOI: 10.3389/fpls.2017.02212] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/18/2017] [Indexed: 05/24/2023]
Abstract
Plant survival in adverse environmental conditions requires a substantial change in the metabolism, which is reflected by the extensive transcriptome rebuilding upon the occurrence of the stress. Therefore, transcriptomic studies offer an insight into the mechanisms of plant stress responses. Here, we present the results of global gene expression profiling of roots and leaves of two barley genotypes with contrasting ability to cope with drought stress. Our analysis suggests that drought tolerance results from a certain level of transcription of stress-influenced genes that is present even before the onset of drought. Genes that predispose the plant to better drought survival play a role in the regulatory network of gene expression, including several transcription factors, translation regulators and structural components of ribosomes. An important group of genes is involved in signaling mechanisms, with significant contribution of hormone signaling pathways and an interplay between ABA, auxin, ethylene and brassinosteroid homeostasis. Signal transduction in a drought tolerant genotype may be more efficient through the expression of genes required for environmental sensing that are active already during normal water availability and are related to actin filaments and LIM domain proteins, which may function as osmotic biosensors. Better survival of drought may also be attributed to more effective processes of energy generation and more efficient chloroplasts biogenesis. Interestingly, our data suggest that several genes involved in a photosynthesis process are required for the establishment of effective drought response not only in leaves, but also in roots of barley. Thus, we propose a hypothesis that root plastids may turn into the anti-oxidative centers protecting root macromolecules from oxidative damage during drought stress. Specific genes and their potential role in building up a drought-tolerant barley phenotype is extensively discussed with special emphasis on processes that take place in barley roots. When possible, the interconnections between particular factors are emphasized to draw a broader picture of the molecular mechanisms of drought tolerance in barley.
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Affiliation(s)
- Agnieszka Janiak
- Department of Genetics, University of Silesia in Katowice, Katowice, Poland
| | - Miroslaw Kwasniewski
- Centre for Bioinformatics and Data Analysis, Medical University of Bialystok, Bialystok, Poland
| | - Marta Sowa
- Department of Plant Anatomy and Cytology, University of Silesia in Katowice, Katowice, Poland
| | - Katarzyna Gajek
- Department of Genetics, University of Silesia in Katowice, Katowice, Poland
| | - Katarzyna Żmuda
- Department of Plant Physiology, Faculty of Agriculture and Economics, University of Agriculture of Krakow, Kraków, Poland
| | - Janusz Kościelniak
- Department of Plant Physiology, Faculty of Agriculture and Economics, University of Agriculture of Krakow, Kraków, Poland
| | - Iwona Szarejko
- Department of Genetics, University of Silesia in Katowice, Katowice, Poland
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4
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Browning KS, Bailey-Serres J. Mechanism of cytoplasmic mRNA translation. THE ARABIDOPSIS BOOK 2015; 13:e0176. [PMID: 26019692 PMCID: PMC4441251 DOI: 10.1199/tab.0176] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Protein synthesis is a fundamental process in gene expression that depends upon the abundance and accessibility of the mRNA transcript as well as the activity of many protein and RNA-protein complexes. Here we focus on the intricate mechanics of mRNA translation in the cytoplasm of higher plants. This chapter includes an inventory of the plant translational apparatus and a detailed review of the translational processes of initiation, elongation, and termination. The majority of mechanistic studies of cytoplasmic translation have been carried out in yeast and mammalian systems. The factors and mechanisms of translation are for the most part conserved across eukaryotes; however, some distinctions are known to exist in plants. A comprehensive understanding of the complex translational apparatus and its regulation in plants is warranted, as the modulation of protein production is critical to development, environmental plasticity and biomass yield in diverse ecosystems and agricultural settings.
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Affiliation(s)
- Karen S. Browning
- Department of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas at Austin, Austin TX 78712-0165
- Both authors contributed equally to this work
| | - Julia Bailey-Serres
- Department of Botany and Plant Sciences and Center for Plant Cell Biology, University of California, Riverside, CA, 92521 USA
- Both authors contributed equally to this work
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5
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Salvato F, Balbuena TS, Nelson W, Rao RSP, He R, Soderlund CA, Gang DR, Thelen JJ. Comparative proteomic analysis of developing rhizomes of the ancient vascular plant Equisetum hyemale and different monocot species. J Proteome Res 2015; 14:1779-91. [PMID: 25716083 DOI: 10.1021/pr501157w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The rhizome is responsible for the invasiveness and competitiveness of many plants with great economic and agricultural impact worldwide. Besides its value as an invasive organ, the rhizome plays a role in the establishment and massive growth of forage, providing biomass for biofuel production. Despite these features, little is known about the molecular mechanisms that contribute to rhizome growth, development, and function in plants. In this work, we characterized the proteome of rhizome apical tips and elongation zones from different species using a GeLC-MS/MS (one-dimensional electrophoresis in combination with liquid chromatography coupled online with tandem mass spectrometry) spectral-counting proteomics strategy. Five rhizomatous grasses and an ancient species were compared to study the protein regulation in rhizomes. An average of 2200 rhizome proteins per species were confidently identified and quantified. Rhizome-characteristic proteins showed similar functional distributions across all species analyzed. The over-representation of proteins associated with central roles in cellular, metabolic, and developmental processes indicated accelerated metabolism in growing rhizomes. Moreover, 61 rhizome-characteristic proteins appeared to be regulated similarly among analyzed plants. In addition, 36 showed conserved regulation between rhizome apical tips and elongation zones across species. These proteins were preferentially expressed in rhizome tissues regardless of the species analyzed, making them interesting candidates for more detailed investigative studies about their roles in rhizome development.
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Affiliation(s)
- Fernanda Salvato
- †Department of Biochemistry, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Tiago S Balbuena
- †Department of Biochemistry, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, United States
| | - William Nelson
- ‡BIO5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
| | - R Shyama Prasad Rao
- †Department of Biochemistry, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Ruifeng He
- §Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - Carol A Soderlund
- ‡BIO5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
| | - David R Gang
- §Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - Jay J Thelen
- †Department of Biochemistry, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, United States
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Singh B, Chauhan H, Khurana JP, Khurana P, Singh P. Evidence for the role of wheat eukaryotic translation initiation factor 3 subunit g (TaeIF3g) in abiotic stress tolerance. Gene 2013; 532:177-85. [PMID: 24084365 DOI: 10.1016/j.gene.2013.09.078] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 09/02/2013] [Accepted: 09/23/2013] [Indexed: 01/02/2023]
Abstract
The gene encoding eIF3g (TaeIF3g), one of the 11 subunits of eukaryotic translation initiation factor 3 (eIF3), was cloned from wheat for carrying out its functional analysis. Transgenic expression of TaeIF3g enhanced the tolerance of TaeIF3g-overexpressing parental yeast cells and Arabidopsis plants under different abiotic stress conditions. Compared to untransformed plants, TaeIF3g-overexpressing Arabidopsis thaliana plants exhibited significantly higher survival rate, soluble proteins and photosynthetic efficiency, and enhanced protection against photooxidative stress under drought conditions. This study provides first evidence that TaeIF3g imparts stress tolerance and could be a potential candidate gene for developing crop plants tolerant to abiotic stress.
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Affiliation(s)
- Brinderjit Singh
- Department of Biotechnology, Guru Nanak Dev University, Amritsar, Punjab 143005, India; Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
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7
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Serino G, Pick E. Duplication and familial promiscuity within the proteasome lid and COP9 signalosome kin complexes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 203-204:89-97. [PMID: 23415332 DOI: 10.1016/j.plantsci.2012.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 12/28/2012] [Accepted: 12/29/2012] [Indexed: 05/13/2023]
Abstract
Two paralogous complexes, the proteasome lid and the COP9 signalosome (CSN), have diverged from a common ancestor; yet fulfill distinctive roles within the ubiquitin-proteasome sphere. The CSN regulates the largest family of E3 ubiquitin ligases, called CRLs (Cullin-RING ubiquitin Ligases), while the lid is a subcomplex of the 26S proteasome, a proteolytic machinery responsible for the degradation of ubiquitinated proteins. Remarkably, in many organisms, several subunits of both complexes are duplicated, a circumstance that can hypothetically increase the number of different complexes that can be formed. Duplication, however, is not the only complexity trait within the lid and the CSN, because many of their subunits are not fully committed only to one of the two complexes, but they are able to associate with both. Indeed, their corresponding mutants have features that can be due to the absence of more than one complex. This could be simply explained by the subunits being able to carry an identical function within more than one paralogous complex or by the subunits having a certain level of promiscuity, i.e. being able to carry more than one function, depending on the complex they are associating with. Recent data show that both options are possible and, although their functional relevance still needs to be fully uncovered, evidence is accumulating, which indicates a promiscuous trading of paralogous subunits, and suggests that this may occur transiently, and/or in response to particular environmental conditions.
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Affiliation(s)
- Giovanna Serino
- Istituto Pasteur- Fondazione Cenci-Bolognetti, Department of Biology and Biotechnology, Sapienza Università di Roma, piazzale Aldo Moro 5, 00185 Rome, Italy.
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8
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A forward genetic screen identifies eukaryotic translation initiation factor 3, subunit H (eIF3h), as an enhancer of variegation in the mouse. G3-GENES GENOMES GENETICS 2012; 2:1393-6. [PMID: 23173090 PMCID: PMC3484669 DOI: 10.1534/g3.112.004036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 09/10/2012] [Indexed: 12/25/2022]
Abstract
We have used a forward genetic screen to identify genes required for transgene silencing in the mouse. Previously these genes were found using candidate-based sequencing, a slow and labor-intensive process. Recently, whole-exome deep sequencing has accelerated our ability to find the causative point mutations, resulting in the discovery of novel and sometimes unexpected genes. Here we report the identification of translation initiation factor 3, subunit H (eIF3h) in two modifier of murine metastable epialleles (Mommes) lines. Mice carrying mutations in this gene have not been reported previously, and a possible involvement of eIF3h in transcription or epigenetic regulation has not been considered.
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9
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Horiguchi G, Van Lijsebettens M, Candela H, Micol JL, Tsukaya H. Ribosomes and translation in plant developmental control. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 191-192:24-34. [PMID: 22682562 DOI: 10.1016/j.plantsci.2012.04.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 04/16/2012] [Accepted: 04/16/2012] [Indexed: 05/06/2023]
Abstract
Ribosomes play a basic housekeeping role in global translation. However, a number of ribosomal-protein-defective mutants show common and rare developmental phenotypes including growth defects, changes in leaf development, and auxin-related phenotypes. This suggests that translational regulation may be occurring during development. In addition, proteomic and bioinformatic analyses have demonstrated a high heterogeneity in ribosome composition. Although this might be a sign of unequal roles of individual ribosomal proteins, it does not explain every ribosomal-protein-defective phenotype. Moreover, comprehensive interpretations concerning the relationship between ribosomal-protein-defective phenotypes and molecular changes in ribosome status are lacking. In this review, we address these phenotypes based on three models, ribosome insufficiency, heterogeneity, and aberrancy, to consider how ribosomes play developmental roles. We propose that the three models are not mutually exclusive, and ribosomal-protein-defective phenotypes can be explained with one or more of these models. The three models with reference to genetic, biochemical, and bioinformatic knowledge will serve as a foundation for future studies of translational regulation.
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Affiliation(s)
- Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan.
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10
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Fang L, Kaake RM, Patel VR, Yang Y, Baldi P, Huang L. Mapping the protein interaction network of the human COP9 signalosome complex using a label-free QTAX strategy. Mol Cell Proteomics 2012; 11:138-47. [PMID: 22474085 DOI: 10.1074/mcp.m111.016352] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The COP9 signalosome (CSN) is a multi-subunit protein complex that performs critical roles in controlling diverse cellular and developmental processes. Aberrant regulation of the CSN complex has been shown to lead to tumorigenesis. Despite its biological significance, our current knowledge of the function and regulation of the CSN complex is very limited. To explore CSN biology, we have developed and employed a new version of the tag team-based QTAX strategy (quantitative analysis of tandem affinity purified in vivo cross-linked (X) protein complexes) by incorporating a label-free MS method for quantitation. Coupled with protein interaction network analysis, this strategy produced a comprehensive and detailed assessment of the protein interaction network of the human CSN complex. In total, we quantitatively characterized 825 putative CSN-interacting proteins, with 270 classified as core interactors (captured by all three bait purifications). Biochemical validation further confirms the validity of selected identified interactors. This work presents the most complete analysis of the CSN interaction network to date, providing an inclusive set of physical interaction data consistent with physiological roles for the CSN. Moreover, the methodology described here is a general proteomic tool for the comprehensive study of protein interaction networks.
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Affiliation(s)
- Lei Fang
- Departments of Physiology & Biophysics and Developmental & Cell Biology, University of California, Irvine, California 92697, USA
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11
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Halimi Y, Dessau M, Pollak S, Ast T, Erez T, Livnat-Levanon N, Karniol B, Hirsch JA, Chamovitz DA. COP9 signalosome subunit 7 from Arabidopsis interacts with and regulates the small subunit of ribonucleotide reductase (RNR2). PLANT MOLECULAR BIOLOGY 2011; 77:77-89. [PMID: 21614643 DOI: 10.1007/s11103-011-9795-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 05/13/2011] [Indexed: 05/30/2023]
Abstract
The COP9 Signalosome protein complex (CSN) is a pleiotropic regulator of plant development and contains eight-subunits. Six of these subunits contain the PCI motif which mediates specific protein interactions necessary for the integrity of the complex. COP9 complex subunit 7 (CSN7) contains an N-terminal PCI motif followed by a C-terminal extension which is also necessary for CSN function. A yeast-interaction trap assay identified the small subunit of ribonucelotide reductase (RNR2) from Arabidopsis as interacting with the C-terminal section of CSN7. This interaction was confirmed in planta by both bimolecular fluorescence complementation and immuoprecipitation assays with endogenous proteins. The subcellular localization of RNR2 was primarily nuclear in meristematic regions, and cytoplasmic in adult cells. RNR2 was constitutively nuclear in csn7 mutant seedlings, and was also primarily nuclear in wild type seedlings following exposure to UV-C. These two results correlate with constitutive expression of several DNA-damage response genes in csn7 mutants, and to increased tolerance of csn7 seedlings to UV-C treatment. We propose that the CSN is a negative regulator of RNR activity in Arabidopsis.
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Affiliation(s)
- Yair Halimi
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, 69978 Ramat Aviv, Israel
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12
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Book AJ, Gladman NP, Lee SS, Scalf M, Smith LM, Vierstra RD. Affinity purification of the Arabidopsis 26 S proteasome reveals a diverse array of plant proteolytic complexes. J Biol Chem 2010; 285:25554-69. [PMID: 20516081 DOI: 10.1074/jbc.m110.136622] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Selective proteolysis in plants is largely mediated by the ubiquitin (Ub)/proteasome system in which substrates, marked by the covalent attachment of Ub, are degraded by the 26 S proteasome. The 26 S proteasome is composed of two subparticles, the 20 S core protease (CP) that compartmentalizes the protease active sites and the 19 S regulatory particle that recognizes and translocates appropriate substrates into the CP lumen for breakdown. Here, we describe an affinity method to rapidly purify epitope-tagged 26 S proteasomes intact from Arabidopsis thaliana. In-depth mass spectrometric analyses of preparations generated from young seedlings confirmed that the 2.5-MDa CP-regulatory particle complex is actually a heterogeneous set of particles assembled with paralogous pairs for most subunits. A number of these subunits are modified post-translationally by proteolytic processing, acetylation, and/or ubiquitylation. Several proteasome-associated proteins were also identified that likely assist in complex assembly and regulation. In addition, we detected a particle consisting of the CP capped by the single subunit PA200 activator that may be involved in Ub-independent protein breakdown. Taken together, it appears that a diverse and highly dynamic population of proteasomes is assembled in plants, which may expand the target specificity and functions of intracellular proteolysis.
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Affiliation(s)
- Adam J Book
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
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13
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Baena-González E. Energy signaling in the regulation of gene expression during stress. MOLECULAR PLANT 2010; 3:300-13. [PMID: 20080814 DOI: 10.1093/mp/ssp113] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Maintenance of homeostasis is pivotal to all forms of life. In the case of plants, homeostasis is constantly threatened by the inability to escape environmental fluctuations, and therefore sensitive mechanisms must have evolved to allow rapid perception of environmental cues and concomitant modification of growth and developmental patterns for adaptation and survival. Re-establishment of homeostasis in response to environmental perturbations requires reprogramming of metabolism and gene expression to shunt energy sources from growth-related biosynthetic processes to defense, acclimation, and, ultimately, adaptation. Failure to mount an initial 'emergency' response may result in nutrient deprivation and irreversible senescence and cell death. Early signaling events largely determine the capacity of plants to orchestrate a successful adaptive response. Early events, on the other hand, are likely to be shared by different conditions through the generation of similar signals and before more specific responses are elaborated. Recent studies lend credence to this hypothesis, underpinning the importance of a shared energy signal in the transcriptional response to various types of stress. Energy deficiency is associated with most environmental perturbations due to their direct or indirect deleterious impact on photosynthesis and/or respiration. Several systems are known to have evolved for monitoring the available resources and triggering metabolic, growth, and developmental decisions accordingly. In doing so, energy-sensing systems regulate gene expression at multiple levels to allow flexibility in the diversity and the kinetics of the stress response.
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Affiliation(s)
- Elena Baena-González
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal.
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14
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Sha Z, Brill LM, Cabrera R, Kleifeld O, Scheliga JS, Glickman MH, Chang EC, Wolf DA. The eIF3 interactome reveals the translasome, a supercomplex linking protein synthesis and degradation machineries. Mol Cell 2009; 36:141-52. [PMID: 19818717 PMCID: PMC2789680 DOI: 10.1016/j.molcel.2009.09.026] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 06/23/2009] [Accepted: 09/11/2009] [Indexed: 01/18/2023]
Abstract
eIF3 promotes translation initiation, but relatively little is known about its full range of activities in the cell. Here, we employed affinity purification and highly sensitive LC-MS/MS to decipher the fission yeast eIF3 interactome, which was found to contain 230 proteins. eIF3 assembles into a large supercomplex, the translasome, which contains elongation factors, tRNA synthetases, 40S and 60S ribosomal proteins, chaperones, and the proteasome. eIF3 also associates with ribosome biogenesis factors and the importins-beta Kap123p and Sal3p. Our genetic data indicated that the binding to both importins-beta is essential for cell growth, and photobleaching experiments revealed a critical role for Sal3p in the nuclear import of one of the translasome constituents, the proteasome. Our data reveal the breadth of the eIF3 interactome and suggest that factors involved in translation initiation, ribosome biogenesis, translation elongation, quality control, and transport are physically linked to facilitate efficient protein synthesis.
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Affiliation(s)
- Zhe Sha
- 1 Baylor Plaza, Molecular and Cellular Biology Department, Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030
| | - Laurence M. Brill
- Burnham Institute for Medical Research, Signal Transduction Program, NCI Cancer Center Proteomics Facility, 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Rodrigo Cabrera
- 1 Baylor Plaza, Molecular and Cellular Biology Department, Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030
| | - Oded Kleifeld
- Department of Biology, Technion - Israel Institute of Technology, 32000 Haifa Israel
| | - Judith S. Scheliga
- Burnham Institute for Medical Research, Signal Transduction Program, NCI Cancer Center Proteomics Facility, 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Michael H. Glickman
- Department of Biology, Technion - Israel Institute of Technology, 32000 Haifa Israel
| | - Eric C. Chang
- 1 Baylor Plaza, Molecular and Cellular Biology Department, Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030
| | - Dieter A. Wolf
- Burnham Institute for Medical Research, Signal Transduction Program, NCI Cancer Center Proteomics Facility, 10901 North Torrey Pines Road, La Jolla, CA 92037
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