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Dobrenel T, Mancera-Martínez E, Forzani C, Azzopardi M, Davanture M, Moreau M, Schepetilnikov M, Chicher J, Langella O, Zivy M, Robaglia C, Ryabova LA, Hanson J, Meyer C. The Arabidopsis TOR Kinase Specifically Regulates the Expression of Nuclear Genes Coding for Plastidic Ribosomal Proteins and the Phosphorylation of the Cytosolic Ribosomal Protein S6. FRONTIERS IN PLANT SCIENCE 2016; 7:1611. [PMID: 27877176 PMCID: PMC5100631 DOI: 10.3389/fpls.2016.01611] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/12/2016] [Indexed: 05/05/2023]
Abstract
Protein translation is an energy consuming process that has to be fine-tuned at both the cell and organism levels to match the availability of resources. The target of rapamycin kinase (TOR) is a key regulator of a large range of biological processes in response to environmental cues. In this study, we have investigated the effects of TOR inactivation on the expression and regulation of Arabidopsis ribosomal proteins at different levels of analysis, namely from transcriptomic to phosphoproteomic. TOR inactivation resulted in a coordinated down-regulation of the transcription and translation of nuclear-encoded mRNAs coding for plastidic ribosomal proteins, which could explain the chlorotic phenotype of the TOR silenced plants. We have identified in the 5' untranslated regions (UTRs) of this set of genes a conserved sequence related to the 5' terminal oligopyrimidine motif, which is known to confer translational regulation by the TOR kinase in other eukaryotes. Furthermore, the phosphoproteomic analysis of the ribosomal fraction following TOR inactivation revealed a lower phosphorylation of the conserved Ser240 residue in the C-terminal region of the 40S ribosomal protein S6 (RPS6). These results were confirmed by Western blot analysis using an antibody that specifically recognizes phosphorylated Ser240 in RPS6. Finally, this antibody was used to follow TOR activity in plants. Our results thus uncover a multi-level regulation of plant ribosomal genes and proteins by the TOR kinase.
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Affiliation(s)
- Thomas Dobrenel
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, AgroParisTech, Centre National de la Recherche Scientifique, Université Paris-SaclayVersailles, France
- Université Paris-Sud–Université Paris-SaclayOrsay, France
- Umeå Plant Science Center, Department of Plant Physiology, Umeå UniversityUmeå, Sweden
| | - Eder Mancera-Martínez
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, Université de StrasbourgStrasbourg, France
| | - Céline Forzani
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, AgroParisTech, Centre National de la Recherche Scientifique, Université Paris-SaclayVersailles, France
| | - Marianne Azzopardi
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, AgroParisTech, Centre National de la Recherche Scientifique, Université Paris-SaclayVersailles, France
| | | | - Manon Moreau
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, AgroParisTech, Centre National de la Recherche Scientifique, Université Paris-SaclayVersailles, France
- Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, DSV, IBEB, SBVME, CEA, CNRS, Aix-Marseille Université, Faculté des Sciences de LuminyMarseille, France
| | - Mikhail Schepetilnikov
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, Université de StrasbourgStrasbourg, France
| | - Johana Chicher
- Plateforme Protéomique Strasbourg-Esplanade, CNRS FRC1589, Institut de Biologie Moléculaire et CellulaireStrasbourg, France
| | | | - Michel Zivy
- Plateforme PAPPSO, UMR GQE-Le MoulonGif sur Yvette, France
| | - Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, UMR 7265, DSV, IBEB, SBVME, CEA, CNRS, Aix-Marseille Université, Faculté des Sciences de LuminyMarseille, France
| | - Lyubov A. Ryabova
- Institut de Biologie Moléculaire des Plantes, UPR 2357 CNRS, Université de StrasbourgStrasbourg, France
| | - Johannes Hanson
- Umeå Plant Science Center, Department of Plant Physiology, Umeå UniversityUmeå, Sweden
| | - Christian Meyer
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, AgroParisTech, Centre National de la Recherche Scientifique, Université Paris-SaclayVersailles, France
- *Correspondence: Christian Meyer,
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Chowdhury T, Köhler JR. Ribosomal protein S6 phosphorylation is controlled by TOR and modulated by PKA in Candida albicans. Mol Microbiol 2015; 98:384-402. [PMID: 26173379 DOI: 10.1111/mmi.13130] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2015] [Indexed: 12/25/2022]
Abstract
TOR and PKA signaling pathways control eukaryotic cell growth and proliferation. TOR activity in model fungi, such as Saccharomyces cerevisiae, responds principally to nutrients, e.g., nitrogen and phosphate sources, which are incorporated into the growing cell mass; PKA signaling responds to the availability of the cells' major energy source, glucose. In the fungal commensal and pathogen, Candida albicans, little is known of how these pathways interact. Here, the signal from phosphorylated ribosomal protein S6 (P-S6) was defined as a surrogate marker for TOR-dependent anabolic activity in C. albicans. Nutritional, pharmacologic and genetic modulation of TOR activity elicited corresponding changes in P-S6 levels. The P-S6 signal corresponded to translational activity of a GFP reporter protein. Contributions of four PKA pathway components to anabolic activation were then examined. In high glucose concentrations, only Tpk2 was required to upregulate P-S6 to physiologic levels, whereas all four tested components were required to downregulate P-S6 in low glucose. TOR was epistatic to PKA components with respect to P-S6. In many host niches inhabited by C. albicans, glucose is scarce, with protein being available as a nitrogen source. We speculate that PKA may modulate TOR-dependent cell growth to a rate sustainable by available energy sources, when monomers of anabolic processes, such as amino acids, are abundant.
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Affiliation(s)
- Tahmeena Chowdhury
- Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA, 02115, USA
| | - Julia R Köhler
- Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA, 02115, USA
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3
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Fu S, Fan J, Blanco J, Gimenez-Cassina A, Danial NN, Watkins SM, Hotamisligil GS. Polysome profiling in liver identifies dynamic regulation of endoplasmic reticulum translatome by obesity and fasting. PLoS Genet 2012; 8:e1002902. [PMID: 22927828 PMCID: PMC3426552 DOI: 10.1371/journal.pgen.1002902] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 07/02/2012] [Indexed: 01/12/2023] Open
Abstract
Obesity-associated metabolic complications are generally considered to emerge from abnormalities in carbohydrate and lipid metabolism, whereas the status of protein metabolism is not well studied. Here, we performed comparative polysome and associated transcriptional profiling analyses to study the dynamics and functional implications of endoplasmic reticulum (ER)–associated protein synthesis in the mouse liver under conditions of obesity and nutrient deprivation. We discovered that ER from livers of obese mice exhibits a general reduction in protein synthesis, and comprehensive analysis of polysome-bound transcripts revealed extensive down-regulation of protein synthesis machinery, mitochondrial components, and bile acid metabolism in the obese translatome. Nutrient availability also plays an important but distinct role in remodeling the hepatic ER translatome in lean and obese mice. Fasting in obese mice partially reversed the overall translatomic differences between lean and obese nonfasted controls, whereas fasting of the lean mice mimicked many of the translatomic changes induced by the development of obesity. The strongest examples of such regulations were the reduction in Cyp7b1 and Slco1a1, molecules involved in bile acid metabolism. Exogenous expression of either gene significantly lowered plasma glucose levels, improved hepatic steatosis, but also caused cholestasis, indicating the fine balance bile acids play in regulating metabolism and health. Together, our work defines dynamic regulation of the liver translatome by obesity and nutrient availability, and it identifies a novel role for bile acid metabolism in the pathogenesis of metabolic abnormalities associated with obesity. Chronic diseases including obesity and associated metabolic abnormalities have become the greatest threat to human health worldwide. How metabolic organs and organelles adapt to nutritional fluctuations, or fail to do so, remains incompletely understood. To explore these issues, we developed a new platform to explore translational responses in the liver, a critical organ for metabolic homeostasis. In this translatomic platform, we integrated polysome profiling and global analysis of polysome-associated mRNAs to systematically quantify protein synthesis on each transcript in obesity and during fasting. Our analysis demonstrated for the first time that protein synthesis is progressively suppressed in the obese liver and that the overall translatome profile of obese liver markedly resembles that of fasting lean mice, particularly in mitochondrial function and bile metabolism. We also examined the physiological impact of some of these alterations and concluded that aberrant bile acid metabolism in the obese liver represents a novel mechanism contributing to hyperglycemia and continuous weight gain. Together, our work reveals abnormal translational regulation as a novel aspect of obesity that could impact future directions in metabolic disease treatment, and we believe translatome profiling represents a new approach to unravel complex mechanisms regulating cellular function and disease pathology.
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Affiliation(s)
- Suneng Fu
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
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JANTZEN HELGA, SCHULZE INGRID, HORSTMANN ULRIKE, CHRISTOFORI GERHARD. Control of Protein Synthesis in Acanthamoeba castellanii. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1983.tb02904.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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Avruch J. MAP kinase pathways: the first twenty years. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:1150-60. [PMID: 17229475 PMCID: PMC2043147 DOI: 10.1016/j.bbamcr.2006.11.006] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Revised: 11/02/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
The MAP kinases, discovered approximately 20 years ago, together with their immediate upstream regulators, are among the most highly studied signal transduction molecules. This body of work has shaped many aspects of our present views of signal transduction by protein kinases. The effort expended in this area reflects the extensive participation of these regulatory modules in the control of cell fate decisions, i.e., proliferation, differentiation and death, across all eukaryotic phylla and in all tissues of metazoans. The discovery of these kinases is reviewed, followed by a discussion of some of the features of this signaling module that account for its broad impact on cell function and its enormous interest to many investigators.
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Affiliation(s)
- Joseph Avruch
- Department of Molecular Biology and the Diabetes Unit, Medical Services, Massachusetts General Hospital, and Department of Medicine, Harvard Medical School, 185 Cambridge St., Boston, MA 02114-2790, USA.
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Lawrence JC, Fadden P, Haystead TA, Lin TA. PHAS proteins as mediators of the actions of insulin, growth factors and cAMP on protein synthesis and cell proliferation. ADVANCES IN ENZYME REGULATION 2001; 37:239-67. [PMID: 9381973 DOI: 10.1016/s0065-2571(96)00016-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PHAS-I and PHAS-II are members of a newly discovered family of proteins that regulate translation initiation. PHAS-I is expressed in a wide variety of cell types, but it is highest in adipocytes, where protein synthesis is markedly increased by insulin. PHAS-II is highest in liver and kidney, where very little PHAS-I is found. PHAS proteins bind to eIF-4E, the mRNA cap-binding protein, and inhibit translation of capped mRNA in vitro and in cells. In rat adipocytes PHAS-I is phosphorylated in at least five sites, all of which conform to the consensus, (Ser/Thr)-Pro. Both PHAS proteins are phosphorylated in response to insulin or growth factors, such as EGF, PDGF and IGF-1. Phosphorylation in the appropriate site(s) promotes dissociation of PHAS/eIF-4E complexes. This allows eIF-4E to bind to eIF-4G (p220), thereby increasing the amount of the eIF-4F complex and the rate of translation initiation. Increasing cAMP promotes PHAS-I dephosphorylation and increases binding to eIF-4E. Unlike PHAS-I, PHAS-II is readily phosphorylated by PKA in vitro, suggesting that regulation of the two proteins differs. However, increasing cAMP in cells also promotes dephosphorylation of PHAS-II. Thus, PHAS proteins appear to be key mediators not only of the stimulatory effects of insulin and growth factors on protein synthesis, but also of the inhibitory effects of cAMP. Moreover, by controlling eIF-4E PHAS proteins may be involved in the control of cell proliferation, as increasing eIF-4E is mitogenic and can even cause malignant transformation of cells. MAP kinase readily phosphorylates both PHAS-I and PHAS-II in vitro, but inhibiting activation of MAP kinase does not attenuate the effects of insulin on increasing phosphorylation of the PHAS proteins in adipocytes or skeletal muscle. MAP kinase phosphorylates neither PHAS-I nor PHAS-II at a significant rate when the proteins are bound to eIF-4E. Therefore, the role of MAP kinase in promoting the dissociation of PHAS/eIF-4E complexes is not clear. Of several protein kinases tested, only casein kinase-II phosphorylated PHAS-I when it was bound eIF-4E. Indeed, the bound form of PHAS-I was phosphorylated more rapidly than the free form. However, it is unlikely that casein kinase II regulates either PHAS protein, as the major site (Ser111) in PHAS-I phosphorylated by casein kinase II in vitro is not phosphorylated in adipocytes, and PHAS-II is not a substrate for casein kinase-II. Pharmacological and genetic evidence indicates that the mTOR/p70S6K pathway is involved in the control of PHAS-I and -II. Thus, PHAS proteins may be mediators of the effects of this pathway on protein synthesis and cell proliferation.
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Affiliation(s)
- J C Lawrence
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville 22908, USA
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Abstract
Using biochemical techniques similar to those used by Krebs and Fischer in elucidating the cAMP kinase cascade, a protein kinase cascade has been found that represents a new pathway for signal transduction. This pathway is activated in almost all cells that have been examined by many different growth and differentiation factors, suggesting control of different cell responses. At this writing, four tiers of growth factor regulated kinases, each tier represented by more than one enzyme, have been reconstituted in vitro to form the MAP kinase cascade. Preliminary findings suggesting multiple feedback or feedforward regulation of several components in the cascade predict higher complexity than a simple linear pathway.
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Affiliation(s)
- N G Ahn
- Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309
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8
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Naranda T, Ballesta JP. Phosphorylation controls binding of acidic proteins to the ribosome. Proc Natl Acad Sci U S A 1991; 88:10563-7. [PMID: 1961721 PMCID: PMC52969 DOI: 10.1073/pnas.88.23.10563] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The replacement of each one of the eight serine residues present in the amino acid sequence of the Saccharomyces cerevisiae acidic ribosomal phosphoprotein YP2 beta (L45) by different amino acids has been performed by heteroduplex site-directed mutagenesis in the cloned gene. The mutated DNA was used to transform a yeast strain previously deprived of the original protein YP2 beta (L45) by gene disruption. The replacement of serine in position 19 by either alanine, aspartic acid, or threonine prevents in vivo phosphorylation of the protein and its interaction with the ribosome. The serine-19 mutated gene is unable to rescue the negative effect on the growth rate caused by elimination of the original protein in YP2 beta (L45) gene disrupted strains. The mutation of any one of the other seven serine residues has no effect on either the phosphorylation or the ribosome binding capacity of the protein, although replacement of serine-72 seems to increase the sensitivity of the polypeptide to degradation. These results provide strong evidence indicating that ribosomal protein phosphorylation plays an important part in the activity of the particle and that it supports the existence of a control mechanism of protein synthesis, which would regulate the level of phosphorylation of acidic proteins.
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Affiliation(s)
- T Naranda
- Centro de Biologia Molecular, Consejo Superior de Investigaciones Científicas, Canto Blanco, Madrid, Spain
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Stephenson GM. A comparative study of the microsomal S6 phosphatase and phosphorylase phosphatase activities in rat liver. Arch Biochem Biophys 1991; 289:324-8. [PMID: 1654855 DOI: 10.1016/0003-9861(91)90418-i] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rat liver microsomes contain type-1 S6 phosphatase (acting on the serine residues phosphorylated by protein kinase A) and type-1 phosphorylase phosphatase activities. The main aim of this study has been to characterize the microsomal S6 phosphatase activity and to compare its properties with those of the phosphorylase phosphatase activity in the same microsomal preparation. The specific activities of both microsomal S6 phosphatase and phosphorylase phosphatase were 1.6- to 1.7-fold higher in the smooth endoplasmic reticulum than in the rough sarcoplasmic reticulum. Both phosphatase activities were inhibited to a similar extent by MgCl2 (10 mM) and NaF (22 mM), were completely suppressed by glycerophosphate (80 mM) and ZnCl2(10 mM), and were stimulated by MnCl2(1 mM). When analyzed by gel filtration on Sephadex G-100 superfine, both phosphatase activities eluted as broad peaks, stretching from the void volume to 45-60 kDa. The microsomal S6 phosphatase and phosphorylase phosphatase activities also displayed the following distinct characteristics: (a) Mn2+ stimulated the S6 phosphatase activity 2.9-fold more than the phosphorylase phosphatase activity, (b) limited trypsin digestion of microsomal preparations increased the phosphorylase phosphatase activity by 1.5- to 2-fold, but decreased the S6 phosphatase activity by 50%, (c) a synthetic peptide analog of S6 (S6229-239) (200 microM), which did not act as a substrate for the microsomal S6 phosphatase and did not affect its activity, inhibited the microsomal phosphorylase phosphatase activity by about 50%, and (d) the elution profile of the phosphorylase phosphatase activity was markedly broader than that of the S6 phosphatase activity. A series of in vivo studies showed that streptozotocin-diabetes and insulin replacement therapy as well as ip injection of insulin or vanadate, which modified the microsomal S6 phosphatase activity, had no statistically significant effects on the microsomal phosphorylase phosphatase activity. Taken together, these results suggest that the microsomal S6 phosphatase and phosphorylase phosphatase activities are due to two distinct enzyme populations.
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Affiliation(s)
- G M Stephenson
- Russell Grimwade School of Biochemistry, University of Melbourne, Parkville, Victoria, Australia
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Traugh JA, Pendergast AM. Regulation of protein synthesis by phosphorylation of ribosomal protein S6 and aminoacyl-tRNA synthetases. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1986; 33:195-230. [PMID: 3541042 DOI: 10.1016/s0079-6603(08)60024-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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11
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Protein synthesis in lysates of Aedes albopictus cells infected with vesicular stomatitis virus. Mol Cell Biol 1983. [PMID: 6294498 DOI: 10.1128/mcb.2.10.1174] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aedes albopictus cells (clone LT-C7) showed a marked cytopathic effect and inhibition of protein synthesis (both host and viral) after infection with vesicular stomatitis virus (VSV), but only if (i) cultures were incubated at 34 degrees C rather than 28 degrees C and (ii) serum was present in the medium (S. Gillies and V. Stollar, Mol. Cell. Biol. 2:66-75, 1982). To learn more about how protein synthesis is shut off in VSV-infected A. albopictus cells, we have compared cell-free protein synthesis in extracts prepared from VSV-infected cells and control cells. Extracts prepared 6 h after infection from VSV-infected cells maintained at 34 degrees C in the presence of serum reflected what was observed with intact cells in at least two respects: (i) they showed a markedly diminished capacity to carry out protein synthesis (whether directed by endogenous or exogenously added mRNA), and (ii) there was decreased phosphorylation in vitro by [gamma-32P]ATP of a specific ribosomal protein (Gillies and Stollar, Mol. Cell. Biol. 2:66-75, 1982). In addition, and consistent with a block at the level of initiation, the formation of 80S initiation complexes, as measured by binding of VSV 12 to 18S mRNA, was reduced in the inactive extracts. Addition of an S-100 fraction from uninfected cells to the inactive extract reversed each of the aforementioned changes; i.e., it restored protein synthetic activity, it stimulated the formation of 80S initiation complexes, and it increased phosphorylation of the specific ribosomal protein referred to above. The active component in the S-100 fraction was heat labile and non-dialyzable and, upon ammonium sulfate fractionation of the S-100 fraction, was found in the 40 to 70% saturation fraction. Our findings suggest that VSV infection of A. albopictus cells inhibits protein synthesis by inactivating a macromolecular component, probably a protein, in the S-100 fraction which may be involved in the initiation of protein synthesis. More specifically, we suggest that this component is involved in the joining of the ribosomal subunits to form 80S initiation complexes.
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12
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Ward GE, Vacquier VD, Michel S. The increased phosphorylation of ribosomal protein S6 in Arbacia punctulata is not a universal event in the activation of sea urchin eggs. Dev Biol 1983; 95:360-71. [PMID: 6825939 DOI: 10.1016/0012-1606(83)90037-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Eggs of the sea urchins Arbacia punctulata (Ap), Lytechinus pictus (Lp), and Strongylocentrotus purpuratus (Sp) were labeled to equilibrium with 32PO3-4. Approximately 65-70% of the label in extractable adenine nucleotides comigrates chromatographically with ATP. Autoradiograms of one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) slab gels show that each species possesses a distinct complement of phosphate-exchangeable phosphoproteins. No changes in the phosphoprotein composition are detected in Lp and Sp eggs as a result of fertilization or development for 2.5 hr (with the possible exception of a 43,000 Mr protein in Lp). In Ap, increases in the phosphorylation of bands at Mr's 30,000, 55,000, and 105,000 are seen during the first 10 min postinsemination. The 30,000 Mr band in Ap eggs has previously been identified as ribosomal protein S6 and the hypothesis presented that its increased phosphorylation may be an important step in the activation of protein synthesis at fertilization (D. G. Ballinger and T. Hunt, 1981, Dev. Biol. 87, 277-285). In Lp and Sp eggs S6 (identified by two-dimensional PAGE) is heavily phosphorylated in the unfertilized state and the extent of labeling does not increase after fertilization. If the increased phosphorylation of S6 seen in Ap is indeed related to translational activation, then these results suggest that different sea urchin species may rely on different mechanisms for the activation of protein synthesis.
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Kruppa J, Darmer D, Kalthoff H, Richter D. The phosphorylation of ribosomal protein S6 from progesterone-stimulated Xenopus laevis oocytes. Kinetic studies and phosphopeptide analysis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1983; 129:537-42. [PMID: 6825671 DOI: 10.1111/j.1432-1033.1983.tb07082.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Xenopus laevis oocytes were prelabeled with [32P]orthophosphate overnight before maturation was induced by progesterone stimulation. The phosphorylation status of ribosomal protein S6 from control oocytes and the temporal changes in S6 phosphorylation after progesterone treatment were analyzed by two-dimensional gel electrophoresis. S6 protein was separated in up to five distinct S6 species, which differed in their degree of phosphorylation. 32P labeling of S6, as judged from the shift of radioactivity into more highly phosphorylated S6 derivatives, continuously increased in progesterone-stimulated oocytes even at later times when germinal vesicle breakdown was completed. S6 protein of unstimulated oocytes was labeled to a lower degree. Trypsin cleavage of total S6 protein, isolated from control and maturing oocytes, gave rise to different complex phosphopeptide patterns reflecting the existence of various multiply phosphorylated S6 derivatives in both samples. Two of the more highly phosphorylated S6 derivatives showed considerable differences between the phosphopeptide elution profiles of control and stimulated oocytes indicating that dissimilar sites had been modified under both physiological conditions. Only phosphoserine was detected in the phosphoamino acid analysis of individual S6 derivatives.
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14
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Wettenhall RE, Cohen P, Caudwell B, Holland R. Differential phosphorylation of ribosomal protein S6 in isolated rat hepatocytes after incubation with insulin and glucagon. FEBS Lett 1982; 148:207-13. [PMID: 6759164 DOI: 10.1016/0014-5793(82)80809-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Glucagon and insulin both stimulated the 32P-labelling of ribosomal protein S6 in rat hepatocytes that had been incubated with 32Pi. Glucagon selectively enhanced the labelling of the tryptic peptide phosphorylated by cyclic AMP-dependent protein kinase, demonstrating that 6 S is a physiological substrate for this enzyme. Insulin stimulated the phosphorylation of distinct tryptic peptides, at least one of which appears to be very close in the primary structure to the sites phosphorylated by cyclic AMP-dependent protein kinase.
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15
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Gillies S, Stollar V. Protein synthesis in lysates of Aedes albopictus cells infected with vesicular stomatitis virus. Mol Cell Biol 1982; 2:1174-86. [PMID: 6294498 PMCID: PMC369916 DOI: 10.1128/mcb.2.10.1174-1186.1982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Aedes albopictus cells (clone LT-C7) showed a marked cytopathic effect and inhibition of protein synthesis (both host and viral) after infection with vesicular stomatitis virus (VSV), but only if (i) cultures were incubated at 34 degrees C rather than 28 degrees C and (ii) serum was present in the medium (S. Gillies and V. Stollar, Mol. Cell. Biol. 2:66-75, 1982). To learn more about how protein synthesis is shut off in VSV-infected A. albopictus cells, we have compared cell-free protein synthesis in extracts prepared from VSV-infected cells and control cells. Extracts prepared 6 h after infection from VSV-infected cells maintained at 34 degrees C in the presence of serum reflected what was observed with intact cells in at least two respects: (i) they showed a markedly diminished capacity to carry out protein synthesis (whether directed by endogenous or exogenously added mRNA), and (ii) there was decreased phosphorylation in vitro by [gamma-32P]ATP of a specific ribosomal protein (Gillies and Stollar, Mol. Cell. Biol. 2:66-75, 1982). In addition, and consistent with a block at the level of initiation, the formation of 80S initiation complexes, as measured by binding of VSV 12 to 18S mRNA, was reduced in the inactive extracts. Addition of an S-100 fraction from uninfected cells to the inactive extract reversed each of the aforementioned changes; i.e., it restored protein synthetic activity, it stimulated the formation of 80S initiation complexes, and it increased phosphorylation of the specific ribosomal protein referred to above. The active component in the S-100 fraction was heat labile and non-dialyzable and, upon ammonium sulfate fractionation of the S-100 fraction, was found in the 40 to 70% saturation fraction. Our findings suggest that VSV infection of A. albopictus cells inhibits protein synthesis by inactivating a macromolecular component, probably a protein, in the S-100 fraction which may be involved in the initiation of protein synthesis. More specifically, we suggest that this component is involved in the joining of the ribosomal subunits to form 80S initiation complexes.
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16
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The phosphorylation of ribosomal protein S6 in rat tissues following cycloheximide injection, in diabetes, and after denervation of diaphragm. A simple immunological determination of the extent of S6 phosphorylation on protein blots. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33716-5] [Citation(s) in RCA: 144] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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17
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Courtois G, Paradis G, Barden A, Lemieux G. Phosphorylation of ribosomal proteins S3, L1 and L24 during spherulation in Physarum polycephalum. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 696:87-93. [PMID: 6282330 DOI: 10.1016/0167-4781(82)90013-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The phosphate content of ribosomal proteins S3, L1 and L24 has been determined in the course of spherulation of Physarum polycephalum. The major phosphoprotein, S3, was completely dephosphorylated after 4 h of differentiation. The phosphate content of L1 and L24 was not altered during the differentiation. The cellular level of ATP remained constant for at least 5 h. A 3-fold reduction of cyclic AMP concentration occurred in the first hour, followed by a slow increase to a final value of twice the level observed in growing cells. The results showed that the phosphorylation of ribosomal proteins is regulated by at least two different mechanisms and that the dephosphorylation of S3 is not induced by a lack of cellular ATP. Although cyclic AMP might trigger the dephosphorylation of S3, the phosphate content of this protein remained at a very low value even when the cellular concentration of cyclic AMP rose significantly. Since the polysome level remains constant during the first 24 h of spherulation, the phosphorylation of S3 is not necessary for active protein synthesis and the phosphorylation of L1 and L24 is not involved in ribosome inactivation, which occurs after 24 h.
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18
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Gordon J, Nielsen PJ, Manchester KL, Towbin H, Jimenez de Asua L, Thomas G. Criteria for establishment of the biological significance of ribosomal protein phosphorylation. CURRENT TOPICS IN CELLULAR REGULATION 1982; 21:89-99. [PMID: 6291857 DOI: 10.1016/b978-0-12-152821-8.50008-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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19
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Roberts S. Ribosomal protein phosphorylation and protein synthesis in the brain. PROGRESS IN BRAIN RESEARCH 1982; 56:195-211. [PMID: 7163502 DOI: 10.1016/s0079-6123(08)63776-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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20
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Mastropaolo W, Henshaw EC. Phosphorylation of ribosomal protein S6 in the Ehrlich ascites tumor cell. Lack of effect of phosphorylation upon ribosomal function in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 656:246-55. [PMID: 7317434 DOI: 10.1016/0005-2787(81)90093-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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21
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Vidales FJ, Sanchez-Madrid F, Ballesta JP. The acidic proteins of eukaryotic ribosomes. A comparative study. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 656:28-35. [PMID: 6796122 DOI: 10.1016/0005-2787(81)90022-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The acidic proteins extracted by 0.4 M NH4Cl and 50% ethanol from ribosomes from Saccharomyces cerevisiae, wheat germ, Artemia salina, Drosophila melanogaster, rat liver and rabbit reticulocytes have been studied comparatively in several structural and functional aspects. All the species studied have in the ribosome two strongly acidic proteins with pI values not greater than pH 4.5., which appear to be monophosphorylated in the case of S. cerevisiae, A.Salina, D. melanogaster and wheat germ. Rat liver proteins are multiphosphorylated, as possibly are those from reticulocytes. The molecular weight of these acidic proteins as determined by SDS electrophoresis ranges from around 13,500 to 17,000 and, except in the case of yeast, of which both proteins have the same molecular weight, the size of the two proteins in the other species differs by approx. 1,000-2,000. In general, the size of the proteins increases with the evolutionary position of the organism, as seems to be the case with the degree of phosphorylation. From an immunological point of view the ribosomal acid proteins of eukaryotic cells are partically related, since antisera against yeast protein cross-react with proteins from wheat germ, rat liver and reticulocytes. Bacterial proteins L7 and L12 are very weakly recognized by the anti-yeast sera. Anti-bacterial acidic proteins do not cross-react with any of the protein from the species studied. The proteins from all the species studied are functional equivalents and can reconstitute the activity of particles of S. cerevisiae deprived of their acidic proteins.
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22
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Ringer DP, Kizer DE, King RL. Differences in the distribution of phosphate content in the ribosomal subunit proteins of free and membrane-bound ribosomes from normal and regenerating rat liver. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 656:62-8. [PMID: 7306551 DOI: 10.1016/0005-2787(81)90027-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Proteins of membrane-bound ribosomes from normal liver contained 60-70% more phosphate than did proteins from free ribosomes. This difference was not a reflection of the phosphate contents of respective 40 S subunits. Instead, it was owing to the presence of high levels of phosphorylated proteins in the 60 S subunits, i.e., phosphate contents equal to or greater than those for 40 S subunits. The proteins of membrane-bound 60 S subunits contained twice the phosphate as free 60 S subunits. In regenerating rat liver, membrane-bound ribosomes had increased phosphate in the proteins of the 40 S subunits and decreased phosphate in proteins of the 60 S subunit when compared to controls for normal rat liver. No significant changes occurred in the proteins of free ribosomes from regenerating rat liver. These findings are discussed with respect to (a) the importance of assessing total phosphate contents of proteins in the study of ribosomal protein phosphorylation, and (b) the possible involvement of ribosomal protein phosphorylation in the segregation of ribosomes into free and membrane-bound populations and the regulation of these distributions to meet changes in the translational demands of the cell.
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23
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Leader DP, Thomas A, Voorma HO. The protein synthetic activity in vitro of ribosomes differing in the extent of phosphorylation of their ribosomal proteins. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 656:69-75. [PMID: 6914202 DOI: 10.1016/0005-2787(81)90028-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We describe a re-examination of the cell-free protein synthetic activity of eukaryotic ribosomes having proteins phosphorylated to different extents. Ribosomal 40 S subunits were isolated both from a variety of cells in which there is relatively little phosphorylation of ribosomal protein S6, and from cells subjected in vivo to different stimuli that promote the extensive phosphorylation of protein S6. The ability of these subunits to bind Met-tRNA as well as the second amino acyl-tRNA (Val-tRNA) was compared in the presence of highly purified initiation factors, elongation factor EF-1 at various concentrations of 60S subunits, 9 S globin mRNA and potassium ions. The ability of the subunits to synthesize polyphenylalanine was also studied using highly purified elongation factors. In no case was any significant difference in activity observed between ribosomes with protein S6 phosphorylated to different extents. Similar, though less extensive, studies were preformed comparing 60 S ribosomal subunits differing in the extent of phosphorylation of the acidic phosphoprotein, L gamma , and of L14. No difference in activity was observed between these ribosomes.
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24
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Belanger G, Godin C, Lemieux G. Turnover rates of phosphoryl groups in ribosomal proteins of Physarum polycephalum. Evidence for two different mechanisms. EUROPEAN JOURNAL OF BIOCHEMISTRY 1981; 120:143-8. [PMID: 7308210 DOI: 10.1111/j.1432-1033.1981.tb05681.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The rate of phosphate exchange in individual ribosomal proteins of Physarum polycephalum was determined in vivo. It was observed that the phosphoryl groups of S3, the major phosphoprotein, had a turnover rate of 1.5% per minute. The phosphoryl groups of proteins L1, L20 and L24 were stable. These results show that the phosphorylation of ribosomal proteins is regulated by at least two different mechanisms. The rapid turnover of phosphoryl groups of the major phosphoprotein is in agreement with the general observation that the phosphate content of this protein is modulated by the physiological state of the cells and possibly involved in the regulation of ribosome activity. The absence of phosphate exchange in acidic proteins suggests that these groups could play a structural role in the ribosome functions.
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25
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Ballinger DG, Hunt T. Fertilization of sea urchin eggs is accompanied by 40 S ribosomal subunit phosphorylation. Dev Biol 1981; 87:277-85. [PMID: 6269932 DOI: 10.1016/0012-1606(81)90151-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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26
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27
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Sánchez-Madrid F, Vidales FJ, Ballesta JP. Effect of phosphorylation on the affinity of acidic proteins from Saccharomyces cerevisiae for the ribosomes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1981; 114:609-13. [PMID: 6786876 DOI: 10.1111/j.1432-1033.1981.tb05187.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Electrofocusing of the acidic proteins extracted from Saccharomyces cerevisiae ribosomes shows the presence of eight bands in the gels, which upon treatment with alkaline phosphatase are reduced to three. Two of them, proteins L44 and L45, correspond to the proteins equivalent to the bacterial L7 and L12 and the third, protein Ax, behaves like a supernatant factor. In the ribosome, proteins L44 and L45 are found unphosphorylated and monophosphorylated while protein Ax is detected mostly in a modified state, showing from one to three phosphate groups per molecule. In the cytoplasm where protein Ax is abundant and proteins L44 and L45 are present in small quantities, the three proteins are unphosphorylated. Protein Ax, having one or two phosphate groups, can be removed from the ribosomes in conditions that release the initiation factors, while the triphosphorylated molecules are tightly bound to the particles. The data indicate a relationship between the degree of phosphorylation of protein Az and its affinity for the ribosome.
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Gressner AM, van de Leur E. Interaction of synthetic polynucleotides with small rat liver ribosomal subunits possessing low and highly phosphorylated protein S6. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 608:459-68. [PMID: 7397197 DOI: 10.1016/0005-2787(80)90191-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The interaction of some synthetic mRNAs (polyuridylate, polyadenylate, polycytidylate) with small rat liver ribosomal subunits which have protein S6 in different states of phosphorylation was studied by BioGel column chromatography, affinity chromatography on poly(U)-Sepharose 4B, and continuous diafiltration at 4 degrees C. 40-S subunits with low phosphorylated protein S6 (isolated from normal liver) and small subunits with highly phosphorylated protein S6 (from galactosamine-, thioacetamide-, dimethylnitrosamine-, puromycin-, and cycloheximide-treated livers) bind initially equal amounts of poly(U) but the dissociation of the radioactive polyuridylate occurs much more rapidly and to a greater extent from the low than from the highly phosphorylated type of subunits. From control- and galactosamine-4-S subunits 62% and 22%, respectively, of originally bound [3H]poly(U) was removed. The release of initially bound poly(A) from 40-S subunits of galactosamine-treated liver ws retarded but reached finally the same level as with control liver ribosomal subunits (removal of 40% of bound [3H]poly(A)). No differences between low and highly phosphorylated subunits were observed with poly(C). If the dissociation reaction was performed at 22 degrees C instead of 4 degrees C the differences in the release of poly(U) described above disappeared.
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29
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Gressner AM. Ribosomal protein modifications in liver injury: effect of carbon tetrachloride and extrahepatic cholestasis on protein phosphorylation. JOURNAL OF CLINICAL CHEMISTRY AND CLINICAL BIOCHEMISTRY. ZEITSCHRIFT FUR KLINISCHE CHEMIE UND KLINISCHE BIOCHEMIE 1980; 18:111-6. [PMID: 7373235 DOI: 10.1515/cclm.1980.18.2.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The phosphorylation of ribosomal proteins in rat liver injured fro various times by carbon tetrachloride and extrahepatic cholestasis was studied. The incorporation of [32P]phosphate into the protein moiety of the small ribosomal subunit was increased over 2-fold 1 to 4 h after injection of the hepatotoxin, whereas the specific activity of the 60 S subunit was low and changed only insignificantly. Two-dimensional electrophoretic analysis of ribosomal proteins complemented by autoradiography revealed that CCl4 stimulated the phosphorylation of only a single protein (S6) in the 40 S subunit. The phosphorylation of S6 led to a measurable anodic shift and elongation of the protein on the 2-dimensional electropherograms. In response to bile duct ligation a similar increase in phosphorylation of protein S6 was noticed.
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30
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Issinger OG, Beier H, Speichermann N, Flokerzi V, Hofmann F. Comparison of phosphorylation of ribosomal proteins from HeLa and Krebs II ascites-tumour cells by cyclic AMP-dependent and cyclic GMP-dependent protein kinases. Biochem J 1980; 185:89-99. [PMID: 6246882 PMCID: PMC1161273 DOI: 10.1042/bj1850089] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Phosphorylation of eukaryotic ribosomal proteins in vitro by essentially homogeneous preparations of cyclic AMP-dependent protein kinase catalytic subunit and cyclic GMP-dependent protein kinase was compared. Each protein kinase was added at a concentration of 30nM. Ribosomal proteins were identified by two-dimensional gel electrophoresis. Almost identical results were obtained when ribosomal subunits from HeLa or ascites-tumour cells were used. About 50-60% of the total radioactive phosphate incorporated into small-subunit ribosomal proteins by either kinase was associated with protein S6. In 90 min between 0.7 and 1.0 mol of phosphate/mol of protein S6 was incorporated by the catalytic subunit of cyclic AMP-dependent protein kinase. Of the other proteins, S3 and S7 from the small subunit and proteins L6, L18, L19 and L35 from the large subunit were predominantly phosphorylated by the cyclic AMP-dependent enzyme. Between 0.1 and 0.2 mol of phosphate was incorporated/mol of these phosphorylated proteins. With the exception of protein S7, the same proteins were also major substrates for the cyclic GMP-dependent protein kinase. Time courses of the phosphorylation of individual proteins from the small and large ribosomal subunits in the presence of either protein kinase suggested four types of phosphorylation reactions: (1) proteins S2, S10 and L5 were preferably phosphorylated by the cyclic GMP-dependent protein kinase; (2) proteins S3 and L6 were phosphorylated at very similar rates by either kinase; (3) proteins S7 and L29 were almost exclusively phosphorylated by the cyclic AMP-dependent protein kinase; (4) protein S6 and most of the other proteins were phosphorylated about two or three times faster by the cyclic AMP-dependent than by the cyclic GMP-dependent enzyme.
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31
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Wettenhall R, Howlett G. Phosphorylation of a specific ribosomal protein during stimulation of thymocytes by concanavalin A and prostaglandin E1. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86847-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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32
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Gressner AM. Two-dimensional electrophoretic analysis of ribosomal proteins from chronically injured liver. JOURNAL OF CLINICAL CHEMISTRY AND CLINICAL BIOCHEMISTRY. ZEITSCHRIFT FUR KLINISCHE CHEMIE UND KLINISCHE BIOCHEMIE 1979; 17:541-5. [PMID: 501300 DOI: 10.1515/cclm.1979.17.8.541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Proteins of the small and large ribosomal subunit, isolated at various times from long-term thioacetamide-damaged rat livers, were analysed by two-dimensional polyacrylamide gel electrophoresis and compared with those from normal liver. Chronic hepatic injury induced a number of time-dependent changes of the structural proteins of the small subunit, whereas the proteins of the large subparticle were essentially unaffected. The most significant alterations were an anodical dislocation of protein S6, a strong diminution in the amounts of proteins S9 and S10 and the occurrence of 3 to 4 additional small subunit proteins. By autoradiographic studies it was established that the modifications of S6 were brought about by an enhanced phosphorylation of this protein, which was the earliest sign of a ribosomal alteration in injured liver tissue.
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33
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Martini OH, Kruppa J. Ribosomal phosphoproteins of mouse myeloma cells. Changes in the degree of phosphorylation induced by hypertonic initiation block. EUROPEAN JOURNAL OF BIOCHEMISTRY 1979; 95:349-58. [PMID: 37077 DOI: 10.1111/j.1432-1033.1979.tb12972.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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34
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Genot A, Reboud JP, Cenatiempo Y, Cozzone AJ. Differential phosphorylation of basic and acidic ribosomal proteins by protein kinases bound to membrane-free rat liver polysomes. FEBS Lett 1979; 99:261-4. [PMID: 34531 DOI: 10.1016/0014-5793(79)80968-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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35
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Kristiansen K, Krüger A. Phosphorylation and degradation of ribosomes in starved Tetrahymena pyriformis. Exp Cell Res 1979; 118:159-69. [PMID: 103736 DOI: 10.1016/0014-4827(79)90594-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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Tas PW, Sells BH. Accessibility of ribosomal proteins to lactoperoxidase-catalyzed iodination following phosphorylation and during subunit interaction. EUROPEAN JOURNAL OF BIOCHEMISTRY 1978; 92:271-8. [PMID: 729591 DOI: 10.1111/j.1432-1033.1978.tb12745.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lactoperoxidase-catalyzed iodination was employed as a probe to monitor conformational change in 40-S ribosomal subunits from rat liver. Using this probe, it was observed that phosphorylation of protein S6 resulted in no detectable change in the iodination pattern of 40-S subunit proteins. These results suggest that the conformation of the small subunit remains unaltered following phosphorylation. On the other hand, the differences noted in the iodination pattern between 40-S ribosomal proteins derived from isolated subunits and those from 80-S monosomes, suggest that the 40-S subunit undergoes a conformational change during association with the 60-S subunit. Following 40-S and 60-S subunit association, proteins S2, S3, S5, S6, S8, S10 and S14 became less accessible to iodination. It is suggested that these proteins may be located at the interface between the 40-S and 60-S subunits.
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37
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Cenatiempo Y, Cozzone AJ, Genot A, Reboud JP. Characterization of two distinct protein kinase activities bound to membrane-free rat liver polysomes. Biochimie 1978; 60:813-6. [PMID: 215239 DOI: 10.1016/s0300-9084(78)80028-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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Arpin M, Madjar JJ, Reboud JP. Occurrence of phosphorylated forms of an acidic protein in the large ribosomal subunit of rat liver. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 519:537-41. [PMID: 667077 DOI: 10.1016/0005-2787(78)90106-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An acidic protein from rat liver 60-S ribosomal subunits was selectively extracted with 50% ethanol. It was revealed as three different spots by two-dimensional gel electrophoresis, two of them being attributable to phosphorylated forms since they disappeared after alkaline phosphatase treatment. The relationship between this protein and similar acidic proteins found in eucaryotic cells is discussed.
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39
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Roberts S, Ashby D. Ribosomal protein phosphorylation in rat cerebral cortex in vitro. Influence of cyclic adenosine 3‘:5‘-monophosphate. J Biol Chem 1978. [DOI: 10.1016/s0021-9258(17)38302-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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40
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Treloar MA, Treloar ME, Kisilevsky R. Ethionine and the phosphorylation of ribosomal protein S6. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(17)40052-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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41
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Robertson MC. Studies of the protein synthetic activity of lysates from HeLa cells incubated in hypertonic medium. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 476:88-95. [PMID: 856283 DOI: 10.1016/0005-2787(77)90288-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
When HeLa S-3 cells are incubated with medium made hypertonic by adding NaCl, protein synthesis is inhibited. When the cells are returned to normal conditions protein synthesis is restored. To study the molecular mechanism of this regulation of protein synthesis, lysates were prepared from HeLa S-3 cells grown in minimum essential medium (normal, N); from cells which were incubated with additional (100 mM) NaCl (hypertonic, H); and from cells which were treated similarly in hypertonic medium and then restored to isotonic conditions (hypertonic-isotonic, H-I). Lysates of H cells exhibited reduced endogenous protein synthesis. Studies with mixed lysates from H and N cells implicated that the H lysate did not contain a soluble, non-labile macromolecule (greater than 10 000 daltons) with an inhibitory activity upon the protein synthesis. Analysis by Edman reaction of H lysates showed a reduced incorporation of [35S]methionine into N-terminal suggesting that the initiation step of protein synthesis was affected. However, sucrose gradietn analysis indicated that lysates of H cells were still able to form 80-S initiation complexes with [35S] methionyl-tRNAIMet. The block in initiation was not complete. The lesion could not be reversed by adding post-ribosomal supernatant or a ribosomal salt wash from N cells to ribosomes from the H cells. The data show that the ribosomal fraction is primarily involved in the inhibition.
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42
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Lastick SM, Nielsen PJ, McConkey EH. Phosphorylation of ribosomal protein S6 in suspension cultured HeLa cells. MOLECULAR & GENERAL GENETICS : MGG 1977; 152:223-30. [PMID: 876026 DOI: 10.1007/bf00693074] [Citation(s) in RCA: 88] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
HeLa cell ribosomal protein S6, and the increase in its phosphorylation level that occurs after resuspending cells in fresh medium plus serum, were studied using two-dimensional gel electrophoresis. The maximum level of S6 phosphorylation occurs about 2 h after adding fresh medium and seum to cells that have been allowed to grow to high density; this results in an almost complete shift of the spot representing S6 in two-dimensional polacrylamide gels to a new location. Mixing experiments showed that the differences in the level of phosphorylation occur in vivo and are not an artifact of in vitro sample preparation. This method of stimulating S6 phosphorylation provides a convenient system for studying the functional significance of the phenomenon. Only one other ribosomal protein was detectably phosphorylated using [32P]-labeling and autoradiography of dried two-dimensional gels. The level of phosphorylation of this protein, L14, does not change after serum stimulation.
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43
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Gressner AM, Greiling H. The phosphorylation of liver ribosomal protein S6 during the development of acute hepatic cell injury induced by D-galactosamine. FEBS Lett 1977; 74:77-81. [PMID: 838077 DOI: 10.1016/0014-5793(77)80756-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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44
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Traugh JA, Tahara SM, Sharp SB, Safer B, Merrick WC. Factors involved in initiation of haemoglobin synthesis can be phosphorylated in vitro. Nature 1976; 263:163-5. [PMID: 184395 DOI: 10.1038/263163a0] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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45
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Leader DP, Rankine AD, Coia AA. The phosphorylation of ribosomal protein S6 in baby hamster kidney fibroblasts. Biochem Biophys Res Commun 1976; 71:966-74. [PMID: 971322 DOI: 10.1016/0006-291x(76)90749-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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46
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Becker-Ursic D, Davies J. In vivo and in vitro phosphorylation of ribosomal proteins by protein kinases from Saccharomyces cerevisiae. Biochemistry 1976; 15:2289-96. [PMID: 179565 DOI: 10.1021/bi00656a007] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
From the high salt wash of the ribosomes of the yeast Saccharomyces cerevisiae, three protein kinases have been isolated and separated by DEAE-cellulose chromatography. The three kinases differ in their abilities to phosphorylate substrates such as histones (calf thymus), casein, and S. cerevisiae ribosomes; two of the kinases showed increased activity in the presence of cyclic adenosine 3',5'-monophosphate when histones and 40S ribosomal subunits were used as substrates. The protein kinases catalyzed phosphorylation of certain proteins of the 40S and 60S ribosomal subunits, and 80S ribosomes in vitro. Nine proteins of the 80S ribosome, seven proteins of the 40S subunit, and eleven of the 60S subunit were phosphorylated; different proteins were modified to various extents when different kinases were used. We have identified several proteins of 40S and 60S ribosomal subunits which are not available to the kinases in the 80S particles. Ribosomes isolated from S. cerevisiae cells growing in logarithmic phase of growth were found to contain a number of phosphorylated proteins. Studies by two-dimensional polyacrylamide gel electrophoresis indicated that the ribosomal proteins phosphorylated in vivo correspond with those phosphorylated in vitro. The relationship of in vivo phsophorylation of ribosomes to the growth and physiology of S. cerevisiae is not known.
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