1
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McCarthy M, Goncalves M, Powell H, Morey B, Turner M, Merrill AR. A Structural Approach to Anti-Virulence: A Discovery Pipeline. Microorganisms 2021; 9:microorganisms9122514. [PMID: 34946116 PMCID: PMC8704661 DOI: 10.3390/microorganisms9122514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/27/2021] [Accepted: 11/30/2021] [Indexed: 11/25/2022] Open
Abstract
The anti-virulence strategy is designed to prevent bacterial virulence factors produced by pathogenic bacteria from initiating and sustaining an infection. One family of bacterial virulence factors is the mono-ADP-ribosyltransferase toxins, which are produced by pathogens as tools to compromise the target host cell. These toxins are bacterial enzymes that exploit host cellular NAD+ as the donor substrate to modify an essential macromolecule acceptor target in the host cell. This biochemical reaction modifies the target macromolecule (often protein or DNA) and functions in a binary fashion to turn the target activity on or off by blocking or impairing a critical process or pathway in the host. A structural biology approach to the anti-virulence method to neutralize the cytotoxic effect of these factors requires the search and design of small molecules that bind tightly to the enzyme active site and prevent catalytic function essentially disarming the pathogen. This method requires a high-resolution structure to serve as the model for small molecule inhibitor development, which illuminates the path to drug development. This alternative strategy to antibiotic therapy represents a paradigm shift that may circumvent multi-drug resistance in the offending microbe through anti-virulence therapy. In this report, the rationale for the anti-virulence structural approach will be discussed along with recent efforts to apply this method to treat honey bee diseases using natural products.
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2
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The N-terminus of Paenibacillus larvae C3larvinA modulates catalytic efficiency. Biosci Rep 2021; 41:227200. [PMID: 33289829 PMCID: PMC7789906 DOI: 10.1042/bsr20203727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 01/21/2023] Open
Abstract
C3larvinA was recently described as a mono-ADP-ribosyltransferase (mART) toxin from the enterobacterial repetitive intergenic consensus (ERIC) III genotype of the agricultural pathogen, Paenibacillus larvae. It was shown to be the full-length, functional version of the previously described C3larvintrunc toxin, due to a 33-residue extension of the N-terminus of the protein. In the present study, a series of deletions and substitutions were made to the N-terminus of C3larvinA to assess the contribution of the α1-helix to toxin structure and function. Catalytic characterization of these variants identified Asp23 and Ala31 residues as supportive to enzymatic function. A third residue, Lys36, was also found to contribute to the catalytic activity of the enzyme. Analysis of the C3larvinA homology model revealed that these three residues were participating in a series of interactions to properly orient both the Q-X-E and S-T-S motifs. Ala31 and Lys36 were found to associate with a structural network of residues previously identified in silico, whereas Asp23 forms novel interactions not previously described. At last, the membrane translocation activity into host target cells of each variant was assessed, highlighting a possible relationship between protein dipole and target cell entry.
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3
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Ogura K, Yahiro K, Moss J. Cell Death Signaling Pathway Induced by Cholix Toxin, a Cytotoxin and eEF2 ADP-Ribosyltransferase Produced by Vibrio cholerae. Toxins (Basel) 2020; 13:toxins13010012. [PMID: 33374361 PMCID: PMC7824611 DOI: 10.3390/toxins13010012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/20/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022] Open
Abstract
Pathogenic microorganisms produce various virulence factors, e.g., enzymes, cytotoxins, effectors, which trigger development of pathologies in infectious diseases. Cholera toxin (CT) produced by O1 and O139 serotypes of Vibrio cholerae (V. cholerae) is a major cytotoxin causing severe diarrhea. Cholix cytotoxin (Cholix) was identified as a novel eukaryotic elongation factor 2 (eEF2) adenosine-diphosphate (ADP)-ribosyltransferase produced mainly in non-O1/non-O139 V. cholerae. The function and role of Cholix in infectious disease caused by V. cholerae remain unknown. The crystal structure of Cholix is similar to Pseudomonas exotoxin A (PEA) which is composed of an N-terminal receptor-recognition domain and a C-terminal ADP-ribosyltransferase domain. The endocytosed Cholix catalyzes ADP-ribosylation of eEF2 in host cells and inhibits protein synthesis, resulting in cell death. In a mouse model, Cholix caused lethality with severe liver damage. In this review, we describe the mechanism underlying Cholix-induced cytotoxicity. Cholix-induced apoptosis was regulated by mitogen-activated protein kinase (MAPK) and protein kinase C (PKC) signaling pathways, which dramatically enhanced tumor necrosis factor-α (TNF-α) production in human liver, as well as the amount of epithelial-like HepG2 cancer cells. In contrast, Cholix induced apoptosis in hepatocytes through a mitochondrial-dependent pathway, which was not stimulated by TNF-α. These findings suggest that sensitivity to Cholix depends on the target cell. A substantial amount of information on PEA is provided in order to compare/contrast this well-characterized mono-ADP-ribosyltransferase (mART) with Cholix.
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Affiliation(s)
- Kohei Ogura
- Advanced Health Care Science Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-0942, Japan
- Correspondence: (K.O.); (K.Y.); Tel.: +81-76-265-2590 (K.O.); +81-43-226-2048 (K.Y.)
| | - Kinnosuke Yahiro
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
- Correspondence: (K.O.); (K.Y.); Tel.: +81-76-265-2590 (K.O.); +81-43-226-2048 (K.Y.)
| | - Joel Moss
- Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1590, USA;
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Mateus-Seidl R, Stahl S, Dengl S, Birzele F, Herrmuth H, Mayer K, Niederfellner G, Liu XF, Pastan I, Brinkmann U. Interplay between reversible phosphorylation and irreversible ADP-ribosylation of eukaryotic translation elongation factor 2. Biol Chem 2019; 400:501-512. [PMID: 30218597 DOI: 10.1515/hsz-2018-0280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/11/2018] [Indexed: 11/15/2022]
Abstract
The functionality of eukaryotic translation elongation factor 2 (eEF2) is modulated by phosphorylation, eEF2 is simultaneously the molecular target of ADP-ribosylating toxins. We analyzed the interplay between phosphorylation and diphthamide-dependent ADP-ribosylation. Phosphorylation does not require diphthamide, eEF2 without it still becomes phosphorylated. ADP-ribosylation not only modifies the H715 diphthamide but also inhibits phosphorylation of S595 located in proximity to H715, and stimulates phosphorylation of T56. S595 can be phosphorylated by CDK2 and CDK1 which affects EEF2K-mediated T56-phosphorylation. Thus, ADP-ribosylation and S595-phosphorylation by kinases occur within the same vicinity and both trigger T56-phosphorylation. Diphthamide is surface-accessible permitting access to ADP-ribosylating enzymes, the adjacent S595 side chain extends into the interior. This orientation is incompatible with phosphorylation, neither allowing kinase access nor phosphate attachment. S595 phosphorylation must therefore be accompanied by structural alterations affecting the interface to ADP-ribosylating toxins. In agreement with that, replacement of S595 with Ala, Glu or Asp prevents ADP-ribosylation. Phosphorylation (starvation) as well as ADP-ribosylation (toxins) inhibit protein synthesis, both affect the S595/H715 region of eEF2, both trigger T57-phosphorylation eliciting similar transcriptional responses. Phosphorylation is short lived while ADP-ribosylation is stable. Thus, phosphorylation of the S595/H715 'modifier region' triggers transient interruption of translation while ADP-ribosylation arrests irreversibly.
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Affiliation(s)
- Rita Mateus-Seidl
- Roche Pharma Research and Early Development, Discovery Oncology, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
| | - Sebastian Stahl
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
| | - Stefan Dengl
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
| | - Fabian Birzele
- Roche Pharma Research and Early Development, Pharmaceutical Sciences- Bioinformatics, Roche Innovation Center Basel, Grenzacherstr. 124, CH-4070 Basel, Germany
| | - Hedda Herrmuth
- Roche Pharma Research and Early Development, Discovery Oncology, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
| | - Klaus Mayer
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
| | - Gerhard Niederfellner
- Roche Pharma Research and Early Development, Discovery Oncology, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
| | - Xiu-Fen Liu
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr, Bethesda, MD 20814, USA
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr, Bethesda, MD 20814, USA
| | - Ulrich Brinkmann
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Nonnenwald 2, D-82377 Penzberg, FRG, Germany
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5
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Tsuda-Sakurai K, Miura M. The hidden nature of protein translational control by diphthamide: the secrets under the leather. J Biochem 2019; 165:1-8. [PMID: 30204891 DOI: 10.1093/jb/mvy071] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/27/2018] [Indexed: 01/16/2023] Open
Abstract
The protein translation elongation factor eEF2 undergoes a unique posttranslational modification called diphthamidation. eEF2 is an essential factor in protein translation, and the diphthamide modification has been a famous target of the diphtheria toxin for a long time. On the other hand, the physiological function of this rare modification in vivo remains unknown. Recent studies have suggested that diphthamide has specific functions for the cellular stress response and active proliferation. In this review, we summarize the history and findings of diphthamide obtained to date and discuss the possibility of a specific function for diphthamide in regulating protein translation.
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Affiliation(s)
- Kayoko Tsuda-Sakurai
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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6
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Narrowe AB, Spang A, Stairs CW, Caceres EF, Baker BJ, Miller CS, Ettema TJG. Complex Evolutionary History of Translation Elongation Factor 2 and Diphthamide Biosynthesis in Archaea and Parabasalids. Genome Biol Evol 2018; 10:2380-2393. [PMID: 30060184 PMCID: PMC6143161 DOI: 10.1093/gbe/evy154] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2018] [Indexed: 12/22/2022] Open
Abstract
Diphthamide is a modified histidine residue which is uniquely present in archaeal and eukaryotic elongation factor 2 (EF-2), an essential GTPase responsible for catalyzing the coordinated translocation of tRNA and mRNA through the ribosome. In part due to the role of diphthamide in maintaining translational fidelity, it was previously assumed that diphthamide biosynthesis genes (dph) are conserved across all eukaryotes and archaea. Here, comparative analysis of new and existing genomes reveals that some archaea (i.e., members of the Asgard superphylum, Geoarchaea, and Korarchaeota) and eukaryotes (i.e., parabasalids) lack dph. In addition, while EF-2 was thought to exist as a single copy in archaea, many of these dph-lacking archaeal genomes encode a second EF-2 paralog missing key residues required for diphthamide modification and for normal translocase function, perhaps suggesting functional divergence linked to loss of diphthamide biosynthesis. Interestingly, some Heimdallarchaeota previously suggested to be most closely related to the eukaryotic ancestor maintain dph genes and a single gene encoding canonical EF-2. Our findings reveal that the ability to produce diphthamide, once thought to be a universal feature in archaea and eukaryotes, has been lost multiple times during evolution, and suggest that anticipated compensatory mechanisms evolved independently.
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Affiliation(s)
- Adrienne B Narrowe
- Department of Integrative Biology, University of Colorado Denver, Denver
| | - Anja Spang
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Utrecht University, AB Den Burg, The Netherlands
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Sweden
| | - Courtney W Stairs
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Sweden
| | - Eva F Caceres
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Sweden
| | - Brett J Baker
- Department of Marine Science, Marine Science Institute, University of Texas Austin, Port Aransas
| | | | - Thijs J G Ettema
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Sweden
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7
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Loss of diphthamide pre-activates NF-κB and death receptor pathways and renders MCF7 cells hypersensitive to tumor necrosis factor. Proc Natl Acad Sci U S A 2015; 112:10732-7. [PMID: 26261303 DOI: 10.1073/pnas.1512863112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The diphthamide on human eukaryotic translation elongation factor 2 (eEF2) is the target of ADP ribosylating diphtheria toxin (DT) and Pseudomonas exotoxin A (PE). This modification is synthesized by seven dipthamide biosynthesis proteins (DPH1-DPH7) and is conserved among eukaryotes and archaea. We generated MCF7 breast cancer cell line-derived DPH gene knockout (ko) cells to assess the impact of complete or partial inactivation on diphthamide synthesis and toxin sensitivity, and to address the biological consequence of diphthamide deficiency. Cells with heterozygous gene inactivation still contained predominantly diphthamide-modified eEF2 and were as sensitive to PE and DT as parent cells. Thus, DPH gene copy number reduction does not affect overall diphthamide synthesis and toxin sensitivity. Complete inactivation of DPH1, DPH2, DPH4, and DPH5 generated viable cells without diphthamide. DPH1ko, DPH2ko, and DPH4ko harbored unmodified eEF2 and DPH5ko ACP- (diphthine-precursor) modified eEF2. Loss of diphthamide prevented ADP ribosylation of eEF2, rendered cells resistant to PE and DT, but does not affect sensitivity toward other protein synthesis inhibitors, such as saporin or cycloheximide. Surprisingly, cells without diphthamide (independent of which the DPH gene compromised) were presensitized toward nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) and death-receptor pathways without crossing lethal thresholds. In consequence, loss of diphthamide rendered cells hypersensitive toward TNF-mediated apoptosis. This finding suggests a role of diphthamide in modulating NF-κB, death receptor, or apoptosis pathways.
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8
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Lugo MR, Merrill AR. The Father, Son and Cholix Toxin: The Third Member of the DT Group Mono-ADP-Ribosyltransferase Toxin Family. Toxins (Basel) 2015. [PMID: 26213968 PMCID: PMC4549722 DOI: 10.3390/toxins7082757] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The cholix toxin gene (chxA) was first identified in V. cholerae strains in 2007, and the protein was identified by bioinformatics analysis in 2008. It was identified as the third member of the diphtheria toxin group of mono-ADP-ribosyltransferase toxins along with P. aeruginosa exotoxin A and C. diphtheriae diphtheria toxin. Our group determined the structure of the full-length, three-domain cholix toxin at 2.1 Å and its C-terminal catalytic domain (cholixc) at 1.25 Å resolution. We showed that cholix toxin is specific for elongation factor 2 (diphthamide residue), similar to exotoxin A and diphtheria toxin. Cholix toxin possesses molecular features required for infection of eukaryotes by receptor-mediated endocytosis, translocation to the host cytoplasm and inhibition of protein synthesis. More recently, we also solved the structure of full-length cholix toxin in complex with NAD+ and proposed a new kinetic model for cholix enzyme activity. In addition, we have taken a computational approach that revealed some important properties of the NAD+-binding pocket at the residue level, including the role of crystallographic water molecules in the NAD+ substrate interaction. We developed a pharmacophore model of cholix toxin, which revealed a cationic feature in the side chain of cholix toxin active-site inhibitors that may determine the active pose. Notably, several recent reports have been published on the role of cholix toxin as a major virulence factor in V. cholerae (non-O1/O139 strains). Additionally, FitzGerald and coworkers prepared an immunotoxin constructed from domains II and III as a cancer treatment strategy to complement successful immunotoxins derived from P. aeruginosa exotoxin A.
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Affiliation(s)
- Miguel R Lugo
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - A Rod Merrill
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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9
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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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10
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Sung VMH. Mechanistic overview of ADP-ribosylation reactions. Biochimie 2015; 113:35-46. [PMID: 25828806 DOI: 10.1016/j.biochi.2015.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 03/20/2015] [Indexed: 10/23/2022]
Abstract
ADP-ribosylation reactions consist of mono-ADP-ribosylation, poly-ADP-ribosylation and cyclic ADP-ribosylation. These reactions play essential roles in many important physiological and pathophysiological events. The types of chemical linkages, the evolutionarily conserved motif within the enzymes to determine the target specificity, stereochemistry of the ADP-ribosylated products, and the chemical reactions taking place among the enzymes and substrates are discussed.
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Affiliation(s)
- Vicky M-H Sung
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Harvard University, MA 02115, USA.
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11
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Glatt S, Zabel R, Vonkova I, Kumar A, Netz DJ, Pierik AJ, Rybin V, Lill R, Gavin AC, Balbach J, Breunig KD, Müller CW. Structure of the Kti11/Kti13 heterodimer and its double role in modifications of tRNA and eukaryotic elongation factor 2. Structure 2014; 23:149-160. [PMID: 25543256 DOI: 10.1016/j.str.2014.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/14/2022]
Abstract
The small, highly conserved Kti11 alias Dph3 protein encoded by the Kluyveromyces lactis killer toxin insensitive gene KTI11/DPH3 is involved in the diphthamide modification of eukaryotic elongation factor 2 and, together with Kti13, in Elongator-dependent tRNA wobble base modifications, thereby affecting the speed and accuracy of protein biosynthesis through two distinct mechanisms. We have solved the crystal structures of Saccharomyces cerevisiae Kti13 and the Kti11/Kti13 heterodimer at 2.4 and 2.9 Å resolution, respectively, and validated interacting residues through mutational analysis in vitro and in vivo. We show that metal coordination by Kti11 and its heterodimerization with Kti13 are essential for both translational control mechanisms. Our structural and functional analyses identify Kti13 as an additional component of the diphthamide modification pathway and provide insight into the molecular mechanisms that allow the Kti11/Kti13 heterodimer to coregulate two consecutive steps in ribosomal protein synthesis.
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Affiliation(s)
- Sebastian Glatt
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Rene Zabel
- Martin-Luther-Universität Halle-Wittenberg, Institut für Biologie, Weinbergweg 10, 06120 Halle (Saale), Germany
| | - Ivana Vonkova
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Amit Kumar
- Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Betty-Heimann-Straße 7, 06120 Halle (Saale), Germany
| | - Daili J Netz
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35037 Marburg, Germany
| | - Antonio J Pierik
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35037 Marburg, Germany
| | - Vladimir Rybin
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Straße 6, 35037 Marburg, Germany; LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Straße, 35043 Marburg, Germany
| | - Anne-Claude Gavin
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Jochen Balbach
- Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Betty-Heimann-Straße 7, 06120 Halle (Saale), Germany
| | - Karin D Breunig
- Martin-Luther-Universität Halle-Wittenberg, Institut für Biologie, Weinbergweg 10, 06120 Halle (Saale), Germany.
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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12
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Davydova E, Ho AYY, Malecki J, Moen A, Enserink JM, Jakobsson ME, Loenarz C, Falnes PØ. Identification and characterization of a novel evolutionarily conserved lysine-specific methyltransferase targeting eukaryotic translation elongation factor 2 (eEF2). J Biol Chem 2014; 289:30499-30510. [PMID: 25231979 DOI: 10.1074/jbc.m114.601658] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The components of the cellular protein translation machinery, such as ribosomal proteins and translation factors, are subject to numerous post-translational modifications. In particular, this group of proteins is frequently methylated. However, for the majority of these methylations, the responsible methyltransferases (MTases) remain unknown. The human FAM86A (family with sequence similarity 86) protein belongs to a recently identified family of protein MTases, and we here show that FAM86A catalyzes the trimethylation of eukaryotic elongation factor 2 (eEF2) on Lys-525. Moreover, we demonstrate that the Saccharomyces cerevisiae MTase Yjr129c, which displays sequence homology to FAM86A, is a functional FAM86A orthologue, modifying the corresponding residue (Lys-509) in yeast eEF2, both in vitro and in vivo. Finally, Yjr129c-deficient yeast cells displayed phenotypes related to eEF2 function (i.e. increased frameshifting during protein translation and hypersensitivity toward the eEF2-specific drug sordarin). In summary, the present study establishes the function of the previously uncharacterized MTases FAM86A and Yjr129c, demonstrating that these enzymes introduce a functionally important lysine methylation in eEF2. Based on the previous naming of similar enzymes, we have redubbed FAM86A and Yjr129c as eEF2-KMT and Efm3, respectively.
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Affiliation(s)
- Erna Davydova
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Angela Y Y Ho
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Jedrzej Malecki
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Anders Moen
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Jorrit M Enserink
- Department of Microbiology, Oslo University Hospital and University of Oslo, 0027 Oslo, Norway, and
| | - Magnus E Jakobsson
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Christoph Loenarz
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Pål Ø Falnes
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway,.
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13
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The amidation step of diphthamide biosynthesis in yeast requires DPH6, a gene identified through mining the DPH1-DPH5 interaction network. PLoS Genet 2013; 9:e1003334. [PMID: 23468660 PMCID: PMC3585130 DOI: 10.1371/journal.pgen.1003334] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 01/07/2013] [Indexed: 01/31/2023] Open
Abstract
Diphthamide is a highly modified histidine residue in eukaryal translation elongation factor 2 (eEF2) that is the target for irreversible ADP ribosylation by diphtheria toxin (DT). In Saccharomyces cerevisiae, the initial steps of diphthamide biosynthesis are well characterized and require the DPH1-DPH5 genes. However, the last pathway step—amidation of the intermediate diphthine to diphthamide—is ill-defined. Here we mine the genetic interaction landscapes of DPH1-DPH5 to identify a candidate gene for the elusive amidase (YLR143w/DPH6) and confirm involvement of a second gene (YBR246w/DPH7) in the amidation step. Like dph1-dph5, dph6 and dph7 mutants maintain eEF2 forms that evade inhibition by DT and sordarin, a diphthamide-dependent antifungal. Moreover, mass spectrometry shows that dph6 and dph7 mutants specifically accumulate diphthine-modified eEF2, demonstrating failure to complete the final amidation step. Consistent with an expected requirement for ATP in diphthine amidation, Dph6 contains an essential adenine nucleotide hydrolase domain and binds to eEF2. Dph6 is therefore a candidate for the elusive amidase, while Dph7 apparently couples diphthine synthase (Dph5) to diphthine amidation. The latter conclusion is based on our observation that dph7 mutants show drastically upregulated interaction between Dph5 and eEF2, indicating that their association is kept in check by Dph7. Physiologically, completion of diphthamide synthesis is required for optimal translational accuracy and cell growth, as indicated by shared traits among the dph mutants including increased ribosomal −1 frameshifting and altered responses to translation inhibitors. Through identification of Dph6 and Dph7 as components required for the amidation step of the diphthamide pathway, our work paves the way for a detailed mechanistic understanding of diphthamide formation. Diphthamide is an unusual modified amino acid found uniquely in a single protein, eEF2, which is required for cells to synthesize new proteins. The name refers to its target function for eEF2 inactivation by diphtheria toxin, the disease-inducing agent produced by the pathogen Corynebacterium diphtheriae. Why cells require eEF2 to contain diphthamide is unclear, although mice unable to make it fail to complete embryogenesis. Cells generate diphthamide by modifying a specific histidine residue in eEF2 using a three-step biosynthetic pathway, the first two steps of which are well defined. However, the enzyme(s) involved in the final amidation step are unknown. Here we integrate genomic and molecular approaches to identify a candidate for the elusive amidase (Dph6) and confirm involvement of a second protein (Dph7) in the amidation step, showing that failure to synthesize diphthamide affects the accuracy of protein synthesis. In contrast to Dph6, however, Dph7 may be regulatory. Our data strongly suggest that it promotes dissociation of eEF2 from diphthine synthase (Dph5), which carries out the second step of diphthamide synthesis, and that Dph5 has a novel role as an eEF2 inhibitor when diphthamide synthesis is incomplete.
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Su X, Chen W, Lee W, Jiang H, Zhang S, Lin H. YBR246W is required for the third step of diphthamide biosynthesis. J Am Chem Soc 2011; 134:773-6. [PMID: 22188241 DOI: 10.1021/ja208870a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Diphthamide, the target of diphtheria toxin, is a post-translationally modified histidine residue that is found in archaeal and eukaryotic translation elongation factor 2. The biosynthesis and function of this modification has attracted the interest of many biochemists for decades. The biosynthesis has been known to proceed in three steps. Proteins required for the first and second steps have been identified, but the protein(s) required for the last step have remained elusive. Here we demonstrate that the YBR246W gene in yeast is required for the last step of diphthamide biosynthesis, as the deletion of YBR246W leads to the accumulation of diphthine, which is the enzymatic product of the second step of the biosynthesis. This discovery will provide important information leading to the complete elucidation of the full biosynthesis pathway of diphthamide.
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Affiliation(s)
- Xiaoyang Su
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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Abstract
Covalent modifications of proteins often modulate their biological functions or change their subcellular location. Among the many known protein modifications, three are exceptional in that they only occur on single proteins: ethanolamine phosphoglycerol, diphthamide and hypusine. Remarkably, the corresponding proteins carrying these modifications, elongation factor 1A, elongation factor 2 and initiation factor 5A, are all involved in elongation steps of translation. For diphthamide and, in part, hypusine, functional essentiality has been demonstrated, whereas no functional role has been reported so far for ethanolamine phosphoglycerol. We review the biosynthesis, attachment and physiological roles of these unique protein modifications and discuss common and separate features of the target proteins, which represent essential proteins in all organisms.
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Affiliation(s)
- Eva Greganova
- Institute for Biochemistry and Molecular Medicine, University of Berne, Berne, Switzerland
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Sharma AK, FitzGerald D. Pseudomonas exotoxin kills Drosophila S2 cells via apoptosis. Toxicon 2010; 56:1025-34. [PMID: 20659495 PMCID: PMC3431163 DOI: 10.1016/j.toxicon.2010.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 07/14/2010] [Accepted: 07/16/2010] [Indexed: 11/15/2022]
Abstract
Pseudomonas exotoxin A (PE) is cytotoxic for eukaryotic cells because it enters cells by receptor-mediated endocytosis, translocates to the cell cytosol and ADP-ribosylates elongation factor 2 (EF2). However, the interaction of this toxin with eukaryotic cells and the mechanism of PE-mediated cell death have not been extensively characterized. The feasibility of carrying out a genome-wide RNAi screen, makes Drosophila melanogaster S2 cells as a good model system to identify essential genes in PE-mediated cytotoxicity, provided a suitable multi-well assay is developed. Here, using the alamarBlue viability assay, we show that Drosophila S2 cells are sensitive to PE at picomolar concentrations and that toxin treatments provoke an increase in caspase activity. This prompted us to use RNAi to characterize the mechanism of cell death. Results indicated that PE-mediated death of S2 cells was dependent on the presence of diphthamide, the post translational modification of EF2, and on the presence of Drice, the terminal caspase of insect cells. RNAi to drice or chemical inhibition of caspase action by z-VAD-fmk protected cells from PE-mediated death. Protection from death by RNAi or z-VAD-fmk did not interfere with toxin delivery to the cytosol leading to inhibition of protein synthesis. Using a convenient alamarBlue assay, our data confirms the cytotoxicity of PE for S2 cells and establishes apoptosis as the mode of PE-mediated death. This confirms the suitability of Drosophila cells as a convenient and simple model to elucidate the role of specific genes and proteins required for PE action.
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Affiliation(s)
- Ashima K Sharma
- Biotherapy Section, Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, HHS, 37 Convent Dr, Bethesda, MD 20892, USA
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A structural domain mediates attachment of ethanolamine phosphoglycerol to eukaryotic elongation factor 1A in Trypanosoma brucei. PLoS One 2010; 5:e9486. [PMID: 20209157 PMCID: PMC2830473 DOI: 10.1371/journal.pone.0009486] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 02/10/2010] [Indexed: 11/19/2022] Open
Abstract
Ethanolamine phosphoglycerol (EPG) represents a protein modification that so far has only been found in eukaryotic elongation factor 1A (eEF1A). In mammals and plants, EPG is covalently attached to two conserved glutamate residues located in domains II and III of eEF1A. In contrast, Trypanosoma brucei eEF1A contains a single EPG attached to Glu362 in domain III. The sequence and/or structural requirements for covalent linkage of EPG to eEF1A have not been determined for any organism. Using a combination of biosynthetic labelling of parasites with tritiated ethanolamine and mass spectrometry analyses, we demonstrate that replacement of Glu362 in T. brucei eEF1A by site-directed mutagenesis prevents EPG attachment, whereas single or multiple amino acid substitutions around the attachment site are not critical. In addition, by expressing a series of eEF1A deletion mutants in T. brucei procyclic forms, we demonstrate that a peptide consisting of 80 amino acids of domain III of eEF1A is sufficient for EPG attachment to occur. Furthermore, EPG addition also occurs if domain III of eEF1A is fused to a soluble reporter protein. To our knowledge, this is the first report addressing amino acid sequence, or structure, requirements for EPG modification of eEF1A in any organism. Using T. brucei as a model organism, we show that amino acid substitutions around the modification site are not critical for EPG attachment and that a truncated version of domain III of eEF1A is sufficient to mediate EPG addition.
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