Diphtheria Disease and Genes Involved in Formation of Diphthamide, Key Effector of the Diphtheria Toxin

Uthman, Shanow; Liu, Shihui; Giorgini, Flaviano; Stark, Michael J. R.; Costanzo, Michael; Schaffrath, Raffael

doi:10.5772/31680

Cited by 11 publications

(16 citation statements)

References 89 publications

(94 reference statements)

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“…Its putative role in translation has been investigated; however, it is still unclear whether diphthamidation has roles in global translation or tissue‐specific translation. In yeast, reduced total protein synthesis and −1 frameshift errors in protein elongation step were observed (Jørgensen et al, ; Uthman et al, ). Previously, when Dph1 , 2 , 4 , and 5 were individually knocked out in the MCF7 human breast cancer cell line, it was observed that only the Dph5‐ deficient cells contained partial ACP‐modified intermediate of eEF2.…”

Section: Discussionmentioning

confidence: 99%

Diphthamide modification of eEF2 is required for gut tumor‐like hyperplasia induced by oncogenic Ras

2020

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Eukaryotic elongation factor 2 (eEF2) undergoes a unique post‐translational modification called diphthamidation. Although eEF2 diphthamidation is highly conserved, its pathophysiological function is still largely unknown. To elucidate the function of diphthamidation in tumor, we examined the involvement of diphthamidation pathway enzyme Dph5 in tumor progression in Drosophila adult gut. Expression of oncogenic RasV12 in gut intestinal stem cells (ISCs) and enteroblasts (EBs) causes hypertrophy and disruption of gut epithelia, and shortened life span. Knockdown of Dph5 ameliorated these pathogenic phenotypes. Dph5 is required for gross translation activation and high dMyc protein level in RasV12 tumor‐like hyperplasia. Transcriptome analysis revealed that Dph5 is involved in the regulation of ribosome biogenesis genes. These results suggest that diphthamidation is required for translation activation partly through the regulation of ribosome biogenesis in Ras‐induced tumor‐like hyperplasia model in Drosophila gut.

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Section: Discussionmentioning

confidence: 99%

Diphthamide modification of eEF2 is required for gut tumor‐like hyperplasia induced by oncogenic Ras

2020

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“…Importantly, with strong activity against EF2 from yeast and fungi, including the human pathogens Candida albicans , Cryptococcus neoformans and Pneumocystis carinii as well as fungal dermatophytes, sordarin fulfills the criterion of a promising antimycotic agent (Domínguez and Martín, ; Shastry et al ., ) in the protection of immunosuppressed patients, especially those suffering from AIDS or cancer, against life‐threatening fungal infections (Andriole, ; Odds et al ., ). Taken together, EF2 therefore constitutes a fungal ‘Achilles heel’, study of which in the S. cerevisiae yeast model system has provided important insights into the fundamentals of diphthamide synthesis (and the diphthamide modification pathway) and its relevance for the control of eukaryotic cell growth and proliferation (Uthman et al ., 2011; 2012; Su et al ., ). Although the latter aspect clearly emphasizes the pathobiological role of diphthamide, it is less well understood why cells, including our own, actually require diphthamide – obviously, conferring sensitivity to lethal bacterial ADP ribosylase toxins or sordarin fungicides cannot be why cells need EF2 to carry diphthamide in the first place.…”

Section: Pathobiological Relevance Of the Diphthamide Modification Onmentioning

confidence: 99%

“…Classical genetic screens for isolating diphthamide‐deficient mutants on the basis of resistance to growth inhibition by DT (and sordarin, see above), had led to the early identification of five diphthamide synthesis genes ( DPH1–DPH5 ) in yeast and higher eukaryotes (Pappenheimer, ; Chen et al ., ; Liu and Leppla, ; Liu et al ., ; Bär et al ., ; Botet et al ., ). More recent studies, however, have shown that the diphthamide pathway is more complex than originally anticipated, and based on genome‐wide approaches including comparative genomics, chemical genomics as well as gene interaction database mining, two more diphthamide synthesis genes ( DPH6 and DPH7 ) have been uncovered in yeast (de Crécy‐Lagard et al ., ; Su et al ., 2012a,b; 2013; Uthman et al ., 2012; 2013). In addition, the pathway itself, which in eukaryotes had largely been thought to involve three biochemical steps, has been recently shown by the group of Hening Lin to include yet another catalytic step that forms a novel and previously overlooked pathway intermediate: methylated diphthamide (Lin et al ., ).…”

Section: The Biosynthetic Pathway For Modification Of Ef2 By Diphthamidementioning

confidence: 99%

“…) involving three DPH gene homologs ( DPH2 , DPH5 and DPH6 ), the eukaryal diphthamide pathway is more sophisticated and appears to differ from the archaeal one in both the complexity of the gene network, i.e. seven DPH1–DPH7 loci, and an additional, fourth methylation/demethylation step (Su et al ., 2012a,b; 2013; Uthman et al ., 2012; 2013; Lin et al ., ) (Fig. ).…”

Section: The Biosynthetic Pathway For Modification Of Ef2 By Diphthamidementioning

confidence: 99%

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The diphthamide modification pathway from Saccharomyces cerevisiae – revisited

Schaffrath

Abdel‐Fattah

Klassen

et al. 2014

Molecular Microbiology

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SummaryDiphthamide is a conserved modification in archaeal and eukaryal translation elongation factor 2 (EF2). Its name refers to the target function for diphtheria toxin, the disease-causing agent that, through ADP ribosylation of diphthamide, causes irreversible inactivation of EF2 and cell death. Although this clearly emphasizes a pathobiological role for diphthamide, its physiological function is unclear, and precisely why cells need EF2 to contain diphthamide is hardly understood. Nonetheless, the conservation of diphthamide biosynthesis together with syndromes (i.e. ribosomal frame-shifting, embryonic lethality, neurodegeneration and cancer) typical of mutant cells that cannot make it strongly suggests that diphthamidemodified EF2 occupies an important and translationrelated role in cell proliferation and development. Whether this is structural and/or regulatory remains to be seen. However, recent progress in dissecting the diphthamide gene network (DPH1-DPH7) from the budding yeast Saccharomyces cerevisiae has significantly advanced our understanding of the mechanisms required to initiate and complete diphthamide synthesis on EF2. Here, we review recent developments in the field that not only have provided novel, previously overlooked and unexpected insights into the pathway and the biochemical players required for diphthamide synthesis but also are likely to foster innovative studies into the potential regulation of diphthamide, and importantly, its ill-defined biological role.

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“…Studies in yeast have proved very useful for investigating diphthamide synthesis, which operates through a multi-step pathway that involves seven genes ( DPH1-DPH7 ) [2,3,4,5,6]. It starts with the transfer of the 3-amino-3-carboxypropyl (ACP) group from S-adenosylmethionine (SAM) to the imidazole ring of His 699 on eEF2 (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Insights into Diphthamide, Key Diphtheria Toxin Effector

Abdel‐Fattah

Scheidt

Uthman

et al. 2013

Toxins

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Diphtheria toxin (DT) inhibits eukaryotic translation elongation factor 2 (eEF2) by ADP-ribosylation in a fashion that requires diphthamide, a modified histidine residue on eEF2. In budding yeast, diphthamide formation involves seven genes, DPH1-DPH7. In an effort to further study diphthamide synthesis and interrelation among the Dph proteins, we found, by expression in E. coli and co-immune precipitation in yeast, that Dph1 and Dph2 interact and that they form a complex with Dph3. Protein-protein interaction mapping shows that Dph1-Dph3 complex formation can be dissected by progressive DPH1 gene truncations. This identifies N- and C-terminal domains on Dph1 that are crucial for diphthamide synthesis, DT action and cytotoxicity of sordarin, another microbial eEF2 inhibitor. Intriguingly, dph1 truncation mutants are sensitive to overexpression of DPH5, the gene necessary to synthesize diphthine from the first diphthamide pathway intermediate produced by Dph1-Dph3. This is in stark contrast to dph6 mutants, which also lack the ability to form diphthamide but are resistant to growth inhibition by excess Dph5 levels. As judged from site-specific mutagenesis, the amidation reaction itself relies on a conserved ATP binding domain in Dph6 that, when altered, blocks diphthamide formation and confers resistance to eEF2 inhibition by sordarin.

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Diphtheria Disease and Genes Involved in Formation of Diphthamide, Key Effector of the Diphtheria Toxin

Cited by 11 publications

References 89 publications

Diphthamide modification of eEF2 is required for gut tumor‐like hyperplasia induced by oncogenic Ras

Diphthamide modification of eEF2 is required for gut tumor‐like hyperplasia induced by oncogenic Ras

The diphthamide modification pathway from Saccharomyces cerevisiae – revisited

Insights into Diphthamide, Key Diphtheria Toxin Effector

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