scholarly journals Iron in Translation: From the Beginning to the End

2021 ◽  
Vol 9 (5) ◽  
pp. 1058
Author(s):  
Antonia María Romero ◽  
María Teresa Martínez-Pastor ◽  
Sergi Puig
Keyword(s):  
Translational Regulation ◽  
Translation Termination ◽  
Protein Biosynthesis ◽  
Regulatory Protein ◽  
Dynamic Control ◽  
Essential Element ◽  
Cellular Functions ◽  
Yeast Saccharomyces Cerevisiae ◽  
Eukaryotic Translation ◽  
Responsive Element

Iron is an essential element for all eukaryotes, since it acts as a cofactor for many enzymes involved in basic cellular functions, including translation. While the mammalian iron-regulatory protein/iron-responsive element (IRP/IRE) system arose as one of the first examples of translational regulation in higher eukaryotes, little is known about the contribution of iron itself to the different stages of eukaryotic translation. In the yeast Saccharomyces cerevisiae, iron deficiency provokes a global impairment of translation at the initiation step, which is mediated by the Gcn2-eIF2α pathway, while the post-transcriptional regulator Cth2 specifically represses the translation of a subgroup of iron-related transcripts. In addition, several steps of the translation process depend on iron-containing enzymes, including particular modifications of translation elongation factors and transfer RNAs (tRNAs), and translation termination by the ATP-binding cassette family member Rli1 (ABCE1 in humans) and the prolyl hydroxylase Tpa1. The influence of these modifications and their correlation with codon bias in the dynamic control of protein biosynthesis, mainly in response to stress, is emerging as an interesting focus of research. Taking S. cerevisiae as a model, we hereby discuss the relevance of iron in the control of global and specific translation steps.

scholarly journals Novel Translational Control through an Iron-Responsive Element by Interaction of Multifunctional Protein YB-1 and IRP2

2002 ◽  
Vol 22 (18) ◽  
pp. 6375-6383 ◽  
Author(s):  
Megumi Ashizuka ◽  
Takao Fukuda ◽  
Takanori Nakamura ◽  
Kanemitsu Shirasuna ◽  
Kazuhiro Iwai ◽  
...  
Keyword(s):  
Translational Control ◽  
Ribosomal Proteins ◽  
Translational Regulation ◽  
Regulatory Protein ◽  
Direct Interaction ◽  
In Vitro Translation ◽  
High Concentration ◽  
Iron Responsive Element ◽  
Responsive Element

ABSTRACT The eukaryotic Y-box-binding protein YB-1 functions in various biological processes, including DNA repair, cell proliferation, and transcriptional and translational controls. To gain further insight into how human YB-1 plays its role in pleiotropic functions, we here used two-hybrid screenings to identify partners of this protein; the results showed that YB-1 itself, iron-regulatory protein 2 (IRP2), and five ribosomal proteins each served as partners to YB-1. We then examined the biological effect of the interaction of YB-1 and IRP2 on translational regulation. Both in vitro binding and coimmunoprecipitation assays showed the direct interaction of YB-1 and IRP2 in the presence of a high concentration of iron. RNA gel shift assays showed that YB-1 reduced the formation of the IRP2-mRNA complex when the iron-responsive element of the ferritin mRNA 5′ untranslated region (UTR) was used as a probe. By using an in vitro translation assay using luciferase mRNA ligated to the ferritin mRNA 5′UTR as a reporter construct, we showed that both YB-1 and IRP2 inhibited the translation of the mRNA. However, coadministration of YB-1 and IRP2 proteins abrogated the inhibition of protein synthesis by each protein. An In vivo coimmunoprecipitation assay showed that IRP2 bound to YB-1 in the presence of iron and a proteasome inhibitor. The direct interaction of YB-1 and IRP2 provides the first evidence of the involvement of YB-1 in the translational regulation of an iron-related protein.

An IRP-like protein from Plasmodium falciparum binds to a mammalian iron-responsive element

Blood ◽  
2001 ◽  
Vol 98 (8) ◽  
pp. 2555-2562 ◽  
Author(s):  
Mark Loyevsky ◽  
Timothy LaVaute ◽  
Charles R. Allerson ◽  
Robert Stearman ◽  
Olakunle O. Kassim ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Regulatory Protein ◽  
Protein S ◽  
Fold Increase ◽  
Binding Activity ◽  
Mobility Shift ◽  
Iron Responsive Element ◽  
Element Binding Protein ◽  
Responsive Element ◽  
Electrophoretic Mobility Shift Assays

Abstract This study cloned and sequenced the complementary DNA (cDNA) encoding of a putative malarial iron responsive element-binding protein (PfIRPa) and confirmed its identity to the previously identified iron-regulatory protein (IRP)–like cDNA from Plasmodium falciparum. Sequence alignment showed that the plasmodial sequence has 47% identity with human IRP1. Hemoglobin-free lysates obtained from erythrocyte-stage P falciparum contain a protein that binds a consensus mammalian iron-responsive element (IRE), indicating that a protein(s) with iron-regulatory activity was present in the lysates. IRE-binding activity was found to be iron regulated in the electrophoretic mobility shift assays. Western blot analysis showed a 2-fold increase in the level of PfIRPa in the desferrioxamine-treated cultures versus control or iron-supplemented cells. Malarial IRP was detected by anti-PfIRPa antibody in the IRE-protein complex fromP falciparum lysates. Immunofluorescence studies confirmed the presence of PfIRPa in the infected red blood cells. These findings demonstrate that erythrocyte P falciparum contains an iron-regulated IRP that binds a mammalian consensus IRE sequence, raising the possibility that the malaria parasite expresses transcripts that contain IREs and are iron-dependently regulated.

scholarly journals Proteomic Signatures of Clostridium difficile Stressed with Metronidazole, Vancomycin, or Fidaxomicin

Cells ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 213 ◽  
Author(s):  
Sandra Maaß ◽  
Andreas Otto ◽  
Dirk Albrecht ◽  
Katharina Riedel ◽  
Anke Trautwein-Schult ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Antibiotic Treatment ◽  
Antimicrobial Agents ◽  
Cell Envelope ◽  
Protein Biosynthesis ◽  
Cellular Functions ◽  
Antibiotic Resistant ◽  
Incidence And Mortality ◽  
A Cell ◽  
Proteomic Response

The anaerobic pathogen Clostridium difficile is of growing significance for the health care system due to its increasing incidence and mortality. As C. difficile infection is both supported and treated by antibiotics, a deeper knowledge on how antimicrobial agents affect the physiology of this important pathogen may help to understand and prevent the development and spreading of antibiotic resistant strains. As the proteomic response of a cell to stress aims at counteracting the harmful effects of this stress, it can be expected that the pattern of a pathogen’s responses to antibiotic treatment will be dependent on the antibiotic mechanism of action. Hence, every antibiotic treatment is expected to result in a specific proteomic signature characterizing its mode of action. In the study presented here, the proteomic response of C. difficile 630∆erm to vancomycin, metronidazole, and fidaxomicin stress was investigated on the level of protein abundance and protein synthesis based on 2D PAGE. The quantification of 425 proteins of C. difficile allowed the deduction of proteomic signatures specific for each drug treatment. Indeed, these proteomic signatures indicate very specific cellular responses to each antibiotic with only little overlap of the responses. Whereas signature proteins for vancomycin stress fulfil various cellular functions, the proteomic signature of metronidazole stress is characterized by alterations of proteins involved in protein biosynthesis and protein degradation as well as in DNA replication, recombination, and repair. In contrast, proteins differentially expressed after fidaxomicin treatment can be assigned to amino acid biosynthesis, transcription, cell motility, and the cell envelope functions. Notably, the data provided by this study hint also at so far unknown antibiotic detoxification mechanisms.

scholarly journals CTELS: A Cell-Free System for the Analysis of Translation Termination Rate

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 911 ◽  
Author(s):  
Kseniya A. Lashkevich ◽  
Valeriya I. Shlyk ◽  
Artem S. Kushchenko ◽  
Vadim N. Gladyshev ◽  
Elena Z. Alkalaeva ◽  
...  
Keyword(s):  
Stop Codon ◽  
Translation Termination ◽  
Protein Biosynthesis ◽  
Inhibitory Effect ◽  
In Vitro Translation ◽  
Nonsense Suppression ◽  
Translation System ◽  
Free System ◽  
Termination Rate

Translation termination is the final step in protein biosynthesis when the synthesized polypeptide is released from the ribosome. Understanding this complex process is important for treatment of many human disorders caused by nonsense mutations in important genes. Here, we present a new method for the analysis of translation termination rate in cell-free systems, CTELS (for C-terminally extended luciferase-based system). This approach was based on a continuously measured luciferase activity during in vitro translation reaction of two reporter mRNA, one of which encodes a C-terminally extended luciferase. This extension occupies a ribosomal polypeptide tunnel and lets the completely synthesized enzyme be active before translation termination occurs, i.e., when it is still on the ribosome. In contrast, luciferase molecule without the extension emits light only after its release. Comparing the translation dynamics of these two reporters allows visualization of a delay corresponding to the translation termination event. We demonstrated applicability of this approach for investigating the effects of cis- and trans-acting components, including small molecule inhibitors and read-through inducing sequences, on the translation termination rate. With CTELS, we systematically assessed negative effects of decreased 3′ UTR length, specifically on termination. We also showed that blasticidin S implements its inhibitory effect on eukaryotic translation system, mostly by affecting elongation, and that an excess of eRF1 termination factor (both the wild-type and a non-catalytic AGQ mutant) can interfere with elongation. Analysis of read-through mechanics with CTELS revealed a transient stalling event at a “leaky” stop codon context, which likely defines the basis of nonsense suppression.

scholarly journals uS3/Rps3 controls fidelity of translation termination and programmed stop codon readthrough in co-operation with eIF3

2019 ◽  
Vol 47 (21) ◽  
pp. 11326-11343 ◽  
Author(s):  
Kristýna Poncová ◽  
Susan Wagner ◽  
Myrte Esmeralda Jansen ◽  
Petra Beznosková ◽  
Stanislava Gunišová ◽  
...  
Keyword(s):  
Translational Control ◽  
Stop Codon ◽  
Translation Termination ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation ◽  
C Terminus ◽  
Context Specific ◽  
Stop Codon Readthrough

Abstract Ribosome was long considered as a critical yet passive player in protein synthesis. Only recently the role of its basic components, ribosomal RNAs and proteins, in translational control has begun to emerge. Here we examined function of the small ribosomal protein uS3/Rps3, earlier shown to interact with eukaryotic translation initiation factor eIF3, in termination. We identified two residues in consecutive helices occurring in the mRNA entry pore, whose mutations to the opposite charge either reduced (K108E) or increased (R116D) stop codon readthrough. Whereas the latter increased overall levels of eIF3-containing terminating ribosomes in heavy polysomes in vivo indicating slower termination rates, the former specifically reduced eIF3 amounts in termination complexes. Combining these two mutations with the readthrough-reducing mutations at the extreme C-terminus of the a/Tif32 subunit of eIF3 either suppressed (R116D) or exacerbated (K108E) the readthrough phenotypes, and partially corrected or exacerbated the defects in the composition of termination complexes. In addition, we found that K108 affects efficiency of termination in the termination context-specific manner by promoting incorporation of readthrough-inducing tRNAs. Together with the multiple binding sites that we identified between these two proteins, we suggest that Rps3 and eIF3 closely co-operate to control translation termination and stop codon readthrough.

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