scholarly journals Proline Residues at the C Terminus of Nascent Chains Induce SsrA Tagging during Translation Termination

2002 ◽  
Vol 277 (37) ◽  
pp. 33825-33832 ◽  
Author(s):  
Christopher S. Hayes ◽  
Baundauna Bose ◽  
Robert T. Sauer
Keyword(s):  
Translation Termination ◽  
C Terminus

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.

scholarly journals Impact of a hypomorphic Artemis disease allele on lymphocyte development, DNA end processing, and genome stability

2009 ◽  
Vol 206 (4) ◽  
pp. 893-908 ◽  
Author(s):  
Ying Huang ◽  
William Giblin ◽  
Martina Kubec ◽  
Gerwin Westfield ◽  
Jordan St. Charles ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Genome Stability ◽  
Molecular Mechanisms ◽  
Translation Termination ◽  
Severe Combined Immunodeficiency ◽  
Strand Break ◽  
Hypomorphic Mutation ◽  
C Terminus ◽  
B And T Lymphocytes

Artemis was initially discovered as the gene inactivated in human radiosensitive T−B− severe combined immunodeficiency, a syndrome characterized by the absence of B and T lymphocytes and cellular hypersensitivity to ionizing radiation. Hypomorphic Artemis alleles have also been identified in patients and are associated with combined immunodeficiencies of varying severity. We examine the molecular mechanisms underlying a syndrome of partial immunodeficiency caused by a hypomorphic Artemis allele using the mouse as a model system. This mutation, P70, leads to premature translation termination that deletes a large portion of a nonconserved C terminus. We find that homozygous Artemis-P70 mice exhibit reduced numbers of B and T lymphocytes, thereby recapitulating the patient phenotypes. The hypomorphic mutation results in impaired end processing during the lymphoid-specific DNA rearrangement known as V(D)J recombination, defective double-strand break repair, and increased chromosomal instability. Biochemical analyses reveal that the Artemis-P70 mutant protein interacts with the DNA-dependent protein kinase catalytic subunit and retains significant, albeit reduced, exo- and endonuclease activities but does not undergo phosphorylation. Together, our findings indicate that the Artemis C terminus has critical in vivo functions in ensuring efficient V(D)J rearrangements and maintaining genome integrity.

scholarly journals MISTERMINATE Mechanistically Links Mitochondrial Dysfunction with Proteostasis Failure

2019 ◽  
Author(s):  
Zhihao Wu ◽  
Ishaq Tantray ◽  
Junghyun Lim ◽  
Songjie Chen ◽  
Yu Li ◽  
...  
Keyword(s):  
Amino Acids ◽  
Mitochondrial Dysfunction ◽  
Complex I ◽  
Mammalian Cells ◽  
Protein C ◽  
Stop Codon ◽  
Translation Termination ◽  
Disease Model ◽  
C Terminus ◽  
Translational Termination

SUMMARYMitochondrial dysfunction and proteostasis failure frequently coexist as hallmarks of neurodegenerative disease. How these pathologies are related is not well understood. Here we describe a phenomenon termed MISTERMINATE (mitochondrial stress-induced translational termination impairment and protein carboxyl terminal extension), which mechanistically links mitochondrial dysfunction with proteostasis failure. We show that mitochondrial dysfunction impairs translational termination of nuclear-encoded mitochondrial mRNAs including complex-I 30kD subunit (C-I30) mRNA, occurring on mitochondrial surface in Drosophila and mammalian cells. Ribosomes stalled at the normal stop codon continue to add to the C-terminus of C-I30 certain amino acids non-coded by mRNA template. C-terminally-extended C-I30 is toxic when assembled into C-I and forms aggregates in the cytosol. Enhancing co-translational quality control prevents C-I30 C-terminal extension and rescues mitochondrial and neuromuscular degeneration in a Parkinson’s disease model. These findings emphasize the importance of efficient translation termination and reveal unexpected link between mitochondrial health and proteome homeostasis mediated by MISTERMINATE.

scholarly journals The C-terminus of eRF1 defines a functionally important domain for translation termination in Saccharomyces cerevisiae

1999 ◽  
Vol 32 (3) ◽  
pp. 485-496 ◽  
Author(s):  
Lily Eurwilaichitr ◽  
Fiona M. Graves ◽  
Ian Stansfield ◽  
Mick F. Tuite
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Translation Termination ◽  
C Terminus

scholarly journals Hibiscus chlorotic ringspot virus p27 and Its Isoforms Affect Symptom Expression and Potentiate Virus Movement in Kenaf (Hibiscus cannabinus L.)

2006 ◽  
Vol 19 (9) ◽  
pp. 948-957 ◽  
Author(s):  
T. Zhou ◽  
Z. F. Fan ◽  
H. F. Li ◽  
S. M. Wong
Keyword(s):  
Translation Termination ◽  
Hibiscus Cannabinus ◽  
Ringspot Virus ◽  
Start Codon ◽  
Wild Type Virus ◽  
Virus Movement ◽  
Membrane Structures ◽  
Systemic Movement ◽  
C Terminus ◽  
Green Fluorescent

Hibiscus chlorotic ringspot virus (HCRSV), a member of the genus Carmovirus, encodes p27 (27-kDa protein) and two other in-frame isoforms (p25 and p22.5) that are coterminal at the carboxyl end. Only p27, which initiates at the 2570CUG codon, was detected in transfected kenaf (Hibiscus cannabinus L.) protoplasts through fusion to a Flag tag at either its N or C terminus. Subcellular localization of a p27-green fluorescent fusion protein in kenaf epidermal cells showed that it was localized to membrane structures close to cell walls. To study the functions of these proteins, a number of start codon mutants and premature translation termination mutants were constructed. Phenotypic differences were observed between the wild-type virus and these mutants during infection. Infectivity assays on plants indicated that p27 is a determinant of symptom severity. Without p25, appearance of symptoms on systemically infected kenaf leaves was delayed by 4 to 8 days. In a timecourse analysis, Western blot assays revealed that the delay corresponded to retardation in virus systemic movement, which suggested that p25 is probably involved in virus systemic movement. Mutations disrupting expression of p22.5 did not affect symptoms or virus movement.

Immunocytochemical localization of β1-4 galactosyltransferase in endometrial carcinoma cells

1990 ◽  
Vol 48 (3) ◽  
pp. 944-945
Author(s):  
Ichiro Yamamoto ◽  
Toshiaki Tachibana ◽  
Hiroko Maruyama ◽  
Noriyuki Komatsu ◽  
Hiroyuki Kuramoto ◽  
...  
Keyword(s):  
Endometrial Carcinoma ◽  
Cell Lines ◽  
Endometrial Adenocarcinoma ◽  
Protein A ◽  
Rabbit Antiserum ◽  
Carcinoma Cells ◽  
Affinity Column ◽  
Antibody Technique ◽  
Galactosyl Transferase ◽  
C Terminus

We have paid attention to the alteration of glycosyltransferase in carcinoma cells, because it might be related to the malignancy of the cells. In this connection, localization of β1-4 galactosyl transferase (β1-4 Gal T) in human endometrial carcinoma cells was examined immunocytochemically using two kinds of cell lines, each of which showed different degree of differentiation.An antibody was purified from the rabbit antiserum against the synthetic peptide, IFNRLVFRGMSC (W89) of human β1-4 Gal T coupled with KLH (keyhole limpet hemocyanine) by protein A column and peptide-affinity column chromatography. The anti-W89 serum reacts to the C-terminus of human β 1-4 Gal T and to both membrane-bound and soluble forms of the enzyme. Cell line of well differentiated endometrial adenocarcinoma (I) and that of poorly differentiated endometrial adenocarcinoma (50B) were cultivated respectively in MEM medium containing 15% FCS and 2 mM glutamine for 4 d at 37°C under 5% CO2. The cells were fixed in a mixture of 4% paraformaldehyde and 0.1% glutaraldehyde in 0.1 M Soerensen’s phosphate buffer (pH 7.4) at 4°C for 30 min, washed with PBS, then freezed and thawed. The indirect method of the peroxidase- labeled antibody technique was used for immunocytochemistry of both LM and TEM on the cell lines. The cells were dehydrated in ethanol and embedded in TAAB 812. Ultrathin sections were observed under a TEM, JEM-100S.

Influence of nascent polypeptide positive charges on translation dynamics

2020 ◽  
Vol 477 (15) ◽  
pp. 2921-2934
Author(s):  
Rodrigo D. Requião ◽  
Géssica C. Barros ◽  
Tatiana Domitrovic ◽  
Fernando L. Palhano
Keyword(s):  
Mrna Decay ◽  
Translation Termination ◽  
Published Data ◽  
Translation Efficiency ◽  
Amino Acid Residues ◽  
High Concentration ◽  
Strong Argument ◽  
Translation Arrest ◽  
Exit Tunnel ◽  
Positively Charged

Protein segments with a high concentration of positively charged amino acid residues are often used in reporter constructs designed to activate ribosomal mRNA/protein decay pathways, such as those involving nonstop mRNA decay (NSD), no-go mRNA decay (NGD) and the ribosome quality control (RQC) complex. It has been proposed that the electrostatic interaction of the positively charged nascent peptide with the negatively charged ribosomal exit tunnel leads to translation arrest. When stalled long enough, the translation process is terminated with the degradation of the transcript and an incomplete protein. Although early experiments made a strong argument for this mechanism, other features associated with positively charged reporters, such as codon bias and mRNA and protein structure, have emerged as potent inducers of ribosome stalling. We carefully reviewed the published data on the protein and mRNA expression of artificial constructs with diverse compositions as assessed in different organisms. We concluded that, although polybasic sequences generally lead to lower translation efficiency, it appears that an aggravating factor, such as a nonoptimal codon composition, is necessary to cause translation termination events.

SAC3B is a target of CML19, the centrin 2 of Arabidopsis thaliana

2020 ◽  
Vol 477 (1) ◽  
pp. 173-189 ◽  
Author(s):  
Marco Pedretti ◽  
Carolina Conter ◽  
Paola Dominici ◽  
Alessandra Astegno
Keyword(s):  
Excision Repair ◽  
Complex Structure ◽  
Binding Motif ◽  
C Terminus ◽  
Repair Protein ◽  
Nucleotide Excision ◽  
Ef Hand ◽  
Molecular Determinants ◽  
Structure In Solution

Arabidopsis centrin 2, also known as calmodulin-like protein 19 (CML19), is a member of the EF-hand superfamily of calcium (Ca2+)-binding proteins. In addition to the notion that CML19 interacts with the nucleotide excision repair protein RAD4, CML19 was suggested to be a component of the transcription export complex 2 (TREX-2) by interacting with SAC3B. However, the molecular determinants of this interaction have remained largely unknown. Herein, we identified a CML19-binding site within the C-terminus of SAC3B and characterized the binding properties of the corresponding 26-residue peptide (SAC3Bp), which exhibits the hydrophobic triad centrin-binding motif in a reversed orientation (I8W4W1). Using a combination of spectroscopic and calorimetric experiments, we shed light on the SAC3Bp–CML19 complex structure in solution. We demonstrated that the peptide interacts not only with Ca2+-saturated CML19, but also with apo-CML19 to form a protein–peptide complex with a 1 : 1 stoichiometry. Both interactions involve hydrophobic and electrostatic contributions and include the burial of Trp residues of SAC3Bp. However, the peptide likely assumes different conformations upon binding to apo-CML19 or Ca2+-CML19. Importantly, the peptide dramatically increases the affinity for Ca2+ of CML19, especially of the C-lobe, suggesting that in vivo the protein would be Ca2+-saturated and bound to SAC3B even at resting Ca2+-levels. Our results, providing direct evidence that Arabidopsis SAC3B is a CML19 target and proposing that CML19 can bind to SAC3B through its C-lobe independent of a Ca2+ stimulus, support a functional role for these proteins in TREX-2 complex and mRNA export.

E3 ubiquitin ligases

2005 ◽  
Vol 41 ◽  
pp. 15-30 ◽  
Author(s):  
Helen C. Ardley ◽  
Philip A. Robinson
Keyword(s):  
Protein Complexes ◽  
Loss Of Function ◽  
Direct Role ◽  
Cellular Processes ◽  
Substrate Protein ◽  
Protein Ubiquitination ◽  
C Terminus ◽  
Full Complement ◽  
Spatio Temporal ◽  
Eukaryotic Organisms

The selectivity of the ubiquitin–26 S proteasome system (UPS) for a particular substrate protein relies on the interaction between a ubiquitin-conjugating enzyme (E2, of which a cell contains relatively few) and a ubiquitin–protein ligase (E3, of which there are possibly hundreds). Post-translational modifications of the protein substrate, such as phosphorylation or hydroxylation, are often required prior to its selection. In this way, the precise spatio-temporal targeting and degradation of a given substrate can be achieved. The E3s are a large, diverse group of proteins, characterized by one of several defining motifs. These include a HECT (homologous to E6-associated protein C-terminus), RING (really interesting new gene) or U-box (a modified RING motif without the full complement of Zn2+-binding ligands) domain. Whereas HECT E3s have a direct role in catalysis during ubiquitination, RING and U-box E3s facilitate protein ubiquitination. These latter two E3 types act as adaptor-like molecules. They bring an E2 and a substrate into sufficiently close proximity to promote the substrate's ubiquitination. Although many RING-type E3s, such as MDM2 (murine double minute clone 2 oncoprotein) and c-Cbl, can apparently act alone, others are found as components of much larger multi-protein complexes, such as the anaphase-promoting complex. Taken together, these multifaceted properties and interactions enable E3s to provide a powerful, and specific, mechanism for protein clearance within all cells of eukaryotic organisms. The importance of E3s is highlighted by the number of normal cellular processes they regulate, and the number of diseases associated with their loss of function or inappropriate targeting.

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