scholarly journals Frameshifting at collided ribosomes is modulated by elongation factor eEF3 and by Integrated Stress Response regulators Gcn1 and Gcn20

RNA ◽  
2021 ◽  
pp. rna.078964.121
Author(s):  
Lisa Houston ◽  
Evan M Platten ◽  
Sara M Connelly ◽  
Jiyu Wang ◽  
Elizabeth J Grayhack
Keyword(s):  
Quality Control ◽  
Stress Response ◽  
Elongation Factor ◽  
Mutant Form ◽  
Control Mechanisms ◽  
Integrated Stress Response ◽  
Response Regulators ◽  
Yeast Saccharomyces Cerevisiae ◽  
Full Spectrum ◽  
Translation Elongation

Ribosome stalls can result in ribosome collisions that elicit quality control responses, one function of which is to prevent ribosome frameshifting, an activity that entails interaction of the conserved yeast protein Mbf1 with uS3 on colliding ribosomes. However, the full spectrum of factors that mediate frameshifting during ribosome collisions is unknown. To delineate such factors in the yeast Saccharomyces cerevisiae, we used genetic selections for mutants that affect frameshifting from a known ribosome stall site, CGA codon repeats. We show that the general translation elongation factor eEF3 and the Integrated Stress Response (ISR) pathway components Gcn1 and Gcn20 modulate frameshifting in opposing manners. We found a mutant form of eEF3 that specifically suppressed frameshifting, but not translation inhibition by CGA codons. Thus, we infer that frameshifting at collided ribosomes requires eEF3, which facilitates tRNA-mRNA translocation and E-site tRNA release in yeast and other single cell organisms. By contrast, we found that removal of either Gcn1 or Gcn20, which bind collided ribosomes with Mbf1, increased frameshifting. Thus, we conclude that frameshifting is suppressed by Gcn1 and Gcn20, although these effects are not mediated primarily through activation of the ISR. Furthermore, we examined the relationship between eEF3-mediated frameshifting and other quality control mechanisms, finding that Mbf1 requires either Hel2 or Gcn1 to suppress frameshifting with wild type eEF3. Thus, these results provide evidence of a direct link between translation elongation and frameshifting at collided ribosomes, as well as evidence that frameshifting is constrained by quality control mechanisms that act on collided ribosomes.

scholarly journals Frameshifting at collided ribosomes is modulated by elongation factor eEF3 and by Integrated Stress Response regulators Gcn1 and Gcn20

2021 ◽  
Author(s):  
Lisa Houston ◽  
Evan M Platten ◽  
Sara M Connelly ◽  
Jiyu Wang ◽  
Elizabeth J Grayhack
Keyword(s):  
Quality Control ◽  
Stress Response ◽  
Elongation Factor ◽  
Mutant Form ◽  
Control Mechanisms ◽  
Integrated Stress Response ◽  
Response Regulators ◽  
Full Spectrum ◽  
Translation Elongation ◽  
Relationship Of

Ribosome stalls can result in ribosome collisions that elicit quality control responses, one function of which is to prevent frameshifting by the stalled ribosome, an activity that entails interaction of the conserved yeast protein Mbf1 with uS3 on colliding ribosomes. However, the full spectrum of factors that mediate frameshifting during ribosome collisions is unknown. To delineate such factors in the yeast Saccharomyces cerevisiae, we used genetic selections for mutants that either suppress or increase frameshifting from a known ribosome stall site, CGA codon repeats. We show that the general translation elongation factor eEF3 promotes frameshifting, while Integrated Stress Response (ISR) pathway components Gcn1 and Gcn20 suppress frameshifting. We found a mutant form of eEF3 that specifically suppressed frameshifting, but not translation inhibition by CGA codons. Thus, we infer that frameshifting at collided ribosomes requires eEF3, which facilitates tRNA-mRNA translocation and E-site tRNA release in yeast and other single cell organisms. By contrast, we found that removal of either Gcn1 or Gcn20, which bind collided ribosomes with Mbf1, increased frameshifting. Thus, we conclude that frameshifting is suppressed by Gcn1 and Gcn20, although these effects are not mediated through activation of the ISR. Furthermore, we examined the relationship of eEF3-mediated frameshifting to other quality control mechanisms, finding that the eEF3-mediated frameshifting competes with No-Go decay, Mbf1 and Gcn1/20. Thus, these results provide evidence of a direct link between translation elongation and frameshifting at collided ribosomes, as well as evidence that frameshifting competes with other quality control pathways that act on collided ribosomes.

scholarly journals Distinct regulatory ribosomal ubiquitylation events are reversible and hierarchically organized

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Danielle M Garshott ◽  
Elayanambi Sundaramoorthy ◽  
Marilyn Leonard ◽  
Eric J Bennett
Keyword(s):  
Quality Control ◽  
Stress Response ◽  
Ribosomal Proteins ◽  
Functional Role ◽  
Stress Recovery ◽  
Integrated Stress Response ◽  
Hierarchical Relationship ◽  
Stress Dependent

Activation of the integrated stress response (ISR) or the ribosome-associated quality control (RQC) pathway stimulates regulatory ribosomal ubiquitylation (RRub) on distinct 40S ribosomal proteins, yet the cellular role and fate of ubiquitylated proteins remain unclear. We demonstrate that uS10 and uS5 ubiquitylation are dependent upon eS10 or uS3 ubiquitylation, respectively, suggesting that a hierarchical relationship exists among RRub events establishing a ubiquitin code on ribosomes. We show that stress dependent RRub events diminish after initial stimuli and that demodification by deubiquitylating enzymes contributes to reduced RRub levels during stress recovery. Utilizing an optical RQC reporter we identify OTUD3 and USP21 as deubiquitylating enzymes that antagonize ZNF598-mediated 40S ubiquitylation and can limit RQC activation. Critically, cells lacking USP21 or OTUD3 have altered RQC activity and delayed eS10 deubiquitylation indicating a functional role for deubiquitylating enzymes within the RQC pathway.

scholarly journals The Translation Elongation Factor eEF1B Plays a Role in the Oxidative Stress Response Pathway

RNA Biology ◽  
2004 ◽  
Vol 1 (2) ◽  
pp. 89-94 ◽  
Author(s):  
Olubunmi Olarewaju ◽  
Pedro A. Ortiz ◽  
Wasimul Q. Chowdhury ◽  
Ishita Chatterjee ◽  
Terri Goss Kinzy
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Elongation Factor ◽  
Oxidative Stress Response ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
Stress Response Pathway

scholarly journals iRQC, a surveillance pathway for 40S ribosomal quality control during mRNA translation initiation

2021 ◽  
Author(s):  
Danielle Marie Garshott ◽  
Heeseon An ◽  
Elayanambi Sundaramoorthy ◽  
Marilyn Leonard ◽  
Alison Vicary ◽  
...  
Keyword(s):  
Quality Control ◽  
Stress Response ◽  
Ribosomal Protein ◽  
Protein Degradation ◽  
Ubiquitin Ligase ◽  
Translation Initiation ◽  
Mrna Translation ◽  
Start Codon ◽  
Independent Manner ◽  
Translation Elongation

Since multiple ribosomes can engage a single mRNA, nonuniform ribosome progression can result in collisions. Ribosome collisions during translation elongation elicit a multifaceted ribosome-associated quality control (RQC) response. Despite advanced mechanistic understanding of translation initiation, a parallel RQC pathway that acts on collided preinitiation complexes has not been described. Here, we show that blocking progression of scanning or elongating ribosomes past the start codon triggers uS3 and uS5 ribosomal ubiquitylation. We demonstrate that conditions that activate the integrated stress response can also induce preinitiation complex collisions. The ubiquitin ligase, RNF10, and the deubiquitylating enzyme, USP10, are the key regulators of uS3 and uS5 ubiquitylation. Prolonged uS3 and uS5 ubiquitylation results in 40S, but not 60S, ribosomal protein degradation in an autophagy-independent manner. This study identifies a distinct arm in the RQC pathway, initiation RQC (iRQC), that acts on pervasive ribosome collisions during translation initiation to modulate translation activity and capacity.

Mitophagy, mitochondrial dynamics and the general stress response in yeast

2011 ◽  
Vol 39 (5) ◽  
pp. 1514-1519 ◽  
Author(s):  
Matthias Müller ◽  
Andreas S. Reichert
Keyword(s):  
Quality Control ◽  
Stress Response ◽  
Neurodegenerative Disorders ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Nutrient Sensing ◽  
Control Mechanisms ◽  
General Stress Response ◽  
General Stress

Autophagy is a fundamental cellular process promoting survival under various environmental stress conditions. Selective types of autophagy have gained much interest recently as they are involved in specific quality control mechanisms removing, for example, aggregated proteins or dysfunctional mitochondria. This is considered to counteract the development of a number of neurodegenerative disorders and aging. Here we review the role of mitophagy and mitochondrial dynamics in ensuring quality control of mitochondria. In particular, we provide possible explanations why mitophagy in yeast, in contrast with the situation in mammals, was found to be independent of mitochondrial fission. We further discuss recent findings linking these processes to nutrient sensing pathways and the general stress response in yeast. In particular, we propose a model for how the stress response protein Whi2 and the Ras/PKA (protein kinase A) signalling pathway are possibly linked and thereby regulate mitophagy.

scholarly journals Improper Organization of the Actin Cytoskeleton Affects Protein Synthesis at Initiation

2006 ◽  
Vol 27 (5) ◽  
pp. 1974-1989 ◽  
Author(s):  
Stephane R. Gross ◽  
Terri Goss Kinzy
Keyword(s):  
Actin Cytoskeleton ◽  
Elongation Factor ◽  
Actin Binding ◽  
Mutant Form ◽  
Translation Elongation ◽  
Eukaryotic Translation ◽  
Unique Effect ◽  
Genes Encoding ◽  
Mutant Forms

ABSTRACT Although the actin cytoskeleton and the translation machinery are considered to be separate cellular complexes, growing evidence supports overlapping regulation of the two systems. Because of its interaction with actin, the eukaryotic translation elongation factor 1A (eEF1A) is proposed to be a regulator or link between these processes. Using a genetic approach with the yeast Saccharomyces cerevisiae, specific regions of eEF1A responsible for actin interactions and bundling were identified. Five new mutations were identified along one face of eEF1A. Dramatic changes in cell growth, cell morphology, and actin cable and patch formation as well as a unique effect on total translation in strains expressing the F308L or S405P eEF1A mutant form were observed. The translation effects do not correlate with reduced translation elongation but instead include an initiation defect. Biochemical analysis of the eEF1A mutant forms demonstrated reduced actin-bundling activity in vitro. Reduced total translation and/or the accumulation of 80S ribosomes in strains with either a mutation or a null allele of genes encoding actin itself or actin-regulating proteins Tpm1p, Mdm20p, and Bnirp/Bni1p was observed. Our data demonstrate that eEF1A, other actin binding proteins, and actin mutants affect translation initiation through the actin cytoskeleton.

Eukaryotic elongation factor 2 kinase regulates the cold stress response by slowing translation elongation

2015 ◽  
Vol 465 (2) ◽  
pp. 227-238 ◽  
Author(s):  
John R. P. Knight ◽  
Amandine Bastide ◽  
Anne Roobol ◽  
Jo Roobol ◽  
Thomas J. Jackson ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Synthesis ◽  
Stress Response ◽  
Cold Stress ◽  
Elongation Factor ◽  
Translation Elongation ◽  
Elongation Factor 2 ◽  
Eukaryotic Elongation Factor 2 ◽  
Eukaryotic Elongation Factor

Modulation of translation elongation rates, and not initiation, is responsible for the reduction of protein synthesis in response to cold-stress induced in mild hypothermic conditions. This is mediated by release of Ca2+ ions from the endoplasmic reticulum (ER) and activation of eEF2K (eukaryotic elongation factor 2 kinase).

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