A novel system to monitor mitochondrial translation in yeast

Suhm, Tamara; Habernig, Lukas; Rzepka, Magdalena; Kaimal, Jayasankar Mohanakrishnan; Andréasson, Claes; Büttner, Sabrina; Ott, Martin

doi:10.15698/mic2018.03.621

Cited by 10 publications

(10 citation statements)

References 30 publications

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“…In fact, the observation that the proteins encoded by mitochondrial genomes are almost entirely nonoverlapping between yeast and mammals suggests that the mito-ribosome adaptations are not necessary for efficient translation, although it should be noted that mito-ribosomes vary much more significantly between organisms than the cytoplasmic ribosomes. Conversely, a super-folding GFP reporter inserted into a mitochondrial ORF was successfully translated in the organelle (Suhm et al 2018), again suggesting that specialization, if it exists, is moderate, and does not preclude the translation of a cytosolic protein.…”

Section: Mitochondrial Ribosomesmentioning

confidence: 99%

Does functional specialization of ribosomes really exist?

Ferretti

Karbstein

2019

RNA

109

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It has recently become clear that ribosomes are much more heterogeneous than previously thought, with diversity arising from rRNA sequence and modifications, ribosomal protein (RP) content and posttranslational modifications (PTMs), as well as bound nonribosomal proteins. In some cases, the existence of these diverse ribosome populations has been verified by biochemical or structural methods. Furthermore, knockout or knockdown of RPs can diversify ribosome populations, while also affecting the translation of some mRNAs (but not others) with biological consequences. However, the effects on translation arising from depletion of diverse proteins can be highly similar, suggesting that there may be a more general defect in ribosome function or stability, perhaps arising from reduced ribosome numbers. Consistently, overall reduced ribosome numbers can differentially affect subclasses of mRNAs, necessitating controls for specificity. Moreover, in order to study the functional consequences of ribosome diversity, perturbations including affinity tags and knockouts are introduced, which can also affect the outcome of the experiment. Here we review the available literature to carefully evaluate whether the published data support functional diversification, defined as diverse ribosome populations differentially affecting translation of distinct mRNA (classes). Based on these observations and the commonly observed cellular responses to perturbations in the system, we suggest a set of important controls to validate functional diversity, which should include gainof-function assays and the demonstration of inducibility under physiological conditions.

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Section: Mitochondrial Ribosomesmentioning

confidence: 99%

Does functional specialization of ribosomes really exist?

Ferretti

Karbstein

2019

RNA

109

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“…In light of the relevance of mitochondrial translation for the biogenesis of the OXPHOS system and, consequently, for cellular metabolism, this effort is an urgent task for the field. Exploiting the possibility to engineer the mitochondrial genome of yeast can be a starting point for constructing genetically encoded reporters to monitor mitochondrial gene expression (Suhm et al, 2018…”

Section: Limitations Of Studymentioning

confidence: 99%

Mitochondrial Translation Efficiency Controls Cytoplasmic Protein Homeostasis

et al. 2018

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Cellular proteostasis is maintained via the coordinated synthesis, maintenance, and breakdown of proteins in the cytosol and organelles. While biogenesis of the mitochondrial membrane complexes that execute oxidative phosphorylation depends on cytoplasmic translation, it is unknown how translation within mitochondria impacts cytoplasmic proteostasis and nuclear gene expression. Here we have analyzed the effects of mutations in the highly conserved accuracy center of the yeast mitoribosome. Decreased accuracy of mitochondrial translation shortened chronological lifespan, impaired management of cytosolic protein aggregates, and elicited a general transcriptional stress response. In striking contrast, increased accuracy extended lifespan, improved cytosolic aggregate clearance, and suppressed a normally stress-induced, Msn2/4-dependent interorganellar proteostasis transcription program (IPTP) that regulates genes important for mitochondrial proteostasis. Collectively, the data demonstrate that cytosolic protein homeostasis and nuclear stress signaling are controlled by mitochondrial translation efficiency in an inter-connected organelle quality control network that determines cellular lifespan.

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“…This result is not due to Cox1 instability as shown by pulse–chase analysis ( Supplementary Figure S1B ). One interpretation of these results is that modest translational defects could be masked due to the cycloheximide treatment that affects cellular protein homeostasis during the in vivo labelling assay ( 37 ). While in organello translation assays are performed without cycloheximide treatment, this approach uses mitochondria removed from the cellular environment which may also limit translational rates.…”

Section: Resultsmentioning

confidence: 99%

“…To show that the OXPHOS reporter translation defects observed were not ARG8 m specific, a mitochondrial-recoded superfolder green fluorescent protein ( sfGFP m ) reporter flanked by COX2 5′- and 3′-UTRs was also assayed ( 37 ). Consistent with our previous results, this reporter exhibited DPC29- dependent expression (Figure 2B ).…”

Section: Resultsmentioning

confidence: 99%

DPC29promotes post-initiation mitochondrial translation inSaccharomyces cerevisiae

Hubble

Henry

2023

Nucleic Acids Research

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Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans—TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We found this 29 kDa protein to be a general mitochondrial translation factor, Dpc29, rather than a COX1-specific translational activator. Its activity was necessary for the optimal expression of OXPHOS mtDNA reporters, and mutations within the mitoribosomal large subunit protein gene MRP7 produced a global reduction of mitochondrial translation in dpc29Δ cells, indicative of a general mitochondrial translation factor. Northern-based mitoribosome profiling of dpc29Δ cells showed higher footprint frequencies at the 3' ends of mRNAs, suggesting a role in translation post-initiation. Additionally, human TACO1 expressed at native levels rescued defects in dpc29Δ yeast strains, suggesting that the two proteins perform highly conserved functions.

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A novel system to monitor mitochondrial translation in yeast

Cited by 10 publications

References 30 publications

Does functional specialization of ribosomes really exist?

Does functional specialization of ribosomes really exist?

Mitochondrial Translation Efficiency Controls Cytoplasmic Protein Homeostasis

DPC29promotes post-initiation mitochondrial translation inSaccharomyces cerevisiae

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