Messenger RNA delivery to mitoribosomes – hints from a bacterial toxin

Bruni, Francesco; Proctor-Kent, Yasmin; Lightowlers, Robert N.

doi:10.1111/febs.15342

Cited by 12 publications

(13 citation statements)

References 45 publications

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“…High-resolution northerns were carried out as described in [ 19 ] with modifications. Total RNA (5 µg) was separated by 15% polyacrylamide-8 M urea gels and electroblotted to Hybond ® -N+ nylon membranes (GE Healthcare Life Sciences, Marlborough, MA, USA).…”

Section: Methodsmentioning

confidence: 99%

Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype

Capriglia

Rizzo

Petrosillo

et al. 2021

Life

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The m.3243A>G mutation within the mitochondrial mt-tRNALeu(UUR) gene is the most prevalent variant linked to mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome. This pathogenic mutation causes severe impairment of mitochondrial protein synthesis due to alterations of the mutated tRNA, such as reduced aminoacylation and a lack of post-transcriptional modification. In transmitochondrial cybrids, overexpression of human mitochondrial leucyl-tRNA synthetase (LARS2) has proven effective in rescuing the phenotype associated with m.3243A>G substitution. The rescuing activity resides in the carboxy-terminal domain (Cterm) of the enzyme; however, the precise molecular mechanisms underlying this process have not been fully elucidated. To deepen our knowledge on the rescuing mechanisms, we demonstrated the interactions of the Cterm with mutated mt-tRNALeu(UUR) and its precursor in MELAS cybrids. Further, the effect of Cterm expression on mitochondrial functions was evaluated. We found that Cterm ameliorates de novo mitochondrial protein synthesis, whilst it has no effect on mt-tRNALeu(UUR) steady-state levels and aminoacylation. Despite the complete recovery of cell viability and the increase in mitochondrial translation, Cterm-overexpressing cybrids were not able to recover bioenergetic competence. These data suggest that, in our MELAS cell model, the beneficial effect of Cterm may be mediated by factors that are independent of the mitochondrial bioenergetics.

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Section: Methodsmentioning

confidence: 99%

Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype

Capriglia

Rizzo

Petrosillo

et al. 2021

Life

Self Cite

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“…Recent work by Bruni et al suggests that the stability of mt-mRNAs also depends on mitoribosome binding [ 111 ]. Depletion of the mt-LSU results in the downregulation of mt-mRNA levels, whereas the depletion of both mt-LSU and mt-SSU partially recovers mtRNA levels.…”

Section: Mitochondrial Rna Surveillance and Decaymentioning

confidence: 99%

“…The authors suggested that when solely mt-LSU is depleted, mt-SSU is available and capable of recruiting mature mt-mRNAs from the LRPPRC/SLIRP complex, thus depriving them of protection from degradation. Under normal conditions, the formation of the ribosome stabilizes mt-mRNAs and protects them from degradation [ 111 ].…”

Section: Mitochondrial Rna Surveillance and Decaymentioning

confidence: 99%

Human Mitochondrial RNA Processing and Modifications: Overview

Jedynak-Slyvka

Jabczynska

Szczęsny

2021

IJMS

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Mitochondria, often referred to as the powerhouses of cells, are vital organelles that are present in almost all eukaryotic organisms, including humans. They are the key energy suppliers as the site of adenosine triphosphate production, and are involved in apoptosis, calcium homeostasis, and regulation of the innate immune response. Abnormalities occurring in mitochondria, such as mitochondrial DNA (mtDNA) mutations and disturbances at any stage of mitochondrial RNA (mtRNA) processing and translation, usually lead to severe mitochondrial diseases. A fundamental line of investigation is to understand the processes that occur in these organelles and their physiological consequences. Despite substantial progress that has been made in the field of mtRNA processing and its regulation, many unknowns and controversies remain. The present review discusses the current state of knowledge of RNA processing in human mitochondria and sheds some light on the unresolved issues.

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“…To ensure that all available high quality data on endogenous protein complexes enter this analysis, the manually curated BioGrid database entry on human ClpX protein associations was downloaded (Table S5). Among these known ClpX interactors, the ClpP-null fibroblasts and brain tissues exhibited consistent significant accumulations for the AAA+ ATPase ClpX itself, another AAA+ ATPase in mitochondria known as VWA8 (Von Willebrand Factor A Domain Containing 8) [39], the nucleoid component POLDIP2 (also known as PDIP38) (DNA Polymerase Delta Interacting Protein 2) [40], the mitochondrial RNA granule component LRPPRC (Leucine Rich Pentatricopeptide Repeat Containing) [41], the mitochondrial precursor RNA processing factor GRSF1 (G-Rich RNA Sequence Binding Factor 1) [42], the mitoribosomal tRNA translocation mediator GFM1 (G Elongation Factor Mitochondrial 1) [43], and the UPR mt sensor CHCHD2 (Coiled-Coil-Helix-Coiled-Coil-Helix Domain Containing 2) [24,44].…”

Section: Selected Dysregulations Are Reproducible In Brain Tissue and Reflect Direct Clpx Impact On Interactorsmentioning

confidence: 99%

Inactivity of Peptidase ClpP Causes Primary Accumulation of Mitochondrial Disaggregase ClpX With Its Interactors at the Nucleoid and RNA Granule

Key¹,

Torres-Odio²,

Bach³

et al. 2021

Preprint

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Biallelic pathogenic variants in CLPP, encoding mitochondrial matrix peptidase ClpP cause a rare autosomal recessive condition, Perrault syndrome type 3 (PRLTS3). It is characterized by primary ovarian insufficiency and early sensorineural hearing loss, often associated with progressive neurological deficits. Mouse models showed that accumulations of (i) its main protein interactor, the substrate-selecting AAA+ ATPase ClpX, (ii) mitoribosomes, and (iii) mtDNA nucleoids are main cellular consequences of ClpP absence. However, the sequence of these events and their validity in human remain unclear. Here, we studied global proteome profiles to define ClpP substrates among mitochondrial ClpX interactors, which accumulated consistently in ClpP-null mouse embryonal fibroblasts and brain. Validation work included novel ClpP-mutant patient fibroblast proteomics. ClpX co-accumulated in mitochondria with POLDIP2 as nucleoid component, LRPPRC as mitochondrial poly(A) mRNA granule element, GFM1 (in mouse also GRSF1) as tRNA processing factors. Only in mouse, accumulated ClpX, GFM1 and GRSF1 appeared in nuclear fractions. Mitoribosomal accumulation was minor. Consistent accumulations in murine and human fibroblasts also affected multimerizing factors not known as ClpX interactors, namely OAT, ASS1, ACADVL, STOM, PRDX3, PC, MUT, ALDH2, PMPCB, UQCRC2 and ACADSB, but the impact on downstream metabolites was marginal. Our data demonstrate the primary impact of ClpXP on the assembly of proteins with nucleic acids, and show nucleoid enlargement in human as a key consequence.

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Messenger RNA delivery to mitoribosomes – hints from a bacterial toxin

Cited by 12 publications

References 45 publications

Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype

Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype

Human Mitochondrial RNA Processing and Modifications: Overview

Inactivity of Peptidase ClpP Causes Primary Accumulation of Mitochondrial Disaggregase ClpX With Its Interactors at the Nucleoid and RNA Granule

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