Arginine-rich C9ORF72 ALS proteins stall ribosomes in a manner distinct from a canonical ribosome-associated quality control substrate

Kriachkov, Viacheslav; Ormsby, Angelique R.; Kusnadi, Eric; McWilliam, Hamish E G; Mintern, Justine D.; Amarasinghe, Shanika L.; Ritchie, Matthew E.; Furic, Luc; Hatters, Danny M.

doi:10.1016/j.jbc.2022.102774

Cited by 16 publications

(16 citation statements)

References 83 publications

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“…Factors from protein surveillance pathways directly associate with ALS/FTD-causing toxic arginine-rich dipeptide repeat (DPR) proteins, GR, and PR (98,100,101,110). AUG-initiated arginine-rich proteins from GR and PR encoding RNAs induce ribosomal stalling in an RNA-independent and DPR protein length-dependent manner in both mammalian cells and GR and PR DPR protein-expressing flies (97,132). In these cases, ZNF598, NEMF, and LTN1 regulate the expression of GR protein in a fashion that does not require the G4C2 repeat RNA sequence or structure, and these effects are thought to be due to interactions of the charged DPR protein due to the charged arginine residue.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies demonstrated that ribosomes stall during the synthesis of C9 ALS/FTDassociated GR and PR dipeptide proteins (97)(98)(99). These stalling events were not seen on similarly sized but uncharged DPR repeats such as GA and were therefore ascribed to positively charged arginine residues within these nascent polypeptide chains.…”

Section: Introductionmentioning

confidence: 93%

“…Previous studies found that knockdown of NEMF and LTN1 can increase the production of GR and PR DPRs from non-GC-rich sequences (98,100). This difference was thought to result from the positively charged arginine residues in PR and GR DPR tracks, which can interact with the ribosome exit tunnel to elicit ribosomal stalling (97,99,110). However, RNA secondary structures can also elicit ribosomal stalling (111)(112)(113).…”

Section: Nemf Ltn1 and Ankzf1 Effects On Ran Translation Are Repeat L...mentioning

confidence: 99%

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Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats

Tseng

Malik

Deng

et al. 2023

Preprint

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A GGGGCC (G4C2) hexanucleotide repeat expansion in C9ORF72 causes amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD), while a CGG trinucleotide repeat expansion in FMR1 causes the neurodegenerative disorder Fragile X-associated tremor/ataxia syndrome (FXTAS). These GC-rich repeats form RNA secondary structures that support repeat-associated non-AUG (RAN) translation of toxic proteins that contribute to disease pathogenesis. Here we assessed whether these same repeats might interfere with translational elongation. We find that depletion of ribosome-associated quality control (RQC) factors NEMF, LTN1, and ANKZF1 markedly boost RAN translation product accumulation from both G4C2 and CGG repeats while overexpression of these factors reduces RAN production in both reporter cell lines and C9ALS/FTD patient iPSC-derived neurons. We also detected partially made products from both G4C2 and CGG repeats whose abundance increased with RQC factor depletion. Repeat RNA sequence, rather than amino acid content, is central to the impact of RQC factor depletion on RAN translation - suggesting a role for RNA secondary structure in these processes. Together, these findings suggest that ribosomal stalling and RQC pathway activation during RAN translation elongation inhibits the generation of toxic RAN products. We propose augmenting RQC activity as a therapeutic strategy in GC-rich repeat expansion disorders.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Section: Nemf Ltn1 and Ankzf1 Effects On Ran Translation Are Repeat L...mentioning

confidence: 99%

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Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats

Tseng

Malik

Deng

et al. 2023

Preprint

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“…From another perspective, arginine‐rich DPRs may be involved in the pathogenesis of C9‐FTD/ALS by interacting with ribosomes (Hartmann et al, 2018; Kanekura et al, 2016; Li et al, 2020; Moens et al, 2019), at least partially by stagnating in the ribosomal tunnel (Loveland et al, 2022), thereby inhibiting protein synthesis. Unlike ribosome stalling by poly‐Lys, a translation product of poly‐adenosine and a canonical ribosome quality control (RQC) substrate, ribosome stalling by arginine‐rich DPR does not appear to be resolved by increased expression of core components of RQC genes including listerin, nuclear export mediator factor (NEMF), and valosin containing protein (VCP) (Kriachkov et al, 2023; Viera Ortiz et al, 2022). This could be because of the lack of Lys residues in the DPR, which prevented proper ubiquitination required for canonical RQC (Viera Ortiz et al, 2022).…”

Section: Mechanisms Of Dpr Toxicitymentioning

confidence: 99%

Aspects of degradation and translation of the expanded C9orf72 hexanucleotide repeat RNA

Mori

Gotoh

Ikeda

2023

Journal of Neurochemistry

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An hexanucleotide repeat expansion mutation in the non-coding region of C9orf72 gene causes frontotemporal dementia and amyotrophic lateral sclerosis. This mutation is estimated to be the most frequent genetic cause of these currently incurable diseases. Since the mutation causes autosomal dominantly inherited diseases, disease cascade essentially starts from the expanded DNA repeats. However, molecular disease mechanism is inevitably complex because possible toxic entity for the disease is not just functional loss of translated C9ORF72 protein, if any, but potentially includes bidirectionally transcribed expanded repeat containing RNA and their unconventional repeat-associated non-AUG translation products in all possible reading frames. Although the field learned so much about the disease since the identification of the mutation in 2011, how the expanded repeat causes a particular type of frontotemporal lobe dominant neurodegeneration and/or motor neuron degeneration is not yet clear. In this review, we summarize and discuss the current understandings of molecular mechanism of this repeat expansion mutation with focuses on the degradation and translation of the repeat containing RNA transcripts.

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“…As such, it is thought that the DRGs exist predominantly in complex with their DFRPs, as obligate heterodimers. The formation of these specific complexes is also likely to be important for their function in protein synthesis, as both the DRG1/DFRP1 and DRG2/DFRP2 complexes have been suggested to promote translation elongation (Kriachkov et al, 2023;Pochopien et al, 2021;Zeng et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Rewiring protein binding specificity in paralogous DRG/DFRP complexes

Westrip

Smerdon

Coleman

2023

Preprint

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The Developmentally Regulated GTP-binding (DRG) proteins are an ancient subfamily of GTPases implicated in the regulation of translation and cell growth. In eukaryotes, there are two paralogs: DRG1 and DRG2, both of which have a conserved binding partner called DRG family regulatory protein 1 and 2 (DFRP1 and DFRP2), respectively. These binding partners are required for the function of DRGs, including their stabilisation at the protein level. Moreover, DFRPs interact with their respective DRG via a conserved region called the DFRP domain. Despite being highly similar, DRG1 and DRG2 have strict binding specificity for their respective DFRP. Using AlphaFold generated structure models of the human DRG/DFRP complexes, we have biochemically characterised their interactions and identified interface residues involved in determining specificity. This analysis revealed that as few as five mutations in DRG1 can switch its binding from DFRP1 to DFRP2. We show how two DRG1 residues in the core of the interface are most important for specifying the interaction with DFRP1 over DFRP2. We also demonstrate that whilst DFRP1 can stimulate the GTPase activity of DRG1, DFRP2 binding cannot. Overall, this work provides new insight into the structural determinants responsible for the binding specificities of the DRG:DFRP translation factor complexes, which are known to be essential for normal development in mice and humans.

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Arginine-rich C9ORF72 ALS proteins stall ribosomes in a manner distinct from a canonical ribosome-associated quality control substrate

Cited by 16 publications

References 83 publications

Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats

Ribosomal quality control factors inhibit repeat-associated non-AUG translation from GC-rich repeats

Aspects of degradation and translation of the expanded C9orf72 hexanucleotide repeat RNA

Rewiring protein binding specificity in paralogous DRG/DFRP complexes

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