1. C9orf72-linked arginine-rich dipeptide repeats aggravate pathological phase separation of G3BP1.
- Author
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Van Nerom M, Ahmed J, Lazar T, Meszaros A, Galand Q, De Malsche W, Van Lindt J, Pancsa R, Maes D, and Tompa P
- Subjects
- Humans, Frontotemporal Dementia metabolism, Frontotemporal Dementia genetics, Frontotemporal Dementia pathology, Stress Granules metabolism, DNA-Binding Proteins metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins chemistry, Heterogeneous Nuclear Ribonucleoprotein A1 metabolism, Heterogeneous Nuclear Ribonucleoprotein A1 genetics, Protein Binding, Phase Separation, RNA Recognition Motif Proteins metabolism, RNA Recognition Motif Proteins genetics, RNA Recognition Motif Proteins chemistry, Poly-ADP-Ribose Binding Proteins metabolism, Poly-ADP-Ribose Binding Proteins genetics, Poly-ADP-Ribose Binding Proteins chemistry, C9orf72 Protein genetics, C9orf72 Protein metabolism, RNA Helicases metabolism, RNA Helicases genetics, Amyotrophic Lateral Sclerosis metabolism, Amyotrophic Lateral Sclerosis genetics, Dipeptides metabolism, Dipeptides chemistry, DNA Helicases metabolism, DNA Helicases genetics, Arginine metabolism, Arginine chemistry, Nucleophosmin genetics
- Abstract
The toxic effects of C9orf72-derived arginine-rich dipeptide repeats (R-DPRs) on cellular stress granules in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia remain unclear at the molecular level. Stress granules are formed through the switch of Ras GTPase-activating protein-binding protein 1 (G3BP1) by RNA from a closed inactive state to an open activated state, driving the formation of the organelle by liquid-liquid phase separation (LLPS). We show that R-DPRs bind G3BP1 a thousand times stronger than RNA and initiate LLPS much more effectively. Their pathogenic effect is underscored by the slow transition of R-DPR-G3BP1 droplets to aggregated, ThS-positive states that can recruit ALS-linked proteins hnRNPA1, hnRNPA2, and TDP-43. Deletion constructs and molecular simulations show that R-DPR binding and LLPS are mediated via the negatively charged intrinsically disordered region 1 (IDR1) of the protein, allosterically regulated by its positively charged IDR3. Bioinformatic analyses point to the strong mechanistic parallels of these effects with the interaction of R-DPRs with nucleolar nucleophosmin 1 (NPM1) and underscore that R-DPRs interact with many other similar nucleolar and stress-granule proteins, extending the underlying mechanism of R-DPR toxicity in cells. Our results also highlight characteristic differences between the two R-DPRs, poly-GR and poly-PR, and suggest that the primary pathological target of poly-GR is not NPM1 in nucleoli, but G3BP1 in stress granules in affected cells., Competing Interests: Competing interests statement:The authors declare no competing interest.
- Published
- 2024
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