C9orf72-linked arginine- rich dipeptide repeats aggravate pathological phase separation of G3BP1

• 成果类型: Article
• 署名作者: Van Nerom, Margot; Ahmed, Junaid; Lazar, Tamas; Meszaros, Attila; Galand, Quentin; De Malsche, Wim; Van Lindt, Joris; Pancsa, Rita; Maes, Dominique; Tompa, Peter
• 署名单位: Vrije Universiteit Brussel; Vrije Universiteit Brussel; HUN-REN; HUN-REN Research Centre for Natural Sciences
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14836
• DOI: 10.1073/pnas.2402847121
• 发表日期: 2024-12-10
• 关键词: ggggcc repeat; proteins; rna; als; expansion; toxicity; translation

摘要

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.