Disease-linked mutations in hnRNPA2B1 accelerate condensate maturation and promote amyloid aggregation
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) is a multifunctional RNA-binding protein that undergoes liquid-liquid phase separation (LLPS), contributing to the assembly of membraneless organelles across different cellular contexts. However, dysregulated phase separation can drive the transition from functional condensates to pathological protein aggregates. Two mutations in the low-complexity domain (LCD) of hnRNPA2B1 (D302V and P310L) have been linked to neurodegenerative diseases. How these mutations alter the interplay between LLPS and aggregation remains poorly understood. Here, we show that these disease-linked mutations accelerate condensate maturation and promote amyloid-like aggregation of hnRNPA2B1, with fibrils emerging from condensate-like cores. To dissect the mechanistic link between phase separation, aggregation, and disease, we focused on a conserved 25-amino-acid region within the LCD harboring both mutation sites. Deletion of this region markedly impairs LLPS and abolishes aggregation, revealing its contribution to both processes. Isolated peptides derived from this region have an intrinsic propensity for amyloid-like fibril formation, which is enhanced by the mutations. Although unable to phase separate, these peptides remodel condensate morphology and nucleate aggregation of the LCD. Together, our results identify a sequence-encoded mechanism linking disease-associated mutations to altered condensate behavior and amyloid aggregation, providing molecular insights into how aberrant phase transitions may contribute to hnRNPA2B1-associated disease.
Significance Statement
We address how disease-linked mutations in hnRNPA2B1 alter the interplay between phase separation and pathological aggregation. We demonstrate that the D302V and P310L mutations accelerate condensate maturation and promote fibril formation. By dissecting its low-complexity domain (LCD), we functionally characterized a short amyloidogenic region that contributes to phase separation and is critical for aggregation. Peptides derived from this region form amyloid fibrils that promote ThT-positive assembly and morphological remodeling of the LCD, with disease-linked mutations enhancing this response. Our findings establish an intrinsic sequence-encoded contribution linking disease-linked mutations to accelerated condensate maturation and amyloid aggregation, providing a mechanistic baseline for future studies incorporating physiological RNA partners.
