Graphene Quantum Dots Modulate Stress Granule Assembly and Prevent Abnormal Phase Transition of Fused in Sarcoma Protein.

Protein liquid-liquid phase separation (LLPS) plays a crucial role in mediating dynamic assembly of different membraneless organelles such as stress granules (SGs). Dysregulation of dynamic protein LLPS leads to aberrant phase transition and amyloid aggregation which is closely associated with neurodegenerative diseases. In this study, we found that three types of graphene quantum dots (GQDs) exhibit potent activity in preventing SG formation and promoting SG disassembly. We next demonstrate that GQDs can directly interact with the SGs-containing protein fused in sarcoma (FUS), inhibit and reverse FUS LLPS, and prevent its abnormal phase transition. Moreover, GQDs display superior activity in preventing amyloid aggregation of FUS and disaggregating preformed FUS fibrils. Mechanistic study further demonstrates that GQDs with different edge-site exhibit distinct binding affinity to FUS monomers and fibrils, which accounts for their distinct activities in modulating FUS LLPS and fibrillation. Our work reveals the potent capability of GQDs in modulating SG assembly, protein LLPS, and fibrillation and sheds light on rational design of GQDs as effective modulators of protein LLPS for therapeutics application.