Regulation of Fused in Sarcoma Condensate Formation and Dissolution Using Butterfly-Shaped Gold Nanoparticles

Abstract

A Biomolecular condensates, formed through liquid–liquid phase separation (LLPS), play a crucial role in organizing various cellular functions. Materials that can regulate condensate dynamics without genetic modification could provide new tools for controlling biomolecular organization. In this study, we explored butterfly-shaped gold nanoparticles (GNBs) as regulators of the phase behavior of maltose-binding protein-tagged fused in sarcoma (MBP–FUS), a model protein containing both folded and intrinsically disordered regions. We established a phase diagram to identify the conditions near the boundary between homogeneous and phase-separated states. Under these conditions, GNBs were found to promote the formation of spherical MBP–FUS condensates, while spherical gold nanoparticles and gold nanorods did not have a similar effect. Additionally, irradiation at 660 nm reduced both the size and abundance of the GNB-associated condensates, consistent with a photothermal response. These findings show that GNBs can influence MBP–FUS condensation near a phase boundary and suggest that nanoparticle geometry plays a significant role in this behavior. This study lays the groundwork for developing externally controlled, gene-modification-free methods for regulating biomolecular condensates.