Targeting G3BP1 Condensate Topology Promotes Stress Granule Assembly via mA-IGF2BP1 for Ischemic Stroke Rescue.

Abstract

Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) mediates stress granules (SGs) via phase separation. However, there is limited understanding of the allosteric mechanism and the identification of regulatory molecules. Here, we identify icariin (ICA), a small-molecule inducer that promotes G3BP1-driven biomolecular condensate formation, which effectively restructures SGs architecture. Moreover, we demonstrate that ICA interacts with the N-terminal nuclear transport factor 2-like (NTF2L) domain of G3BP1, inducing a conformational switch from "closed-to-open" that facilitates G3BP1 oligomerization and phase separation. Crucially, G3BP1 condensates recruit N-methyladenosine (mA) reader insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) through topology-selective scaffolding, establishing epitranscriptomic hubs that resolve proteotoxic stress via mA-dependent AMP-activated protein kinase (AMPK)-mitogen-activated protein kinase (MAPK)-glutathione peroxidase 4 (GPX4) signaling pathways. Strikingly, this chemical intervention shows translational potential, as ICA reduces cerebral infarct volume in ischemia models via G3BP1-dependent SGs remodeling. Additionally, single-nucleus transcriptomics identify Fezf2, Pou3f1, and Kcnn2 neuronal subpopulations as mechanistically aligned responders. Furthermore, ischemic stroke patients reveal G3BP1-IGF2BP1-mA axis within peripheral blood mononuclear cells. Taken together, this study redefines SGs as dynamically druggable epitranscriptomic processors for precision neuroprotection. In particular, a framework for leveraging biomolecular condensate topology in the development of next-generation neurological therapeutics is offered.