Preincubation with G3Ia or G3Ib prevents the formation of stress granules in living cells. (A) Schematic showing the preincubation paradigm used in B and C. Indicated doses of the compound were added to cells for 20 min, followed by exposure to 500 μM NaAsO₂ stress and live cell imaging to monitor stress granule formation. (B) Representative images of G3BP1-GFP signal in U2OS cells after 10 or 20 min of oxidative stress. Scale bars, 40 μm. (C) Quantification of cells as in B showing the percentage of stress granule area per cell. (D) Schematic showing the preincubation paradigm used in E and F. 50 μM of indicated compounds was added to cells for 20 min, followed by exposure to 43°C heat shock for 30 min. Live-cell imaging was used to monitor stress granule formation. (E) Representative images of G3BP1-GFP signal in U2OS cells 15 min after heat shock. Scale bar, 40 μm. (F) Quantification of cells as in E showing the percentage of stress granule area per cell throughout heat shock (43°C, 30 min) and recovery (37°C, 43 min). Error bars represent mean ± SEM in all graphs.