Fig. 6. (A) Stress granules do not have uniform composition. HeLa cells grown in the absence of treatment (naive), the presence of 20 µM AdOx for 24 hours, or the presence of 0.5 mM sodium arsenite for 30 minutes, or pre-treated with 20 µM AdOx for 24 hours and then treated with 0.5 mM sodium arsenite for 30 minutes were immunostained with anti-FXR1P pAb (green) and anti-FMRP mAb (red) as in Fig. 3. Arrows show granules that do not contain FXR1P. (B) AdOx alters the distribution of FXR1P-containing granules. HeLa cells grown in the presence of 0.5 mM sodium arsenite for 30 minutes, or pre-treated with 20 µM AdOx for 24 hours and then treated with 0.5 mM sodium arsenite for 30 minutes were immunostained with anti-FXR1P pAb (red) and anti-PABP (green). The area outlined in red shows a cluster of granules lacking PABP, while the areas outlined in green show clusters of granules lacking FXR1P. The grayscale images of FXR1P and PABP immunostaining alone highlight the effect of AdOx. (C) AdOx treatment results in a loss of FMRP from FXR1P immunoprecipitates. HeLa cells were treated with 20 µM AdOx for 24 hours and then immunoprecipitated with anti-FXR1P pAb as described. The resulting supernatant (S) or immunoprecipitate (P) fractions were resolved by SDS-PAGE and then probed with anti-FMRP mAb. As controls, untreated HeLa cells were subject to immunoprecipitation with anti-FXR1P pAb and AdOx-treated cells were run through the immunoprecipitation protocol without anti-FXR1P pAb.