IgG control Anti-A1 Cells counted 537 530 Colocalizations 19 30 Average ± SD colocalizations per image (n=10 images/group) 1.9 ± 1.101 3.0 ± 1.491* % cells containing colocalizations 3.54% 5.66%

Table 1: Quantification of Antibody Colocalization within Stress Granules. Approximately 500 cells were imaged and the number of antibodies that colocalized to stress granules was counted (see Methods). The increase in colocalization was quantified using a onetailed t-test based on a previously observed trend. *(p≤0.05).