Fig. 7.

eIF4E2 becomes a component of SGs during heat shock but not in a arsenite stress. U2OS cells were grown in stress-free conditions (a, d), treated with sodium arsenite (B, E) or exposed to heat (C, F), and then stained with antibodies against eIF4E1 (a–c, green), eIF4E2 (d–f, green) and eIF3B (SG marker, red). Co-localization of the particular eIF4E with SGs is demonstrated by merge (on the right of each panel) and the intensity profile along the dashed white line in the boxed area (shown again in 3× magnification on the right side of the corresponding intensity profile). In agreement with experiments based on GFP-tagged proteins, the immunostaining of endogenous eIF4E1 and IF4E2 shows a specific recruitment of eIF4E2 to SGs during heat stress (f). Left B/W image in each panel shows localization of the corresponding endogenous eIF4E protein, right B/W image in each panel shows eIF3B. Noticeable fractions of both eIF4E1 and eIF4E2 are visibly localized in the cellular nuclei. Nuclei were stained with DAPI (blue). Approximately 50 cells were observed in each parallel. Scale bar, 20 µm