In response to oxidative stress, HspBP1 concentrates in cytoplasmic SGs, but not in PBs. HeLa cells were incubated for 4 hours with vehicle (control) or DEM, fixed and processed for indirect immunofluorescence and in situ hybridization (Materials and Methods). Nuclei were demarcated with DAPI. (A) HspBP1 located together with the SG markers HuR, G3BP1 or TIA. With the antibody used here, TIA was detected in both SGs and processing bodies (PBs). (B) HspBP1 co-localized with polyA-RNA in SGs. HeLa cells were treated 4 hours with vehicle or DEM. Samples were hybridized with Cy3-labeled oligo-dT(50) and subsequently immunostained with antibodies against HspBP1. (C) HspBP1 did not concentrate in PBs under control or oxidative stress conditions. Co-immunostaining was performed with antibodies against HspBP1 and the PB marker Dcp1. Some SGs (>) and PBs (►) are marked. Scale bar is 20 μm.