FIGURE 5.

Endogenous TDP-43 is sequestered into heat shock-induced SG upon inhibition of Importin α/β-dependent nuclear import. HeLa cells were transfected with an Importin α/β-specific peptide inhibitor fused to GFP (GFP-Bimax) or GFP as a control (green). 24 h post-transfection cells were subjected to heat shock (44 °C for 1 h) or kept at control temperature (37 °C) before fixation. Cells were co-stained for endogenous TDP-43 (red) and TIA-1 (white) and analyzed by confocal microscopy. Expression of GFP-Bimax resulted in cytosolic mislocalization of endogenous TDP-43 and recruitment into SG upon heat shock. Under control conditions (GFP), TDP-43 was predominantly nuclear and did not colocalize with SG after heat shock. Scale bars = 20 μm.