Fig. 3.

Importin 13 is rate-limiting for transport of cargo proteins. HeLa cells were co-transfected with plasmids coding for eIF1A-GFP, GFP-GST-Ubc9, GFP-GST-Mago, dGFP-GST-cNLS or HA-snurportin 1 and FLAG-importin 13 or an empty vector. For endogenous eIF1A, HeLa cells were transfected with FLAG-importin 13 or an empty vector and stained with an antibody against eIF1A. FLAG-importin 13 and HA-snurportin 1 were visualized by indirect immunofluorescence using anti-FLAG and anti-HA antibodies, respectively. DNA was stained with DAPI. Scale bars, 20 μm. Note that eIF1A-GFP is enriched in nucleoli whereas endogenous eIF1A appears to be excluded from these sites. This, however, can be ascribed to the eIF1A antibody, which does not detect nucleolar eIF1A (data not shown).