Fig. 3. In vitro nuclear import assay of recombinant Egd1p and Egd2p. Recombinant Egd1p and Egd2p were labelled with fluorescein-5'-maleimide. Dependency of in vitro nuclear import of Egd1p on different importin proteins (left); import of Egd2p (middle); import of the standard substrate nucleoplasmin (NPL) by the different importin proteins (right). The images s, t and u represent the negative controls (import assay without importin). HeLa cells were permeabilized, the cytosol was washed out and recombinant import factors, energy mix, and labelled substrate were added. After fixation the fluorescence of the cells was observed by confocal microscopy.