Figure 6.

Identification of a cytosolic NES-binding activity that stimulates nuclear export of PKI. HeLa cytosol (HeLa), or HeLa cytosol incubated with phenyl-Sepharose to remove Crm1 (PS HeLa), or kidney cytosol (Kidney), were each preadsorbed with peptide-BSA-Sepharose conjugates containing the WT NES or a mutant NES (Mut NES). The unbound fractions were recovered and tested in the PKI export assay. Significant depletion of export activity was observed in control cytosol (HeLa), in cytosols lacking Crm1 (PS HeLa), and in the cytosol containing an extremely low level of Crm1 (Kidney). This result indicates the presence of an export activity that can specifically recognize and bind to the WT NES.