FIG 5.

S9 and Y10 phosphorylation weakens binding of NP to importin-α. (A) Interaction of WT NP and its mutants with importin-α family members. Plasmids encoding WT NP or its mutants appended with a MYC tag were cotransfected with pCDNA3-Flag-importin-α (1/3/5/7) into 293T cells. FLAG-importin-α (1/3/5/7) was immunoprecipitated (IP) with anti-FLAG agarose, and the associated NP was detected by immunoblotting (IB) with the anti-MYC antibody. (B) Effects of phosphorylation of S9 and Y10 on the association of NP and importin-α, as assessed by IFAs. NP and FLAG-importin-α were coexpressed in 293T cells, which were stained with anti-NP (red) and anti-FLAG (green) antibodies. The nucleus was stained with DAPI (blue).