FIGURE 5.

The serine-48 charge property of NPM1 determines its oligomerization and NPM1/Cap interaction. (A,B) The serine-48 charge property of NPM1 is essential for interaction with PCV4 Cap. HEK293T cells were co-transfected with NPM1 or NPM1 mutant plasmids (NPM1-S48A, NPM1-S48D, NPM1-S48E, NPM1-S48K, NPM1-S48R, or NPM1-S48T), together with the Flag-PCV4-Cap or Flag-gst-PCV4-Cap plasmid, and the cell lysate extracts were immunoprecipitated or subjected to GST pull-down assay followed by western blotting using the indicated antibodies. (C) Charged amino acids replaced by serine-48 disrupted the oligomerization of NPM1. Lysate extracts of PK-15 cells co-transfected with an empty vector, GFP-NPM1-WT, GFP-NPM1-S48A, GFP-NPM1-S48D, GFP-NPM1-S48E, GFP-NPM1-S48K, GFP-NPM1-S48R, or GFP-NPM1-S48T for 48 h were immunoprecipitated with anti-GFP purified IgG and then subjected to Co-IP assays.