Rac1 activity drives NPM1 out of nucleoli.

<p>HeLa cells were grown on glass cover slips and (co)-transfected with GFP-NPM1 (A) or mCherry Rac1Q61L and GFP-NPM1 (B). After 24 hours, cells were fixed and stained with the nuclear dye DAPI and the F-actin binding toxin Phalloidin fluorescently-labeled with Alxa633. Samples were analyzed by confocal laser scanning microscopy. Higher magnification images of the boxed areas are included. Scale bars, 20 µm.