Nucleolin regulates nuclear export of FGF1 via phosphorylation.

<p>U2OSR1 cells were transfected with siRNA as indicated, and serum starved for 24 h before stimulation for 6 h (left panel) or 10 h (right panel) with 100 ng/ml FGF1 (wt) or 100 ng/ml FGF1 S130E and 10 U/ml heparin. Cells were also treated with 10 nM BafA1 or 5 ng/ml LMB, where indicated. The cells were fractionated into membrane (M), cytosolic (C) and nuclear (N) fractions, and FGFs were extracted from the fractions by adsorption to Heparin-Sepharose and analyzed by SDS-PAGE and immunoblotting (IB). The fractions were also analyzed for nucleolin, γ-tubulin and lamin A by IB, as indicated.