Figure 4.
Tyrosine phosphorylation of p27Kip1 contributes to nuclear translocation. (A) NIH/3T3 cells were incubated with BrdU for 4 hours. p27Kip1 distribution and BrdU incorporation were detected with the appropriate antibodies. (B) NB4 cells (with or without stimulation with G-CSF for 60 minutes) were fractionated, lysate (100 μg) from cytosolic fraction C and nuclear fraction N was probed by Western blotting as indicated. Transcription factor PU.1 and Src kinase were used as markers for nuclear and cytosolic fraction, respectively.