Distinct and Site-Specific Phosphorylation of the Retinoblastoma Protein at Serine 612 in Differentiated Cells
Figure 4
pRB phosphorylated at Ser612 tightly associates with chromatin and the nuclear structure in differentiated cells.
U-937 cells were treated with 20 nM TPA for the indicated periods and the cells were harvested. The cells were fractionated as described in the Materials and Methods section. The extracts were analyzed by immunoblotting with the indicated antibodies.