A, HeLa cells were treated with nocodazole or taxol for 16 hours and then fixed. Before the cells were immunostained with the T24 phospho-antibody, the antibody was incubated for 16 hours at 4°C with either PBS (no peptide), peptide, or phospo-peptide. White and yellow arrows mark some of the metaphase cells and the interphase cells, respectively. B, HeLa cells were synchronized by the double thymidine block and release method. Cells were stained with antibodies against p-PBK T24, β-tubulin, and with DAPI. C, A low power (40X objective) lens was used to view various phases of the cells in a field from (B). D, HeLa cells were synchronized by a double thymidine block and release method. Total cell lysates were harvested at the specified time points after release and subjected to Western blotting analysis with the indicated antibodies.