Figure 4

Potential role of hCdc14A in regulating p53 and Cdk1/cyclin B. A) The results in Table I were used to compare the relationship between the expression level of hCdc14A and p53 status of the cell lines. The cell lines CAK-1 and SF-539 were excluded in the analysis since they have been shown to not arrest in G1 following exposure to ionizing radiation [35] and the HCT116 cells were excluded because of conflicting results of hCdc14A expression between two different sources of this cell line. B) COS cells were transiently transfected with the pEGFP-hCdc14A vector and 24 hours later the GFP positive cells were sorted from the GFP negative cells and expression of hCdc14A and phosphorylation of the ser315 site of p53 was assessed using immunoblotting using anti-hCdc14A (Ab-2) and anti-ser315 phospho-specific p53 antibodies. C) HCT116 cells were mock treated or treated with the microtubular inhibitor colchicine for 18 hours. Cells were then lysed and cyclin B was immunoprecipitated using specific antibodies. The proteins recovered were then denatured and separated using SDS-PAGE. Anti-hCdc14A and anti-Cdk1 antibodies were then used in immunoblotting. The star denotes the phosphorylated inactive form of Cdk1.