| First Author | Escargueil AE | Year | 2000 |
| Journal | J Biol Chem | Volume | 275 |
| Issue | 44 | Pages | 34710-8 |
| PubMed ID | 10942766 | Mgi Jnum | J:65475 |
| Mgi Id | MGI:1926643 | Doi | 10.1074/jbc.M005179200 |
| Citation | Escargueil AE, et al. (2000) Mitotic phosphorylation of DNA topoisomerase II alpha by protein kinase CK2 creates the MPM-2 phosphoepitope on ser-1469. J Biol Chem 275(44):34710-8 |
| abstractText | DNA topoisomerase IIalpha is required for chromatin condensation during prophase. This process is temporally linked with the appearance of mitosis-specific phosphorylation sites on topoisomerase IIalpha including one recognized by the MPM-2 monoclonal antibody. We now report that the ability of mitotic extracts to create the MPM-2 epitope on human topoisomerase IIalpha is abolished by immunodepletion of protein kinase CK2. Furthermore, the MPM-2 phosphoepitope on topoisomerase IIalpha can be generated by purified CK2. Phosphorylation of C-truncated topoisomerase IIalpha mutant proteins conclusively shows, that the MPM-2 epitope is present in the last 163 amino acids. Use of peptides containing all conserved CK2 consensus sites in this region indicates that only the peptide containing Arg-1466 to Ala-1485 is able to compete with topoisomerase IIalpha for binding of the MPM-2 antibody. Replacement of Ser-1469 with Ala abolishes the ability of the phosphorylated peptide to bind to the MPM-2 antibody while a peptide containing phosphorylated Ser-1469 binds tightly. Surprisingly, the MPM-2 phosphoepitope influences neither the catalytic activity of topoisomerase IIalpha nor its ability to form molecular complexes with CK2 in vitro. In conclusion, we have identified protein kinase CK2 as a new MPM-2 kinase able to phosphorylate an important mitotic protein, topoisomerase IIalpha, on Ser-1469. |
