Decreased accumulation and dephosphorylation of the mitosis-specific form of nucleophosmin/B23 in staurosporine-induced chromosome decondensation.
Nucleophosmin/B23 is highly phosphorylated by cdc2 kinase during mitosis, and this phosphorylation most probably has a role in initiating and controlling the entry of cells into mitosis [Peter, Nakagawa, Doree, Labbe and Nigg (1990) Cell 60, 791-801]. In the present study, the protein kinase inhibitor staurosporine has been used to examine possible changes in nucleophosmin/B23 at mitosis in HeLa cells. Addition of staurosporine to HeLa cells already arrested at mitosis by nocodazole causes: (i) decreased accumulation of the mitosis-specific form of nucleophosmin/B23, (ii) dephosphorylation of nucleophosmin/ B23, (iii) redistribution of nucleophosmin/B23 to the cytosol, and (iv) concomitant decondensation of chromosomes. These results suggest that the mitosis-specific phosphorylated form of nucleophosmin/B23 may play a role in maintaining mitotic chromosomes in their condensed state.
Lu
Y Y
YY
Department of Pharmacology, Chang Gung Medical & Engineering College, Tao-Yuan, Taiwan, Republic of China.
Lam
C Y
CY
Yung
B Y
BY
D000470:Alkaloids / Q000494:pharmacology*; D002875:Chromosomes / Q000187:drug effects / Q000648:ultrastructure*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D000090243:Nucleophosmin; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D019311:Staurosporine
D000470:Alkaloids; D004791:Enzyme Inhibitors; C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; D000090243:Nucleophosmin; D019311:Staurosporine