title: Inactivation of the p34cdc2-cyclin B complex by the human WEE1 tyrosine kinase.
abstract: Entry into mitosis in Schizosaccharomyces pombe is negatively regulated by the wee1+ gene, which encodes a protein kinase with serine-, theonine-, and tyrosine-phosphorylating activities. The wee1+ kinase negatively regulates mitosis by phosphorylating p34cdc2 on tyrosine 15, thereby inactivating the p34cdc2-cyclin B complex. The human homolog of the wee1+ gene (WEE1Hu) was overproduced in bacteria and assayed in an in vitro system. Unlike its fission yeast homolog, the product of the WEE1Hu gene encoded a tyrosine-specific protein kinase. The human WEE1 kinase phosphorylated the p34cdc2-cyclin B complex on tyrosine 15 but not on threonine 14 in vitro and inactivated the p34cdc2-cyclin B kinase. This inhibition was reversed by the human Cdc25C protein, which catalyzed the dephosphorylation of p34cdc2. These results indicate that the product of the WEE1Hu gene directly regulates the p34cdc2-cyclin B complex in human cells and that a kinase other than that encoded by WEE1Hu phosphorylates p34cdc2 on threonine 14.
authors.affiliation: Department of Physiology, Tufts University School of Medicine, Boston, MA 02111.
authors.forename: L L
authors.initials: LL
authors.lastname: Parker
authors.forename: H
authors.initials: H
authors.lastname: Piwnica-Worms
mesh_terms: D001483:Base Sequence; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D016213:Cyclins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D010766:Phosphorylation; D019000:Phosphotyrosine; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D016213:Cyclins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011494:Protein Kinases; C068689:wee1 protein, S pombe; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; D016203:CDC2 Protein Kinase