Purification of a serine kinase that associates with and phosphorylates human Cdc25C on serine 216.
Human Cdc25C is a protein phosphatase that dephosphorylates and activates Cdc2-cyclin B to trigger entry into mitosis. Cdc25C is itself regulated by phosphorylation. In asynchronously growing HeLa cells, we have determined that serine 216 is the major site of Cdc25C phosphorylation. We have isolated a protein kinase that binds to Cdc25C and phosphorylates serine 216. The kinase binds within amino acids 200-256 of Cdc25C. This region is conserved in some Cdc25 homologues and contains a putative bipartite nuclear localization signal just downstream from serine 216. Finally, the Cdc25C-associating kinase was purified over 8000-fold from rat liver as a 36-38-kDa doublet of proteins.
Ogg
S
S
Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111.
Gabrielli
B
B
Piwnica-Worms
H
H
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000302:isolation & purification; D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins; D002455:Cell Division; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D006224:Cricetinae; D017931:DNA Primers; D005982:Glutathione Transferase / Q000302:isolation & purification / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000302:isolation & purification* / Q000378:metabolism*; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*; D011898:Ranidae; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012694:Serine; D013379:Substrate Specificity; D013552:Swine; D020687:cdc25 Phosphatases
D000906:Antibodies; D018797:Cell Cycle Proteins; D017931:DNA Primers; D011506:Proteins; D011993:Recombinant Fusion Proteins; D012694:Serine; D005982:Glutathione Transferase; C111833:MARK3 protein, human; D017346:Protein Serine-Threonine Kinases; C517009:CDC25C protein, human; C517010:Cdc25c protein, mouse; D020687:cdc25 Phosphatases