Proper eukaryotic DNA replication requires temporal separation of helicase loading from helicase activation and replisome assembly. Using an in vitro assay for eukaryotic origin-dependent replication initiation, we investigated the control of these events. After helicase loading, we found that the Dbf4-dependent Cdc7 kinase (DDK) but not S phase cyclin-dependent kinase (S-CDK) is required for t...

cyclins or CDKs, and loss or decreased level of endogenous CDKinhibitor proteins such as pi6 and p27 in various tumors have been reported2). Flavopiridol, a specific small molecule-CDK inhibitor, showed potent antitumor activity in a series of experimental tumor models and is currently in clinical trial3). Thus, the CDKs are considered as new molecular targets for cancer chemotherapy. Weestabli...

We have used a chemically diverse panel of kinase inhibitors to assess the chemical similarity of the ATP-binding sites of cyclin-dependent kinase (CDK) subfamily members in a range of activation states. Using this approach, we find that different activation states of a particular CDK may differ from each other as much as different CDKs in the same activation state. We also find that inhibitors...

Wee1 kinases regulate the cell cycle through inhibitory phosphorylation of cyclin-dependent kinases (CDKs). Eukaryotic cells express multiple CDKs, each having a kinase subunit (Cdk) and a regulatory "cyclin" subunit that function at different stages of the cell cycle to regulate distinct processes. The cyclin imparts specificity to CDK-substrate interactions and also determines whether a parti...

Cyclin-dependent kinases (Cdks) are fully active only when phosphorylated by a Cdk-activating kinase (CAK) [1]. Metazoan CAK is itself a Cdk, Cdk7, whereas the CAK of Saccharomyces cerevisiae is a distinct enzyme unrelated to Cdks [1]. The Mcs6-Mcs2 complex of Schizosaccharomyces pombe is a putative CAK related to the metazoan enzyme [2] [3]. Although the loss of Mcs6 is lethal, it results in a...