S-phase cyclin-dependent kinase Cdc28-Clb5 (CDK-S) and Dbf4-dependent kinase Cdc7-Dbf4 (DDK) are highly conserved kinases well known for their roles in the initiation of DNA replication. CDK-S is also essential for initiation of meiotic recombination because it phosphorylates Ser30 of Mer2, a meiosis-specific double-strand break (DSB) protein. This work shows that the phosphorylation of Mer2 Se...

Cyclin-dependent kinases (CDK) are master regulators of the cell cycle in eukaryotes. CDK activity is regulated by the presence, post-translational modification and spatial localization of its regulatory subunit cyclin. In budding yeast, the B-cyclin Clb1 is phosphorylated and localizes to the nucleus during meiosis I. However the functional significance of Clb1's phosphorylation and nuclear lo...

Activation of the DNA-damage checkpoint culminates in the inhibition of cyclin-dependent kinase (Cdk) complexes to prevent cell-cycle progression. We have shown recently that Cdk activity is required for activation of the Forkhead transcription factor FoxM1, an important regulator of gene expression in the G2 phase of the cell cycle. Here, we show that FoxM1 is transcriptionally active during a...

One oscillation of Cyclin-dependent kinase (Cdk) activity, largely driven by periodic synthesis and destruction of cyclins, is tightly coupled to a single complete eukaryotic cell division cycle. Tight linkage of different steps in diverse cell-cycle processes to Cdk activity has been proposed to explain this coupling. Here, we demonstrate an intrinsically oscillatory module controlling nucleol...

Resveratrol (trans-3,4',5,-trihydroxystilbene), a phytoalexin found in grapes, nuts, fruits, and red wine, is a potent antioxidant with cancer-preventive properties. The mechanism by which resveratrol imparts cancer chemopreventive effects is not clearly defined. Here, we demonstrate that resveratrol, via modulations in cyclin-dependent kinase (cdk) inhibitor-cyclin-cdk machinery, results in a ...

Cdc25A, a phosphatase essential for G1-S transition, associates with, dephosphorylates, and activates the cell cycle kinase cyclin E-cdk2. p21CIP1 and p27 are cyclin-dependent kinase (cdk) inhibitors induced by growth-suppressive signals such as p53 and transforming growth factor beta (TGF-beta). We have identified a cyclin binding motif near the N terminus of Cdc25A that is similar to the cycl...

conclusions despite the fact that abnormalities in p53 and p27kip1 may be involved in the development of oscc, their clinical significance in the studied population seems limited. further investigation on the combined p53/p27kip1 expression may be helpful in predicting the biologic behavior of this tumor. results p53 and p27kip1 expression were found in 28.57% (8 positive versus 20 negative) an...

Although Cks proteins were the first identified binding partners of cyclin-dependent protein kinases (cdks), their cell cycle functions have remained unclear. To help elucidate the function of Cks proteins, we examined whether their binding to p34(cdc2) (the mitotic cdk) varies during the cell cycle in Xenopus egg extracts. We observed that binding of human CksHs2 to p34(cdc2) was stimulated by...

We have found that ectopic expression ofcyclin A increases hormone-dependent and hormone-independent transcriptional activation by the estrogen recep-tor in vivo in a number of cell lines, including HeLa cells, U-2OS osteosarcoma cells and Hs 578Bst breast epithelial cells.This effect can be further enhanced in HeLa cells by theconcurrent expression of the cyclin-depende...