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Updated: Jul 14, 2026

Analysis of Cell Cycle Position in Mammalian Cells
Published on: January 21, 2012
A cyclin A-protein kinase complex possesses sequence-specific DNA binding activity: p33cdk2 is a component of the
S H Devoto1, M Mudryj, J Pines
1Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Abstract:
The E2F transcription factor has been found in association with the cyclin A protein, and this complex accumulates during the S phase of the cell cycle, suggesting that E2F may play a role in cell cycle control. In independent studies, cyclin A has been shown to be associated with two other proteins, the Rb-related p107 protein and the cdc2-related p33 cdk2 protein kinase. Through an analysis of the E2F-cyclin A complex, we now find that both the p107 protein and the cdc2-related p33cdk2 kinase are components of the previously described complex. Moreover, the complex possesses H1 kinase activity. These results thus define a cyclin A-cdk2 kinase complex that possesses sequence-specific DNA binding activity. This suggests that the cdk2 kinase may phosphorylate other DNA-bound substrates, and that one role of the E2F factor may be to localize this protein kinase to the DNA.
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