Cyclin E

Cyclin E is a member of the cyclin family.

Cyclin E binds to G₁ phase Cdk2, which is required for the transition from G₁ to S phase of the cell cycle that determines cell division. The Cyclin E/CDK2 complex phosphorylates p27Kip1 (an inhibitor of Cyclin D), tagging it for degradation, thus promoting expression of Cyclin A, allowing progression to S phase.