cyclin dependent kinase 2

Cyclin-Dependent Kinase 2 (CDK2), also known as p33cdk2 is expressed earlier in the cell cycle than is p34cdc2. Like p34cdc2, p33cdk2 associates with cyclin A in human cells. However, kinase activity associated with cyclin A-cdc2 is found only in G2-phase. Cdk2 also complexes with cyclins E, D1, and D3. Cyclin E-cdk2 kinase is active in the G1- and S-phases of the cell cycle and is important (as does cyclin A-cdk2) for the progression from G1-to S-phase. The levels of cyclin A-cdk2 is maximal at the G1/S transition and both cdk2 and cyclin A are found associated with DNA in the initiation complex during replication. Rb protein acts as substrate for cdk2-cyclin E and/or cdk2-cyclin A in vivo. Cdk2 is activated and specifically localized to the nucleus during late G1-, S-, and G2-phase. This antibody recognizes only phosphorylated cdk2 protein.