Cyclin-dependent kinase 2–cyclin A or E complex (CDK2–cyclin A complex, CDK2–cyclin E complex)

The **Cyclin-dependent kinase 2–cyclin A or E complex** is a heterodimeric protein complex where CDK2, a serine/threonine kinase, binds to cyclin A or cyclin E, forming the active kinase complex required for cell cycle progression. CDK2 bound to cyclin E is key for the G1-to-S phase transition, while CDK2–cyclin A acts predominantly during S phase to facilitate DNA replication. CDK2 is activated through phosphorylation and allosteric changes upon cyclin binding, which primes the complex for substrate phosphorylation, notably of proteins such as the retinoblastoma protein, driving cell cycle transitions[1][2][3][4][5][6][7]. Dysregulation or hyperactivation of CDK2–cyclin complexes is closely associated with tumorigenesis, making the complex a validated cancer drug target[5]. Several selective inhibitors have been developed, largely aiming to arrest cell proliferation by inhibiting this kinase complex.

Other names

CDK2/cyclin A complexCDK2/cyclin E complexCDK2–cyclin complex

Inhibition of kinase activity (cell cycle arrest) Prevention of phosphorylation of cell cycle proteins