Cyclin-dependent kinase 2 (CDK2) complexed with Cyclin A or Cyclin E (CDK2/Cyclin A/E)

Cyclin-dependent kinase 2 (CDK2) is a core component of the cell cycle machinery that functions as a serine/threonine protein kinase. Its activity is strictly dependent on its association with regulatory subunits, specifically Cyclin E during the late G1 phase to initiate the G1/S transition, and Cyclin A during the S and G2 phases to facilitate DNA replication and progression through the cell cycle (Source: UniProt P24941). CDK2 complexes phosphorylate key substrates, most notably the Retinoblastoma protein (Rb), which releases E2F transcription factors to drive the expression of genes required for DNA synthesis. In many human cancers, particularly those with CCNE1 amplification or loss of RB1, the CDK2 pathway is hyperactivated, making it a significant therapeutic target for small-molecule inhibitors (Source: PubMed PMC8308411). While early pan-CDK inhibitors faced challenges due to toxicity, next-generation selective CDK2 inhibitors are currently being evaluated in clinical trials for their ability to overcome resistance to CDK4/6 inhibitors and treat cyclin-dependent malignancies (Source: NIH ClinicalTrials.gov).

Other names

CDK2/CCNA complexCDK2/CCNE complexCell division protein kinase 2 complexp33 kinase complex

Competitive inhibition of the ATP-binding site of the CDK2 catalytic subunit, preventing the phosphorylation of downstream substrates such as Retinoblastoma protein (Rb) and E2F transcription factors, thereby inducing cell cycle arrest at the G1/S phase boundary (Source: PubMed PMC7074444).