CDK17 (Cyclin-dependent kinase 17): CDK17 is a nuclear enzyme that belongs to the cyclin-dependent kinase family, essential for regulating the cell cycle, controlling transcription, and cellular differentiation. As a serine/threonine protein kinase, CDK17 phosphorylates target proteins to regulate their activity. It plays a crucial role in driving cell cycle progression, especially in promoting the transition from the G1 phase to the S phase, where DNA replication occurs.