What characterizes the role of CDKs within the cell cycle?

CDKs, or cyclin-dependent kinases, play a crucial role in regulating the cell cycle by needing to bind with cyclins to become active. Cyclins are proteins whose concentrations fluctuate throughout the cell cycle. When a CDK forms a complex with a specific cyclin, it becomes activated, allowing it to phosphorylate target proteins that are essential for cell cycle progression. This phosphorylation can drive the cell from one phase of the cycle to the next, ensuring proper timing and regulation of events such as DNA replication, mitosis, and cell division.

The relationship between CDKs and cyclins is a key mechanism that regulates the cell cycle's progression; without this interaction, CDKs would remain inactive and unable to fulfill their regulatory roles. This dynamic interplay is crucial for maintaining the normal functioning and integrity of the cell.