What role do cyclins play in the cell cycle?

Cyclins play a crucial role in regulating the timing and progression of the cell cycle. They are proteins whose levels fluctuate throughout the cell cycle and activate cyclin-dependent kinases (CDKs). This activation leads to the phosphorylation of specific target proteins, driving the cell through various phases of the cell cycle, including G1, S, G2, and M phases. The precise timing of cyclin synthesis and degradation ensures that the cell cycle progresses in an orderly manner, allowing for proper cell division and functioning.

Understanding this regulatory mechanism is essential for insights into cellular behavior in normal and cancerous tissues, where dysregulation of cyclins and CDKs can lead to uncontrolled cell proliferation. Thus, the role of cyclins in coordinating cell cycle progression establishes them as key players in cellular division and growth.