What role do cyclins play in the cell cycle?

Cyclins are essential proteins that regulate the progression of the cell cycle by activating cyclin-dependent kinases (CDKs). Each phase of the cell cycle requires specific cyclins that bind to their respective CDKs to form active complexes. These complexes phosphorylate target proteins that are crucial for the transition between different stages of the cell cycle, such as moving from the G1 phase to the S phase or from G2 to mitosis. The activation of CDKs by cyclins ensures that the cell cycle progresses in a timely and orderly manner, allowing for proper cell division and function.

This coordinated regulation is vital for maintaining cellular health and preventing errors in cell division, which could lead to genomic instability and diseases such as cancer. Understanding the role of cyclins highlights their importance in the cell cycle and how their dysregulation can contribute to uncontrolled cell proliferation.