What role does cyclin play in the cell cycle?

Cyclin plays a crucial role in regulating the cell cycle by acting as a protein that controls the progression of cells through the different phases of the cycle. It does this through its involvement in the formation and activation of cyclin-dependent kinases (CDKs). These CDKs, when activated by binding to cyclins, phosphorylate target proteins that are essential for transitioning between cell cycle phases, such as from G1 to S phase or from G2 to M phase.

The production and degradation of cyclins are tightly regulated and occur in a cyclical fashion throughout the cell cycle. This ensures that the cell only progresses to the next phase when it is ready, thereby maintaining proper cell division and function. If cyclins are not functioning correctly, it can lead to issues like uncontrolled cell division, which is a hallmark of cancerous growths. Understanding the role of cyclins highlights their importance in maintaining cellular integrity and normal physiological processes.