Here's why:
* Cyclins: These proteins are regulatory subunits that fluctuate in concentration throughout the cell cycle. Their levels rise and fall in a cyclical pattern, hence the name "cyclins."
* Cyclin-dependent kinases (CDKs): These are catalytic subunits that are always present but only become active when bound to the appropriate cyclin.
* CDK-Cyclin Complexes: The formation of these complexes triggers specific events in the cell cycle. Different cyclin-CDK complexes are active at different phases of the cell cycle, controlling events such as DNA replication, nuclear envelope breakdown, and chromosome segregation.
Key points:
* CDKs are enzymes that phosphorylate other proteins, which can activate or deactivate them.
* CDKs are only active when bound to a cyclin.
* The specific cyclin that binds to a CDK determines which target proteins are phosphorylated and what cellular events are regulated.
Therefore, cyclin-dependent kinases (CDKs) are crucial regulators of the cell cycle, ensuring its orderly progression and preventing errors in cell division.
