CDK Signaling Pathway

1. CDK Signaling Pathway The transition between different states of the eukaryotic cell cycle is mainly controlled by checkpoints, which consist of two protein families: cyclin-dependent protein kinase (CDK) and cycling. The former monomer has no enzymatic activity and can only be activated when it forms a CDK-cyclin complex with the latter. A series of events associated with cell state transitions in the cell cycle are then initiated by specifically phosphorylating specific serine and threonine residues on the target protein. The latter is a class of proteins that aggregate and degrade in the cell cycle as cells change, and they regulate their activity by forming complexes with CDK, which are essential for CDK expression activity. The aggregation, activation, and depolymerization of the periodic CDK-cyclin complex are critical events driving cell cycle cell turnover. The regulation of cyclin-dependent protein kinase activation and inactivation is central to the control of the cell cycle. CDK family CDK is a class of cyclin-dependent protein kinases, and the substrate is a heterodimeric silk/threonine kinase family. So far, the named CDKS family has 13 members: CDK1~CDK13. CDK is activated by binding to cyclins, which catalyze the phosphorylation of substrates and drive the phase of the cell cycle to complete DNA synthesis and mitosis, leading to cell growth and proliferation. At the same time, CDKs can also play a negative regulatory role in combination with CDKs inhibitory factor (CKI), inhibit cell cycle progression and prevent cell division. In the different cell cycle phases, the main controlling G1 phase is CDK2, 4 and 6, and the S phase and G2 phase are dependent on CDK2, while the M phase is mainly regulated by CDK1. In view of the important role of CDK2 activity abnormality in tumorigenesis and development, CDK2 inhibitors have become a new direction in tumor treatment research. Studies have shown that direct inhibition of CDK2 kinase activity or inhibition of CDK2 by enhancing p27 and p21 can cause growth inhibition of ovarian cancer cells. Cyclin is a family of positive regulatory proteins and is an active factor of CDK.