cellekontroll

Cellekontroll, or cell cycle control, refers to the regulatory networks that govern the progression of cells through the cell cycle, coordinating growth, DNA replication, and division. The core machinery involves cyclin-dependent kinases (CDKs) and their regulatory partners, cyclins. Activity of CDKs is tightly regulated by synthesis and degradation of cyclins, phosphorylation, and CDK inhibitors, ensuring cells only proceed to the next phase when conditions are appropriate.

Cell cycle progression is checked at several checkpoints. The G1/S checkpoint evaluates cell size, nutrients, and DNA integrity before replication. The G2/M checkpoint confirms that DNA has been completely and accurately replicated. The spindle assembly checkpoint ensures chromosomes are properly attached to the mitotic spindle before separation.

Key players include tumor suppressors such as p53 and the retinoblastoma (RB) protein, which act to halt the cycle in response to damage. The DNA-damage response involves ATM/ATR kinases and BRCA1/BRCA2. Cyclin-CDK activity is regulated by inhibitors like p21, p27, and p16, and by ubiquitin-mediated proteolysis via APC/C and SCF complexes that control cyclin and inhibitor levels.

Disruption of cellulekontroll is a hallmark of cancer and a major focus of therapy. CDK inhibitors, including several approved drugs, aim to restore control of the cell cycle in tumor cells. Beyond oncology, research into cell cycle control informs aging, developmental biology, and regenerative medicine.