Molecular Mechanisms Regulating the Cell Cycle in Eukaryotic Cells

Abstract

The cell cycle is a fundamental process that regulates cellular growth, replication, and division, ensuring that cells proliferate under controlled conditions. Dysregulation of the cell cycle can lead to various diseases, including cancer. This article reviews the molecular mechanisms that govern the eukaryotic cell cycle, focusing on key regulators such as cyclins, cyclin-dependent kinases (CDKs), checkpoints, tumor suppressors, and oncogenes. Cyclins and CDKs are pivotal in regulating transitions between the different phases of the cell cycle: G1, S, G2, and M. The cell cycle is regulated by various checkpoints that ensure the cell is ready to proceed to the next phase. These checkpoints include the G1/S checkpoint, the G2/M checkpoint, and the spindle assembly checkpoint. Tumor suppressors such as p53, retinoblastoma (Rb), and CDK inhibitors (CKIs) like p21 act as negative regulators of the cell cycle, whereas oncogenes such as MYC and RAS promote unchecked cell division. Furthermore, the article discusses how DNA damage can lead to cell cycle arrest or apoptosis via proteins like p53 and members of the Bcl-2 family. Understanding these molecular mechanisms provides insights into the development of cancer therapies targeting the cell cycle. The article also discusses potential therapeutic approaches to restore proper cell cycle control in cancer cells.