Demystified ... cell cycle.

Abstract

The cell cycle is a highly organised and complex process, which ensures that there is complete and accurate replication of the cell before division. Our understanding of the molecules behind these events is both relatively new and as yet incomplete. There are three main proteins that regulate the cell cycle, namely: cyclin dependent kinases (CDKs), the cyclins, and cyclin dependent kinase inhibitors (CKIs).TheCDKs,onceactivated,phosphorylate other proteins, allowing them to carry out their role at a particular stage of the cell cycle. The CDKs are regulated by cyclins, which only activate CDKs when they reach a critical concentration. The CKIs control the activation of the CDK–cyclin complex by inhibiting its formation. A basic understanding of the interaction between these three main groups of proteins and other regulating molecules during the different phases of the cell cycle should help to clarify this fundamental procedure.