When we first learned about the cell cycle in high school, we learned about the stunning simplicity of certain proteins that cycle in order to promote progression through the cell cycle. In reality, that picture is quite complex, with many layers of regulation that affect those cycling proteins. A recent paper from the Nurse lab pares down all of that complexity to show us that the simplicity really has been there all along.
The cell cycle is the sequence of events that leads to a cell’s division and is regulated by two classes of molecules – cyclins and cyclin-dependent kinases (CDKs). Progression through the cell cycle is an orderly process, yet the integration of all players involved is complex—different CDKs associate with different cyclins, which are synthesized and degraded at different times, and these associations are regulated by their localization, interaction with inhibitors, checkpoint mechanisms, and complex feedback loops. A recent paper shows that a single cyclin-CDK “engine” is the core mechanism driving cell cycle progression in fission yeast. Coudreuse and Nurse show that without all of the regulatory inputs and feedback loops, a single engineered module containing Cdc2 (a CDK) and Cdc13 (cyclin B) is sufficient to drive cell division. Image above is of a fission yeast cell going through the cell cycle with this engineered module – top row shows the appearance and degradation of the engineered module, while the bottom row shows the DNA.Adapted by permission from Macmillan Publishers Ltd, copyright 2010.
Coudreuse, D., & Nurse, P. (2010). Driving the cell cycle with a minimal CDK control network Nature, 468 (7327), 1074-1079 DOI: 10.1038/nature09543