Cell size and cell cycle progression: the cyclin-dependent kinase link in green algae

The coordination of cell growth and cell division is a fundamental problem in biology. The experiments with unicellular algae of Zachleder et al. (2019) show that up-regulation of cyclin-dependent kinase (CDK) activity can drive cell progression even when biosynthesis is reduced, indicating that the main link between cell growth and cell division is CDK activity rather than overall biosynthesis. Understanding this coupling between cellular growth and CDK activity will be important not just in these algae, but also in higher plants.