A cell controls its volume by keeping tabs on the tension of its internal ‘skeleton’, experiments suggest.

A cell must finely control its volume: it needs to grow to replicate, but if it swells too large, it teeters towards cancerous malignancy. Scientists have struggled to learn how individual cells achieve this balance, but one clue came from research that pointed to a pair of proteins called YAP and TAZ.

To study whether the YAP/TAZ pair influences cell volume, Sean Sun at Johns Hopkins University in Baltimore, Maryland, and his colleagues tracked the volumes of individual cells throughout the cell cycle. The team also tinkered with genes that varied YAP/TAZ activity.

The researchers found that the proteins’ activity peaked just before a cell split in two, and seemed to be tied to increasing tension in the cell’s outer layer. Such a rise in tension occurs when a cell’s volume expands, pushing its internal framework outwards. YAP/TAZ seems to communicate this growing tension to the nucleus of the cell to let it know when to stop growing and split.