A research team at Freie Universität Berlin has discovered a class of enzymes, CDC-like kinases, whose activity changes as a function of very subtle shifts in body temperature to control gene expression globally. “Our body temperature changes by 1-2°C between day and night. The enzymes we have characterized are active during the resting phase, when our body temperature is around 36°C, but they are inactivated during the active day, when our body temperature rises to around 37°C. These enzymes help our cells to adapt to different requirements,” explains Prof. Dr. Florian Heyd, who led the study.

This mechanism can, for example, coordinate cellular function in a way that depends on the time of the day, but it also plays a role during an infection with fever, or in the female hormone cycle or ageing, as these conditions also influence body temperature. In addition, this highly sensitive cellular thermometer has been preserved through evolution and adapted to the living temperature of various organisms, like flies and reptiles.

For some reptiles, including alligators and turtles, the sex of the offspring is determined by the temperature at which the eggs are incubated. The enzymes from these species are switched on and off exactly in the temperature range where sex determination happens. Therefore, the enzymes may help explain how small differences in temperature can be sensed to then control fundamental biological decisions.

In addition to a fundamental discovery in basic research, this mechanism has many potential applications, e.g. clinical implications. It could also someday allow scientists to alter temperature-sensing processes in whole organisms, which could help them adapt to global warming.