Have you ever wondered why some people (like me) need several cups of rocket-fuel-strength espresso just to get out of bed, whereas others can go all day on the strength of just one instant coffee?

According to a paper in Nature, this is due to the phosphorylation and dephosphorylation of a protein called DARPP-32.

“When a mouse drinks coffee or when a scientist injects it with caffeine ... the caffeine stimulates the mouse's nerves. The mouse gets jittery, its heart rate increases, and it runs around. Once the effects from caffeine get started, DARPP-32 keeps them going”, said CNN (14 August 2002).

“When this protein is combined with small doses of caffeine, it helps reduce the amount of other brain chemicals which would inhibit excess nerve activity”, explained BBC News (14 August 2002). “The caffeine/protein combination also subdues a protein called kinase A, whose job it is to stop DARPP-32 working. The net effect is a circular one, with the combination working to effectively knock down various mechanisms designed to end the caffeine buzz”.

“DARPP-32 keeps us going until the next coffee break by extending the effects of the last cup”, wrote Dr Jean Marie Vaugeois in the accompanying News and Views article in Nature. “This knowledge should provide an even better understanding of caffeine's effects. So, wake up, smell the fresh coffee and enjoy its effects for a long time, thanks to your dependable DARPP-32!”