Cell 134, 317–328 (2008), Cell 134, 329–340 (2008)

A protein that is associated with metabolism and short lifespan also regulates the body's internal clock, two research groups report.

Ueli Schibler at the University of Geneva in Switzerland and his colleagues discovered that the protein, called SIRT1, is needed for normal expression of several important clock genes. Meanwhile, Paolo Sassone-Corsi of the University of California, Irvine, and his colleagues found that deleting the gene that encodes SIRT1 from the DNA of liver cells disrupted the circadian rhythms of mice.

Both teams also showed that SIRT1 forms a complex with CLOCK, a protein that, as its name suggests, has a key role in regulating the body clock. Because SIRT1 activity is dependent on NAD+, a cellular metabolite, the protein provides a molecular link between metabolism and the circadian clock.