Sci. Signal., 5 May 2009
Circadian Rhythms Circadian Oscillations
Science, AAAS, Washington, DC 20005, USA
The 24-hour day-night cycle plays an important role in mammalian physiology and behavior, and, as most travelers are well aware, there is an intimate link between our built-in circadian clocks and metabolic rhythms. This link is in part forged by the protein deacetylase SIRT1, which regulates the clocks molecular circuitry. SIRT1 uses as a cofactor the cellular metabolite NAD+, which is synthesized through a salvage pathway that includes the enzyme nicotinamide phosphoribosyltransferase (NAMPT) (see the Perspective by Wijnen). Ramsey et al. and Nakahata et al. now show that NAMPT and NAD+ levels oscillate during the daily 24-hour cycle and that this oscillation is regulated by the circadian clock. Furthermore, the oscillations in NAD+ modulate the activity of SIRT1 feeding back into the circadian clock.
K. M. Ramsey, J. Yoshino, C. S. Brace, D. Abrassart, Y. Kobayashi, B. Marcheva, H.-K. Hong, J. L. Chong, E. D. Buhr, C. Lee, J. S. Takahashi, S. Imai, J. Bass, Circadian clock feedback cycle through NAMPT-mediated NAD+ biosynthesis. Science 324, 651–654 (2009). [Abstract] [Full Text]
Citation: G. Riddihough, Circadian Oscillations. Sci. Signal. 2, ec157 (2009).
The editors suggest the following Related Resources on Science sites:
In Science Signaling
Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882