Body clock ensures steady energy supply to cells during times of rest

U.S. researchers said they found a new way a body's timekeeping mechanism fires a cell's so-called furnace to use stored energy properly when a body is at rest. The interdisciplinary team identified the "match" and "flint" responsible for lighting a cell's furnace, discovering the match is only available when the circadian clock says so -- highlighting the importance of the biological timing system to metabolism, Northwestern University in Evanston, Ill., said Thursday in a release. "Circadian clocks are with us on Earth because they have everything to do with energy," said Dr. Joe Bass, who led the research. "If an organism burns its energy efficiently, it has a better chance of survival. Our results tell us how the circadian clock triggers the cell's energy-burning process. Cells are most capable of using fuel when the clock is working properly." In their study of mice, the researchers said they found the circadian clock supplies the match to light the furnace and on the match tip is a compound called NAD+. The compound combines with an enzyme in mitochondria called Sirtuin 3, which acts as the flint, to light the furnace. Results demonstrate the circadian clock, a genetic timekeeper that enables organisms to track the daily transition from light to dark, generates oscillations in mitochondrial energy capacity through rhythmic regulation of the compound's biosynthesis. Bass said the findings could be useful in developing therapies to treat metabolic disorders related to circadian disruption.