Chronotherapy Treadmill (IMAGE) University of Pennsylvania School of Medicine Caption The image depicts transcription factors SREBP and PPAR-alpha, which develop circadian rhythms that control the newly oscillating fat metabolism. SREBP, the rear wheel, directly drives fat synthesis and indirectly drives synchronous changes in fat burning via the front wheel, PPAR-alpha. The water bottle contains an agonist ligand for PPAR-alpha, which adds driving force to PPAR-alpha. Credit Annie Spikes, Dongyin Guan and Mitchell A. Lazar, Perelman School of Medicine, University of Pennsylvania; <i>Cell</i> Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.