Editors' ChoiceCircadian Biology

SUMO Wrestles Circadian Clock Components

Science's STKE  30 Aug 2005:
Vol. 2005, Issue 299, pp. tw317
DOI: 10.1126/stke.2992005tw317

Core components of the mammalian circadian clock are transcription factors the expression of which is controlled by feedback loops embedded in a complex regulatory circuitry. Cardone et al. report that posttranslational modification of BMAL1, an essential component of the circadian clock, adds another level of complexity to controlling the clock mechanism. In the mouse liver, SUMO is covalently attached to BMAL1, which increases its rate of decay. Sumoylation of BMAL1 follows a daily cycle with timing that parallels its circadian activation. The modification is also induced by CLOCK, the heterodimerization partner of BMAL1. Expression of a mutated, nonsumoylated form of BMAL1 altered rhythmic gene expression, indicating that modification by SUMO is important to the oscillatory function of the circadian clock.

L. Cardone, J. Hirayama, F. Giordano, T. Tamaru, J. J. Palvimo, P. Sassone-Corsi, Circadian clock control by SUMOylation of BMAL1. Science 309, 1390-1394 (2005). [Abstract] [Full Text]