Decoupling circadian clock protein turnover from circadian period determination

Abstract

Defining necessary circadian clock elements The circadian clock in organisms as diverse as fungi and humans have a rather similar structure: Timing depends on daily cycles of transcription in circuits in which feedback loops control the timing of oscillations. A critical role has been ascribed to negative elements, which lead to inhibition of their own transcription, and to degradation of these elements, which is signaled by phosphorylation events. However, Larrando et al. show that in the fungus Neurospora , after manipulations that prevent phosphorylation-signaled degradation of the negative element FREQUENCY (FRQ), rhythms still persist (see the Perspective by Kramer). They suggest a model in which other phosphorylation events on Frq (of which there are over 100) must have critical roles in controlling the clock, independent of negative element degradation. Science , this issue 10.1126/science.1257277 ; see also p. 476