Phosphorylation of the Neurospora clock protein FREQUENCY determines its degradation rate and strongly influences the period length of the circadian clock

摘要: Under free running conditions, FREQUENCY (FRQ) protein, a central component of the Neurospora circadian clock, is progressively phosphorylated, becoming highly phosphorylated before its degradation late in day. To understand biological function FRQ phosphorylation, kinase inhibitors were used to block phosphorylation vivo and effects on clock observed. 6-dimethylaminopurine (a general inhibitor) able vivo, reducing rate lengthening period dose-dependent manner. confirm role this effect, sites identified by systematic mutagenesis ORF. The mutation one site at Ser-513 leads dramatic reduction very long (>30 hr) clock. Taken together, these data strongly suggest that triggers degradation, major determining factor for length