title: Circadian activity and abundance rhythms of the Neurospora clock transcription factor WCC associated with rapid nucleo-cytoplasmic shuttling.
abstract: The Neurospora clock protein FREQUENCY (FRQ) inhibits its transcriptional activator WHITE COLLAR COMPLEX (WCC) in a negative feedback loop and supports its accumulation in a positive loop. We show that positive feedback is a delayed effect of negative feedback underlying the same post-translational mechanisms: DNA-binding-competent active WCC commits rapidly to degradation. FRQ-dependent phosphorylation of WCC, which interferes with DNA binding (negative feedback), leads to reduced turnover and slow accumulation of newly expressed WCC (positive feedback). When DNA binding of WCC is compromised by mutation, its accumulation is independent of FRQ. Cycles of FRQ-dependent inactivation and PP2A-dependent reactivation of WCC occur in the minute range and are coupled to obligate rapid cycles of nucleo-cytoplasmic shuttling. WCC shuttling and activity cycles are modulated by FRQ in circadian fashion.
authors.affiliation: University of Heidelberg Biochemistry Center, 69120 Heidelberg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schafmeier
authors.forename: Axel
authors.initials: A
authors.lastname: Diernfellner
authors.forename: Astrid
authors.initials: A
authors.lastname: Schäfer
authors.forename: Orfeas
authors.initials: O
authors.lastname: Dintsis
authors.forename: Andrea
authors.initials: A
authors.lastname: Neiss
authors.forename: Michael
authors.initials: M
authors.lastname: Brunner
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D025461:Feedback, Physiological / Q000502:physiology; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D009491:Neurospora / Q000235:genetics* / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D014157:Transcription Factors; C103772:white collar 2 protein, Neurospora