Posttranslational regulation of Neurospora circadian clock by CK1a-dependent phosphorylation.
Frequency (FRQ) and its transcriptional activator, the White Collar Complex (WCC), are essential components of interconnected feedback loops of the circadian clock of Neurospora. In a negative feedback loop, FRQ inhibits the WCC by recruiting casein kinase 1a (CK1a) and supporting its phosphorylation. In an interconnected positive loop, FRQ supports accumulation of high levels of WCC. Phosphorylation of clock proteins is crucial for the temporal and spatial coordination of these functions. We identified three isoforms of CK1a generated by alternative splicing that all interact with FRQ. Furthermore, we show that WC-2 is phosphorylated by CK1a in vitro and that WC-2 phosphorylation is inhibited in vivo by the CK1-specific inhibitor IC261. Finally, we demonstrate that CK1a activity regulates levels of WC-2.
Querfurth
C
C
Heidelberg University Biochemistry Center, 69120 Heidelberg, Germany.
Diernfellner
A
A
Heise
F
F
Lauinger
L
L
Neiss
A
A
Tataroglu
O
O
Brunner
M
M
Schafmeier
T
T
D056926:CLOCK Proteins; D047389:Casein Kinase I / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D025461:Feedback, Physiological; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009491:Neurospora / Q000235:genetics* / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000494:pharmacology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; C087405:FRQ protein, Neurospora crassa; D005656:Fungal Proteins; C411652:IC 261; D007211:Indoles; D007527:Isoenzymes; D047428:Protein Kinase Inhibitors; D015534:Trans-Activators; D014157:Transcription Factors; C103772:white collar 2 protein, Neurospora; D010696:Phloroglucinol; D056926:CLOCK Proteins; D047389:Casein Kinase I