Similar phosphate-based daily timing modules made by casein kinase 1 and unstable clock proteins in fungi and mammals

CK1 promotes hyperphosphorylation of FRQ and mouse PER2 on a circadian timescale.

• CK1 targets numerous low-affinity phosphorylation sites on FRQ and mPER2.
• The process of phosphorylation is influenced by the recruitment of CK1 to specific sites.
• Phosphorylation kinetics are affected by the accessibility of disordered segments of FRQ and mPER2.
• Compromising CK1 activity disrupts circadian rhythms in both fungal and mammalian cells.
• CK1 and clock proteins FRQ and PER may function as equivalent timing mechanisms in various organisms.

Simplified