How circadian clocks keep time: the discovery of slowness

Circadian clocks are molecular timers that measure 24-hour periods through a series of slow but precise biochemical processes. While circadian clocks of cyanobacteria are driven by interactions and ordered phosphorylation of highly structured protein assemblies, timekeeping by circadian clocks of eukaryotes involves slow progressive hyperphosphorylation of a large number of redundant sites in intrinsically disordered regions of clock proteins. © 2022 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.