In vivo circadian function of casein kinase 2 phosphorylation sites in Drosophila PERIOD.
Phosphorylation plays a key role in the precise timing of circadian clocks. Daily rhythms of phosphorylation of the Drosophila circadian clock component PERIOD (PER) were first described more than a decade ago, yet little is known about their phosphorylation sites and their function in circadian behavior. Here we show that serines 151 and 153 in PER are required for robust in vitro phosphorylation by the casein kinase 2 (CK2) holoenzyme, a cytoplasmic kinase shown to be involved in circadian rhythms. Mutation of these sites in transgenic flies results in significant period lengthening of behavioral rhythms, altered PER rhythms, and delayed PER nuclear localization in circadian pacemaker neurons. In many respects, mutation of these phosphorylation sites phenocopies mutation of the catalytic subunit of CK2. We propose that CK2 phosphorylation at these sites triggers PER nuclear localization.
Lin
Jui-Ming
JM
Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA.
Schroeder
Analyne
A
Allada
Ravi
R
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D047390:Casein Kinase II / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology*; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D056950:Period Circadian Proteins; D010766:Phosphorylation; D012694:Serine
D029721:Drosophila Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D012694:Serine; D047390:Casein Kinase II