A role for O-GlcNAcylation in setting circadian clock speed.
Post-translational modifications of one or more central "clock" proteins, most notably time-of-day-dependent changes in phosphorylation, are critical for setting the pace of circadian (≅24 h) clocks. In animals, PERIOD (PER) proteins are the key state variable regulating circadian clock speed and undergo daily changes in abundance and cytoplasmic-nuclear distribution that are partly driven by a complex phosphorylation program. Here, we identify O-GlcNAcylation (O-GlcNAc) as a critical post-translational modification in circadian regulation that also contributes to setting clock speed. Knockdown or overexpression of Drosophila O-GlcNAc transferase (ogt) in clock cells either shortens or lengthens circadian behavioral rhythms, respectively. The Drosophila PERIOD protein (dPER) is a direct target of OGT and undergoes daily changes in O-GlcNAcylation, a modification that is mainly observed during the first half of the night, when dPER is predominantly located in the cytoplasm. Intriguingly, the timing of when dPER translocates from the cytoplasm to the nucleus is advanced or delayed in flies, wherein ogt expression is reduced or increased, respectively. Our results suggest that O-GlcNAcylation of dPER contributes to setting the correct pace of the clock by delaying the timing of dPER nuclear entry. In addition, OGT stabilizes dPER, suggesting that O-GlcNAcylation has multiple roles in circadian timing systems.
Neuroscience Graduate Program, Institute for Medical Sciences, Ajou University School of Medicine, Wonchon-dong, Suwon, Kyunggi-do, Korea. ekim@ajou.ac.kr
Eun Young
EY
Kim
Eun Hee
EH
Jeong
Sujin
S
Park
Hyun-Jeong
HJ
Jeong
Isaac
I
Edery
Jin Won
JW
Cho
D000215:Acylation; D000818:Animals; D048149:Casein Kinase 1 epsilon / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D057906:Circadian Clocks / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000378:metabolism / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D055785:Gene Knockdown Techniques; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D009474:Neurons / Q000201:enzymology / Q000378:metabolism; D056950:Period Circadian Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D029721:Drosophila Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D012333:RNA, Messenger; C113519:dco protein, Drosophila; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; D048149:Casein Kinase 1 epsilon