A role for O-GlcNAcylation in setting circadian clock speed
- 1Neuroscience Graduate Program, Institute for Medical Sciences, Ajou University School of Medicine, Wonchon-dong, Suwon, Kyunggi-do 443-721, Korea;
- 2Department of Integrated OMICS for Biomedical Science, WCU Program, Graduate School, Yonsei University, Seodaemun-gu, Seoul 120-749, Korea;
- 3Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, USA
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↵4 These authors contributed equally to this work.
Abstract
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.
Keywords
- O-GlcNAcylation
- PERIOD protein
- O-GlcNAc transferase (OGT)
- circadian rhythms
- Drosophila
- nuclear entry
Footnotes
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↵5 Corresponding author.
E-mail ekim{at}ajou.ac.kr.
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Supplemental material is available for this article.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.182378.111.
- Received October 31, 2011.
- Accepted January 17, 2012.
- Copyright © 2012 by Cold Spring Harbor Laboratory Press