A role for casein kinase 2α in the Drosophila circadian clock

Jul Ming Lin, Valerie L. Kilman, Kevin Keegan, Brie Paddock, Myai Emery-Le, Michael Rosbash, Ravi Allada*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

284 Scopus citations


Circadian clocks drive rhythmic behaviour in animals and are regulated by transcriptional feedback loops. For example, the Drosophila proteins Clock (Clk) and Cycle (Cyc) activate transcription of period (per) and timeless (tim). Per and Tim then associate, translocate to the nucleus, and repress the activity of Clk and Cyc. However, post-translational modifications are also critical to proper timing. Per and Tim undergo rhythmic changes in phosphorylation, and evidence supports roles for two kinases in this process: Doubletime (Dbt) phosphorylates Per, whereas Shaggy (Sgg) phosphorylates Tim. Yet Sgg and Dbt often require a phosphoserine in their target site, and analysis of Per phosphorylation in dbt mutants suggests a role for other kinases. Here we show that the catalytic subunit of Drosophila casein kinase 2 (CK2α) is expressed predominantly in the cytoplasm of key circadian pacemaker neurons. CK2α mutant flies show lengthened circadian period, decreased CK2 activity, and delayed nuclear entry of Per. These effects are probably direct, as CK2α specifically phosphorylates Per in vitro. We propose that CK2 is an evolutionary link between the divergent circadian systems of animals, plants and fungi.

Original languageEnglish (US)
Pages (from-to)816-820
Number of pages5
Issue number6917
StatePublished - Dec 26 2002

ASJC Scopus subject areas

  • General

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