Posttranslational regulation of Drosophila PERIOD protein by protein phosphatase 2A

Cell. 2004 Feb 20;116(4):603-15. doi: 10.1016/s0092-8674(04)00128-x.


The posttranscriptional mechanisms that control the cycling of circadian clock protein levels are not known. Here we demonstrate a role for protein phosphatase 2A (PP2A) in the cyclic expression of the PER protein. PP2A regulatory subunits TWS and WDB target PER and stabilize it in S2 cells. In adult fly heads, expression of tws cycles robustly under control of the circadian clock. Hypomorphic tws mutants show delayed accumulation of PER, while overexpression of tws in clock neurons produces shorter, weaker rhythms. Reduction of PP2A activity reduces PER expression in central clock neurons and results in long periods and arrhythmia. In addition, overexpression of the PP2A catalytic subunit results in loss of behavioral rhythms and constitutive nuclear expression of PER. PP2A also affects PER phosphorylation in vitro and in vivo. We propose that the posttranslational mechanisms that drive cycling of PER require the rhythmic expression of PP2A.

MeSH terms

  • Animals
  • Blotting, Western
  • Catalytic Domain
  • Cell Line
  • Cell Nucleus / metabolism
  • Circadian Rhythm
  • Dose-Response Relationship, Drug
  • Drosophila
  • Drosophila Proteins*
  • Gene Expression Regulation*
  • Immunohistochemistry
  • Insecta
  • Marine Toxins
  • Models, Biological
  • Models, Genetic
  • Mutation
  • Neurons / metabolism
  • Nuclear Proteins / biosynthesis*
  • Oxazoles / pharmacology
  • Period Circadian Proteins
  • Phosphoprotein Phosphatases / chemistry
  • Phosphoprotein Phosphatases / metabolism
  • Phosphoprotein Phosphatases / physiology*
  • Phosphorylation
  • Precipitin Tests
  • Protein Phosphatase 2
  • Protein Processing, Post-Translational
  • RNA / chemistry
  • RNA Interference
  • RNA, Messenger / metabolism
  • Ribonucleases / metabolism
  • Transfection


  • Drosophila Proteins
  • Marine Toxins
  • Nuclear Proteins
  • Oxazoles
  • PER protein, Drosophila
  • Period Circadian Proteins
  • RNA, Messenger
  • RNA
  • calyculin A
  • Ribonucleases
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 2
  • tws protein, Drosophila