The circadian regulatory proteins BMAL1 and cryptochromes are substrates of casein kinase Iepsilon.

Journal Article (Journal Article)

The serine/threonine protein kinase casein kinase I epsilon (CKIepsilon) is a key regulator of metazoan circadian rhythm. Genetic and biochemical data suggest that CKIepsilon binds to and phosphorylates the PERIOD proteins. However, the PERIOD proteins interact with a variety of circadian regulators, suggesting the possibility that CKIepsilon may interact with and phosphorylate additional clock components as well. We find that CRY1 and BMAL1 are phosphoproteins in cultured cells. Mammalian PERIOD proteins act as a scaffold with distinct domains that simultaneously bind CKIepsilon and mCRY1 and mCRY2 (mCRY). mCRY is phosphorylated by CKIepsilon only when both proteins are bound to mammalian PERIOD proteins. BMAL1 is also a substrate for CKIepsilon in vitro, and CKIepsilon kinase activity positively regulates BMAL1-dependent transcription from circadian promoters in reporter assays. We conclude that CKIepsilon phosphorylates multiple circadian substrates and may exert its effects on circadian rhythm in part by a direct effect on BMAL1-dependent transcription.

Full Text

Duke Authors

Cited Authors

  • Eide, EJ; Vielhaber, EL; Hinz, WA; Virshup, DM

Published Date

  • May 10, 2002

Published In

Volume / Issue

  • 277 / 19

Start / End Page

  • 17248 - 17254

PubMed ID

  • 11875063

Pubmed Central ID

  • PMC1513548

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M111466200


  • eng

Conference Location

  • United States