Negative control of circadian clock regulator E4BP4 by casein kinase Iε-mediated phosphorylation

Masao Doi, Toshiyuki Okano, Irene Yujnovsky, Paolo Sassone-Corsi*, Yoshitaka Fukada


研究成果: Article査読

35 被引用数 (Scopus)


Light-dependent transcriptional regulation of clock genes is a crucial step in the entrainment of the circadian clock [1]. E4bp4 is a light-inducible gene in the chick pineal gland [2], and it encodes a bZIP protein that represses transcription of cPer2, a chick pineal clock gene [2, 3]. Here, we demonstrate that prolonged light period-dependent accumulation of E4BP4 protein is temporally coordinated with a delay of the rising phase of cPer2 in the morning. E4BP4 was phosphorylated progressively and then disappeared in parallel with induced cPer2 expression. Characterization of E4BP4 revealed Ser182, a phosphoacceptor site located at the amino-terminal border of the Ser/Thr cluster, which forms the phosphorylation motifs for casein kinase 1ε (CK1ε). CK1ε physically associated with E4BP4 and phosphorylated it. CK1ε-catalyzed phosphorylation of E4BP4 resulted in proteasomal proteolysis-dependent decrease of E4BP4 levels, while E4BP4 nuclear accumulation was attenuated by CK1ε in a kinase activity-independent manner. CK1ε-mediated posttranslational regulation was accompanied by reduction of the transcriptional repression executed by E4BP4. These results not only demonstrate a phosphorylation-dependent regulatory mechanism for E4BP4 function but also highlight the role of CK1ε as a negative regulator for E4BP4-mediated repression of cPer2.

ジャーナルCurrent Biology
出版ステータスPublished - 2004 6月 8

ASJC Scopus subject areas

  • 生化学、遺伝学、分子生物学(全般)
  • 農業および生物科学(全般)


「Negative control of circadian clock regulator E4BP4 by casein kinase Iε-mediated phosphorylation」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。