Related Experiment Video

Updated: May 9, 2026

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

CK1δ kinase activity is modulated by Chk1-mediated phosphorylation

Joachim Bischof1, Sven-Jannis Randoll, Nadine Süßner

  • 1Department of General and Visceral Surgery, Ulm University Hospital, Ulm, Germany.

Plos One
|July 18, 2013
PubMed

Insights

Checkpoint kinase 1 (Chk1) phosphorylates casein kinase 1 delta (CK1δ) at specific sites, altering its activity. This phosphorylation by Chk1 suggests a regulatory relationship impacting CK1δ function in cellular processes.

Area of Science:

  • Molecular Biology
  • Cellular Signaling
  • Biochemistry

Background:

  • Casein kinase 1 delta (CK1δ) is implicated in neurodegenerative diseases and cancer.
  • CK1δ activity is modulated by its phosphorylation state, affecting therapeutic inhibitor efficacy.
  • Understanding site-specific phosphorylation is crucial for CK1δ targeted therapies.

Purpose of the Study:

  • To identify kinases that phosphorylate CK1δ in its C-terminal domain.
  • To investigate the functional consequences of CK1δ phosphorylation by Chk1.
  • To elucidate the regulatory relationship between Chk1 and CK1δ.

Main Methods:

  • Site-directed mutagenesis to create CK1δ phosphorylation site mutants.
  • Kinetic analysis of wild-type and mutant CK1δ proteins.
  • Co-immunoprecipitation assays to detect protein interactions.
  • Measurement of cellular CK1δ kinase activity upon Chk1 activation.

Main Results:

  • Chk1 was identified as a kinase phosphorylating rat CK1δ at Ser328, Ser331, Ser370, and Thr397, and human CK1δ variants 1 and 2.
  • CK1δ mutants with altered phosphorylation sites showed distinct kinetic properties compared to wild-type.
  • CK1δ and Chk1 co-precipitated, and Chk1 activation reduced CK1δ kinase activity.

Conclusions:

  • Chk1 directly phosphorylates CK1δ at identified sites, modulating its kinase activity.
  • A functional regulatory link exists between Chk1 and CK1δ.
  • These findings offer insights into CK1δ regulation and potential therapeutic strategies.

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