Related Experiment Video

Updated: Aug 19, 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

Chkl binds and phosphorylates BAD protein

Edward Kyu-ho Han1, Chris Butler, Haichao Zhang

  • 1Department R47S, AP9A, Cancer Research, Global Pharmaceutical Research Division, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, USA. edward.k.han@abbott.com

Anticancer Research
|March 2, 2005
PubMed

Insights

Checkpoint kinase 1 (Chk1) phosphorylates the pro-apoptotic protein BAD at serine-155, suggesting a role for Chk1 in regulating apoptosis following DNA damage.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Checkpoint kinase 1 (Chk1) is essential for cell cycle arrest in response to DNA damage.
  • Chk1 regulates cell cycle progression by phosphorylating key proteins like Cdc25C and Cdc25A.
  • The pro-apoptotic protein BAD plays a crucial role in programmed cell death.

Purpose of the Study:

  • To investigate the potential interaction between Chk1 and the pro-apoptotic protein BAD.
  • To determine if Chk1 directly phosphorylates BAD.
  • To elucidate the functional consequences of Chk1-mediated BAD phosphorylation in response to DNA damage.

Main Methods:

  • In vitro kinase assays using BAD peptides.
  • Site-directed mutagenesis of BAD phosphorylation sites.
  • Co-immunoprecipitation to assess protein-protein interactions.
  • Adriamycin treatment to induce DNA damage in transfected cells.

Main Results:

  • Chk1 directly phosphorylates BAD in vitro at serine-155 and serine-170.
  • Chk1 and BAD associate in cells, and this interaction is enhanced by DNA damage.
  • Phosphorylation of BAD at serine-155 increases following adriamycin-induced DNA damage.
  • Mutational analysis confirmed serine-155 as a key Chk1 phosphorylation site on BAD.

Conclusions:

  • Chk1 directly phosphorylates the pro-apoptotic protein BAD at serine-155.
  • Chk1 associates with BAD, and this interaction is modulated by DNA damage.
  • Chk1-mediated phosphorylation of BAD may inactivate its pro-apoptotic function, suggesting a novel role for Chk1 in apoptosis regulation.

More Related Videos

Understanding the Development of Compensatory Pathways in a Mutant Malaria Parasite Harbouring Hypomorphic Allele of Plant-Like Kinases09:13

Understanding the Development of Compensatory Pathways in a Mutant Malaria Parasite Harbouring Hypomorphic Allele of Plant-Like Kinases

Published on: November 22, 2024

Oligopeptide Competition Assay for Phosphorylation Site Determination09:16

Oligopeptide Competition Assay for Phosphorylation Site Determination

Published on: May 18, 2017

Related Concept Videos

Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
Calmodulin-dependent Signaling01:16

Calmodulin-dependent Signaling

Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...