Related Experiment Video

Updated: May 15, 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

Cdk1 protein-mediated phosphorylation of receptor-associated protein 80 (RAP80) serine 677 modulates DNA

Hyun Jung Cho1, Yun Jung Oh, Seung Hun Han

  • 1Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Hanyang University, Seoul 133-791, Korea.

The Journal of Biological Chemistry
|December 25, 2012
PubMed

Insights

Cyclin-dependent kinase 1 (Cdk1) phosphorylates RAP80 at Ser-677, impacting DNA damage repair and cell cycle control. This phosphorylation is crucial for RAP80

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Post-translational phosphorylation is vital for DNA damage response pathways.
  • RAP80, part of the BRCA1-A complex, is essential for cell cycle checkpoints and DNA repair.
  • The precise molecular function of RAP80 remains incompletely understood.

Purpose of the Study:

  • To elucidate the molecular mechanism of RAP80 in DNA damage response.
  • To identify novel RAP80-binding proteins and phosphorylation sites.
  • To investigate the role of RAP80 phosphorylation in cell cycle control and DNA repair.

Main Methods:

  • Identified Cdk1 as a RAP80-binding protein.
  • Utilized in vitro kinase assays to confirm Cdk1-cyclin B(1) phosphorylation of RAP80 at Ser-677.
  • Developed a phospho-specific antibody for detecting RAP80 Ser-677 phosphorylation.
  • Analyzed RAP80 phosphorylation during the cell cycle and after ionizing radiation (IR).
  • Created a Ser-677 alanine mutant to assess functional consequences.

Main Results:

  • Cdk1-cyclin B(1) complex phosphorylates RAP80 at Ser-677.
  • RAP80 Ser-677 phosphorylation occurs during M phase and is induced by IR.
  • Mutation of Ser-677 to alanine leads to increased sensitivity to IR.
  • The Ser-677 mutation affects G(2)/M checkpoint control.

Conclusions:

  • Cdk1-cyclin B(1) mediated phosphorylation of RAP80 at Ser-677 is a key regulatory event.
  • This phosphorylation is critical for RAP80's role in DNA damage response, particularly IR sensitivity.
  • RAP80 phosphorylation by Cdk1 influences G(2)/M checkpoint activation.

More Related Videos

Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols12:02

Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols

Published on: June 6, 2017

Detection and Visualization of DNA Damage-induced Protein Complexes in Suspension Cell Cultures Using the Proximity Ligation Assay13:10

Detection and Visualization of DNA Damage-induced Protein Complexes in Suspension Cell Cultures Using the Proximity Ligation Assay

Published on: June 9, 2017

Related Concept Videos

Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
Inhibition of CDK Activity02:34

Inhibition of CDK Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
DNA Damage can Stall the Cell Cycle02:36

DNA Damage can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
DNA Damage Can Stall the Cell Cycle02:36

DNA Damage Can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.