Related Experiment Video

Updated: Jul 15, 2026

Purification of Ubiquitinated p53 Proteins from Mammalian Cells
10:55

Purification of Ubiquitinated p53 Proteins from Mammalian Cells

Published on: March 21, 2022

Cytoplasmic localization and ubiquitination of p21(Cip1) by reactive oxygen species

Chae Young Hwang1, Ick Young Kim, Ki-Sun Kwon

  • 1Laboratory of Cell Signaling, Proteome Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-333, Republic of Korea.

Biochemical and Biophysical Research Communications
|May 5, 2007
PubMed

Insights

Reactive oxygen species trigger p21(Cip1) protein degradation via a pathway involving nuclear export, Skp2, and ubiquitination. Antioxidants like N-acetylcysteine prevent this process, highlighting a novel mechanism for controlling p21(Cip1) levels.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Reactive oxygen species (ROS) are known to induce p21(Cip1) protein degradation.
  • The precise molecular mechanisms underlying ROS-mediated p21(Cip1) degradation remain incompletely understood.

Purpose of the Study:

  • To elucidate the detailed mechanism by which ROS induce p21(Cip1) protein degradation.
  • To investigate the role of specific cellular components and pathways in this degradation process.

Main Methods:

  • Treatment of various cell types with hydrogen peroxide (H2O2) to induce ROS.
  • Use of N-acetylcysteine as an antioxidant to assess its protective effect.
  • Generation and analysis of a mutant p21(Cip1) lacking lysine residues.
  • Assessment of p21(Cip1) and Skp2 interaction.
  • Investigation of nuclear export signals (NES) and leptomycin B treatment.

Main Results:

  • Low-dose H2O2 treatment rapidly degraded p21(Cip1) in multiple cell types.
  • N-acetylcysteine preincubation significantly prolonged p21(Cip1) half-life.
  • A mutant p21(Cip1) with all lysines substituted by arginines was resistant to H2O2-induced degradation.
  • H2O2 treatment increased the interaction between p21(Cip1) and Skp2.
  • Disruption of NES sequences or leptomycin B treatment inhibited H2O2-induced p21(Cip1) degradation.

Conclusions:

  • ROS induce p21(Cip1) degradation through a mechanism dependent on nuclear export, Skp2, and ubiquitination.
  • This pathway involves the direct interaction of p21(Cip1) with Skp2 and its subsequent ubiquitination and proteasomal degradation.
  • Understanding this pathway offers insights into cellular responses to oxidative stress and potential therapeutic targets.

More Related Videos

Detection of Protein Ubiquitination09:00

Detection of Protein Ubiquitination

Published on: August 19, 2009

Quantitative Detection of DNA-Protein Crosslinks and Their Post-Translational Modifications10:12

Quantitative Detection of DNA-Protein Crosslinks and Their Post-Translational Modifications

Published on: April 21, 2023

Related Concept Videos

Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
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...
Regulated Protein Degradation02:58

Regulated Protein Degradation

It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
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.
Regulation of the Unfolded Protein Response01:31

Regulation of the Unfolded Protein Response

Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...