Related Experiment Video

Updated: Feb 7, 2026

Residue-Specific Exchange of Proline by Proline Analogs in Fluorescent Proteins: How "Molecular Surgery" of the Backbone Affects Folding and Stability
10:31

Residue-Specific Exchange of Proline by Proline Analogs in Fluorescent Proteins: How "Molecular Surgery" of the Backbone Affects Folding and Stability

Published on: February 3, 2022

3.4K

PHD3 Regulates p53 Protein Stability by Hydroxylating Proline 359

Javier Rodriguez1, Ana Herrero2, Shuijie Li3

  • 1Systems Biology Ireland, University College Dublin, Dublin 4, Ireland; Cancer Research UK Edinburgh Centre, IGMM, University of Edinburgh, Edinburgh EH4 2XR, UK.

Cell Reports
|August 2, 2018
PubMed

Insights

Hydroxylation of the p53 protein by PHD3 at proline 359 regulates its interaction with deubiquitinating enzymes (DUBs), affecting p53 protein stability and ubiquitination levels.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Background:

  • Cellular p53 protein levels are tightly regulated by ubiquitination and de-ubiquitination processes.
  • Deubiquitinating enzymes (DUBs), specifically USP7 (HAUSP) and USP10, are key regulators in removing ubiquitin chains from p53.
  • Dysregulation of p53 stability is implicated in various cellular processes, including cancer.

Purpose of the Study:

  • To investigate the role of PHD3 in the regulation of p53 protein stability.
  • To identify the specific site of p53 modification by PHD3 and its functional consequences.
  • To elucidate the mechanism by which PHD3 influences p53 ubiquitination and degradation.

Main Methods:

  • Site-directed mutagenesis to target proline 359 in p53.
  • Co-immunoprecipitation assays to assess protein-protein interactions.
  • Western blotting to analyze p53 protein levels and ubiquitination status.
  • Quantitative PCR to measure mRNA expression.

Main Results:

  • PHD3 was identified as an enzyme that hydroxylates p53 at proline 359.
  • Hydroxylation at proline 359 directly impacts the binding affinity of p53 to USP7 and USP10.
  • Inhibition of p53 hydroxylation by PHD3 led to decreased p53 association with USP7/USP10, increased p53 ubiquitination, and rapid reduction in p53 protein levels.
  • These changes in p53 protein levels occurred independently of alterations in p53 mRNA expression.

Conclusions:

  • p53 is a novel substrate for PHD3, with hydroxylation occurring at proline 359.
  • PHD3-mediated hydroxylation of p53 is a critical regulatory mechanism controlling p53 protein stability.
  • This hydroxylation event modulates p53 ubiquitination by affecting its interaction with USP7 and USP10, thereby influencing proteasomal degradation.
Keywords:
EglN3PHD3USP7hydroxylaseshypoxiap53proteomics

More Related Videos

Purification of Ubiquitinated p53 Proteins from Mammalian Cells10:55

Purification of Ubiquitinated p53 Proteins from Mammalian Cells

Published on: March 21, 2022

2.8K
Laser-free Hydroxyl Radical Protein Footprinting to Perform Higher Order Structural Analysis of Proteins09:59

Laser-free Hydroxyl Radical Protein Footprinting to Perform Higher Order Structural Analysis of Proteins

Published on: June 4, 2021

4.0K

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....
9.6K
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

2.0K
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...
8.9K
Regulated Protein Degradation02:58

Regulated Protein Degradation

3.2K
RNA Stability01:53

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...
35.8K
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.
38.5K