Related Experiment Video

Updated: Mar 6, 2026

Visualization of DNA Repair Proteins Interaction by Immunofluorescence
07:55

Visualization of DNA Repair Proteins Interaction by Immunofluorescence

Published on: June 26, 2020

11.3K

Ataxin-3 consolidates the MDC1-dependent DNA double-strand break response by counteracting the SUMO-targeted

Annika Pfeiffer1, Martijn S Luijsterburg2, Klara Acs1

  • 1Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.

The EMBO Journal
|March 10, 2017
PubMed

Insights

Ataxin-3 counteracts RNF4 activity in DNA double-strand break (DSB) repair by regulating MDC1 ubiquitylation. Loss of ataxin-3 impairs DSB signaling and repair, sensitizing cells to DNA damaging agents.

Area of Science:

  • Molecular Biology
  • Cellular Biology
  • Biochemistry

Background:

  • RNF4 is a SUMO-targeted ubiquitin ligase crucial for DNA damage response.
  • The deubiquitylation enzyme ataxin-3's role in DNA double-strand break (DSB) repair is not fully understood.

Purpose of the Study:

  • To investigate the role of ataxin-3 in counteracting RNF4 activity during DSB repair.
  • To elucidate the mechanism by which ataxin-3 regulates the checkpoint mediator MDC1.

Main Methods:

  • Investigated ataxin-3's effect on MDC1 ubiquitylation and chromatin dwell time at DSBs.
  • Utilized SUMOylation-dependent recruitment assays and in vitro enzyme activity assays.
  • Assessed the impact of ataxin-3 loss on DNA damage-induced ubiquitylation and recruitment of repair factors like RNF8, RNF168, 53BP1, and BRCA1.

Main Results:

  • Ataxin-3 negatively regulates MDC1 ubiquitylation, counteracting RNF4.
  • Loss of ataxin-3 reduces MDC1 chromatin dwell time at DSBs, which is reversible by RNF4 depletion.
  • Ataxin-3 is SUMOylation-dependently recruited to DSBs and its DUB activity towards MDC1 is SUMO-stimulated.
  • Ataxin-3 deficiency impairs DNA damage-induced ubiquitylation and recruitment of key repair proteins.
  • Ataxin-3 is essential for efficient DSB repair via non-homologous end-joining and homologous recombination.

Conclusions:

  • Ataxin-3 plays a critical role in DSB repair by opposing RNF4 activity and modulating MDC1 ubiquitylation.
  • The balance between RNF4 and ataxin-3 activities is crucial for robust MDC1-dependent signaling and DSB repair.
  • Loss of ataxin-3 sensitizes cells to ionizing radiation and PARP inhibitors, highlighting its therapeutic relevance.
Keywords:
SUMODNA damage responseDNA repairdeubiquitylation enzymeubiquitin

More Related Videos

Laser Microirradiation to Study In Vivo Cellular Responses to Simple and Complex DNA Damage10:44

Laser Microirradiation to Study In Vivo Cellular Responses to Simple and Complex DNA Damage

Published on: January 31, 2018

10.8K
CD Spectroscopy to Study DNA-Protein Interactions06:48

CD Spectroscopy to Study DNA-Protein Interactions

Published on: February 10, 2022

7.7K

Related Concept Videos

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...
10.3K
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...
3.3K
Restarting Stalled Replication Forks02:37

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart,...
6.5K
Homologous Recombination02:31

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
64.7K
Fixing Double-strand Breaks02:04

Fixing Double-strand Breaks

The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
15.6K
Other Unique Bacteria01:18

Other Unique Bacteria

Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic...
517