title: Ataxin-3 consolidates the MDC1-dependent DNA double-strand break response by counteracting the SUMO-targeted ubiquitin ligase RNF4.
abstract: The SUMO-targeted ubiquitin ligase RNF4 functions at the crossroads of the SUMO and ubiquitin systems. Here, we report that the deubiquitylation enzyme (DUB) ataxin-3 counteracts RNF4 activity during the DNA double-strand break (DSB) response. We find that ataxin-3 negatively regulates ubiquitylation of the checkpoint mediator MDC1, a known RNF4 substrate. Loss of ataxin-3 markedly decreases the chromatin dwell time of MDC1 at DSBs, which can be fully reversed by co-depletion of RNF4. Ataxin-3 is recruited to DSBs in a SUMOylation-dependent fashion, andin vitroit directly interacts with and is stimulated by recombinant SUMO, defining a SUMO-dependent mechanism for DUB activity toward MDC1. Loss of ataxin-3 results in reduced DNA damage-induced ubiquitylation due to impaired MDC1-dependent recruitment of the ubiquitin ligases RNF8 and RNF168, and reduced recruitment of 53BP1 and BRCA1. Finally, ataxin-3 is required for efficient MDC1-dependent DSB repair by non-homologous end-joining and homologous recombination. Consequently, loss of ataxin-3 sensitizes cells to ionizing radiation and poly(ADP-ribose) polymerase inhibitor. We propose that the opposing activities of RNF4 and ataxin-3 consolidate robust MDC1-dependent signaling and repair of DSBs.
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Pfeiffer
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Martijn S
authors.initials: MS
authors.lastname: Luijsterburg
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Klara
authors.initials: K
authors.lastname: Acs
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Wouter W
authors.initials: WW
authors.lastname: Wiegant
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Angela
authors.initials: A
authors.lastname: Helfricht
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Herzog
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Melania
authors.initials: M
authors.lastname: Minoia
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Claudia
authors.initials: C
authors.lastname: Böttcher
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Florian A
authors.initials: FA
authors.lastname: Salomons
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands h.van.attikum@lumc.nl nico.dantuma@ki.se.
authors.forename: Haico
authors.identifier: 0000-0001-8590-0240
authors.initials: H
authors.lastname: van Attikum
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden h.van.attikum@lumc.nl nico.dantuma@ki.se.
authors.forename: Nico P
authors.identifier: 0000-0002-6090-4170
authors.initials: NP
authors.lastname: Dantuma
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000067699:Ataxin-3 / Q000235:genetics / Q000378:metabolism*; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005720:Gamma Rays; D057809:HEK293 Cells; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000071857:Tumor Suppressor p53-Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; C413163:MDC1 protein, human; D009687:Nuclear Proteins; C114070:RNF4 protein, human; C486521:RNF8 protein, human; D012097:Repressor Proteins; D025842:SUMO-1 Protein; C498301:TP53BP1 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D000071857:Tumor Suppressor p53-Binding Protein 1; C535210:RNF168 protein, human; D044767:Ubiquitin-Protein Ligases; C092341:ATXN3 protein, human; D000067699:Ataxin-3
keywords: 
  SUMO
  ; DNA damage response; DNA repair; deubiquitylation enzyme; ubiquitin