2. Academic Validation
  3. The scaffold protein WRAP53β orchestrates the ubiquitin response critical for DNA double-strand break repair

The scaffold protein WRAP53β orchestrates the ubiquitin response critical for DNA double-strand break repair

  • Genes Dev. 2014 Dec 15;28(24):2726-38. doi: 10.1101/gad.246546.114.
Sofia Henriksson 1,  Hanif Rassoolzadeh 1,  Elisabeth Hedström 1,  Christos Coucoravas 1,  Alexander Julner 1,  Michael Goldstein 2,  Gabriela Imreh 3,  Boris Zhivotovsky 3,  Michael B Kastan 2,  Thomas Helleday 4,  Marianne Farnebo 5
Affiliations

Affiliations

  • 1 Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm 171 76, Sweden;
  • 2 Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710, USA;
  • 3 Institute for Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden;
  • 4 Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 171 65, Sweden.
  • 5 Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm 171 76, Sweden; marianne.farnebo@ki.se.
PMID: 25512560 DOI: 10.1101/gad.246546.114
Abstract

The WD40 domain-containing protein WRAP53β (WD40 encoding RNA antisense to p53; also referred to as WDR79/TCAB1) controls trafficking of splicing factors and the Telomerase enzyme to Cajal bodies, and its functional loss has been linked to carcinogenesis, premature aging, and neurodegeneration. Here, we identify WRAP53β as an essential regulator of DNA double-strand break (DSB) repair. WRAP53β rapidly localizes to DSBs in an ATM-, H2AX-, and MDC1-dependent manner. We show that WRAP53β targets the E3 Ligase RNF8 to DNA lesions by facilitating the interaction between RNF8 and its upstream partner, MDC1, in response to DNA damage. Simultaneous binding of MDC1 and RNF8 to the highly conserved WD40 scaffold domain of WRAP53β facilitates their interaction and accumulation of RNF8 at DSBs. In this manner, WRAP53β controls proper ubiquitylation at DNA damage sites and the downstream assembly of 53BP1, BRCA1, and RAD51. Furthermore, we reveal that knockdown of WRAP53β impairs DSB repair by both homologous recombination (HR) and nonhomologous end-joining (NHEJ), causes accumulation of spontaneous DNA breaks, and delays recovery from radiation-induced cell cycle arrest. Our findings establish WRAP53β as a novel regulator of DSB repair by providing a scaffold for DNA repair factors.

Keywords

DNA repair; MDC1; RNF8 E3 ligase; WD40 scaffold; WRAP53β; ubiquitin.

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