HERC2 coordinates ubiquitin-dependent assembly of DNA repair factors on damaged chromosomes.
Regulatory ubiquitylation is emerging as an important mechanism to protect genome integrity in cells exposed to DNA damage. However, the spectrum of known ubiquitin regulators of the DNA damage response (DDR) is limited and their functional interplay is poorly understood. Here, we identify HERC2 as a factor that regulates ubiquitin-dependent retention of repair proteins on damaged chromosomes. In response to ionising radiation (IR), HERC2 forms a complex with RNF8, a ubiquitin ligase involved in the DDR. The HERC2-RNF8 interaction requires IR-inducible phosphorylation of HERC2 at Thr 4827, which in turn binds to the forkhead-associated (FHA) domain of RNF8. Mechanistically, we provide evidence that HERC2 facilitates assembly of the ubiquitin-conjugating enzyme Ubc13 with RNF8, thereby promoting DNA damage-induced formation of Lys 63-linked ubiquitin chains. We also show that HERC2 interacts with, and maintains the levels of, RNF168, another ubiquitin ligase operating downstream of RNF8 (Refs 7, 8). Consequently, knockdown of HERC2 abrogates ubiquitin-dependent retention of repair factors such as 53BP1, RAP80 and BRCA1. Together with the increased radiosensitivity of HERC2-depleted cells, these results uncover a regulatory layer in the orchestration of protein interactions on damaged chromosomes and they underscore the role of ubiquitin-mediated signalling in genome maintenance.
Bekker-Jensen
Simon
S
Centre for Genotoxic Stress Research, Department of Proteomics in Cancer, Institute of Cancer Biology, Danish Cancer Society, Copenhagen, Denmark.
Rendtlew Danielsen
Jannie
J
Fugger
Kasper
K
Gromova
Irina
I
Nerstedt
Annika
A
Lukas
Claudia
C
Bartek
Jiri
J
Lukas
Jiri
J
Mailand
Niels
N
D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002877:Chromosomes, Human / Q000528:radiation effects*; D004249:DNA Damage / Q000502:physiology*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000037:antagonists & inhibitors / Q000502:physiology*; D056488:Histone Chaperones; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000494:pharmacology; D000071857:Tumor Suppressor p53-Binding Protein 1; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination; D014466:Ultraviolet Rays
D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D056488:Histone Chaperones; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C486521:RNF8 protein, human; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; C466234:UIMC1 protein, human; D025801:Ubiquitin; C118566:HERC2 protein, human; D044767:Ubiquitin-Protein Ligases; D008239:Lysine