title: RNF168 forms a functional complex with RAD6 during the DNA damage response.
abstract: Protein ubiquitination plays an important role in initiating the DNA damage response. Following DNA damage, E2 ubiquitin conjugating enzymes are crucial for catalyzing substrate ubiquitination that recruits downstream DNA repair factors to DNA lesions. To identify novel E2 conjugating enzymes important for initiating the DNA-damage-induced ubiquitination cascade, we screened most of the known E2 enzymes and found that RAD6A and RAD6B function together with RNF168 in the ionizing radiation (IR)-induced DNA damage response. Similarly to RNF168-deficient cells, RAD6A- or RAD6B-deficient cells exhibit a reduction in DNA-damage-induced protein ubiquitination. Correspondingly, DNA-damage-induced foci formation of DNA damage repair proteins, such as BRCA1 and 53BP1, is impaired in the absence of RAD6A or RAD6B. Moreover, the RNF168-RAD6 complex targeted histone H1.2 for ubiquitination in vitro and regulated DNA-damage-induced histone H1.2 ubiquitination in vivo. Collectively, these data demonstrate that RNF168, in complex with RAD6A or RAD6B, is activated in the DNA-damage-induced protein ubiquitination cascade.
authors.affiliation: State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, 200433, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.forename: Degui
authors.initials: D
authors.lastname: Wang
authors.forename: Jiaxue
authors.initials: J
authors.lastname: Wu
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keller
authors.forename: Teng
authors.initials: T
authors.lastname: Ma
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Yu
mesh_terms: D000818:Animals; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology*
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D006657:Histones; C471545:UBE2A protein, human; C471546:UBE2B protein, human; C512786:Ube2a protein, mouse; C465394:Ube2b protein, mouse; D044763:Ubiquitin-Conjugating Enzymes; C535210:RNF168 protein, human; C579124:RNF168 protein, mouse; D044767:Ubiquitin-Protein Ligases
keywords: DNA damage response; RAD6; RNF168; Ubiquitination