RNF4, a SUMO-targeted ubiquitin E3 ligase, promotes DNA double-strand break repair.
Protein ubiquitylation and sumoylation play key roles in regulating cellular responses to DNA double-strand breaks (DSBs). Here, we show that human RNF4, a small ubiquitin-like modifier (SUMO)-targeted ubiquitin E3 ligase, is recruited to DSBs in a manner requiring its SUMO interaction motifs, the SUMO E3 ligases PIAS1 and PIAS4, and various DSB-responsive proteins. Furthermore, we reveal that RNF4 depletion impairs ubiquitin adduct formation at DSB sites and causes persistent histone H2AX phosphorylation (γH2AX) associated with defective DSB repair, hypersensitivity toward DSB-inducing agents, and delayed recovery from radiation-induced cell cycle arrest. We establish that RNF4 regulates turnover of the DSB-responsive factors MDC1 and replication protein A (RPA) at DNA damage sites and that RNF4-depleted cells fail to effectively replace RPA by the homologous recombination factors BRCA2 and RAD51 on resected DNA. Consistent with previous data showing that RNF4 targets proteins to the proteasome, we show that the proteasome component PSMD4 is recruited to DNA damage sites in a manner requiring its ubiquitin-interacting domains, RNF4 and RNF8. Finally, we establish that PSMD4 binds MDC1 and RPA1 in a DNA damage-induced, RNF4-dependent manner and that PSMD4 depletion cause MDC1 and γH2AX persistence in irradiated cells. RNF4 thus operates as a DSB response factor at the crossroads between the SUMO and ubiquitin systems.
The Gurdon Institute, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
Yaron
Y
Galanty
Rimma
R
Belotserkovskaya
Julia
J
Coates
Stephen P
SP
Jackson
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051135:Rad51 Recombinase / Q000378:metabolism; D051716:Replication Protein A / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D004277:DNA, Single-Stranded; C468783:H2AX protein, human; D006657:Histones; C413163:MDC1 protein, human; D009687:Nuclear Proteins; C114070:RNF4 protein, human; C497167:RPA1 protein, human; D051716:Replication Protein A; D015534:Trans-Activators; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D051135:Rad51 Recombinase; D046988:Proteasome Endopeptidase Complex