NBS1 promotes the endonuclease activity of the MRE11‐RAD50 complex by sensing CtIP phosphorylation

DNA end resection initiates DNA double-strand break repair by homologous recombination. MRE11-RAD50-NBS1 and phosphorylated CtIP perform the first resection step via MRE11-catalyzed endonucleolytic DNA cleavage. Human NBS1, more than its homologue Xrs2 in Saccharomyces cerevisiae, is crucial for this process, highlighting complex mechanisms that regulate the MRE11 nuclease in higher eukaryotes. Using a reconstituted system, we show here that...