hSSB1 interacts directly with the MRN complex stimulating its recruitment to DNA double-strand breaks and its endo-nuclease activity.
hSSB1 is a recently discovered single-stranded DNA binding protein that is essential for efficient repair of DNA double-strand breaks (DSBs) by the homologous recombination pathway. hSSB1 is required for the efficient recruitment of the MRN complex to sites of DSBs and for the efficient initiation of ATM dependent signalling. Here ... we explore the interplay between hSSB1 and MRN. We demonstrate that hSSB1 binds directly to NBS1, a component of the MRN complex, in a DNA damage independent manner. Consistent with the direct interaction, we observe that hSSB1 greatly stimulates the endo-nuclease activity of the MRN complex, a process that requires the C-terminal tail of hSSB1. Interestingly, analysis of two point mutations in NBS1, associated with Nijmegen breakage syndrome, revealed weaker binding to hSSB1, suggesting a possible disease mechanism.
Mesh Terms:
Acid Anhydride Hydrolases, Binding Sites, Cell Cycle Proteins, DNA Breaks, Double-Stranded, DNA Repair Enzymes, DNA, Single-Stranded, DNA-Binding Proteins, Endodeoxyribonucleases, Humans, MRE11 Homologue Protein, Mitochondrial Proteins, Mutation, Nuclear Proteins
Acid Anhydride Hydrolases, Binding Sites, Cell Cycle Proteins, DNA Breaks, Double-Stranded, DNA Repair Enzymes, DNA, Single-Stranded, DNA-Binding Proteins, Endodeoxyribonucleases, Humans, MRE11 Homologue Protein, Mitochondrial Proteins, Mutation, Nuclear Proteins
Nucleic Acids Res
Date: May. 01, 2011
PubMed ID: 21227926
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