Interaction between RNF8 and DYRK2 is required for the recruitment of DNA repair molecules to DNA double-strand breaks.

The genome of eukaryotic cells is frequently exposed to damage by various genotoxins. Phosphorylation of histone H2AX at Serine 139 (γ-H2AX) is a hallmark of DNA damage. RNF8 monoubiquitinates γ-H2AX with the Lys63-linked ubiquitin chain to tether DNA repair molecules at DNA lesions. A high-throughput screening identified RNF8 as a binding partner of dual-specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2). Notably, DNA damage-induced monoubiquitination of γ-H2AX is impaired in DYRK2-depleted cells. The foci formation of p53-binding protein 1 at DNA double-strand break sites is suppressed in DYRK2 knockdown cells, which fail to repair the DNA damage. A homologous recombination assay showed decreased repair efficiency in DYRK2-depleted cells. Our findings indicate direct interaction of DYRK2 with RNF8 in regulating response to DNA damage.