Histone H2A variants alpha1-extension helix directs RNF168-mediated ubiquitination

• Published in: Nature communications 2020-05, Vol.11 (1), p.2462-14, Article 2462
• Main Authors: Kelliher, Jessica L., West, Kirk L., Gong, Qingguo, Leung, Justin W. C.
• Format: Article
• Language: English
• Subjects: 13; 13/1; 13/44; 14/19; 14/35; 631/337/100/1701; 631/337/100/2285; 631/337/100/2286; 631/337/1427/2566; 82/29; 82/80; Amino Acid Sequence; BRCA1 protein; Chromatin; Damage; Deoxyribonucleic acid; Divergence; DNA; DNA damage; Electrostatic properties; Evolution, Molecular; HEK293 Cells; Histone H2A; Histones; Histones - chemistry; Histones - genetics; Histones - metabolism; Humanities and Social Sciences; Humans; Ionizing radiation; Lysine; Lysine - metabolism; multidisciplinary; Mutation; Protein Structure, Secondary; Radiation effects; Residues; Science; Science (multidisciplinary); Substrate Specificity; Tumor Suppressor p53-Binding Protein 1 - metabolism; Ubiquitin-Protein Ligases - metabolism; Ubiquitination
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-16307-4

Histone ubiquitination plays an important role in the DNA damage response (DDR) pathway. RNF168 catalyzes H2A and H2AX ubiquitination on lysine 13/15 (K13/K15) upon DNA damage and promotes the accrual of downstream repair factors at damaged chromatin. Here, we report that RNF168 ubiquitinates the non-canonical H2A variants H2AZ and macroH2A1/2 at the divergent N-terminal tail lysine residue. In addition to their evolutionarily conserved nucleosome acidic patch, we identify the positively charged alpha1-extension helix as essential for RNF168-mediated ubiquitination of H2A variants. Moreover, mutation of the RNF168 UMI (UIM- and MIU-related UBD) hydrophilic acidic residues abolishes RNF168-mediated ubiquitination as well as 53BP1 and BRCA1 ionizing radiation-induced foci formation. Our results reveal a juxtaposed bipartite electrostatic interaction utilized by the nucleosome to direct RNF168 orientation towards the target lysine residues in proximity to the H2A alpha1-extension helix, which plays an important role in the DDR pathway. Histone ubiquitination plays a critical role in the DNA damage response pathway. Here the authors reveal how RNF168 ubiquitinates the H2A family including noncanonical variants, H2AZ and macroH2A1/2, at the divergent N-terminal tail lysine residue.