RNF20-RNF40: A ubiquitin-driven link between gene expression and the DNA damage response

► The RNF20-RNF40 heterodimer acts as an E3 ligase in histone H2B monoubiquitylation. ► H2B monoubiquitylation at transcribed chromatin selectively regulates gene expression. ► In response to DNA damage, RNF20-RNF40 is recruited to damage sites and phosphorylated by ATM. ► H2B monoubiquitylation is required for timely repair of DNA double strand breaks. ► The DNA damage response temporarily recruits functional modules from other processes.