Fig. 5
Molecular mechanism of NHEJ in humans and S. cerevisiae. When a DSB is created, the NHEJ reaction is initiated by the binding of the Ku protein (the heterodimer of Ku70 and Ku80) to the end of the DSB in both humans and S. cerevisiae (top). In humans, Ku subsequently recruits a complex of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and Artemis, and undergoes end-processing to make ligatable ends (middle). The processed ends are finally joined by a complex containing DNA ligase IV and XRCC4 (bottom). In S. cerevisiae that lacks DNA-PKcs homolog, processing of broken DNA ends are carried out by Mre11p-Rad50p-Xrs2p complex (middle), recruiting homologs of DNA ligase IV and XRCC4 for religation (bottom)