NHEJ involves several key proteins, including Ku70/Ku80 heterodimer, DNA-PKcs, XRCC4, Ligase IV, and Artemis. The Ku70/Ku80 complex first binds to the DNA ends, protecting them and recruiting DNA-PKcs. This forms a synaptic complex that bridges the DNA ends. DNA-PKcs then activates Artemis, which processes the DNA ends to make them suitable for ligation by Ligase IV, in association with XRCC4.
