(A) Domain organization of Ku80 is modified from a previous review (for review see )

Ku80 domains include vWA, N-terminal von Willibrand A domain; Core, central core domain; CT, C-terminal region; PK, DNA-PKcs–interacting peptide (). The core DNA-binding region is indicated in light blue, and the other regions of the protein included in the atomic structure are in yellow. Regions of the protein not included in the structure are white. Numbers to the left indicate amino acids included in the protein. An asterisk indicates the location of amino acid W275. Truncations were generated as indicated and labeled with S in rabbit reticulocyte lysate. Proteins were then mixed with egg extract, to which was added either SB-DNA beads to assess DNA binding or cut linear DNA to measure degradation. Half-lives of the unmodified bands after addition of cut DNA, quantified using a phosphorimager, are indicated. (B) The structure of the human Ku70/Ku80 heterodimer bound to DNA (). Residues up to the equivalent of amino acid 543 of the Ku80 are included in the structure. Red, Ku70; yellow, Ku80; white, DNA. The region of Ku80 required for DNA binding ( residues 244–540) is light blue. (C) Truncations were mixed with extract and incubated with SB-DNA beads for 45 min. Bound proteins were visualized by exposing to film. I, input; B, beads.<p><b>Copyright information:</b></p><p>Taken from "Ku80 removal from DNA through double strand break–induced ubiquitylation"</p><p></p><p>The Journal of Cell Biology 2008;182(3):467-479.</p><p>Published online 11 Aug 2008</p><p>PMCID:PMC2500133.</p><p>