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Updated: Jun 1, 2026

In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
Destroying the ring: Freeing DNA from Ku with ubiquitin
1Laboratory of Chromosome and Cell Biology, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA. PostowL@rockfeller.edu
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The Ku heterodimer, consisting of the proteins Ku70 and Ku80, is the central component of the non-homologous end joining (NHEJ) pathway of double strand break (DSB) repair. Ku is able to recognize and bind a DSB by virtue of its ring-like structure. Both pre-repair and topologically trapped post-repair Ku heterodimers are thought to be inhibitory to multiple cellular processes. Thus, a regulated mechanism for the removal of Ku from chromatin was predicted to exist. Recent evidence shows that Ku80 is removed from DNA through a ubiquitin-mediated process. Similar processes have been shown to be involved in the regulated dissociation of a host of other proteins from chromatin, and this appears to be a general and conserved mechanism for the regulation of chromatin-associated factors. A potential mechanism for this pathway is discussed.
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