National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM135651
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
5T32GM008382
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
U24GM129547
米国
National Institutes of Health/National Cancer Institute (NIH/NCI)
P01CA092584
米国
American Cancer Society
IRG-15-173-21
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM047251
米国
引用
ジャーナル: Nature / 年: 2021 タイトル: Structural basis of long-range to short-range synaptic transition in NHEJ. 著者: Siyu Chen / Linda Lee / Tasmin Naila / Susan Fishbain / Annie Wang / Alan E Tomkinson / Susan P Lees-Miller / Yuan He / 要旨: DNA double-strand breaks (DSBs) are a highly cytotoxic form of DNA damage and the incorrect repair of DSBs is linked to carcinogenesis. The conserved error-prone non-homologous end joining (NHEJ) ...DNA double-strand breaks (DSBs) are a highly cytotoxic form of DNA damage and the incorrect repair of DSBs is linked to carcinogenesis. The conserved error-prone non-homologous end joining (NHEJ) pathway has a key role in determining the effects of DSB-inducing agents that are used to treat cancer as well as the generation of the diversity in antibodies and T cell receptors. Here we applied single-particle cryo-electron microscopy to visualize two key DNA-protein complexes that are formed by human NHEJ factors. The Ku70/80 heterodimer (Ku), the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs), DNA ligase IV (LigIV), XRCC4 and XLF form a long-range synaptic complex, in which the DNA ends are held approximately 115 Å apart. Two DNA end-bound subcomplexes comprising Ku and DNA-PKcs are linked by interactions between the DNA-PKcs subunits and a scaffold comprising LigIV, XRCC4, XLF, XRCC4 and LigIV. The relative orientation of the DNA-PKcs molecules suggests a mechanism for autophosphorylation in trans, which leads to the dissociation of DNA-PKcs and the transition into the short-range synaptic complex. Within this complex, the Ku-bound DNA ends are aligned for processing and ligation by the XLF-anchored scaffold, and a single catalytic domain of LigIV is stably associated with a nick between the two Ku molecules, which suggests that the joining of both strands of a DSB involves both LigIV molecules.