A noncatalytic function of the ligation complex during nonhomologous end joining.
A noncatalytic function of the ligation complex during nonhomologous end joining.
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DOI：
10.1083/jcb.201203128
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发表时间：
2013-01-21
期刊：
影响因子：
--
通讯作者：
Calsou P
中科院分区：
文献类型：
--
作者：
Cottarel J;Frit P;Bombarde O;Salles B;Négrel A;Bernard S;Jeggo PA;Lieber MR;Modesti M;Calsou P
在非同源末端连接过程中，DNA-PK依赖的末端突触需要连接酶IV，而不是其催化功能。非同源末端连接是多细胞真核生物中主要的脱氧核糖核酸双链断裂修复途径。为了启动修复，Ku结合DNA末端并招募DNA依赖的蛋白激酶(DNA-PK)催化亚单位(DNA-PKcs)形成全酶。早期末端突触与激酶的自磷酸化有关。XRCC4(X4)-DNA连接酶IV(LIG4)复合体(X4LIG4)执行Cernunnos(Cer)-X4样因子(XLF)促进的最终连接。在这篇文章中，我们使用一个无细胞系统来概括末端突触和DNA-PKcs自动磷酸化，我们发现缺乏LIG4的人细胞提取物中这两种活性都存在缺陷。在重组实验中，LIG4还刺激DNA-PKcs的自磷酸化。此外，我们还在LIG4缺陷细胞中发现了一个激酶自动磷酸化缺陷，该缺陷通过异位表达催化死亡的LIG4而得到纠正。最后，我们的数据支持Cer-XLF对连接复合体在末端连接中这一出人意料的早期作用的贡献。我们认为，生产性末端连接是通过在DNA末端形成包含DNA-PK和X4LIG4-Cer-XLF络合物的超分子实体来实现的。
Ligase IV, but not its catalytic function, is required for DNA-PK–dependent end synapsis during nonhomologous end joining. Nonhomologous end joining is the primary deoxyribonucleic acid (DNA) double-strand break repair pathway in multicellular eukaryotes. To initiate repair, Ku binds DNA ends and recruits the DNA-dependent protein kinase (DNA-PK) catalytic subunit (DNA-PKcs) forming the holoenzyme. Early end synapsis is associated with kinase autophosphorylation. The XRCC4 (X4)–DNA Ligase IV (LIG4) complex (X4LIG4) executes the final ligation promoted by Cernunnos (Cer)–X4-like factor (XLF). In this paper, using a cell-free system that recapitulates end synapsis and DNA-PKcs autophosphorylation, we found a defect in both activities in human cell extracts lacking LIG4. LIG4 also stimulated the DNA-PKcs autophosphorylation in a reconstitution assay with purified components. We additionally uncovered a kinase autophosphorylation defect in LIG4-defective cells that was corrected by ectopic expression of catalytically dead LIG4. Finally, our data support a contribution of Cer-XLF to this unexpected early role of the ligation complex in end joining. We propose that productive end joining occurs by early formation of a supramolecular entity containing both DNA-PK and X4LIG4–Cer-XLF complexes on DNA ends.
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DOI：
10.1016/s0921-8777(98)00063-9
发表时间：
1999-01-26
期刊：
MUTATION RESEARCH-DNA REPAIR
影响因子：
--
作者：
Bryans, M;Valenzano, MC;Stamato, TD
通讯作者：
Stamato, TD
影响因子：
4.3
作者：
Britton, Sebastien;Froment, Carine;Calsou, Patrick
通讯作者：
Calsou, Patrick
影响因子：
3.5
作者：
Girard, PM;Kysela, B;Jeggo, PA
通讯作者：
Jeggo, PA
DOI：
10.1073/pnas.94.9.4267
发表时间：
1997-04-29
影响因子：
11.1
作者：
Cary, RB;Peterson, SR;Chen, DJ
通讯作者：
Chen, DJ
影响因子：
4.8
作者：
Chen, L;Trujillo, K;Tomkinson, AE
通讯作者：
Tomkinson, AE