Binding of inositol phosphate to DNA-PK and stimulation of double-strand break repair
Binding of inositol phosphate to DNA-PK and stimulation of double-strand break repair
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DOI：
10.1016/s0092-8674(00)00061-1
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发表时间：
2000-09-15
期刊：
影响因子：
64.5
通讯作者：
West, SC
中科院分区：
文献类型：
--
作者：
Hanakahi, LA;Bartlet-Jones, M;West, SC
在哺乳动物细胞中，DNA双链断裂可以通过非同源末端连接（NHEJ）修复，这是一个依赖于Ku 70/80，DNA-PKcs，XRCC 4和DNA连接酶IV的过程。从HeLa细胞的无细胞提取物，促进NHEJ在依赖于所有这些蛋白质的反应，我们已经纯化了一种新的因子，刺激DNA末端连接在体外。使用磷NMR，质谱和强阴离子交换色谱的组合，我们确定这个因素为肌醇六磷酸（IP 6）。纯化的IP 6与DNA-PK结合，并在体外特异性刺激DNA-PK依赖性末端连接。由于DNA-PKcs的催化结构域与磷脂酰肌醇3（PI 3）-激酶家族中发现的催化结构域相似，因此磷酸肌醇参与DNA-PK依赖性NHEJ是特别令人感兴趣的。
In mammalian cells, double-strand breaks in DNA can be repaired by nonhomologous end-joining (NHEJ), a process dependent upon Ku70/80, DNA-PKcs, XRCC4, and DNA ligase IV. Starting with HeLa cell-free extracts, which promote NHEJ in a reaction dependent upon all of these proteins, we have purified a novel factor that stimulates DNA end-joining in vitro. Using a combination of phosphorus NMR, mass spectroscopy, and strong anion exchange chromatography, we identify this factor as inositol hexakisphosphate (IP6). Purified IP6 is bound by DNA-PK and specifically stimulates DNA-PK-dependent end-joining in vitro. The involvement of inositol phosphate in DNA-PK-dependent NHEJ is of particular interest since the catalytic domain of DNA-PKcs is similar to that found in the phosphatidylinositol 3 (PI 3)-kinase family.