Structure of an activated DNA-PK and its implications for NHEJ.
Structure of an activated DNA-PK and its implications for NHEJ.
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DOI：
10.1016/j.molcel.2020.12.015
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发表时间：
2021-02-18
期刊：
影响因子：
16
通讯作者：
Yang W
中科院分区：
文献类型：
--
作者：
Chen X;Xu X;Chen Y;Cheung JC;Wang H;Jiang J;de Val N;Fox T;Gellert M;Yang W
DNA依赖性蛋白激酶（DNA-PK）与所有磷脂酰肌醇3-激酶相关激酶（PIKK）一样，由保守的FAT和激酶结构域（FATKIN）沿着由HEAT重复序列构成的螺线管结构组成。这些激酶响应细胞应激信号而被激活，但是控制激活和调节的机制仍然没有得到解决。对于DNA-PK，所有现有的结构都代表非活性状态，分辨率最多限于4.3 μ m。在这里，我们报告的cryoEM结构的DNA-PKcs（催化亚基）结合到DNA末端，或与Ku 70/80和DNA复合，在非活性和活化形式的分辨率为3.7 μ m的整体，和3.2 μ m的脂肪蛋白。这些结构揭示了DNA-PK从失活形式到活化形式的顺序转变。最值得注意的是，激酶的激活涉及以前未知的拉伸和扭曲在个别螺线管段和松散的DNA末端结合。这种前所未有的螺旋重复序列的结构可塑性可能是HEAT重复序列蛋白的一种普遍调节机制。DNA-PK在其ABCDE簇游离和去磷酸化时保护DNA末端，并通过非同源末端连接（NHEJ）协调DNA修复。DNA-PK-DNA复合物周期性地在激酶失活和激活状态之间切换。通过柔性HEAT重复连接，DNA-PK的自磷酸化变构地将DNA末端暴露于NHEJ修复因子。
DNA-dependent protein kinase (DNA-PK), like all phosphatidylinositol 3-kinase-related kinases (PIKKs), is composed of conserved FAT and kinase domains (FATKIN) along with solenoid structures made of HEAT repeats. These kinases are activated in response to cellular stress signals, but the mechanisms governing activation and regulation remain unresolved. For DNA-PK, all existing structures represent inactive states with resolution limited to 4.3 Å at best. Here we report the cryoEM structures of DNA-PKcs (catalytic subunit) bound to a DNA end, or complexed with Ku70/80 and DNA, in both inactive and activated forms at resolutions of 3.7 Å overall, and 3.2 Å for FATKIN. These structures reveal the sequential transition of DNA-PK from inactive to activated forms. Most notably, activation of the kinase involves previously unknown stretching and twisting within individual solenoid segments and loosens DNA-end binding. This unprecedented structural plasticity of helical repeats may be a general regulatory mechanism of HEAT-repeat proteins. DNA-PK protects DNA ends when its ABCDE cluster is free and dephosphorylated, and coordinates DNA repair by non-homologous end joining (NHEJ). DNA-PK-DNA complex periodically toggles between kinase inactive and activated states. Linked by flexible HEAT repeats, autophosphorylation of DNA-PK allosterically exposes the DNA end to NHEJ repair factors.
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影响因子：
4.8
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
Block, WD;Yu, YP;Lees-Miller, SP
通讯作者：
Lees-Miller, SP
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH