The RNF168 paralog RNF169 defines a new class of ubiquitylated histone reader involved in the response to DNA damage
The RNF168 paralog RNF169 defines a new class of ubiquitylated histone reader involved in the response to DNA damage
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DOI：
10.7554/elife.23872
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发表时间：
2017-04-13
期刊：
影响因子：
7.7
通讯作者：
Kay, Lewis E.
中科院分区：
文献类型：
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作者：
Kitevski-LeBlanc, Julianne;Fradet-Turcotte, Amelie;Kay, Lewis E.
位点特异性组蛋白泛素化在协调对DNA双链断裂（DSB）的反应中起着核心作用。DSB引发由泛素连接酶RNF 168控制的级联事件，其促进修复因子如53 BP 1和BRCA 1在断裂位点侧翼的染色质上的积累。RNF 168也促进其自身的积累，以及它的副产物RNF 169的积累，但它们如何识别泛素化的染色质尚不清楚。使用甲基-TROSY溶液核磁共振光谱和分子动力学模拟，我们提出了人类RNF 169与遍在化核小体结合的原子分辨率模型，并通过电子低温显微镜验证了它。我们确定RNF 169以一种方式结合泛素化的H2 A-Lys 13/Lys 15，这种方式涉及其典型的泛素结合螺旋和一对富含丝氨酸的基序，这些基序与核小体酸性补丁相互作用。这种三管齐下的相互作用机制与53 BP 1结合泛素化H2 A-Lys 15的机制不同，突出了泛素化核小体位点特异性识别的多样性。
Site-specific histone ubiquitylation plays a central role in orchestrating the response to DNA double-strand breaks (DSBs). DSBs elicit a cascade of events controlled by the ubiquitin ligase RNF168, which promotes the accumulation of repair factors such as 53BP1 and BRCA1 on the chromatin flanking the break site. RNF168 also promotes its own accumulation, and that of its paralog RNF169, but how they recognize ubiquitylated chromatin is unknown. Using methyl-TROSY solution NMR spectroscopy and molecular dynamics simulations, we present an atomic resolution model of human RNF169 binding to a ubiquitylated nucleosome, and validate it by electron cryomicroscopy. We establish that RNF169 binds to ubiquitylated H2A-Lys13/Lys15 in a manner that involves its canonical ubiquitin-binding helix and a pair of arginine-rich motifs that interact with the nucleosome acidic patch. This three-pronged interaction mechanism is distinct from that by which 53BP1 binds to ubiquitylated H2A-Lys15 highlighting the diversity in site-specific recognition of ubiquitylated nucleosomes.