Insights into the recruitment of the NMD machinery from the crystal structure of a core EJC-UPF3b complex.
Insights into the recruitment of the NMD machinery from the crystal structure of a core EJC-UPF3b complex.
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DOI：
10.1073/pnas.1000993107
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发表时间：
2010-06-01
影响因子：
11.1
通讯作者：
Conti, Elena
中科院分区：
文献类型：
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作者：
Buchwald, Gretel;Ebert, Judith;Conti, Elena
在哺乳动物中，上移码蛋白(UPF)形成一个监视复合体，与外显子连接复合体(EJC)相互作用，引发无义介导的mRNA衰退(NMD)。UPF3b是监测复合体的组成部分，它架起了与EJC互动的桥梁。在这里，我们报道了一个最小的UPF3b-EJC组件的3.4埃分辨率的晶体结构，由五种蛋白质(UPF3b、Mago、Y14、eIF4AIII和Barentsz)与RNA和腺苷二磷酸相互作用的结构域组成。人UPF3b与由eIF4AIII、MAGO和Y14形成的复合表面上延伸的C-末端结构域结合。突变时影响NMD的残基位于核心相互作用表面，而UPF3b和UPF3a的差异映射在外围相互作用残基。与蛋白质结合模式的比较强调了MAGO和Y14的共同分子表面是如何识别在同一途径中不同时间作用的不同蛋白质的。与eIF4AIII的结合模式识别出一个表面热点，不同的死盒蛋白利用该热点来招募它们的调节器。
In mammals, Up-frameshift proteins (UPFs) form a surveillance complex that interacts with the exon junction complex (EJC) to elicit nonsense-mediated mRNA decay (NMD). UPF3b is the component of the surveillance complex that bridges the interaction with the EJC. Here, we report the 3.4 angstrom resolution crystal structure of a minimal UPF3b-EJC assembly, consisting of the interacting domains of five proteins (UPF3b, MAGO, Y14, eIF4AIII, and Barentsz) together with RNA and adenylyl-imidodiphosphate. Human UPF3b binds with the C-terminal domain stretched over a composite surface formed by eIF4AIII, MAGO, and Y14. Residues that affect NMD when mutated are found at the core interacting surfaces, whereas differences between UPF3b and UPF3a map at peripheral interacting residues. Comparison with the binding mode of the protein PYM underscores how a common molecular surface of MAGO and Y14 recognizes different proteins acting at different times in the same pathway. The binding mode to eIF4AIII identifies a surface hot spot that is used by different DEAD-box proteins to recruit their regulators.