Human nonsense-mediated mRNA decay factor UPF2 interacts directly with eRF3 and the SURF complex.
Human nonsense-mediated mRNA decay factor UPF2 interacts directly with eRF3 and the SURF complex.
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DOI：
10.1093/nar/gkv1527
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发表时间：
2016-02-29
影响因子：
14.9
通讯作者：
Llorca O
中科院分区：
文献类型：
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作者：
López-Perrote A;Castaño R;Melero R;Zamarro T;Kurosawa H;Ohnishi T;Uchiyama A;Aoyagi K;Buchwald G;Kataoka N;Yamashita A;Llorca O
无义介导的mRNA衰变（NMD）是一种调控基因表达和mRNA质量的mRNA降解途径。一个复杂的大分子相互作用网络调节NMD的启动，这只是部分了解。根据流行的模型，NMD开始于核糖体上SURF （SMG1-UPF1-eRF1-eRF3）复合物的组装，随后UPF1被其他因子如UPF2和UPF3激活。阐明NMD因子之间的相互作用对于理解NMD至关重要，在这里，我们从生物化学和结构上证明了人类UPF2与真核释放因子3 （eRF3）之间的相互作用。此外，我们发现UPF2以不依赖于UPF2的方式与细胞中的SURF和核糖体结合。使用UPF2截断变体集合的结合分析显示，eRF3与UPF2的c端部分结合。UPF2 - erf3复合物的电子显微镜显示，UPF2的这一区域部分与upf3结合位点一致。因此，我们发现UPF2与UPF3b的相互作用干扰了UPF2 - eRF3复合物的组装，并且UPF2与UPF3b的结合比eRF3更强。总之，我们的研究结果强调了UPF2作为几个NMD因子（包括SURF的几个组成部分）瞬时相互作用的平台的作用。
Nonsense-mediated mRNA decay (NMD) is an mRNA degradation pathway that regulates gene expression and mRNA quality. A complex network of macromolecular interactions regulates NMD initiation, which is only partially understood. According to prevailing models, NMD begins by the assembly of the SURF (SMG1–UPF1–eRF1–eRF3) complex at the ribosome, followed by UPF1 activation by additional factors such as UPF2 and UPF3. Elucidating the interactions between NMD factors is essential to comprehend NMD, and here we demonstrate biochemically and structurally the interaction between human UPF2 and eukaryotic release factor 3 (eRF3). In addition, we find that UPF2 associates with SURF and ribosomes in cells, in an UPF3-independent manner. Binding assays using a collection of UPF2 truncated variants reveal that eRF3 binds to the C-terminal part of UPF2. This region of UPF2 is partially coincident with the UPF3-binding site as revealed by electron microscopy of the UPF2–eRF3 complex. Accordingly, we find that the interaction of UPF2 with UPF3b interferes with the assembly of the UPF2–eRF3 complex, and that UPF2 binds UPF3b more strongly than eRF3. Together, our results highlight the role of UPF2 as a platform for the transient interactions of several NMD factors, including several components of SURF.