PDF(Pubmed)
Abstract：
mRNAs containing premature stop codons are responsible for various genetic diseases as well as cancers. The truncated proteins synthesized from these aberrant mRNAs are seldom detected due to the nonsense-mediated mRNA decay (NMD) pathway. Such a surveillance mechanism detects most of these aberrant mRNAs and rapidly destroys them from the pool of mRNAs. Here, we implemented chemical cross-linking mass spectrometry (CLMS) techniques to trace novel biology consisting of protein-protein interactions (PPIs) within the NMD machinery. A set of novel complex networks between UPF2 (Regulator of nonsense transcripts 2), SMG1 (Serine/threonine-protein kinase SMG1), and SMG7 from the NMD pathway were identified, among which UPF2 was found as a connection bridge between SMG1 and SMG7. The UPF2 N-terminal formed most interactions with SMG7, and a set of residues emerged from the MIF4G-I, II, and III domains docked with SMG1 or SMG7. SMG1 mediated interactions with initial residues of UPF2, whereas SMG7 formed very few interactions in this region. Modelled structures highlighted that PPIs for UPF2 and SMG1 emerged from the well-defined secondary structures, whereas SMG7 appeared from the connecting loops. Comparing the influence of cancer-derived mutations over different CLMS sites revealed that variants in the PPIs for UPF2 or SMG1 have significant structural stability effects. Our data highlights the protein-protein interface of the SMG1, UPF2, and SMG7 genes that can be used for potential therapeutic approaches. Blocking the NMD pathway could enhance the production of neoantigens or internal cancer vaccines, which could provide a platform to design potential peptide-based vaccines.
摘要：
含有过早终止密码子的mRNA负责各种遗传疾病以及癌症。由于无义介导的mRNA衰变（NMD）途径，从这些异常mRNA合成的截短蛋白很少被检测到。这样的监测机制检测大多数这些异常的mRNA,并从mRNA池中迅速破坏它们。这里,我们实施了化学交联质谱(CLMS)技术来追踪NMD机制中由蛋白质-蛋白质相互作用(PPI)组成的新生物学.UPF2（无义转录物2的调节剂）之间的一组新颖的复杂网络，SMG1（丝氨酸/苏氨酸蛋白激酶SMG1），和来自NMD途径的SMG7被鉴定出来，其中UPF2被发现是SMG1和SMG7之间的连接桥。UPF2N端与SMG7形成了最多的相互作用，一组残基从MIF4G-I中出现，II,和III域与SMG1或SMG7对接。SMG1介导与UPF2初始残基的相互作用，而SMG7在该区域形成的相互作用很少。建模结构突出表明，UPF2和SMG1的PPI从定义明确的二级结构中出现，而SMG7从连接环中出现。比较癌症来源的突变对不同CLMS位点的影响揭示UPF2或SMG1的PPI中的变体具有显著的结构稳定性效应。我们的数据突出了SMG1，UPF2和SMG7基因的蛋白质-蛋白质界面，可用于潜在的治疗方法。阻断NMD途径可以增强新抗原或内部癌症疫苗的产生，这可以为设计潜在的基于肽的疫苗提供平台。
