Regulation of human eIF4A activity in health and disease: Mechanisms of canonical and aberrant translation initiation

健康和疾病中人类 eIF4A 活性的调节：规范和异常翻译起始的机制

• 批准号: 445431620
• 负责人: Professorin Dr. Dagmar Klostermeier
• 金额: --
• 依托单位: Institut für Physikalische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/445431620?language=en
• 关键词: Regulation; human; eIF4A; activity; health

Translation of eukaryotic mRNAs starts with the recognition of the 5’-cap by the translation initiation factor complex eIF4F, comprised of the cap-binding protein eIF4E, the scaffold protein eIF4G, and the DEAD-box helicase eIF4A. eIF4A is believed to unwind secondary structures in the 5’-untranslated region (5’-UTR) during ribosomal scanning towards the start codon. RNA unwinding by eIF4A is tightly linked to its conformational cycle, driven by ATP binding and hydrolysis. Yeast eIF4A acts as a conformational sensor and a regulatory hub in translation initiation: other translation initiation factors, as well as the 5’-UTR itself, modulate the conformational landscape of eIF4A, and thereby regulate its activities. Translation initiation in humans employs a similar set of translation initiation factors. However, the mechanisms of regulation of eIF4A activities and conformational dynamics by the functional interaction of these factors and the consequences for translation initiation and gene expression are not understood. Transcriptome-wide studies have identified a set of eIF4A-dependent mRNAs, among them many oncogene mRNAs. eIF4A also plays a key role in repeat-associated translation on mRNAs lacking an AUG start codon (RAN translation), a process linked to a number of neurological disorders. To understand the mechanism of eIF4A-dependent translation initiation and the coupling of its conformational cycle to ATPase and RNA unwinding activities and translation efficiencies, we propose to investigate the regulation of human eIF4A by other translation initiation factors and by 5’-UTRs, both in canonical and aberrant translation initiation. We will investigate the effects of eIF4B, 4E, 4G, and 4H, of model 5’-UTRs and of selected 5’-UTRs of eIF4A-dependent genes on the kinetics of eIF4A conformational changes in single-molecule FRET experiments. We will also determine the effect of these factors and the 5’-UTRs on the ATPase and RNA unwinding activities of eIF4A. Translation efficiencies of reporter genes under the control of these 5’-UTRs will be determined in in vitro translation assays to correlate eIF4A conformational dynamics with gene expression. To understand the role of eIF4A in aberrant translation initiation, we will investigate the mechanisms of RAN translation and the translation of oncogenes. Altogether, these studies will reveal the effect of other translation initiation factors and 5’-UTRs on eIF4A conformational dynamics, the link between conformational dynamics of eIF4A and translation efficiencies, and the mechanisms of regulation of eIF4A activities in health and disease.

真核生物mRNA的翻译始于翻译起始因子复合物eIF 4F对5 '-帽的识别，该复合物由帽结合蛋白eIF 4 E、支架蛋白eIF 4G和DEAD盒解旋酶eIF 4A组成。eIF 4A被认为在核糖体向起始密码子扫描期间解开5 '-非翻译区（5'-UTR）中的二级结构。eIF 4A的RNA解旋与其构象循环紧密相关，由ATP结合和水解驱动。酵母eIF 4A在翻译起始中充当构象传感器和调节中心：其他翻译起始因子以及5 '-UTR本身调节eIF 4A的构象景观，从而调节其活性。人类的翻译起始采用类似的一组翻译起始因子。然而，eIF 4A活性和构象动力学的调节机制，这些因素的功能相互作用和翻译起始和基因表达的后果还不清楚。转录组范围的研究已经鉴定了一组eIF 4A依赖性mRNA，其中包括许多癌基因mRNA。eIF 4A还在缺乏AUG起始密码子的mRNA的重复相关翻译（RAN翻译）中发挥关键作用，这是一个与许多神经系统疾病相关的过程。为了了解eIF 4A依赖性翻译起始的机制及其构象循环与ATP酶和RNA解旋活性和翻译效率的偶联，我们建议研究其他翻译起始因子和5 '-UTR对人eIF 4A在经典和异常翻译起始中的调节。我们将研究eIF 4 B，4 E，4G和4 H，模型5 '-UTR和选择的5'-UTR的eIF 4A依赖性基因的eIF 4A构象变化的动力学在单分子FRET实验的影响。我们还将确定这些因子和5 '-UTR对eIF 4A的ATP酶和RNA解旋活性的影响。将在体外翻译测定中测定在这些5 '-UTR控制下的报告基因的翻译效率，以将eIF 4A构象动力学与基因表达相关联。为了了解eIF 4A在异常翻译起始中的作用，我们将研究RAN翻译和癌基因翻译的机制。总之，这些研究将揭示其他翻译起始因子和5 '-UTR对eIF 4A构象动力学的影响，eIF 4A构象动力学与翻译效率之间的联系，以及健康和疾病中eIF 4A活性的调节机制。