The eIF3 complex of Leishmania-subunit composition and mode of recruitment to different cap-binding complexes.
The eIF3 complex of Leishmania-subunit composition and mode of recruitment to different cap-binding complexes.
复制标题
利什曼原虫亚基组成的 eIF3 复合物以及招募不同帽结合复合物的模式。
DOI：
10.1093/nar/gkv564
复制
发表时间：
2015
影响因子：
14.9
通讯作者：
Shapira,Michal
中科院分区：
文献类型：
--
作者：
Meleppattu,Shimi;Kamus-Elimeleh,Dikla;Zinoviev,Alexandra;Cohen-Mor,Shahar;Orr,Irit;Shapira,Michal
真核起始因子3 （Eukaryotic initiation factor 3, eIF3）是一种多蛋白复合物，是翻译起始机制组装的关键参与者。在哺乳动物中，eIF3由13个亚基组成，其中大多数具有保守的结构域。锥虫eIF3亚基保守性较差。在这里，我们通过结合生物信息学、亲和纯化和质谱分析鉴定了12个组成利什曼原虫if3复合体（leishif3a - 1）的亚基。这些结果突出了LeishIF3与LeishIF1、LeishIF2和LeishIF5的强相关性，提示存在多因子复合物。在锥虫中，翻译机制在这些生物体的不同生命阶段受到严格调节，这是它们在不断变化的环境中适应和生存的一部分。因此，我们研究了LeishIF3被招募到不同mRNA帽结合复合物的机制。在体外观察到完全组装的LeishIF3复合物与重组LeishIF4G3（利什曼原虫帽结合复合物的典型支架蛋白）之间的直接相互作用。我们进一步强调了LeishIF3a的c端和LeishIF4E1之间的一种新的相互作用，LeishIF4E1是唯一在热休克条件下有效结合帽结构的帽结合蛋白，锚定了缺乏任何基于mif4g的支架亚基的复合物。
Eukaryotic initiation factor 3 (eIF3) is a multi-protein complex and a key participant in the assembly of the translation initiation machinery. In mammals, eIF3 comprises 13 subunits, most of which are characterized by conserved structural domains. The trypanosomatid eIF3 subunits are poorly conserved. Here, we identify 12 subunits that comprise theLeishmaniaeIF3 complex (LeishIF3a-l) by combining bioinformatics with affinity purification and mass spectrometry analyses. These results highlight the strong association of LeishIF3 with LeishIF1, LeishIF2 and LeishIF5, suggesting the existence of a multi-factor complex. In trypanosomatids, the translation machinery is tightly regulated in the different life stages of these organisms as part of their adaptation and survival in changing environments. We, therefore, addressed the mechanism by which LeishIF3 is recruited to different mRNA cap-binding complexes. A direct interaction was observedin vitrobetween the fully assembled LeishIF3 complex and recombinant LeishIF4G3, the canonical scaffolding protein of the cap-binding complex inLeishmaniapromastigotes. We further highlight a novel interaction between the C-terminus of LeishIF3a and LeishIF4E1, the only cap-binding protein that efficiently binds the cap structure under heat shock conditions, anchoring a complex that is deficient of any MIF4G-based scaffolding subunit.