The human homologue of the yeast Prt1 protein is an integral part of the eukaryotic initiation factor 3 complex and interacts with p170
The human homologue of the yeast Prt1 protein is an integral part of the eukaryotic initiation factor 3 complex and interacts with p170
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DOI：
10.1074/jbc.272.2.1110
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发表时间：
1997-01-10
影响因子：
4.8
通讯作者：
Sonenberg, N
中科院分区：
文献类型：
--
作者：
Methot, N;Rom, E;Sonenberg, N
真核起始因子3（eIF3）是一种稳定三元复合物eIF2的大型多亚基复合物。GTP tRNA（i）（Met），并促进mRNA与40 S核糖体亚基结合。eIF3也作为核糖体亚基抗结合因子发挥作用。eIF3发挥这些功能的分子机制知之甚少。我们在这里描述的cDNA编码的酵母eIF3亚基Prt1的人类同源物的克隆。人PRT1 cDNA编码的蛋白质的预测分子量为98.9 kDa，迁移在SDS聚丙烯酰胺凝胶上的116 kDa。人和酵母Prt1在氨基酸水平上有31%的同一性和50%的相似性。同源性分布在整个蛋白质中，除了氨基末端，并且在蛋白质的中心部分特别高，其含有推定的RNA识别基序。hPrt1被针对eIF3产生的抗体识别，并且重组hPrt1的亲和纯化抗体识别纯化的eIF3制剂中以116 kDa迁移的蛋白质。远Western分析表明，hPrt1直接与eIF3的p170亚基相互作用。作图研究确定RNA识别基序为与p170相关所需的区域。综上所述，这些实验证明hPrt1是eIF3的组分。结合Hershey及其同事的数据，我们的数据表明哺乳动物eIF3至少由10个亚基组成：p170，p116（hPrt1），p110，p66，p48，p47，p44，p40，p36和p35。
Eukaryotic initiation factor 3 (eIF3) is a large multisubunit complex that stabilizes the ternary complex, eIF2 . GTP . tRNA(i)(Met), and promotes mRNA binding to the 40 S ribosomal subunit. eIF3 also functions as a ribosome subunit anti-association factor. The molecular mechanisms by which eIF3 exerts these functions are poorly understood. We describe here the cloning of the cDNA encoding the human homologue of the yeast eIF3 subunit Prt1. The human PRT1 cDNA encodes a protein of predicted molecular mass of 98.9 kDa that migrates at 116 kDa on SDS polyacrylamide gels. Human and yeast Prt1 share 31% identity and 50% similarity at the amino acid level. The homology is distributed throughout the entire protein, except for the amino terminus, and is particularly high in the central portion of the protein, which contains a putative RNA recognition motif. hPrt1 is recognized by an antibody raised against eIF3, and an affinity-purified antibody to recombinant hPrt1 recognizes a protein migrating at 116 kDa in a purified eIF3 preparation. Far Western analysis shows that hPrt1 interacts directly with the p170 subunit of eIF3. Mapping studies identify the RNA recognition motif as the region required for association with p170. Taken together, these experiments demonstrate that hPrt1 is a component of eIF3. Our data, combined with those of Hershey and co-workers, suggest that mammalian eIF3 is composed of at least 10 subunits: p170, p116 (hPrt1), p110, p66, p48, p47, p44, p40, p36, and p35.