Translation in eukaryotes is dependent on the activity of translation initiation factor (eIF) 4G family of proteins, a scaffold protein that, during the initiation step, coordinates the activity of other eIFs to recruit the 40S ribosomal subunit to the mRNA. Three decades of research on protein synthesis and its regulation has provided a wealth of evidence supporting the crucial role of cap-dependent translation initiation, which involves eIF4G. However, the recent discovery of a surprising variety of alternative mechanisms to initiate translation in the absence of eIF4G has stirred the orthodox view of how protein synthesis is performed. These mechanisms involve novel interactions among known eIFs, or between known eIFs and other proteins not previously linked to translation. Thus, a new picture is emerging in which the unorthodox translation initiation complexes contribute to the diversity of mechanisms that regulate gene expression in eukaryotes.

真核生物中的翻译取决于翻译起始因子（eIF）4G家族蛋白的活性，该蛋白是一种支架蛋白，在起始步骤中，它协调其他eIF的活性以将40S核糖体亚基募集到mRNA。关于蛋白质合成及其调控的三十年研究提供了大量证据，证明了涉及eIF4G的cap依赖性翻译起始的关键作用。但是，最近发现在eIF4G不存在的情况下引发翻译的惊人机制多种令人吃惊，这激起了蛋白质合成如何进行的正统观点。这些机制涉及已知eIF之间或已知eIF与先前未与翻译关联的其他蛋白质之间的新颖相互作用。从而，