During amino acid limitation, the protein kinase Gcn2 phosphorylates the α subunit of eIF2, thereby regulating mRNA translation. In yeast Saccharomyces cerevisiae and mammals, eIF2α phosphorylation regulates translation of related transcription factors Gcn4 and Atf4 through upstream open reading frames (uORFs) to activate transcription genome wide. However, mammals encode three more eIF2α kinases activated by distinct stimuli. Did the translational control system involving eIF2α phosphorylation evolve from so simple (as found in yeast S. cerevisiae) to complex (as found in humans)? Recent genome-wide translational profiling studies of amino acid starvation response in the fission yeast Schizosaccharomyces pombe provide an unexpected answer to this question.

在氨基酸限制期间，蛋白激酶 Gcn2 磷酸化 eIF2 的 α 亚基，从而调节 mRNA 翻译。在酿酒酵母和哺乳动物中，eIF2α 磷酸化通过上游开放阅读框 (uORF) 调节相关转录因子 Gcn4 和 Atf4 的翻译，从而激活全基因组转录。然而，哺乳动物编码另外三种由不同刺激激活的 eIF2α 激酶。涉及 eIF2α 磷酸化的翻译控制系统是否从简单（如在酿酒酵母中发现）进化到复杂（如在人类中发现）？最近对裂殖酵母裂殖酵母氨基酸饥饿反应的全基因组翻译分析研究为这个问题提供了意想不到的答案。