Arginyltransferase ATE1 mediates posttranslational arginylation and plays key roles in multiple physiological processes. ATE1 utilizes arginyl (Arg)-tRNA^Arg as the donor of Arg, putting this reaction into a direct competition with the protein synthesis machinery. Here, we address the question of ATE1- Arg-tRNA^Arg specificity as a potential mechanism enabling this competition in vivo. Using in vitro arginylation assays and Ate1 knockout models, we find that, in addition to full-length tRNA, ATE1 is also able to utilize short tRNA^Arg fragments that bear structural resemblance to tRNA-derived fragments (tRF), a recently discovered class of small regulatory non-coding RNAs with global emerging biological role. Ate1 knockout cells show a decrease in tRF^Arg generation and a significant increase in the ratio of tRNA^Arg:tRF^Arg compared with wild type, suggesting a functional link between tRF^Arg and arginylation. We propose that generation of physiologically important tRFs can serve as a switch between translation and protein arginylation.

精氨酸转移酶ATE1介导翻译后的精氨酰化，并在多个生理过程中发挥关键作用。ATE1利用精氨酸（Arg）-tRNA ^Arg作为^Arg的供体，使该反应与蛋白质合成机制直接竞争。在这里，我们解决了ATE1- Arg-tRNA ^Arg特异性的问题，这是一种在体内实现这种竞争的潜在机制。使用体外精氨酰化测定和Ate1敲除模型，我们发现，除了全长tRNA外，ATE1还能够利用短tRNA ^Arg与tRNA来源的片段（tRF）具有结构相似性的片段，这是最近发现的一类具有全球新兴生物学功能的小型监管非编码RNA。与野生型相比，Ate1敲除细胞显示tRF ^Arg的生成减少，tRNA ^Arg：tRF ^Arg的比率显着增加，表明tRF ^Arg与精氨酰化之间存在功能联系。我们建议生理重要的tRF的生成可以充当翻译和蛋白质精氨酰化之间的转换。