MicroRNAs (miRNAs) bind to complementary target RNAs and regulate their gene expression post-transcriptionally. These non-coding regulatory RNAs become functional after loading into Argonaute (AGO) proteins to form the effector complexes. Humans have four AGO proteins, AGO1, AGO2, AGO3 and AGO4, which share a high sequence identity. Since most miRNAs are found across the four AGOs, it has been thought that they work redundantly, and AGO2 has been heavily studied as the exemplified human paralog. Nevertheless, an increasing number of studies have found that the other paralogs play unique roles in various biological processes and diseases. In the last decade, the structural study of the four AGOs has provided the field with solid structural bases. This review exploits the completed structural catalog to describe common features and differences in target specificity across the four AGOs.

中文翻译：

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四种人类 Argonaute 蛋白的解剖结构

微小 RNA (miRNA) 与互补靶 RNA 结合并在转录后调节其基因表达。这些非编码调节 RNA 在加载到 Argonaute (AGO) 蛋白中形成效应复合物后变得有功能。人类有四种 AGO 蛋白，AGO1、AGO2、AGO3 和 AGO4，它们具有很高的序列同一性。由于大多数 miRNA 都存在于四个 AGO 中，因此人们认为它们是冗余工作的，并且 AGO2 已作为人类旁系同源物的例证进行了大量研究。然而，越来越多的研究发现其他旁系同源物在各种生物过程和疾病中发挥着独特的作用。在过去的十年中，四个 AGO 的结构研究为该领域提供了坚实的结构基础。