Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
Biochemistry (Mosc). 2021 Jan;86(Suppl 1):S38-S49. doi: 10.1134/S0006297921140042.
Members of the Lsm protein family are found in all three domains of life: bacteria, archaea, and eukarya. They are involved in numerous processes associated with RNA processing and gene expression regulation. A common structural feature of all Lsm family proteins is the presence of the Sm fold consisting of a five-stranded β-sheet and an α-helix at the N-terminus. Heteroheptameric eukaryotic Sm and Lsm proteins participate in the formation of spliceosomes and mRNA decapping. Homohexameric bacterial Lsm protein, Hfq, is involved in the regulation of transcription of different mRNAs by facilitating their interactions with small regulatory RNAs. Furthermore, recently obtained data indicate a new role of Hfq as a ribosome biogenesis factor, as it mediates formation of the productive structure of the 17S rRNA 3'- and 5'-sequences, facilitating their further processing by RNases. Lsm archaeal proteins (SmAPs) form homoheptamers and likely interact with single-stranded uridine-rich RNA elements, although the role of these proteins in archaea is still poorly understood. In this review, we discuss the structural features of the Lsm family proteins from different life domains and their structure-function relationships.
Lsm 蛋白家族的成员存在于生命的三个领域：细菌、古菌和真核生物。它们参与了与 RNA 加工和基因表达调控相关的许多过程。所有 Lsm 家族蛋白的一个共同结构特征是存在 Sm 折叠，由一个五股β-sheet 和一个 N 端的α-螺旋组成。异源七聚体真核 Sm 和 Lsm 蛋白参与剪接体和 mRNA 去帽的形成。同源六聚体细菌 Lsm 蛋白 Hfq 参与不同 mRNA 转录的调控，通过促进它们与小调控 RNA 的相互作用。此外，最近获得的研究数据表明 Hfq 具有新的核糖体生物发生因子的作用，因为它介导 17S rRNA 3'和 5'序列的有活性结构的形成，促进它们进一步被 RNase 加工。Lsm 古菌蛋白（SmAPs）形成同源七聚体，可能与单链富含尿嘧啶的 RNA 元件相互作用，尽管这些蛋白在古菌中的作用仍知之甚少。在这篇综述中，我们讨论了来自不同生命领域的 Lsm 家族蛋白的结构特征及其结构-功能关系。
