Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain.
Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain.
Biomolecules. 2024 Jul 22;14(7):882. doi: 10.3390/biom14070882.
Ribosomes are not totally globular machines. Instead, they comprise prominent structural protrusions and a myriad of tentacle-like projections, which are frequently made up of ribosomal RNA expansion segments and N- or C-terminal extensions of ribosomal proteins. This is more evident in higher eukaryotic ribosomes. One of the most characteristic protrusions, present in small ribosomal subunits in all three domains of life, is the so-called beak, which is relevant for the function and regulation of the ribosome's activities. During evolution, the beak has transitioned from an all ribosomal RNA structure (helix h33 in 16S rRNA) in bacteria, to an arrangement formed by three ribosomal proteins, eS10, eS12 and eS31, and a smaller h33 ribosomal RNA in eukaryotes. In this review, we describe the different structural and functional properties of the eukaryotic beak. We discuss the state-of-the-art concerning its composition and functional significance, including other processes apparently not related to translation, and the dynamics of its assembly in yeast and human cells. Moreover, we outline the current view about the relevance of the beak's components in human diseases, especially in ribosomopathies and cancer.
核糖体并非完全呈球形的机器。相反，它们由突出的结构突起和无数类似触手的突起组成，这些突起通常由核糖体 RNA 扩展片段和核糖体蛋白的 N 或 C 末端延伸组成。在高等真核核糖体中，这一点更为明显。在所有三个生命领域的小核糖体亚基中，最具特征的突起之一是所谓的喙，它与核糖体的功能和调节有关。在进化过程中，喙从细菌中所有核糖体 RNA 结构（16S rRNA 中的 helix h33）转变为由三个核糖体蛋白（eS10、eS12 和 eS31）以及较小的 h33 核糖体 RNA 组成的结构。在这篇综述中，我们描述了真核生物喙的不同结构和功能特性。我们讨论了其组成和功能意义的最新进展，包括与翻译无关的其他过程，以及其在酵母和人类细胞中的组装动力学。此外，我们概述了目前关于喙成分在人类疾病中的相关性的观点，特别是在核糖体病和癌症中。
