PDF(Pubmed)
Abstract：
The signal recognition particle is essential for targeting transmembrane and secreted proteins to the endoplasmic reticulum. Remarkably, because they work together in the cytoplasm, the SRP and ribosomes are assembled in the same biomolecular condensate: the nucleolus. How important is the nucleolus for SRP assembly is not known. Using quantitative proteomics, we have investigated the interactomes of SRP components. We reveal that SRP proteins are associated with scores of nucleolar proteins important for ribosome biogenesis and nucleolar structure. Having monitored the subcellular distribution of SRP proteins upon controlled nucleolar disruption, we conclude that an intact organelle is required for their proper localization. Lastly, we have detected two SRP proteins in Cajal bodies, which indicates that previously undocumented steps of SRP assembly may occur in these bodies. This work highlights the importance of a structurally and functionally intact nucleolus for efficient SRP production and suggests that the biogenesis of SRP and ribosomes may be coordinated in the nucleolus by common assembly factors.
摘要：
信号识别颗粒对于将跨膜和分泌蛋白靶向内质网是必需的。值得注意的是,因为它们在细胞质中一起工作，SRP和核糖体组装在相同的生物分子缩合物中：核仁。核仁对SRP组装的重要性尚不清楚。使用定量蛋白质组学，我们已经研究了SRP组件的相互作用。我们发现SRP蛋白与许多对核糖体生物发生和核仁结构重要的核仁蛋白相关。在受控核仁破坏后监测SRP蛋白的亚细胞分布，我们得出的结论是，需要完整的细胞器才能正确定位。最后,我们在Cajal体内检测到两种SRP蛋白,这表明SRP组装的先前未记录的步骤可能发生在这些主体中。这项工作强调了结构和功能完整的核仁对于有效SRP生产的重要性，并表明SRP和核糖体的生物发生可能通过共同的组装因子在核仁中协调。
