相关实验视频
Updated: Jul 8, 2025

09:33
Methods to Classify Cytoplasmic Foci as Mammalian Stress Granules
Published on: May 12, 2017
14.6K
一个孤独的停滞80S核糖体阻止mRNA招募压力颗粒
Artem G Fedorovskiy1,2, Anton V Burakov1, Ilya M Terenin1,3
1Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
Biochemistry. Biokhimiia
|December 17, 2023
概括
压力颗粒 (SGs) 在mRNA有自由段时形成,但特定的核糖体抑制剂阻止了它们的组装. 即使是mRNA上的一个核糖体也会阻止SG的形成,这挑战了先前的理论.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 生物化学 生化学
背景情况:
- 细胞在压力下抑制蛋白质合成,从mRNA和RNA结合蛋白中形成压力颗粒 (SGs).
- 压力颗粒含有40S核糖体子单元,但缺乏60S子单元.
- 以前的理解表明,扩展的核糖体自由的mRNA段触发了SG的形成.
研究的目的:
- 研究各种小分子转化抑制剂如何在氧化应激下影响应力颗粒组装.
- 挑战关于扩展的核糖体自由mRNA段对于SG形成的必要性的普遍假设.
主要方法:
- 利用酸来诱导真核细胞中严重的氧化应激.
- 服用各种小分子转化抑制剂,包括特定的核糖体延长抑制剂.
- 观察和量化了应力颗粒组装作为对这些处理的反应.
主要成果:
- 与预期相反,特定的核糖体延长抑制剂 (例如,哈林顿因,乳胺素,T-2毒素) 完全阻止了酸盐诱导的压力颗粒形成.
- 这些抑制剂在编码区域开始时阻止了单独的80S核糖体,但允许下游翻译.
- 研究结果表明,即使在mRNA上存在单个80S核糖体,也足以抑制SG组装.
结论:
- 扩展的核糖体自由mRNA区域的存在不足以形成压力颗粒.
- 在压力颗粒中的mRNA招募可能涉及RNA结合蛋白和特定的40S核糖体子单元区域之间的相互作用.
- 这项研究完善了对压力颗粒组装机制的理解,以及在细胞压力期间核糖体在mRNA调节中的作用.
相关概念视频
Regulation of the Unfolded Protein Response
2.4K
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
2.4K
Directing Proteins to the Rough Endoplasmic Reticulum
7.3K
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
7.3K
Nonsense-mediated mRNA Decay
10.6K
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
10.6K
Ribosomal RNA Synthesis
13.2K
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
13.2K
Ribosomes
7.6K
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome...
7.6K
Post-translational Translocation of Proteins to the RER
5.7K
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
5.7K

