在核糖体-Sec61复合体中新生的多链的导管的对齐
R Beckmann1, D Bubeck, R Grassucci
1Howard Hughes Medical Institute, Laboratory of Cell Biology, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. beckmar@rockvax.rockefeller.edu
概括
该Sec61复合体形成了一条通道,用于蛋白质运输穿过内 плазма网膜. 化EM揭示了它的寡合物附着在核糖体上,指导蛋白质通过共享孔隙转移.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 结构生物学 结构生物学
背景情况:
- Sec61复合物是一种异构三聚物,是内细胞网膜中蛋白质导通通道的主要组成部分.
- 它在蛋白质转位过程中与核糖体的精确相互作用仍然不完全理解.
研究的目的:
- 为了研究核糖体-Sec61复杂相互作用的结构基础.
- 阐明Sec61寡合物的作用在蛋白质在内质网膜中的转位.
主要方法:
- 酵母的净化Sec61复杂和单体酵母核糖体.
- 电子显微镜 (Cryo-EM) 用于结构分析.
- 核糖体-Sec61复合体的三维重建.
主要成果:
- 观察到纯化的酵母Sec61复合物以一种可和的方式将单质酵母核糖体结合为寡合体.
- 冷EM检测显示,Sec61寡合体与大型核糖体亚单元之间存在单一的联系.
- 发现Sec61寡合体内的漏斗状孔与核糖体道出口保持一致.
结论:
- 在蛋白质转位过程中,Sec61寡合体和大型核糖体子单元可能会协同工作.
- 这种结构安排有助于蛋白质进入内质网膜.
相关概念视频
Termination of Translation
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
Directing Proteins to the Rough Endoplasmic Reticulum
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...
Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Insertion of Single-pass Transmembrane Proteins in the RER
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Post-translational Translocation of Proteins to the RER
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...
Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.


