関連する実験動画
Updated: Aug 12, 2025

10:24
Visualization of Endoplasmic Reticulum Localized mRNAs in Mammalian Cells
Published on: December 17, 2012
14.4K
ER膜におけるトランスレーションとタンパク質バイオゲネシスの可視化
Max Gemmer1, Marten L Chaillet1, Joyce van Loenhout1
1Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
Nature
|January 25, 2023
まとめ
研究者らは,リボソーム-トランスロコン機構を,内プラズマ網膜で視覚化しました. 重要な中間物質と相互作用を記録し タンパク質がどのように合成され 処理されるかを明らかにしました
科学分野:
- 細胞生物学
- 分子生物学
- 構造生物学
背景:
- ER膜にあるリボソーム-トランスロコン複合体は,ほとんどのヒトタンパク質を合成します.
- その構成要素の相互作用を理解することは 極めて重要ですが 限られています
- 新生タンパク質の処理には,合成,転位,挿入,グリコシル化,折りたたみ,および二酸化炭素結合の形成が含まれます.
研究 の 目的:
- ER膜でのmRNA翻訳とタンパク質成熟のスナップショットを分子解像度で捕捉する.
- リボソーム-トランスロコン機構の構成要素の相互作用を,その本来の膜環境で解明する.
- ERタンパク質の 生成に関する 原子レベルの洞察を提供するためです
主な方法:
- クリオ電子トモグラフィー
- 広範な分類とデータ分析
- 分子モデリングと構造決定
主要な成果:
- 拡張した形状で真核延伸因数1a (eEF1a) を有する転移前中間物質を特定した.
- 信号ペプチドまたは多通路トランスメブランタンパク質に特化したERトランスロコンへの明確なポリソーム結合が観察された.
- TRAPの相互作用を詳細に記述したSEC61-TRAP-OSTAトランスロコンのほぼ完全な原子モデルを決定した.
- タンパク質イソメラーゼを含む,オリゴサカルトランスフェラーゼ複合体A (OSTA) と関連した共因体が検出された.
結論:
- ER結合ポリソームと,分子解像度で調整された下流機構を視覚化した.
- タンパク質の合成と成熟過程における リボソーム-トランスロコン複合体内のダイナミックな相互作用についての洞察を提供した.
- 特殊なERトランスロコンを明らかにし,新生タンパク質処理に関与する主要成分を特定しました.
関連する概念動画
Post-translational Translocation of Proteins to the RER
5.8K
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...
5.8K
Cotranslational Protein Translocation
7.5K
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...
7.5K
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
Insertion of Single-pass Transmembrane Proteins in the RER
6.9K
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...
6.9K
Protein Translocation Machinery on the ER Membrane
4.8K
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...
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...
4.8K
The Endoplasmic Reticulum
15.1K
The endoplasmic reticulum or ER makes up for more than half of the membranes in a cell and accounts for 10% of total cell volume. It is also the primary protein and lipid synthesis factory for most cell organelles, such as the Golgi apparatus, lysosomes, secretory vesicles, and the plasma membrane. Despite being the most extensive and functionally complex subcellular organelle, ER was the last to be discovered. After years of deliberation, Keith Porter and George Palade in the year 1954,...
15.1K

