酵母Secタンパク質は,エンドプラズマ網膜膜を通過するポリペプチドと相互作用する
A Müsch1, M Wiedmann, T A Rapoport
1Max-Delbrück-Center for Molecular Medicine, Berlin Buch, Germany.
Cell
|April 17, 1992
まとめ
新生分泌タンパク質は,酵母におけるエンドプラズマ網膜転位の間にSec61pとSec62pと相互作用する. これらの必須タンパク質は,タンパク質が膜を通過する際に直接的な役割を果たします.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- タンパク質がエンドプラズマ網膜 (ER) 膜を横断して転移することは,分泌経路の機能にとって極めて重要です.
- Sec61pとSec62pは,タンパク質輸送に関与するSaccharomyces cerevisiaeの重要な遺伝子として知られています.
- これらのタンパク質が転位する正確なメカニズムと直接的な関与は,まだ完全に解明されていない.
研究 の 目的:
- 転位中の新生分泌タンパク質とER膜タンパク質の間の物理的な相互作用を調査する.
- タンパク質転位過程におけるSec61pとSec62pの役割を決定する.
- 転位中のSecタンパク質とのタンパク質相互作用のダイナミクスを解明する.
主な方法:
- タンパク質間の物理的接触を検出するために,光クロスリンク実験が実施されました.
- 酵母Saccharomyces cerevisiaeのモデルシステムで研究が行われました.
- 転位のATP依存およびATP依存の2つの段階におけるタンパク質相互作用の分析.
主要な成果:
- 新生分泌タンパク質は,ER膜通過時にSec61pとSec62pと物理的に接触することが示されました.
- Sec61pは継続的な接触を示し,Sec62pは一時的な関与を示した.
- タンパク質の転位には,Secタンパク質と異なるATP依存型と非依存型の相互作用が伴う.
結論:
- Sec61pとSec62pは,ER膜を横断する分泌タンパク質の転位に直接関与しています.
- この発見は,これらの重要な転位因子の役割に関するメカニズム的洞察を提供します.
- この研究は,Secタンパク質がタンパク質輸送の直接管として作用するモデルをサポートしています.
関連する概念動画
Yeast Signaling
15.7K
Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
15.7K
Directing Proteins to the Rough Endoplasmic Reticulum
12.1K
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...
12.1K
Cotranslational Protein Translocation
8.4K
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...
8.4K
Tail-anchoring of Proteins in the ER Membrane
2.8K
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
2.8K
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
Protein Translocation Machinery on the ER Membrane
5.6K
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...
5.6K


