分泌タンパク質は,内プラズマの網膜膜を通って,水分で閉ざされた毛穴を通って移動します
K S Crowley1, S Liao, V E Worrell
1Department of Chemistry and Biochemistry, University of Oklahoma, Norman 73019.
Cell
|August 12, 1994
まとめ
分泌タンパク質は,コトランスレーションによる転移の間に,ER膜を横断する水性毛穴を通って移動する. この孔は,最初は細胞質から封じ込められ,新生鎖が約70の残留値に達した後にのみ開きます.
科学分野:
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
背景:
- 分泌タンパク質は,エンドプラズマ網膜 (ER) 膜を横切る必要があります.
- タンパク質転位の正確な環境と経路は完全に理解されていません.
研究 の 目的:
- ER膜を横切るトランスロケーション中の新生分泌タンパク質の環境を決定する.
- コトランスレーション・トランスロケーションの地形的な性質を明らかにする.
主な方法:
- トランスレーション中の新生ポリペプチド鎖に光センサーを組み込む.
- 探査機の光寿命とヨウ素イオンによる衝突解消の分析.
- リボソーム内およびER膜の二重層にわたって探査機の位置づけ.
主要な成果:
- 新生連鎖とリボソーム内の探査機は,一貫して水性環境を示した.
- 新生連鎖は,ER膜全体に広がる水性毛穴を占有しています.
- この毛穴は細胞質から封じ込められ,約70個の残留物が合成された後にのみ ER ルーメンに開かれます.
結論:
- 新生分泌タンパク質は,ER膜を横断する連続した水性孔を通って転位する.
- トポグラフィのコトランスレーション的転位は,この膜を横断する水道によって促進されます.
- 毛穴の開口メカニズムは,新生鎖の長さによって調節されます.
関連する概念動画
01:17Role of ER in the Secretory Pathway
Eukaryotic cells have a special pathway that enables communication between various intracellular membrane-bound compartments and also with the extracellular environment. This pathway is termed as the secretory pathway.
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
01:33Overview of Secretory Vesicles
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
01:20Cotranslational 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...
01:26Insertion 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...
01:27Post-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...
01:28Protein 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.