SecAタンパク質は,その活性状態のE. coli内膜の周 plazmic 表面に露出します
Y J Kim1, T Rajapandi, D Oliver
1Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, Connecticut 06459.
Cell
|September 9, 1994
まとめ
統合膜SeCAタンパク質は,細菌のタンパク質分泌の活性形態である. secD secFのロカスプロダクトは,SecaAのSecaAを調節する.
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
- バクテリアのタンパク質分泌
背景:
- SecAタンパク質は,バクテリアの内膜にわたってタンパク質の転位を推進する重要なATPアゼモーターである.
- SecAと膜の相互作用の正確な局所化と調節は,タンパク質分泌を理解する上で重要な問題である.
研究 の 目的:
- SecAの局所化と活動を調節する secD secF ローカスの役割を調査する.
- SecAの触媒的に活性な形態と内膜内でのアクセシビリティを決定する.
主な方法:
- E. coli. での secD secF 場所の表現
- 膜膀を用いた生化学分析 (プロテアゼとバイオチニレーションのアクセシビリティ研究).
- SecAタンパク質の局所化と転位活動の分析.
主要な成果:
- SecAタンパク質は,主に統合膜の形態で発見され,正常なタンパク質転位活性を示した.
- SecAは,内膜の周回プラズマ表面にアクセス可能でした.
- secD secF ローカス産物は,SecA の内膜との関連を調節することが示されました.
結論:
- Integral membrane SecAは,酵素の触媒的に活性化された形態である.
- secD secFのロカスプロダクトは,SecAの内膜への挿入/脱入を調節し,タンパク質伝導チャネルアセンブリを調節する.
- SecAが内膜に挿入され,SecY/E/Gと結合すると,活性分泌チャネルが形成されるモデルが提案されています.
関連する概念動画
Role 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...
ER Retrieval Pathway
In the secretory pathway, vesicles transport proteins from one cellular compartment to another in forward transport to deliver the protein to its correct location. Occasionally, misfolded proteins and incorrect proteins escape their original compartments, and a retrieval pathway is used to return the escaped proteins to their original compartment.
The ER uses many checkpoints to prevent the entry of incorrectly folded or a resident protein as cargo onto a transport vesicle. These mechanisms...
The ER uses many checkpoints to prevent the entry of incorrectly folded or a resident protein as cargo onto a transport vesicle. These mechanisms...
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...


