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Updated: May 31, 2026

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Assays for the Degradation of Misfolded Proteins in Cells
Published on: August 28, 2016
タンパク質ターゲティングと分解は,誤って局所化されたタンパク質の除去のために結合されます
Tara Hessa1, Ajay Sharma, Malaiyalam Mariappan
1Cell Biology and Metabolism Program, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Nature
|July 12, 2011
まとめ
誤った局所化された膜タンパク質は,リボソームからそれらを捕獲するBag6複合体によって急速に分解されます. これにより,集積を防止し,ターゲティングとユビキチネーション経路をリンクすることにより,タンパク質のホメオスタシスを確保します.
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.
- タンパク質の分解
背景:
- ゲノムの重要な部分は,特定のエンドプラズマ網膜ターゲティングを必要とする膜タンパク質をコードしています.
- ターゲティングに失敗すると,誤った局所化タンパク質 (MLP) が発生し,細胞塩分タンパク質のホメオスタシスを維持するために急速な分解が必要になります.
研究 の 目的:
- 誤局的膜タンパク質 (MLP) の分解を制御する未知のメカニズムを解明する.
- MLPの分解経路に関与する重要な要因を,in vitro溶解システムを使用して特定する.
主な方法:
- MLPの分解の復元 in vitro.
- 新生膜タンパク質のユビキチン化状態の分析.
- MLPの捕獲と分解におけるBag6複合体の役割の調査.
- クライアントタンパク質の移転におけるTRC40の関与の評価.
- MLPのユビキチン化に対するBag6複合体の影響を評価するための枯渇研究.
主要な成果:
- 新生膜タンパク質は,サイトゾールに放出されるとのみ,ユビキチン化されます.
- Bag6複合体は,放出されたMLPを捕捉し,未処理の疎水領域によって区別します.
- Bag6複合体クライアントは,膜挿入のためにTRC40に転送されるか,分解のためにユビキチン化される.
- Bag6複合体の枯渇は,MLPの効率的なユビキチネーションを損なう.
結論:
- リボソームに関連したBag6複合体は,タンパク質ターゲティングとユビキチネーション経路をリンクしています.
- この結合は,MLPの急速な分解を促進し,その集積と細胞溶液の折りたたみ機械との無駄な相互作用を防ぐ.
関連する概念動画
The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important amongst these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important among these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important amongst these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
Regulated Protein Degradation
It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Regulated Protein Degradation
It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...

