関連する実験動画
Updated: Jun 10, 2026

05:52
Reconstitution of Msp1 Extraction Activity with Fully Purified Components
Published on: August 10, 2021
A リボソーム関連因子 チャペロン 尾を固定した膜タンパク質
Malaiyalam Mariappan1, Xingzhe Li, Sandra Stefanovic
1Cell Biology and Metabolism Program, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Nature
|August 3, 2010
まとめ
新しく発見されたBat3複合体は,テールアンカリング (TA) タンパク質の護衛として作用し,TRC40.0経由でエンドプラズマ網膜 (ER) に適切な配送を保証します. これにより,TAタンパク質の誤局と集積を防ぐことができます.
科学分野:
- 細胞生物学 細胞生物学
- プロテイン・ターゲティング (Protein Targeting) とは
- メンブラン生物学 メンブラン生物学
背景:
- テイルアンクルド (TA) タンパク質は,単一のC端末トランスメブラン領域 (TMD) を通して,エンドプラズマ網膜 (ER) 膜に挿入されます.
- TRC40のようなサイトソリックチャペロンは,これらの水性TAタンパク質をERに標的とし,集積を防止するために不可欠です.
- TRC40が混雑したサイトゾール内のTAタンパク質を効率的に捕獲する正確なメカニズムは不明である.
研究 の 目的:
- TAタンパク質のキャプチャとERへのターゲティングのメカニズムを解明する.
- TRC40のTAタンパク質との相互作用を促進する要因を特定する.
主な方法:
- タンパク質複合体を特定するための生化学分析.
- タンパク質合成とターゲティングを研究するためにリボソームプロファイリング.
- TAタンパク質の局所化における特定された複合体の役割を評価するための枯渇研究.
主要な成果:
- 保存された3つのタンパク質複合体 (Bat3,TRC35,Ubl4A) が特定されました.
- このBat3複合体はリボソームに集約され,新たに合成されたTAタンパク質TMDと相互作用する.
- Bat3複合体は,TAタンパク質をTRC40に移し,後にERを挿入します.
- Bat3複合体の枯渇は,TRC40以外の因子によって媒介されるTAタンパク質の誤局化につながる.
結論:
- バット3複合体は,TAタンパク質のTMD選択的なチャペロンとして機能する.
- TRC40挿入経路へのTAタンパク質の効率的なチャネリングを促進します.
- このメカニズムは,TAタンパク質を正確に標的にし,誤った局所化を防止します.
関連する概念動画
Tail-anchoring of Proteins in the ER Membrane
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...
Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...
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...
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...
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...
Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...

