グルタミン酸トランスポーターホモログのトランスポートダイナミクス
Nurunisa Akyuz1, Roger B Altman, Scott C Blanchard
1Department of Physiology and Biophysics, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10064, USA.
Nature
|June 25, 2013
まとめ
グルタミン酸トランスポーターは,大きなドメインシフトを経由して移動します. 重要なステップは,トランスポートドメインが,トランスポート速度を制御する可能性があるトランスメブランの動きの前に,その脚架から脱離することです.
科学分野:
- バイオケミストリーと分子生物学
- 神経科学は神経科学である.
- 構造生物学 構造生物学とは
背景:
- グルタマートトランスポーターは,神経伝達物質の吸収を司る重要な統合膜タンパク質です.
- 彼らの機能は,外向きと内向きの状態の間の構成変化に依存しています.
- 以前のモデルでは,トリメリック・スカフォールド内の離散輸送ドメインのトランスメブラン運動を提案していた.
研究 の 目的:
- グルタミン酸トランスポーターにおける大規模な輸送ドメインの動きを直接視覚化するために.
- 神経伝達物質の輸送中の構成変化のメカニズムを解明する.
主な方法:
- 単分子光共振エネルギー伝送 (smFRET) 画像を用いた.
- ドメインのダイナミクスを観察するために,グルタミン酸トランスポーターのバクテリアの同類体を研究しました.
主要な成果:
- 輸送領域の大規模な動きを直接観察した.
- トランスポートドメインは,イオンチャネル破裂に類似した,急速な移行と交互に静止期を示す.
- トランスメブランの移動を先行するトリメア基架から,基板に負荷された輸送ドメインのゆっくりと自発的な脱離を特定しました.
結論:
- グルタミン酸トランスポーターのダイナミックモードは,トランスポートドメインが支架から分離することによって開始されます.
- この脱離のステップは,その後のトランスメブランの動きよりもかなり遅いです.
- ドメイン分離メカニズムは,グルタミン酸トランスポーターサイクルにおける速度を制限するステップである可能性があります.
関連する概念動画
01:16Facilitated Diffusion
The plasma membrane, a critical structure in cellular biology, houses an array of transporters, or carrier proteins, interspersed within its lipid bilayer. These proteins play a crucial role in solute transport through facilitated diffusion, a form of passive diffusion that uses transporters to move the molecules across the membrane.
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:55Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:44The Significance of Membrane Transport
The transport of solutes across the cell membrane is essential for metabolic processes, like maintaining cell size and volume, generating the action potential, exchanging nutrients and gases, etc. Membrane transport can be either passive or active. It can be simple diffusion, facilitated, or mediated transport aided by transport proteins such as transporters and channels.
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
01:14Active Transport
Active transport is a critical biological process that allows cells to move solutes against an electrochemical gradient. This process requires direct energy input and is characterized by its selectivity, saturability, and susceptibility to competitive inhibition.
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...
01:30Membrane Proteins
Plasma membranes have integral transmembrane proteins involved in facilitated transport. These proteins are collectively referred to as transport proteins, and they function as either channels for the material or as carriers themselves. Channel proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and a hydrophilic channel through their core that provides a hydrated opening for solutes to pass through the membrane layers. Passage through the channel allows...