ハイパーポラライゼーションで活性化されたK+チャンネルKAT1における電機結合
Michael David Clark1, Gustavo F Contreras1, Rong Shen1
1Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
Nature
|May 29, 2020
まとめ
研究者は,KAT1構造を使用して,電圧ゲートポータシウム (Kv) チャンネルにおけるゲート極性メカニズムを解明した. 主にアロステリーではなく,直接のセンサーと毛穴の相互作用が,チャネルゲート方向を決定する.
科学分野:
- 分子生物学
- バイオ物理学
- 構造生物学
背景:
- 電気信号と細胞容量の調節には,電圧ゲートされたカリウム (Kv) チャンネルが不可欠である.
- 電圧センサーは電場を変換しますが,Kvチャネルゲーティングの極性に関する決定因子は完全に理解されていません.
研究 の 目的:
- 非ドメイン交換のKvチャネルにおける電機結合とゲーティング極性の分子メカニズムを解明する.
- KAT1チャネルにおけるハイパーポラライゼーションの活性化の構造的基礎を決定する.
主な方法:
- クリオ電子顕微鏡で KAT1チャネルの構造を決定する.
- 構造誘導変異と機能的電気生理学により,変異経路の活性が評価される.
主要な成果:
- KAT1の構造は,直接的および間接的なインターフェイスを通じて閉じた孔領域と相互作用するデポラライズされた電圧センサーを明らかにしました.
- 変異分析は,ゲートポラリティの主要な決定因子として,電圧センサとC-リンカーヘアピン間の直接的な相互作用を特定しました.
- S4ヘリックス運動とC-リンクアの再定位を含む直接結合メカニズムが提案されました.
結論:
- 直接的なセンサ-毛穴の相互作用,特に電圧センサと隣接する毛穴サブユニットC-リンクヤー間の相互作用は,Kvチャネルゲーティングの極性を決定する.
- この直接結合メカニズムは,アロステリックモデルと対比する新しい視点を提供し,デポラライゼーションとハイパーポラライゼーションで活性化されたチャネルをリンクすることができます.
関連する概念動画
Primary Active Transport
13.3K
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would...
13.3K
Primary Active Transport
195.3K
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction...
195.3K
Mechanically-gated Ion Channels
7.4K
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
7.4K
The Role of Ion Channels in Neuronal Computation
3.5K
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
3.5K
Excitation-Contraction Coupling in Skeletal Muscles
13.4K
Excitation-contraction coupling is a series of events that occur between generating an action potential and initiating a muscle contraction. It occurs at the triad, a structure found in skeletal muscle fibers that comprise a T-tubule and terminal cisternae of the sarcoplasmic reticulum on each side. These triads are visible in longitudinally sectioned muscle fibers. They are typically located at the A-I junction — the junction between the A and I bands of the sarcomere.
When an action...
When an action...
13.4K
Ligand-Gated Ion Channel Receptor: Gating Mechanism
3.6K
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
3.6K


