電圧感知メカニズムは,対極電圧によってゲートされたイオンチャネルの間に保存されます
Roope Männikkö1, Fredrik Elinder, H Peter Larsson
1Department of Neuroscience, The Nobel Institute for Neurophysiology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Nature
|October 25, 2002
まとめ
脳と心臓の細胞発射に不可欠な,ハイパーポラライゼーションで活性化された循環核酸ゲート (HCN) チャンネルは,カリウムチャンネルに似た電圧感知機構を使用します. この保存されたS4セグメントの動きは,正反対の電圧依存関係にもかかわらず,共有されたゲーティング原理を示唆しています.
科学分野:
- イオンチャネル生物物理学 イオンチャネル生物物理学
- 分子神経科学は分子神経科学である.
- 心血管の生理学 心血管の生理学
背景:
- ハイパーポラライゼーションで活性化された循環型核酸ゲート (HCN) チャンネルは,心臓細胞と神経細胞で重要な電流 (I) (h) /I (f) を発生させ,発火パターンを調節する.
- HCNチャネルは,シナプス調節と可塑性のための非ペース細胞にも関与しています.
- HCNチャネルは,S4トランスメブランセグメントを含む,電圧ゲートされたカリウム (Kv) チャネルと構造的類似性を共有しています.
研究 の 目的:
- HCNチャネルにおけるS4セグメントが,KVチャネルにおけるS4セグメントの役割と同様の動きを経験するかどうかを調査する.
- S4がHCNチャネルにおける電圧センサーとして機能するかどうかを判断する.
- HCNとKVチャネルの電圧感知メカニズムを比較する.
主な方法:
- システインアクセシビリティアッセイは,HCNチャネルのS4セグメントの構造変化を調査するために使用されました.
- HCNとKVチャンネル間の構造モチーフの比較分析.
主要な成果:
- HCNチャネルにおけるS4セグメントの動きの証拠が示され,電圧センサーとしての役割が確認されました.
- HCNチャネルにおけるS4の動きは,KVチャネルで観測されたものと保持されます.
- 保存された電圧センサーにもかかわらず,電圧センサーとアクティベーションゲートとの間の明確な結合メカニズムがHCNとKVチャンネルに存在します.
結論:
- S4セグメントを含む保存電圧感知メカニズムは,対極電圧ゲートされた Kv チャンネルと HCN チャンネルの両方で動作します.
- 発見は,イオンチャネル電圧感知における守られた原理を明らかにしますが,異なるゲートとカップリング戦略を強調しています.
- この研究は,さまざまな生理学的文脈におけるHCNチャネル機能と規制の理解を深める.
関連する概念動画
Resting Potential Decay
The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane through...
At rest, the K+ is the main ion that moves across the membrane through...
Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Mechanically-gated Ion Channels
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...
DC Battery
A conductor needs to be a component of a path that creates a closed loop or full circuit to have a continuous current flowing through it. A current starts to flow if an electric field is created inside an isolated conductor that is not part of a full circuit. The conductor quickly develops a net positive charge at one end and a net negative charge at the other. These charges generate an electric field opposite the direction of the applied electric field, which reduces the current. Eventually,...
Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Resting Potential Decay
The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane through...
At rest, the K+ is the main ion that moves across the membrane through...


