电压感应机制保留在离子通道中,这些离子通道被相反的电压封锁
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
概括
超极化激活的循环核酸门 (HCN) 通道,对于大脑和心脏细胞发射至关重要,利用类似于通道的电压感应机制. 这种保存的S4段运动表明,尽管存在相反的电压依赖性,但共享的网关原理.
科学领域:
- 离子通道生物物理 离子通道生物物理
- 分子神经科学分子神经科学
- 心血管生理学心血管生理学
背景情况:
- 超极化激活的循环核酸门 (HCN) 通道在心脏和神经细胞中产生关键电流 (I(h) /I(f),调节发射模式.
- 在非节奏细胞中,HCN通道也与突触调制和可塑性有关.
- HCN通道与电压通道 (Kv) 具有结构上的相似之处,包括S4跨膜段.
研究的目的:
- 调查HCN通道中的S4段是否经历了运动,类似于其在KV通道中的作用.
- 为了确定S4是否在HCN通道中充当电压传感器.
- 为了比较HCN和KV通道的电压传感机制.
主要方法:
- 氨酸可访问性测试被用来探测HCN通道S4段的结构变化.
- 对HCN和KV通道之间的结构图案进行比较分析.
主要成果:
- 证明了HCN通道中S4段运动的证据,证实其作为电压传感器的作用.
- 在HCN通道中的S4运动与在KV通道中观察到的运动保持一致.
- 尽管保留了电压传感器,但在HCN和KV通道中,电压传感器和激活门之间存在着不同的合机制.
结论:
- 涉及S4段的保护电压传感机制在两种相反电压的KV和HCN通道中运行.
- 这些发现揭示了离子通道电压传感中保留的原理,但突出了不同的关和合策略.
- 这项研究加深了对在不同生理背景下HCN通道功能和调节的理解.
相关概念视频
01:15Resting 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...
01:26Voltage-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...
01:12Mechanically-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...
01:21DC 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,...
01:26Voltage-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...
01:15Resting 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...