在CNGA2通道中,与激活关的相关联体结合
Christoph Biskup1, Jana Kusch, Eckhard Schulz
1Institut für Physiologie II, Friedrich-Schiller-Universität Jena, D 07740 Jena, Germany.
Nature
|February 27, 2007
概括
研究人员研究了循环核酸 (CNG) 离子通道激活. 他们发现,第二个带结合步骤对于通道开放至关重要,揭示了感觉转导中的子单元相互作用.
科学领域:
- 分子生物学分子生物学
- 离子通道生理学 离子通道生理学
- 感官神经科学是一种神经科学.
背景情况:
- 循环核酸门 (CNG) 离子通道对于光受体和嗅觉细胞中的感官信号转导至关重要.
- 这些通道是异质四体,它们的激活是一个涉及多个子单元的合作过程,但确切的机制尚不清楚.
研究的目的:
- 阐明嗅觉类型CNGA2通道激活的合作机制.
- 确定连接体结合和通道封锁如何促进合作性和子单元相互作用.
主要方法:
- 使用内外膜贴片来研究同位四度CNGA2通道.
- 使用光cGMP模拟器8-DY547-cGMP同时测量通道激活和带结合.
- 进行了稳定状态约束/激活关系和激活时间过程的全球分析.
主要成果:
- 观察到在不同度的连接物中稳定状态结合和激活关系的交叉.
- 证明了四个连接体与通道结合,结合部位之间有显著的相互作用.
- 确定了第二个连接体结合步骤对于通道开放至关重要,触发了切换到最大开放状态.
结论:
- 第二个带结合事件是CNGA2通道开通的最关键事件.
- 在CNG通道的合作激活机制中,子单位的相互作用起着重要作用.
- 这些发现为参与信号传导的离子通道和受体的功能提供了洞察力.
相关概念视频
Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...
Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
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...
Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...


