转基因GABA受体激活的结构基础
Hamidreza Shaye1,2, Andrii Ishchenko1,2, Jordy Homing Lam1,3
1Bridge Institute, USC Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA.
Nature
|June 20, 2020
概括
研究人员使用冷EM可视化metabotropic γ-aminobutyric酸受体 (GABAB) 的非活性和活性状态. 这些结构揭示了激素结合和基调节器如何控制GABAB受体信号传递.
科学领域:
- 神经科学
- 结构生物学
- 生物化学
背景情况:
- 甲基氨酸受体 (GABAB) 对于调节中枢神经系统中的突触活动至关重要.
- GABAB受体的功能障碍与神经心理障碍,如成和精神病有关.
- GABAB受体是属于C类的G-蛋白合受体 (GPCR),作为义务GB1-GB2异构体起作用.
研究的目的:
- 阐明GABAB受体激活的结构机制.
- 为了可视化GB1-GB2异构体在连接时的构造变化.
- 提供有关正调节剂在稳定活性受体状态方面的见解.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定高分辨率结构.
- 人体全长GB1 - GB2异构体的四个不同的结构状态得到了解决.
- 结构包括非活跃的apo状态,中间的激动剂结合状态,以及具有激动剂和正异位调节器的活跃状态.
主要成果:
- 在GB1子单元中,激素结合会诱导金星域的关闭.
- 这就启动了形状转换,使跨膜领域接近.
- 一个涉及GB2跨膜领域的杆式机制调解下游信号.
- 阳性基调节剂通过结合在跨膜界面来稳定活性受体构成.
结论:
- 这项研究揭示了控制GABAB受体激活的动态构造变化.
- 这些发现阐明了配体调节受体功能的复杂机制.
- 结构性见解为开发针对神经和精神疾病的向疗法铺平了道路.
更多相关视频
相关概念视频
Activation and Inactivation of G Proteins
10.2K
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...
10.2K
Ligand-Gated Ion Channel Receptor: Gating Mechanism
3.5K
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...
3.5K
GPCRs Regulate Adenylyl Cylase Activity
7.0K
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...
7.0K
G-Protein Gated Ion Channels
5.4K
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory...
Sensory...
5.4K
Transducer Mechanism: G Protein–Coupled Receptors
3.6K
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical,...
GPCRs are also called heptahelical,...
3.6K
Antiepileptic Drugs: GABAergic Pathway Potentiators
1.1K
γ-aminobutyric acid or GABA, plays a pivotal role as an inhibitory neurotransmitter in the brain. GABA pathway potentiators, also known as GABAergic drugs, are a class of pharmaceutical agents designed to enhance the functioning of the GABAergic system. These medications primarily treat epilepsy, a neurological disorder characterized by recurrent seizures.
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for...
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for...
1.1K


