Mechanism of functional modulation of glutamate receptors by their auxiliary subunits

谷氨酸受体辅助亚基的功能调节机制

• 批准号: 10176871
• 负责人: Terunaga Nakagawa
• 金额: $ 38.3万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10176871
• 关键词: AMPA Receptors; Affect; Alanine; Alzheimer' s Disease; Architecture; Binding; Brain; Cognition; Complex; Conflict (Psychology); Corpus striatum structure; Cryoelectron Microscopy; Detergents; Drug Targeting; Electrophysiology (science); Environment; Excision; Family; Future; Glutamate Receptor; Glutamates; Goals; Heterogeneity; Hippocampus (Brain); Human; Ion Channel; Ion Channel Gating; Kinetics; Knowledge; Learning; Ligands; Limbic Encephalitis; Lipid Bilayers; Lipids; Location; Mediating; Memory; Mental disorders; Missense Mutation; Modeling; Molecular; Molecular Conformation; Mutate; Mutation; Neurotransmitters; Outcome; Outcome Study; Play; Production; Regulation; Resolution; Role; Seizures; Side; Signal Transduction; Specimen; Stroke; Structure; Synapses; Synaptic Transmission; Synaptic plasticity; System; Testing; Therapeutic; Transmembrane Domain; autism spectrum disorder; density; desensitization; design; experience; experimental study; member; nanodisk; nervous system disorder; neurotransmission; novel therapeutics; receptor binding; receptor function; reconstitution; reduce symptoms; stoichiometry; structured data; trafficking

The AMPA type ionotropic glutamate receptors (AMPARs), a ligand gated ion channel activated by the neuro- transmitter glutamate, mediate the majority of excitatory neurotransmission in the brain. The signals trans- duced by these complexes are critical for synaptic plasticity, learning and memory. AMPAR auxiliary subunits regulate trafficking and gating modulation of AMPARs. In this proposal we will investigate the mechanism of AMPAR regulation by their auxiliary subunits. The two major AMPAR auxiliary subunits, in the hippocampus, cortex, and striatum, are TARPs and cornichons (CNIHs). The TARPs are extensively studied and therapeutic compounds to alleviate seizure are already available to target γ-8 TARP, a hippocampus enriched TARP. On the other hand, our understanding on CNIHs is limited. Within the CNIH family, CNIH2/3 is known to function as AMPAR auxiliary subunits. In humans, the N-terminus of CNIH2 that forms the interaction interface with AMPAR is intolerant to missense mutations, indicating an essential role of CNIH2-AMPAR interaction in hu- mans. Our hypothesis is that CNIHs play fundamental roles in regulating AMPAR gating during synaptic transmission and plasticity. To further establish this hypothesis, we will study the functional mechanism of complexes made of GluA2 subunit of AMPAR and CNIH3 as a model. Our lab has recently solved the cryo-EM structure of GluA2/CNIH3 complex in GluA2:CNIH3=4:4 stoichiometry at high resolution. In Aim 1 we hypothe- size that the GluA2/CNIH3 complex could exists in other stoichiometry, and propose to reveal the architecture of complex in GluA2:CNIH3=4:2 stoichiometry using cryo-EM. CNIH1 is currently not categorized as AMPAR auxiliary subunit. However the cryo-EM structure of the GluA2/CNIH3 complex tells us that CNIH1 possess AMPAR binding motif that is present in CNIH2/3. The cryo-EM structure also revealed the presence of lipids surrounding the complex. We hypothesize that these lipids may play important functional roles in AMPAR gat- ing modulation. In Aim2 we will test roles of CNIH1 and lipids in gating modulation of AMPAR. Finally, we hy- pothesize that revealing the allosteric gating modulation mechanism of CNIH3 would require obtaining snap- shots of lipid embedded GluA2/CNIH3 complex in channel closed, open, and desensitized states. In Aim 3, we propose to solve high resolution cryo-EM structures of GluA2/CNIH3 complex embedded in a lipid bilayer mi- metic environment, and compare them in different functional states. The role of auxiliary subunits in tuning ion channel gating kinetics is predicted to have significant impact on circuit dynamics. In summary, the outcomes of this study are expected to advance our mechanistic understanding of AMPAR function and assist developing new therapeutic compounds that can alleviate dysregulation of AMPARs seen in neurological and psychiatric disorders, such as Alzheimer's disease, stroke, autism, Rasmussen's and limbic encephalitis, and seizure.

AMPA型离子型谷氨酸受体（AMPAR）是一种由神经元激活的配体门控离子通道， 谷氨酸递质介导大脑中的大部分兴奋性神经传递。信号传输- 由这些复合物诱导的突触对于突触可塑性、学习和记忆至关重要。AMPAR辅助亚基 监管AMPAR的贩运和门控调节。在本提案中，我们将研究 AMPAR通过其辅助亚基调节。海马体中两个主要的AMPAR辅助亚基， 皮质和纹状体是TARPs和cornichons（CNIH）。TARP被广泛研究和治疗 缓解癫痫发作的化合物已经可用于靶向γ-8 TARP，海马富集的TARP。对 另一方面，我们对CNIH的了解有限。在CNIH家族中，已知CNIH 2/3起作用 作为AMPAR辅助亚基。在人类中，CNIH 2的N-末端形成与 AMPAR对错义突变不耐受，表明CNIH 2-AMPAR相互作用在hu-2中的重要作用。 人.我们的假设是CNIH在调节突触过程中的AMPAR门控中起着重要作用。 传输和可塑性。为了进一步证实这一假说，我们将研究 以AMPAR的GluA 2亚基和CNIH 3的复合物为模型。我们的实验室最近解决了冷冻电镜 GluA 2：CNIH 3 =4：4化学计量GluA 2/CNIH 3复合物的高分辨率结构。在目标1中，我们假设- GluA 2/CNIH 3复合物可能以其他化学计量存在，并建议揭示其结构 GluA 2：CNIH 3 =4：2化学计量中的复合物。CNIH 1目前未归类为AMPAR 辅助亚基。然而，GluA 2/CNIH 3复合物的冷冻电镜结构告诉我们，CNIH 1具有 存在于CNIH 2/3中的AMPAR结合基序。冷冻电镜结构也显示了脂质的存在 围绕着复杂。我们推测这些脂质可能在AMPAR gat中发挥重要的功能作用。 调制。在Aim 2中，我们将测试CNIH 1和脂质在AMPAR门控调节中的作用。最后，我们- 推测揭示CNIH 3的变构门控调节机制需要获得snap- 脂质包埋的GluA 2/CNIH 3复合物在通道关闭、开放和脱敏状态下的注射。在目标3中，我们 建议解决嵌入脂质双层膜中的GluA 2/CNIH 3复合物的高分辨率冷冻-EM结构， 模拟环境，并在不同的功能状态下进行比较。辅助亚基在离子调谐中的作用 预测沟道门控动力学对电路动力学具有显著影响。总而言之， 本研究的结果有望促进我们对AMPAR功能机制的理解，并有助于开发 新的治疗化合物，可以减轻神经和精神疾病中观察到的AMPAR调节异常， 在一些实施方案中，本发明的组合物用于治疗疾病，例如阿尔茨海默病、中风、自闭症、拉斯穆森和边缘系统脑炎以及癫痫。

项目成果

GSG1L-containing AMPA receptor complexes are defined by their spatiotemporal expression, native interactome and allosteric sites.

• DOI: 10.1038/s41467-023-42517-7
• 发表时间: 2023-10-26
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Perozzo, Amanda M.;Schwenk, Jochen;Kamalova, Aichurok;Nakagawa, Terunaga;Fakler, Bernd;Bowie, Derek
• 通讯作者: Bowie, Derek

Modulatory mechanisms of TARP γ8-selective AMPA receptor therapeutics.

• DOI: 10.1038/s41467-023-37259-5
• 发表时间: 2023-03-25
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Zhang, Danyang;Lape, Remigijus;Shaikh, Saher A.;Kohegyi, Bianka K.;Watson, Jake F.;Cais, Ondrej;Nakagawa, Terunaga;Greger, Ingo H.
• 通讯作者: Greger, Ingo H.