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)，一种由神经激活的配体门控离子通道 递质谷氨酸，介导大脑中大部分兴奋性神经传递。信号传输 这些复合物引起的对突触可塑性、学习和记忆至关重要。 AMPAR 辅助亚基 调节 AMPAR 的运输和门控调节。在本提案中，我们将研究以下机制： AMPAR 通过其辅助亚基进行调节。海马体中的两个主要 AMPAR 辅助亚基， 皮质和纹状体分别是 TARP 和 Cornichons (CNIH)。 TARP 已被广泛研究并具有治疗作用 缓解癫痫发作的化合物已经可用于靶向 γ-8 TARP（一种富含海马的 TARP）。在 另一方面，我们对CNIH的了解是有限的。在 CNIH 家族中，已知 CNIH2/3 的功能 作为 AMPAR 辅助亚基。在人类中，CNIH2 的 N 末端与 AMPAR 不耐受错义突变，表明 CNIH2-AMPAR 相互作用在 hu- 勒芒。我们的假设是 CNIH 在突触过程中调节 AMPAR 门控中发挥重要作用 传输性和可塑性。为了进一步证实这一假设，我们将研究其作用机制 AMPAR 和 CNIH3 的 GluA2 亚基形成的复合物作为模型。我们实验室最近解决了冷冻电镜 高分辨率的 GluA2/CNIH3 复合物结构（GluA2:CNIH3=4:4 化学计量）。在目标 1 中，我们假设 - GluA2/CNIH3 复合物可以以其他化学计量存在的大小，并建议揭示其结构 使用冷冻电镜分析 GluA2:CNIH3=4:2 化学计量中的复合物。 CNIH1 目前未归类为 AMPAR 辅助亚基。然而，GluA2/CNIH3 复合物的冷冻电镜结构告诉我们，CNIH1 具有 CNIH2/3 中存在的 AMPAR 结合基序。冷冻电镜结构还揭示了脂质的存在 综合体周围。我们假设这些脂质可能在 AMPAR gat 中发挥重要的功能作用。 荷兰国际集团调制。在 Aim2 中，我们将测试 CNIH1 和脂质在 AMPAR 门控调节中的作用。最后，我们嘿- 假设揭示 CNIH3 的变构门控调制机制需要获得快照 通道关闭、开放和脱敏状态下脂质嵌入的 GluA2/CNIH3 复合物的照片。在目标 3 中，我们 提出解决嵌入脂质双层 mi- 的 GluA2/CNIH3 复合物的高分辨率冷冻电镜结构 metic环境，并在不同的功能状态下进行比较。辅助亚基在调节离子中的作用 预计通道选通动力学会对电路动力学产生重大影响。总而言之，结果 这项研究预计将增进我们对 AMPAR 功能的机制理解并协助开发 新的治疗化合物可以缓解神经和精神疾病中 AMPAR 的失调 疾病，如阿尔茨海默氏病、中风、自闭症、拉斯穆森氏病和边缘脑炎以及癫痫发作。

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.