Illuminating the structure and function of CACNG5 and 7

阐明 CACNG5 和 7 的结构和功能

• 批准号: 10452080
• 负责人: Terunaga Nakagawa
• 金额: $ 15.85万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-15 至 2024-05-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10452080
• 关键词: AMPA Receptors; Affect; Attenuated; Binding; Binding Proteins; Biological Models; Biology; Brain; Brain Neoplasms; Calcium; Calcium ion; Cell membrane; Cell physiology; Cells; Cerebellum; Cognition; Complex; Cryoelectron Microscopy; Cytoplasmic Granules; Development; Disease; Distant; Drug Targeting; Electrophysiology (science); Family; Functional disorder; Future; G-substrate; Genes; Glaucoma; Glioblastoma; Glutamate Receptor; Glutamates; Goals; Golgi Apparatus; Hippocampus (Brain); Homo; Impaired cognition; Intellectual functioning disability; Ion Channel; Ion Channel Gating; Ischemic Brain Injury; Kinetics; Learning; Ligands; Long-Term Depression; Mediating; Membrane; Membrane Proteins; Memory; Mental disorders; Molecular; Motor; Movement Disorders; Neuroglia; Neurons; Neurotransmitters; Nomenclature; Outcome; Outcomes Research; Pain; Pathologic; Permeability; Pharmacology; Physiological; Polyamines; Probability; Protein Family; Proteins; Reagent; Regulation; Relapse; Research; Resolution; Resources; Role; Second Messenger Systems; Seizures; Sequence Homology; Signal Transduction; Specificity; Structure; Synapses; Synaptic Transmission; Synaptic plasticity; addiction; base; cell type; conditioned fear; drug development; genetic regulatory protein; improved; insight; molecular modeling; nervous system disorder; neuronal survival; novel therapeutics; positive allosteric modulator; protein function; rational design; reduce symptoms; side effect; trafficking; tumor addiction

Project Summary The majority of excitatory synaptic transmission in the CNS synapses are mediated by the AMPA-type ionotropic glutamate receptor (AMPAR), a ligand gated ion channel activated by the neurotransmitter glutamate. The pore forming subunits of AMPARs (GluA1-4 subunits) assemble as homo- or hetero-tetramers. The native AMPARs co-assemble with a rich repertoire of transmembrane auxiliary subunits which belong to different protein families, such as TARP, GSG1L, CNIH, CKAMP, and synDIG. Incorporation of different auxiliary subunit confers AMPAR with unique ion channel gating kinetics, pharmacology, and in many cases trafficking regulation. The varying expression patters of auxiliary subunits in brain provides opportunities to produce drugs that target specific AMPAR auxiliary subunit combinations, which would have improved target specificity and less side effects over existing ones such as Perampanel (NAM) and ampakines (PAM) that bind to the common pore forming subunits of AMPARs (GluA1-4). Indeed, several NAMs that are selective to TARP gamma-8 containing AMPARs are already available and effective in seizures and pain. All the TARPs except for the TARP gamma-2 (encoded by CACNG2) are understudied and present in Phanos and IDG resource. Among these the biology is least understood for the type-II TARPs (CACNG5 and 7, which encodes TARP gamma-5 and 7), whose sequences are distant from the type-I TARPs (CACNG2, 3, 4, and 8, which encodes TARP gamma-2, 3, 4, and 8). Currently, it is established that type-II TARPs bind to calcium permeable AMPA-Rs (CP-AMPAR) that lacks the GluA2 subunit and regulate their functions. TARP gamma-5 is expressed in the CA2 of hippocampus and Bergmann glia of cerebellum, whereas TARP gamma-7 is enriched in cerebellar neurons (Purkinje, basket, stellate, granule, Bergmann glia, and Golgi cells). Consistently, CP-AMPARs were functionally detectable in these cell types. The function of CP-AMPARs is highly relevant to ischemic brain damages, brain tumors, addiction, fear-conditioning, and motor function. Compounds that selectively target type-II TARP containing CP-AMPARs are promising reagents for pharmacological manipulation to study the cellular function of these complexes and may facilitate the future development of drugs for treating the pathological conditions described above. We hypothesize that the type-II TARPs operate under different molecular mechanism from type-I TARPs, which do not specialize in CP-AMPAR modulation. To illuminate the structural basis for the mechanism of type-II TARP function, we propose to solve the high-resolution structures of a type-II TARP in complex with CP-AMPAR, which is currently missing. Based on the insights obtained from the structures of other AMPAR/auxiliary subunit complexes we predict that the differences in sidechain interaction network at the protein interaction interface determine the types of functional readout of modulation. The outcome of this research is expected to produce high resolution molecular model of the interaction interfaces between AMPAR and type-II TARP, which in turn would facilitate further functional research at the molecular level of currently understudied type-II TARPs (i.e. CACNG5 and 7).

项目摘要 中枢神经系统突触中的大多数兴奋性突触传播都是由AMPA型离子型介导的 谷氨酸受体（AMPAR），一种由神经递质谷氨酸激活的配体门控离子通道。孔 形成AMPAR（GLUA1-4亚基）的亚基组装为同型或异性四聚体。本地ampars 与属于不同蛋白质家族的跨膜辅助亚基的丰富曲目共同组装 例如TARP，GSG1L，CNIH，CKAMP和SYNDIG。不同辅助亚基的合并赋予AMPAR 具有独特的离子通道门控动力学，药理学，在许多情况下进行贩运调节。变化 大脑中辅助亚基的表达模式提供了生产针对特定药物的机会 AMPAR辅助亚基组合，这将提高目标特异性，而副作用更少 现有的，例如Perampanel（NAM）和Ampakines（PAM），它们与普通孔形成亚基结合 AMPARS（GLUA1-4）。实际上，有几个对含TARPγ-8的NAM含有AMPAR的NAM是 已经可用且有效地癫痫发作和痛苦。除防尘伽马2（由 CACNG2）被研究并存在于Phanos和IDG资源中。其中最少的生物学 理解用于II型防水布（CACNG5和7，它编码TARP伽马-5和7）的序列 远离I型TARP（CACNG2、3、4和8），它编码TARP GAMMA-2、3、4和8）。现在， 已经确定II型防水石与缺乏GLUA2的钙可渗透AMPA-RS（CP-AMPAR）结合 亚基和调节其功能。 TARP GAMMA-5在海马和Bergmann的CA2中表达 小脑的神经胶质，而TARP GAMMA-7富含小脑神经元（Purkinje，Basket，Stellate，Stellate，Granule， Bergmann Glia和Golgi细胞）。一致地，在这些细胞类型中可以检测到CP-AMPAR。这 CP-AMPAR的功能与缺血性脑部损伤，脑肿瘤，成瘾，恐惧条件高度相关， 和运动功能。选择性靶向含有CP-Ampars的II型TARP的化合物有希望 药理操作的试剂研究这些复合物的细胞功能，并可能促进 用于治疗上述病理状况的药物的未来发展。我们假设这一点 II型篷布以I型TARP的不同分子机制运行，不专注于 CP-Ampar调制。为了阐明II型TARP功能机理的结构基础，我们 提议解决与CP-Ampar复合物中II型防水布的高分辨率结构，目前是 丢失的。基于从其他AMPAR/辅助亚基复合物的结构获得的见解，我们 预测蛋白质相互作用接口处的Sidechain相互作用网络的差异决定了 调制功能读数的类型。这项研究的结果有望产生高分辨率 AMPAR和II型篷布之间相互作用接口的分子模型，这又有促进 在当前研究的II型篷布的分子水平上进行进一步的功能研究（即CACNG5和7）。