TARP modulation of AMPA receptors

AMPA 受体的 TARP 调节

• 批准号: 8976615
• 负责人: Vasanthi Jayaraman
• 金额: $ 29.75万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-05 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8976615
• 关键词: AMPA Receptors; Accounting; Address; Affect; Agonist; Automobile Driving; Binding; Brain; Cataloging; Catalogs; Chimera organism; Cleaved cell; Complex; Coupling; Data; Defect; Electrophysiology (science); Exhibits; Exposure to; Extracellular Domain; Fluorescent Probes; Glutamate Receptor; Glutamates; Health; Investigation; Kinetics; Label; Laboratories; Ligands; Maps; Mass Spectrum Analysis; Measurement; Measures; Mediating; Mediator of activation protein; Methods; Molecular Conformation; Mutate; Mutation; Neuraxis; Neurons; Phenylalanine; Physiological; Play; Positioning Attribute; Process; Property; Protein Family; Proteins; Receptor Activation; Resolution; Role; Seizures; Shapes; Signal Transduction; Site; Specificity; Structure; Synapses; Synaptic Transmission; Tertiary Protein Structure; Testing; Time; Western Blotting; Work; base; biophysical tools; cognitive function; crosslink; desensitization; dimer; excitotoxicity; fluorophore; genetic regulatory protein; insight; luminescence resonance energy transfer; member; millisecond; motor control; mutant; receptor; receptor function; response; tandem mass spectrometry; trafficking; unnatural amino acids

 DESCRIPTION (provided by applicant): AMPA receptors mediate fast excitatory responses in the mammalian central nervous system, and ultimately control motor and cognitive functions. In neurons AMPA receptors co-assemble with auxiliary subunits. One member being transmembrane AMPA receptor regulatory proteins (TARPs), which are essential for the normal physiological functioning of these receptors. One of the dramatic effects of TARPs on AMPA receptor gating is a large increase in efficacy such that even some antagonists such as 6-cyano-7-nitroquinoxaline-2,3-dione act as partial agonists. Additionally, TARPs slow deactivation of AMPA receptor when agonist is removed and slow the rate and extent of desensitization when agonist is continually applied. These changes in properties are expected to dictate the kinetics and shape of synaptic transmission. In addition to the rapid modulations, the presence of certain subtypes of TARP's leads to resensitization on longer time scales, from the tens of milliseconds to seconds. The prolonged opening of the receptors in these long resensitization processes may play a role in glutamate mediated excitotoxicity. Here we propose to gain a fundamental understanding of the structure-dynamic changes controlling the increase in efficacy and resensitization in the AMPA receptors in the presence of TARPs using a combination of biophysical and electrophysiological methods. For the proposed study, we will use luminescence resonance energy transfer to study the conformational changes in the protein. For specific labeling of the protein with fluorescent probes we will introduce unnatural amino acids at specific sites on the protein. The conformational changes thus observed will be further verified with functional investigations of mutant proteins with mutations introduced at strategic sites that affect the observed conformational change or the stability of a specific conformational state. Finally, the position of the TARP ecto domain will be mapped to the AMPA receptor extracellular domain using mass spectrometry. To study the interaction sites between the two proteins the unnatural amino acid p-benzoyl phenylalanine will be introduced at various sites and those sites leading to crosslinking will be analyzed using high resolution tandem mass spectrometry. The proposed functional and structural investigations will provide a comprehensive understanding of the mechanism by which TARPs modulates AMPA receptor function.