Synaptic targeting and regulation of NMDAR subunits

描述(申请人提供)：这项研究计划的总体目标是更好地了解N-甲基-D-天冬氨酸受体(NMDAR)调节突触发育和突触可塑性的分子机制，以及这些过程如何在复杂的神经精神障碍(如精神分裂症)中被破坏。K08指导临床科学家研究职业发展奖的申请者John Gray博士是一名精神病学家，也是加州大学旧金山分校Roger Nicoll博士的博士后研究员。格雷博士的长期研究目标是在一家结合了细胞、分子、电生理和遗传学方法的学术机构领导一个独立的精神神经科学研究实验室，研究突触功能，目的是了解突触发育的正常机制中断如何可能成为主要神经精神疾病的病理生理学基础。尽管精神分裂症的病因机制在很大程度上仍不清楚，但药理学和遗传学数据的融合意味着NMDAR功能的失调。NMDAR在神经发育和突触可塑性中起着关键作用，NMDAR功能的细微变化可以产生广泛的发育和认知影响。大多数前脑NMDAR含有两个GluN1和两个GluN2A或GluN2B亚基，受体的运输和功能特性在很大程度上由GluN2亚基的组成决定。直到最近，该领域的教条还认为NMDAR是相对固定的固定结构，尽管现在很明显，突触NMDAR具有显著的可塑性。事实上，不同NMDAR亚型的表达、运输、突触定位和功能都处于动态的细胞控制之下，尽管其机制尚不清楚。在这项研究计划中，将使用一种创新的分子置换方法来系统地研究GluN2亚单位C末端尾巴在NMDAR突触靶向、运输和调控中的作用。在该方法中，单个神经元中的天然NMDAR被移除并被重组的NMDAR亚基取代。通过结合他在分子和细胞生物学、受体药理学和突触电生理学方面的培训，格雷博士将继续进行生化和蛋白质组学方面的额外培训，以解决以下具体目标：1)确定GluN2B-S1480磷酸化在NMDAR运输中的作用；2)确定GluN2A靶向突触的机制；以及3)确定酪氨酸磷酸化在NMDAR运输和调控中的作用。这项提议的成功完成将确定新的运输机制、新的靶向基序和新的蛋白质，对NMDAR的调节以及突触的发展和可塑性非常重要，并将为精神分裂症和其他神经精神疾病的疾病修改治疗方法的开发开辟新的前沿。

DESCRIPTION (provided by applicant): The overall goal of this research program is to better understand the molecular mechanisms by which N-methyl-D-aspartate receptors (NMDARs) are regulated to modulate synapse development and synaptic plasticity, and how these processes might be disrupted in complex neuropsychiatric disorders such as schizophrenia. The applicant for this K08 Mentored Clinical Scientist Research Career Development Award, Dr. John Gray, is a psychiatrist and a postdoctoral fellow with Dr. Roger Nicoll at UCSF. Dr. Gray's long-term research goals are to lead an independent research laboratory in psychiatric neuroscience at an academic institution combining cellular, molecular, electrophysiological, and genetic approaches to study synapse function with the goal of understanding how disruptions of the normal mechanisms of synapse development might underlie the pathophysiology of major neuropsychiatric disorders. Though etiological mechanisms underlying schizophrenia remain largely unknown, a convergence of pharmacologic and genetic data implicates a dysregulation of NMDAR function. NMDARs play critical roles in neurodevelopment and synaptic plasticity and subtle changes in NMDAR functioning can have wide-ranging developmental and cognitive effects. Most forebrain NMDARs contain two GluN1 and two GluN2A or GluN2B subunits, with receptor trafficking and functional properties largely dictated by the GluN2 subunit composition. Until recently the dogma in the field was that NMDARs were relatively immobile fixed structures, though it is now apparent that there is a remarkable plasticity of synaptic NMDARs. Indeed, the expression, trafficking, synaptic localization and functioning of different NMDARs subtypes are under dynamic cellular control, though the mechanisms are poorly understood. In this research plan, the roles of GluN2 subunit C-terminal tails in NMDAR synaptic targeting, trafficking, and regulation will be systematically investigated using an innovative molecular replacement approach in which native NMDARs are removed and replaced by recombinant NMDAR subunits in individual neurons. By combining his training in molecular and cellular biology, receptor pharmacology, and synaptic electrophysiology, Dr. Gray will pursue additional training in biochemical and proteomic analysis to address the following specific aims: 1) to determine the role of GluN2B-S1480 phosphorylation in NMDAR trafficking; 2) to determine the mechanism of GluN2A targeting to synapses; and 3) to determine the role of tyrosine phosphorylation in NMDAR trafficking and regulation. Successful completion of this proposal will identify novel trafficking mechanisms, new targeting motifs and new proteins important in NMDAR regulation and synaptic development and plasticity and will open new frontiers for the development of disease-modifying therapeutic approaches for schizophrenia and other neuropsychiatric disorders.