PDZ scaffold regulation of astrocytic glutamate receptors and transporters

描述(申请人提供)：谷氨酸是哺乳动物中枢的主要兴奋性神经递质。 神经系统。神经元之间的谷氨酸能信号是由 邻近的星形胶质细胞，环绕着大多数突触连接，表达特定的 通过去除谷氨酸来控制谷氨酸浓度的谷氨酸转运体 从突触裂隙。星形胶质细胞也表达谷氨酸受体，特别是 代谢型谷氨酸受体亚型mGluR3和mGluR5由 谷氨酸和已知调节谷氨酸转运体活性。然而，很多都是 对神经元中谷氨酸受体的调节和分类知之甚少 已知谷氨酸受体和谷氨酸受体的特殊调节的潜力 星形胶质细胞中的转运蛋白。MGluR亚型3和5，以及星形细胞 谷氨酸转运体EAAT1都具有大的胞内羧基末端(CT)， 在控制他们的活动方面扮演着关键的角色。由于这些CTs以协商一致的方式终止 与一类保守的蛋白质-蛋白质相互作用潜在联系的基序 结构域被称为PDZ结构域，我们筛选出一个定制的PDZ结构域蛋白质组 阵列，发现mGluR3、mGluR5和EAAT1的CT都表现出健壮性和 多功能支架蛋白与PDZ结构域的特异性相互作用 NHERF-2。这些相互作用在细胞环境中得到了证实，并且 免疫组织化学研究显示NHERF-2在 大脑中的星形胶质细胞。我们假设NHERF-2是一种中枢调节因子。 MGluRs和EAAT1在星形胶质细胞的活性和定位，并可能促进相互作用 MGluRs和谷氨酸转运体之间的调控。我们将通过以下方式测试这一想法 检测NHERF-2对mGluR3、mGluR5和EAAT1功能活性的调节 串扰，以及探索NHERF-2可能控制mGluR和 脑组织免疫组织化学分析EAAT1在体内的定位 来自野生型和NHERF-2基因敲除小鼠。这些研究具有重要的临床意义。 之所以重要，是因为代谢型谷氨酸受体和谷氨酸转运体 被认为是治疗中风的极具潜力的治疗靶点， 阿尔茨海默病，帕金森氏病，肌萎缩侧索硬化症，精神分裂症， 以及其他脑部疾病。

DESCRIPTION (provided by applicant): Glutamate is the primary excitatory neurotransmitter in the mammalian central nervous system. Glutamatergic signaling between neurons is critically regulated by neighboring astrocytes, which surround most synaptic junctions and express specific glutamate transporters that control glutamate concentrations by removing glutamate from the synaptic cleft. Astocytes also express glutamate receptors, specifically the metabotropic glutamate receptor subtypes mGluR3 and mGluR5, which are activated by glutamate and known to regulate glutamate transporter activity. Whereas much is known about the regulation and sorting of glutamate receptors in neurons, very little is known about the potential for specialized regulation of glutamate receptors and transporters in astrocytes. The mGluR subtypes 3 and 5, as well as the astrocytic glutamate transporter EAAT1, all possess large intracellular carboxyl-termini (CT) that play key roles in the control of their activity. Since these CTs terminate in consensus motifs for potential association with a class of conserved protein-protein interaction domains known as PDZ domains, we screened a custom-made PDZ domain proteomic array and found that the CTs of mGluR3, mGluR5 and EAAT1 all exhibit robust and specific interactions with the PDZ domains of the multifunctional scaffold protein NHERF-2. These interactions were confirmed in a cellular context, and immunohistochemical studies revealed that NHERF-2 is abundantly expressed in astrocytes in the brain. We hypothesize that NHERF-2 is a central regulator of the activity and localization of mGluRs and EAAT1 in astrocytes, and may facilitate mutual regulation between mGluRs and glutamate transporters. We will test this idea by examining NHERF-2 regulation of mGluR3, mGluR5 and EAAT1 functional activity and cross-talk, as well as by exploring the possibility that NHERF-2 may control mGluR and EAAT1 localization in vivo by performing immunohistochemical analyses on brain tissue from wild-type versus NHERF-2 knockout mice. These studies are of significant clinical importance because metabotropic glutamate receptors and glutamate transporters are considered to be excellent potential therapeutic targets in the treatment of stroke, Alzheimer's Disease, Parkinson's Disease, amyotrophic lateral sclerosis, schizophrenia, and other brain disorders.