Modulation and Targeting of Kainate Receptors

产品说明： 谷氨酸门控NMDA、AMPA和红藻氨酸离子型受体。为了红藻氨酸 受体，相对而言，很少有人知道它们的功能是如何调节的。 通过亚单位组成或锚定分子如突触后密度 蛋白质（PSD/SAP）。我们最近的工作表明PSD-95/SAP9O共定位 在突触处与红藻氨酸受体结合，结合红藻氨酸受体KA2和GIuR6 亚基，并显著改变GluR6和KA2/G1uR6生理学（Garcia et 例如，1998年）。我们发现酪氨酸磷酸化与 生理反应的修饰和潜在的调节分子， SRC和MSS 4（一种鸟嘌呤核苷酸交换因子）优先结合 分别与KA2和PSD-95/SAP90。此外，我们还发现， 关联受KA2-PSD-95/SAP90相互作用调节， 此外，SAP 97不能结合含KA 2的受体。在一起， 这些结果表明PSD蛋白可能不仅在锚定中起作用， 受体在突触部位，但也在调节受体活性， 受体亚型存在于给定位点。 该提案将建立PSD-95/SAP9O调节红藻氨酸盐的机制 受体功能和靶向。我们将评估它如何调节受体 活性和调节是否取决于受体亚基组成， 激动剂亲和力、脱敏特性和对抑制剂的敏感性。 对于潜在的机制，我们将研究如何结合配体，如GKAP， GK结构域可能促进PSD-95的SH3结构域与 KA2，KA2和PSD-95上决定酪氨酸的分子位点 磷酸化，以及mss4和PSD-95/SAP90上的调节磷酸化的位点。 将鉴定mss4-PSD-95/SAP90-KA2相互作用。生理 这些相互作用和src对KA2和PSD-95的影响，将是 通过表达具有受体亚单位的活性和非活性酶来建立 （野生型与突变型）。为了确定受体的潜在mss4调节， 靶向、受体的表面表达和受体分布 （集群与非集群）将被评估。这些研究预计将 提供了关于如何确定功能特性的新信息 通过控制受体聚集/靶向的机制， 特定亚基组成。

DESCRIPTION: Glutamate gates NMDA, AMPA and kainate ionotropic receptors. For kainate receptors, comparatively little is known about how their function is regulated by subunit composition or anchoring molecules such as postsynaptic density proteins (PSD/SAP). Our recent work demonstrates that PSD-95/SAP9O colocalizes with kainate receptors at synapses, binds the kainate receptor KA2 and GIuR6 subunits, and significantly modifies GluR6 and KA2/G1uR6 physiology (Garcia et al., 1998). We find that tyrosine phoshorylation correlates with the modification of physiological response and that potential regulatory molecules, src and mss4 (a guanine nucleotide exchange factor) preferentially associate with, respectively, KA2 and PSD-95/SAP9O. Furthermore, we also find that both associations are regulated by the KA2-PSD-95/SAP9O interaction, and additionally that SAP97 is unable to bind KA2-containing receptors. Together, the results imply that PSD proteins may function not only in anchoring receptors at synaptic Sites, but also in regulating receptor activity and which receptor subtypes are present in a given site. This proposal will establish mechanisms by which PSD-95/SAP9O regulates kainate receptor function and targeting. We will assess how it regulates receptor activity and if regulation depends on receptor subunit composition, determining agonist affinities, desensitization properties and sensitivity to inhibitors. For potential mechanisms, we will examine how binding of ligands, such as GKAP, to the GK domain may promote the association of the SH3 domain of PSD-95 with KA2, the molecular sites on KA2 and PSD-95 that determine tyrosine phosphorylation, as well as the sites on mss4 and PSD-95/SAP9O that regulate mss4-PSD-95/SAP9O-KA2 interactions will be identified. The physiological effects of these interactions and those of src on KA2 and PSD-95, will be established by expressing active and inactive enzymes with receptor subunits (wild-type vs. mutated). To determine potential mss4 regulation of receptor targeting, the surface expression of receptors and receptor distribution (clustered vs. unclustered) will be evaluated. These studies are expected to provide novel information on how functional properties can be determined through mechanisms controlling the clustering/targeting of receptors of specific subunit composition.