The Role of Calcyon in Synaptic Integration

描述（由申请人提供）：获得对 内源性神经调节剂如多巴胺（DA）调节 谷氨酰胺能兴奋性传输可能会导致更好的患者患有 患有癫痫、帕金森氏症、精神分裂症和药物成瘾。 特别是D1多巴胺受体亚型的激活， 谷氨酸诱导的额叶皮层、海马和 新纹状体关于D1受体与细胞凋亡的分子机制知之甚少。 信号传导调节兴奋性传递。我们最近发现了一个 称为钙蛋白的跨膜蛋白，其与D1 DA受体相互作用 并定位于树突棘中的囊泡。通过与Calcyon，D1的相互作用 受体刺激细胞内Ca ~（++）释放 异源表达系统中的活性依赖性方式。类似的 活性依赖性，D1受体激动剂刺激的反应可通过 皮质和海马神经元原代培养物的Fura-2 Ca++成像。 我们的总体假设是钙蛋白增强D1受体信号传导 通过Gq/11作为连接D1受体与IP 3调节的连接， Ca++存储。我们将确定D1 DA受体如何通过Gq/11信号传导， 引发，以及钙蛋白如何增强D1受体介导的IP 3信号传导。使用Ca++ 成像和肽阻断D1受体：钙蛋白相互作用，我们将 确定D1激动剂刺激的Ca++i释放是否需要Calcyon。 树突棘我们建议鉴定其他GPCR和辅助蛋白 通过酵母双杂交和噬菌体展示筛选与Calcyon相互作用。我们 将确定这些蛋白质如何参与调节Ca++的释放 从泡状存储器中取出。这项研究的结果应该提供洞察力， 选择性增强或减弱D1受体介导的 兴奋性传递的神经调节。

DESCRIPTION (provided by applicant): Obtaining a precise understanding of the mechanism(s) by which endogenous neuromodulators such as dopamine (DA) regulate glutamergic excitatory transmission could lead to better for patients afflicted with epilepsy, Parkinson's Disease, schizophrenia, and drug addiction. Activation of the D1 dopamine receptor subtype, in particular, modulates glutamate-induced neuronal excitability in frontal cortex, hippocampus and neostriatum. Little is known about molecular mechanism(s) by which D1 receptor signaling modulates excitatory transmission. We recently identified a single transmembrane protein designated Calcyon which interacts with D1 DA receptors and localizes to vesicles in dendritic spines. Via interaction with Calcyon, D1 receptors stimulate release of Ca++ from internal stores (Ca++i) in an activity-dependent manner in heterologous expression system. A similar activity-dependent, D1 receptor agonist stimulated response is detectable by Fura-2 Ca++ imaging of primary cultures of cortical and hippocampal neurons. Our overarching hypothesis is that Calcyon enhances D1 receptor signaling through Gq/11 by serving as a link connecting D1 receptors to IP3 regulated Ca++ stores. We will determine how D1 DA receptor signaling through Gq/11 is primed, and how Calcyon enhances D1 receptor-mediated IP3 signaling. Using Ca++ imaging and peptides to block the D1 receptor:Calcyon interaction, we will determine if Calcyon is required for D1 agonist stimulated Ca++i release in dendritic spines. We propose to identify other GPCRs and accessory proteins that interact with Calcyon by yeast two-hybrid and phage display screens. We will determine how these proteins are involved in regulating release of Ca++ from vesicular stores. The results of this research should provide insight into clinical strategies to selectively boost or dampen D1 receptor mediated neuromodulation of excitatory transmission.