Calcium Signaling & Prefrontal Function in Schizophrenia

皮质多巴胺受体(DR)介导的信号传递失衡被认为是精神分裂症认知和精神方面的不足。利用酵母双杂交筛选，我们鉴定了几个显著参与细胞内钙(Ca)稳态的DR相互作用蛋白(Drop)(Calcyon、NCS-1、TRPC-1和CAPS)。在精神分裂症患者的背外侧前额叶皮质(DLPFC)，检测到与疾病相关的钙蛋白和NCS-1蛋白水平的升高。我们建议扩大我们对DR信号复合体(DRSCs)的研究，以多巴胺介导的异常钙信号是精神分裂症前额叶功能障碍的基础这一假说为指导。这种方法也可能识别潜在的精神分裂症易感基因(SSG)的可能性得到了最近的一项遗传关联研究的支持，该研究发现了位于10q26的SSG的证据，10q26是钙蛋白基因的染色体位置。我们将利用MALDI TOF-TOF质谱仪来鉴定从大鼠和猴的前额叶皮质和纹状体中免疫沉淀的含有D1DR和D2DR的DRSCs的区域和受体特异性成分。很可能，在DrSc组分中，一些蛋白质将直接与受体相互作用(DRPS)，而另一些蛋白质(DRPS或DR相关蛋白)可能与复合体的外周成分相互作用。我们将使用生化和免疫组织化学相结合的方法来确认DrSc蛋白之间的相互作用。水滴和水滴相互作用对DR功能的影响 将在转基因的哺乳动物细胞和天然神经系统中进行研究，重点是钙信号和动态平衡。水滴和滴滴的表达将在集合中进行分析 精神分裂症患者的大脑。我们将产生在前额叶皮质过度表达NCS-1或Calcyon的转基因小鼠，以了解这些与精神分裂症相关的候选滴注是否与疾病的病因有关。转基因小鼠将与其他受试者合作，接受一系列与精神分裂症表现出的前额叶缺陷相关的行为、解剖和生理测试。识别与DRS直接或间接相关的未知蛋白质将为DLPFC的多巴胺能信号机制提供新的见解，并为精神分裂症表现出的自然和生理缺陷的病因提供线索。

Imbalances in cortical dopamine receptor (DR) mediated signaling are believed to underly both the cognitive and psychotic aspects of schizophrenia. Using yeast two-hybrid screens, we identified several DR-interacting proteins (DRIPs) that are prominently involved in intracellular calcium (Ca++) homeostasis (calcyon, NCS-1, TRPC-1, and CAPS). Disease-related increases in calcyon and NCS-1 protein levels were detected in dorsolateral prefrontal cortex (DLPFC) of patients with schizophrenia. We propose to extend our discovery based research on DR signaling complexes (DRSCs) guided by the hypothesis that abnormal dopamine-mediated Ca++ signaling is the basis of prefrontal dysfunction in schizophrenia. The possibility that this approach may also identify potential schizophrenia susceptibility genes (SSGs) is supported by a recent genetic association study which found evidence for an SSG at 10q26, the chromosomal position of the calcyon gene. We will utilize MALDI TOF-TOF mass spectrometry to identify the regional and receptor-specific composition of D1 and D2 DR-containing DRSCs immunoprecipitated from rat and monkey prefrontal cortex and striatum. It is likely that among the DRSC components, some proteins will interact directly with the receptor (DRIPs), while others (DRAPs or DR associated proteins) may interact with peripheral components of the complex. We will confirm interaction of DRSC proteins using a combination of biochemical and immunohistochemical methods. The effects of DRIP and DRAP interactions on DR function will be studied in transfected mammalian cells and native neural systems with a focus on Ca++ signaling and homeostasis. Expression of DRIPs and DRAPs will be analyzed in collections of schizophrenic brains. We will generate transgenic mice overexpressing NCS-1 or calcyon within the prefrontal cortex to learn whether these candidate schizophrenia-associated DRIPs are involved in the etiology of the disease. Transgenic mice will be subjected to a battery of behavioral, anatomical, and Physiological tests relevant to prefrontal deficits manifested in schizophrenia in collaboration with other subrojects. Identifying previously unknown proteins directly or indirectly associated with DRs should provide new insights into mechanisms of dopaminergic signaling in DLPFC, and clues as to the etiology of natomical and physiological defects manifested in schizophrenia.