Structure and function of DISC1 in the cAMP pathway

DISC 1（Disrupted-In-Schizophrenia-1）已成为广泛的遗传风险因素。 一系列精神疾病，如精神分裂症、躁郁症和抑郁症。DISC 1的产物是 一种在几种神经元信号通路中起关键作用的长支架蛋白。尽管越来越多 尽管人们对它在精神障碍病因学中的作用有所了解，但对它的结构几乎一无所知。 DISC 1及其相互作用和调节机制。该研究项目将特别关注 DISC 1在cAMP通路中的作用。cAMP水平降低见于患有严重的 抑郁症，并与神经退行性疾病有关。控制细胞内水平的酶 cAMP的合成，例如磷酸二酯酶家族PDE 4，具有相当大的药学重要性， 抗抑郁和增强记忆药物的发展。该项目的总体目标是 提供描述DISC 1在cAMP通路中的作用的结构框架，并了解DISC 1如何在cAMP通路中发挥作用。 该途径的改变有助于精神疾病的病因学。目标1将提供完整的 DISC 1的结构模型，包括其寡聚化和磷酸化调节机制。 我们还将研究疾病相关突变的结构后果。我们提议 在此，结合氢氘交换质谱的综合结构方法 （HDX-MS）、溶液NMR光谱、X射线晶体学、小角X射线散射（SAXS）和 分子模拟重建DISC 1的完整结构和动力学特征。我们 初步数据表明，我们可以通过溶液NMR表征DISC 1 N-末端结构 尽管包含中心和/或C-末端结构域的构建体非常适合X-射线光谱， 射线晶体学研究。目标2将结合联合收割机的生化和结构的方法来表征 DISC 1和ATF 4之间的相互作用，ATF 4是一种主要的转录因子，cAMP途径控制着 CRE元件和磷酸二酯酶PDE 4D 9的表达。初步数据显示， DISC 1-ATF 4复合物可以在体外用两种蛋白质的截短构建体重建。这一目标将 为理解DISC 1作为转录辅阻遏物的作用提供了一个机制框架， DISC 1-ATF 4复合物在cAMP通路中的功能。目的3将阐明变构的机制 DISC 1对长和短PDE 4同种型的抑制，使用生物化学、结构和 计算技术总的来说，该项目的完成将提供一个全面的，统一的 这是理解DISC 1在cAMP通路中作用的框架。我们的工作还将提供新的 用于开发调节cAMP水平的分子的结构靶点。

DISC1 (Disrupted-In-Schizophrenia-1) has emerged as a significant genetic risk factor for a wide range of mental illness such as schizophrenia, bipolar disorders and depression. The product of DISC1 is a long scaffold protein that plays a critical role in several neuronal signaling pathways. Despite growing appreciation of its role in the etiology of mental disorders, almost nothing is known about the structure of DISC1 and its mechanisms of interaction and regulation. This research project will specifically focus on the role of DISC1 in the cAMP pathway. Reduced cAMP levels are found in patients suffering from major depression and are associated with neurodegenerative diseases. Enzymes controlling intracellular levels of cAMP, such as the phosphodiesterase family PDE4, have considerable pharmaceutical importance for the development of antidepressant and memory enhancing drugs. The overall goal of this project is to provide a structural framework describing the role of DISC1 in the cAMP pathway and to understand how alterations in this pathway contribute to the etiology of psychiatric disorders. Aim 1 will provide a complete structural model of DISC1, including its mechanism of oligomerization and modulation by phosphorylation. We will also investigate the structural consequences of disease-associated mutations. We are proposing here an integrative structural approach combining Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS), solution NMR spectroscopy, X-ray crystallography, Small-angle X-ray Scattering (SAXS) and molecular simulations to reconstitute the complete structural and dynamical features of DISC1. Our preliminary data demonstrate that we can characterize DISC1 N-terminal constructs by solution NMR spectroscopy while constructs encompassing the central and/or C-terminal domains are well suited for X- ray crystallography study. Aim 2 will combine biochemical and structural approaches to characterize the interaction between DISC1 and ATF4, a major transcription factor the cAMP pathway controlling the expression of the CRE-elements and of the phosphodiesterase PDE4D9. Our preliminary data show that DISC1-ATF4 complex can be reconstituted in vitro with truncated constructs of both proteins. This aim will provide a mechanistic framework for understanding the role of DISC1 as transcriptional co-repressor and the function of DISC1-ATF4 complex in the cAMP pathway. Aim 3 will unravel the mechanisms of allosteric inhibition of long and short PDE4 isoforms by DISC1, using a combination of biochemical, structural and computational techniques. Overall, completion of this project will provide a comprehensive, unifying framework for understanding the role of DISC1 in the cAMP pathway. Our work will also provide new structural targets for the development of molecules regulating cAMP levels.