Structural Basis of Sigma-1 Receptor Ligand Interactions and Signalling

细胞有专门用于能量产生和蛋白质生产等独特功能的内部隔间。隔室由选择性可渗透的内膜隔开。这些膜含有蛋白质分子(“膜蛋白”)，其关键作用是允许物质和信息进出细胞内的隔室，以实现细胞功能的协调。Sigma-1受体(S1R)是一种参与调节产生能量的线粒体和内质网(ER)之间的通讯的蛋白质，内质网需要能量来产生细胞有效运作所需的蛋白质。S1R嵌入神经细胞的内质网细胞膜，位于与线粒体紧密相对的区域，并向线粒体发出能量需求的信号。由于S1R活动在维持神经元对能量需求的适当反应方面发挥着核心作用，因此它影响着一系列神经疾病。S1R受内源性分子和外源性药物的调节，其中一些目前被用于治疗疼痛、抑郁症和精神分裂症。我们的工作旨在了解S1R活性的分子基础，即它如何与这些药物相互作用，以及这些相互作用如何导致内质网和线粒体之间的通信。像S1R这样的跨膜传递信号的膜蛋白是细胞内通讯网络中的关键开关点。由于它们的功能重要性，了解这些蛋白质是如何工作的在医学上以及对生物技术和工业都是重要的。与宏观世界一样，了解蛋白质如何工作的最好方法之一是详细观察它们。然而，用传统方法研究膜蛋白是极具挑战性的，因为它们必须从进化到最稳定的自然细胞环境中提取。我们已经开发出大量生产S1R并从细菌和哺乳动物细胞中大量纯化S1R的方法--这是进行稳健的原子水平观察的必要条件。我们建议利用我们已经开发的方法来详细研究S1R的结构和相互作用。拟议研究的一项核心技术是核磁共振(核磁共振)。核磁共振是一种灵活的、信息丰富的光谱学，它提供原子水平的信息，在详细研究分子间相互作用方面特别强大。我们期望这项研究的结果将有助于(I)了解S1R在神经系统疾病中的机制，(Ii)有助于设计新的治疗药物，以及(Iii)有助于其他膜蛋白信号蛋白的结构特征。

Cells have internal compartments that are specialised for unique functions including energy generation and protein production. The compartments are segregated by internal membranes that are selectively permeable. The membranes contain protein molecules ("membrane proteins") with the critical job of permitting the transfer of matter and information into and out of the intracellular compartments to enable coordination of cellular function. The Sigma-1 Receptor (S1R) is one such protein that is involved in regulating the communication between energy generating mitochondria and the endoplasmic reticulum (ER), which requires energy to produce the proteins necessary for the cell to function effectively. S1R is embedded in the ER membrane of neural cells in a region closely apposed to mitochondria and signals energy demands to the mitochondria. Because of its central role in maintaining an appropriate response to energy demands in neurons, S1R activity impacts a range of neurological conditions. S1R is regulated by both endogenous molecules and exogenous drugs, some of which are currently used therapeutically for the treatment of pain, depression, and schizophrenia. Our work aims to understand the molecular basis of S1R activity in terms of how it interacts with those drugs and how those interactions lead to communication between the ER and mitochondria. Membrane proteins like S1R that transmit signals across membranes are critical switching points in intracellular communication networks. Because of their functional importance, understanding how these proteins work is important both medically and for biotechnology and industry. As with the macroscopic world, one of the best approaches for understanding how proteins work is by observing them in detail. However, membrane proteins are extremely challenging to study by conventional methods since they must be extracted from the native cellular environment in which they have evolved to be most stable. We have developed methods to produce S1R in large quantities and purify it in large quantities from both bacterial and mammalian cells -- a necessity for robust, atomic-level observation. We propose here to take advantage of the approaches we have developed to study the structure and interactions of S1R in detail. A central technique of the proposed research is Nuclear Magnetic Resonance (NMR). NMR is a flexible, information-rich spectroscopy that provides atomic level information, and is particularly powerful in studying inter-molecular interactions in detail. We anticipate that the results of this study will (i) help to understand the mechanism of S1R in neurological disease, (ii) facilitate design of novel therapeutic agents, and (iii) facilitate structural characterisation of other membrane protein signaling proteins.