Mechanisms that govern assembly and function of higher order protein structures of purine metabolic enzymes

越来越多地发现，从加工体到粘着斑的超分子复合物， 细胞结构和功能的共同元素。嘌呤体是近年来发现的一种超分子物质 在时间和空间上调节嘌呤核苷酸代谢的蛋白质复合物。因为 嘌呤生物合成的基本意义，这种时空调节的新奇，以及 由于该途径作为药物靶点的重要性，因此迫切需要阐明决定其作用的机制。 嘌呤体的结构和功能。人们对这种结构是如何形成、管制或贩运的知之甚少， 也不清楚这些系统如何控制代谢流。我的长期目标 研究计划是了解瞬时，超分子蛋白质复合物如何调节细胞 新陈代谢.建议资助期的整体目标是：1）界定结构特点， 控制嘌呤体功能的外在因素，2）量化动力学和代谢优势， 蛋白质结构提供，和3）鉴定嘌呤体与其他细胞的功能关联， 结构.这些研究的核心假设是嘌呤体蛋白质经历结构性变化， 响应外部信号而改变，从而驱动装配过程。此外，我们假设， 嘌呤体响应于特定信号，沿着沿着被积极地运输到某些细胞， 结构，如细胞核或质膜。这种水平的控制使细胞能够特异性地上调 嘌呤和代谢中间产物在特定细胞位点的产生。建议的理由 研究表明，嘌呤体是嘌呤生物合成的重要调节机制， 生物合成途径对生命至关重要，并且是临床验证的药物靶标。因此，更好地了解 嘌呤体将提供更清晰的整体核苷酸代谢的图像，并有可能转化为更多的 选择性和有效的抗代谢药物。我们采取的方法是创新的，在申请人的 因为它通过整合一套跨学科的工具来探索系统， 在多个时间和长度尺度上。这将使我们能够直接将功能的分子决定因素与 在生理相关的时间和长度尺度上对应的生物输出。这些研究的结果 将阐明关键的，生理相关的和潜在的药物，相互作用的核心， 嘌呤体功能，一种可能推广到类似蛋白质结构的机制模型，以及一种 该结构的体外酶促和体内代谢作用的定量测定。拟议 研究是重要的，因为它将提供急需的结构，功能和机制的细节， 代谢调节的新范式--大分子蛋白质的动态可控组装 代谢酶的复合体。最终，嘌呤体的机制基础的阐明 功能将有助于指导改进抗癌，抗病毒和抗炎治疗的发展。

Supramolecular complexes ranging from processing bodies to focal adhesion sites are increasingly found to be common elements of cellular structure and function. The purinosome is a recently discovered supramolecular protein complex that regulates, both temporally and spatially, the metabolism of purine nucleotides. Because of the fundamental significance of purine biosynthesis, the novelty of this type of spatiotemporal regulation, and the importance of this pathway as a drug target, there is a critical need to elucidate the mechanisms that dictate purinosome structure and function. Little is known about how such structures are formed, regulated or trafficked, nor is there a clear understanding of how these systems control metabolic flux. The long term goal of my research program is to understand how transient, supramolecular protein complexes regulate cellular metabolism. The overall objectives for the proposed funding period are to 1) define the structural features and extrinsic factors that control purinosome function, 2) quantify the kinetic and metabolic advantages that this protein structure provides, and 3) identify functional associations that purinosomes make with other cellular structures. The central hypothesis underlying these studies is that purinosome proteins undergo structural changes, in response to external signals, which drive the assembly process. In addition, we hypothesize that purinosomes are actively trafficked along microtubules, in response to specific signals, towards certain cellular structures such as the nucleus or plasma membrane. This level of control enables cells to specifically upregulate the production of purines and metabolic intermediates at a specific cellular locus. The rationale for the proposed research is that the purinosome is an important regulatory mechanism for the biosynthesis of purines, the purine biosynthetic pathway is critical to life, and is a clinically validated drug target. Thus, a better understanding of the purinosome will provide a clearer picture of overall nucleotide metabolism with potential to translate into more selective and potent antimetabolite drugs. The approach that we are taking is innovative, in the applicant’s opinion, because it departs from the status quo by integrating a suite of interdisciplinary tools to probe the system at multiple time and length scales. This will enable us to directly link molecular determinants of function with the corresponding biological outputs at physiologically relevant time and length scales. The outcome of these studies will be the elucidation of key, physiologically relevant and potentially druggable, interactions central to purinosome function, a mechanistic model that is likely generalizable to similar protein structures, and a quantitative determination of in vitro enzymatic and in vivo metabolic effects of this structure. The proposed research is significant, because it will provide sorely needed details of the structure, function and mechanism of a new paradigm in metabolic regulation – the dynamic and controllable assembly of a macromolecular protein complex of metabolic enzymes. Ultimately, the elucidation of the mechanistic underpinnings of purinosome function will help guide the development of improved anti-cancer, anti-viral and anti-inflammatory treatments.