Defining the biological roles of PRPS isozymes in normal and diseased settings

项目总结 磷酸核糖焦磷酸合成酶(PRPS)是核苷酸的重要调节因子 所有生命的生产，从细菌到人类。这些酶产生一种关键的前体，是 产生所有的核苷酸物种，并作为一个‘分子油门’，能够增加或减少 这些基因构建块的制造速度。虽然靶向这种代谢酶代表着一种 强大的茎核苷酸生产方法，提供的冗余是由两个截然不同的 同一种酶的形式(PRPS1和PRPS2)也提供了选择性地 治疗某些疾病，如癌症。然而，为了实现这一目标，我们首先必须有一个更好的 对它们重叠和不同的生物学作用以及产生这些相似性的机制基础的理解 和差异。这项提议试图通过使用新的 小鼠模型和优雅的结构/功能研究，从而准确地确定了可能的作用机制和 为未来的药物开发建立合理的基础。我们将集中努力澄清不同的 控制两种不同异构体表达的调控模式以及如何不同 个体同工酶的生化特性调节核苷酸的产生和代谢的动态平衡。 为了使我们的工作与临床相关并适用于人类疾病，我们还将开发和表征 寻求概括PRPS1过度活动和功能丧失的新的疾病特异性小鼠模型 在人类先天性代谢缺陷中观察到的突变和表型。我们的研究计划最终 致力于了解核苷酸在细胞代谢中的复杂作用以及它们的异常 生产、分解、运输或利用都会导致疾病。例如，特别是在这个范围内 提案中，我们将通过确定如何破坏核苷酸来阐明核苷酸代谢的经济学 供应会影响细胞的整体生物化学。总而言之，拟议的研究和我们的研究计划 一般说来，这将对我们理解这些关键分子在正常和 疾病的设定，并为下一代的发展提供了新的基础，更安全、更 改善与核苷酸干扰相关疾病的靶向治疗和合理途径 动态平衡。

PROJECT SUMMARY The phosphoribosyl pyrophosphate synthetase (PRPS) enzymes are critical regulators of nucleotide production in all life, from bacteria to man. These enzymes generate a critical precursor necessary for producing all nucleotide species and function as a `molecular throttle' capable of increasing or decreasing the rate at which these genetic building blocks are made. While targeting this metabolic enzyme represents a powerful approach to stymie nucleotide production, the redundancy afforded by the existence of two distinct forms of the same enzyme (PRPS1 and PRPS2) also presents a phenomenal opportunity for selectively treating certain diseases such as cancer. In order to realize this goal, however, we must first have a better understanding of their overlapping and distinct biological roles and the mechanistic basis for these similarities and differences. This proposal seeks to unravel the molecular basis for this selectivity through use of novel mouse models and elegant structure/function studies, thus pinpointing a putative mechanism of action and developing a rational basis for future drug development. We will focus our efforts on elucidating the distinct modes of regulation that control expression of the two separate isoforms as well as how the different biochemical properties of the individual isozymes regulate nucleotide production and metabolic homeostasis. To make our work clinically-relevant and applicable to human disease, we will also develop and characterize novel disease-specific mouse models of PRPS1 superactivity and loss of function that seek to recapitulate the mutations and phenotypes observed in human inborn errors of metabolism. Our research program ultimately strives to understand the complicated role of nucleotides in cellular metabolism and how their aberrant production, breakdown, transport, or utilization contributes to disease. For example, specifically within this proposal, we will elucidate the economics of nucleotide metabolism by determining how disrupting nucleotide supply affects the overall biochemistry of the cell. Collectively, the proposed studies and our research program in general will be transformative in our understanding of the roles of these key molecules in the normal and disease setting, and provide a new foundation for the development of the next generation of safer, more targeted therapies and rational approaches for ameliorating diseases associated with perturbed nucleotide homeostasis.