Karki Bibek R, Macmillan Austin C, Vicente-Muñoz Sara, Greis Kenneth D, Romick Lindsey E, Cunningham J Tom
Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45219, USA.
bioRxiv. 2024 Oct 1:2024.10.01.616059. doi: 10.1101/2024.10.01.616059.
The phosphoribosyl pyrophosphate synthetase (PRPS) enzyme conducts a chokepoint reaction connecting central carbon metabolism and nucleotide production pathways, making it essential for life. Here, we show that the presence of multiple PRPS-encoding genes is a hallmark trait of eukaryotes, and we trace the evolutionary origins and define the individual functions of each of the five mammalian PRPS homologs - three isozymes (one testis-restricted) and two non-enzymatic associated proteins (APs) - which we demonstrate operate together as a large molecular weight complex capable of attaining a heterogeneous array of functional multimeric configurations. Employing a repertoire of isogenic fibroblast clones in all viable individual or combinatorial assembly states, we define preferential interactions between subunits, and we show that cells lacking PRPS2, PRPSAP1, and PRPSAP2 render PRPS1 into aberrant homo-oligomeric assemblies with diminished metabolic flux and impaired proliferative capacity. We demonstrate how numerous evolutionary innovations in the duplicated genes have created specialized roles for individual complex members and identify translational control mechanisms that enable fine-tuned regulation of PRPS assembly and activity, which provide clues into the positive and negative selective pressures that facilitate metabolic flexibility and tissue specialization in advanced lifeforms. Collectively, our study demonstrates how evolution has transformed a single PRPS gene into a multimeric complex endowed with functional and regulatory features that govern cellular biochemistry.
磷酸核糖焦磷酸合成酶（PRPS）催化的反应是连接中心碳代谢和核苷酸生成途径的关键反应，对生命至关重要。在此，我们表明多个编码PRPS的基因的存在是真核生物的标志性特征，我们追溯了其进化起源，并确定了五种哺乳动物PRPS同源物各自的功能——三种同工酶（一种睾丸特异性）和两种非酶相关蛋白（APs），我们证明它们作为一个能够形成多种功能多聚体构型的大分子量复合物共同发挥作用。利用处于所有可行的个体或组合组装状态的同基因成纤维细胞克隆库，我们确定了亚基之间的优先相互作用，并表明缺乏PRPS2、PRPSAP1和PRPSAP2的细胞会使PRPS1形成异常的同型寡聚体组装，代谢通量降低且增殖能力受损。我们展示了重复基因中的众多进化创新如何为单个复合物成员创造了专门的作用，并确定了能够对PRPS组装和活性进行微调调控的翻译控制机制，这些机制为促进高等生命形式中代谢灵活性和组织特化的正负选择压力提供了线索。总体而言，我们的研究展示了进化如何将单个PRPS基因转变为一个具有控制细胞生物化学功能和调节特征的多聚体复合物。
