The de novo purine biosynthetic pathway relies on six enzymes to catalyze the conversion of phosphoribosylpyrophosphate to inosine 5'-monophosphate. Under purine-depleted conditions, these enzymes form a multienzyme complex known as the purinosome. Previous studies have revealed the spatial organization and importance of the purinosome within mammalian cancer cells. In this study, time-lapse fluorescence microscopy was used to investigate the cell cycle dependency on purinosome formation in two cell models. Results in HeLa cells under purine-depleted conditions demonstrated a significantly higher number of cells with purinosomes in the G1 phase, which was further confirmed by cell synchronization. HGPRT-deficient fibroblast cells also exhibited the greatest purinosome formation in the G1 phase; however, elevated levels of purinosomes were also observed in the S and G2/M phases. The observed variation in cell cycle-dependent purinosome formation between the two cell models tested can be attributed to differences in purine biosynthetic mechanisms. Our results demonstrate that purinosome formation is closely related to the cell cycle.
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http://dx.doi.org/10.1073/pnas.1423009112 | DOI Listing |
Eur J Hum Genet
November 2024
Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
De novo synthesis of purines (DNPS) is a biochemical pathway that provides the purine bases for synthesis of essential biomolecules such as nucleic acids, energy transfer molecules, signaling molecules and various cofactors. Inborn errors of DNPS enzymes present with a wide spectrum of neurodevelopmental and neuromuscular abnormalities and accumulation of characteristic metabolic intermediates of the DNPS in body fluids and tissues. In this study, we present the second case of PAICS deficiency due to bi-allelic variants of PAICS gene encoding for a missense p.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China. Electronic address:
Purines are ancient metabolites with established and emerging metabolic and non-metabolic signaling attributes. The expression of purine metabolism-related genes is frequently activated in human malignancies, correlating with increased cancer aggressiveness and chemoresistance. Importantly, under certain stimulating conditions, the purine biosynthetic enzymes can assemble into a metabolon called "purinosomes" to enhance purine flux.
View Article and Find Full Text PDFJ Biol Chem
September 2024
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, USA. Electronic address:
In this study, we advance our understanding of the spatial relationship between the purinosome, a liquid condensate consisting of six enzymes involved in de novo purine biosynthesis, and mitochondria. Previous research has shown that purinosomes move along tubulin toward mitochondria, suggesting a direct uptake of glycine from mitochondria. Here, we propose that the purinosome is located proximally to the mitochondrial transporters SLC25A13 and SLC25A38, facilitating the uptake of glycine, aspartate, and glutamate, essential factors for purine synthesis.
View Article and Find Full Text PDFActa Histochem Cytochem
June 2024
Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Saitama, Japan.
Neural stem/progenitor cells (NSPCs) in specific brain regions require precisely regulated metabolite production during critical development periods. Purines-vital components of DNA, RNA, and energy carriers like ATP and GTP-are crucial metabolites in brain development. Purine levels are tightly controlled through two pathways: synthesis and salvage synthesis.
View Article and Find Full Text PDFInt J Mol Sci
June 2024
Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy.
Tumor cells reprogram their metabolism to meet the increased demand for nucleotides and other molecules necessary for growth and proliferation. In fact, cancer cells are characterized by an increased "de novo" synthesis of purine nucleotides. Therefore, it is not surprising that specific enzymes of purine metabolism are the targets of drugs as antineoplastic agents, and a better knowledge of the mechanisms underlying their regulation would be of great help in finding new therapeutic approaches.
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