American Association for Cancer Research
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Figure S2 from Conversion of PRPS Hexamer to Monomer by AMPK-Mediated Phosphorylation Inhibits Nucleotide Synthesis in Response to Energy Stress

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posted on 2023-04-03, 22:03 authored by Xu Qian, Xinjian Li, Lin Tan, Jong-Ho Lee, Yan Xia, Qingsong Cai, Yanhua Zheng, Hongxia Wang, Philip L. Lorenzi, Zhimin Lu

AMPK phosphorylates PRPS1 S180 and PRPS2 S183 in response to glucose deprivation.

Funding

National Institute of Neurological Disorders and Stroke

National Cancer Institute

MD Anderson Cancer Center

National Natural Science Foundation of China

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ARTICLE ABSTRACT

Tumors override energy stress to grow. However, how nucleotide synthesis is regulated under energy stress is unclear. We demonstrate here that glucose deprivation or hypoxia results in the AMPK-mediated phosphorylation of phosphoribosyl pyrophosphate synthetase 1 (PRPS1) S180 and PRPS2 S183, leading to conversion of PRPS hexamers to monomers and thereby inhibiting PRPS1/2 activity, nucleotide synthesis, and nicotinamide adenine dinucleotide (NAD) production. Knock-in of nonphosphorylatable PRPS1/2 mutants, which have uninhibited activity, in brain tumor cells under energy stress exhausts cellular ATP and NADPH and increases reactive oxygen species levels, thereby promoting cell apoptosis. The expression of those mutants inhibits brain tumor formation and enhances the inhibitory effect of the glycolysis inhibitor 2-deoxy-d-glucose on tumor growth. Our findings highlight the significance of recalibrating tumor cell metabolism by fine-tuning nucleotide and NAD synthesis in tumor growth.Significance: Our findings elucidate an instrumental function of AMPK in direct regulation of nucleic acid and NAD synthesis in tumor cells in response to energy stress. AMPK phosphorylates PRPS1/2, converts PRPS1/2 hexamers to monomers, and inhibits PRPS1/2 activity and subsequent nucleotide and NAD synthesis to maintain tumor cell growth and survival. Cancer Discov; 8(1); 94–107. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 1

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