mTORC1 induces purine synthesis through control of the mitochondrial tetrahydrofolate cycle

I Ben-Sahra, G Hoxhaj, SJH Ricoult, JM Asara… - Science, 2016 - science.org
Science, 2016science.org
In response to growth signals, mechanistic target of rapamycin complex 1 (mTORC1)
stimulates anabolic processes underlying cell growth. We found that mTORC1 increases
metabolic flux through the de novo purine synthesis pathway in various mouse and human
cells, thereby influencing the nucleotide pool available for nucleic acid synthesis. mTORC1
had transcriptional effects on multiple enzymes contributing to purine synthesis, with
expression of the mitochondrial tetrahydrofolate (mTHF) cycle enzyme …
In response to growth signals, mechanistic target of rapamycin complex 1 (mTORC1) stimulates anabolic processes underlying cell growth. We found that mTORC1 increases metabolic flux through the de novo purine synthesis pathway in various mouse and human cells, thereby influencing the nucleotide pool available for nucleic acid synthesis. mTORC1 had transcriptional effects on multiple enzymes contributing to purine synthesis, with expression of the mitochondrial tetrahydrofolate (mTHF) cycle enzyme methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) being closely associated with mTORC1 signaling in both normal and cancer cells. MTHFD2 expression and purine synthesis were stimulated by activating transcription factor 4 (ATF4), which was activated by mTORC1 independent of its canonical induction downstream of eukaryotic initiation factor 2α eIF2α phosphorylation. Thus, mTORC1 stimulates the mTHF cycle, which contributes one-carbon units to enhance production of purine nucleotides in response to growth signals.
AAAS