Abstract
Glutamine and leucine are important mTORC1 modulators, although their roles are not precisely defined. In HepG2 and HeLa cells glutamine-free incubation lowers mTORC1 activity, although cell leucine is not decreased. mTORC1 activity, suppressed by amino acid-free incubation, is completely rescued only if essential amino acids (EAA) and glutamine are simultaneously restored, although cell leucine is higher in the absence than in the presence of glutamine. Thus, glutamine stimulates mTORC1 independent of cell leucine, suggesting the existence of two distinct stimulatory signals from either glutamine or EAA.
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Acknowledgments
M.C. is supported by a fellowship of the Doctorate School of Molecular Medicine, University of Milan. A.B. and M.G.B. are supported by research scholarships of the University of Parma Medical School.
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The authors declare that they have no conflict of interest.
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M. Chiu and S. Tardito contributed equally to this work.
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Chiu, M., Tardito, S., Barilli, A. et al. Glutamine stimulates mTORC1 independent of the cell content of essential amino acids. Amino Acids 43, 2561–2567 (2012). https://doi.org/10.1007/s00726-012-1312-0
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DOI: https://doi.org/10.1007/s00726-012-1312-0