Glutamine and asparagine activate mTORC1 independently of Rag GTPases

Delong Meng,Qianmei Yang,Huanyu Wang,Chase H Melick,Rishika Navlani,Anderson R Frank,Jenna L Jewell

doi:10.1074/jbc.ac119.011578

Delong Meng, Qianmei Yang + Show 5 more

Open Access

https://doi.org/10.1074/jbc.ac119.011578

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Abstract

Nutrient sensing by cells is crucial, and when this sensing mechanism is disturbed, human disease can occur. mTOR complex 1 (mTORC1) senses amino acids to control cell growth, metabolism, and autophagy. Leucine, arginine, and methionine signal to mTORC1 through the well-characterized Rag GTPase signaling pathway. In contrast, glutamine activates mTORC1 through a Rag GTPase-independent mechanism that requires ADP-ribosylation factor 1 (Arf1). Here, using several biochemical and genetic approaches, we show that eight amino acids filter through the Rag GTPase pathway. Like glutamine, asparagine signals to mTORC1 through Arf1 in the absence of the Rag GTPases. Both the Rag-dependent and Rag-independent pathways required the lysosome and lysosomal function for mTORC1 activation. Our results show that mTORC1 is differentially regulated by amino acids through two distinct pathways.

Highlights

Nutrient sensing by cells is crucial, and when this sensing mechanism is disturbed, human disease can occur. mTOR complex 1 senses amino acids to control cell growth, metabolism, and autophagy
Utilizing the 20 standard amino acids, we found that 10 of these (Ala, Arg, Asn, Gln, His, Leu, Met, Ser, Thr, and Val; hereafter referred to as AAmTORC1) activate mTOR complex 1 (mTORC1) in mouse embryonic fibroblast (MEF) and human embryonic kidney 293A (HEK293A) cells as judged by immunoblotting for the phosphorylation of its well-characterized substrate S6K1 at threonine 389 (Fig. 1A)
To determine the kinetics of AAmTORC1-induced activation of mTORC1, we starved MEF and HEK293A cells of all amino acids and performed a dose response, utilizing concentrations of each individual amino acid ranging from 100 nM to 1 mM and analyzed mTORC1 activity (Fig. 1B and Fig. S1 (A and B))

Summary

Introduction

Nutrient sensing by cells is crucial, and when this sensing mechanism is disturbed, human disease can occur. mTOR complex 1 (mTORC1) senses amino acids to control cell growth, metabolism, and autophagy. The Rag GTPases link amino acid signaling to mTORC1 activation at the lysosome [5, 15]. Utilizing the 20 standard amino acids, we found that 10 of these (Ala, Arg, Asn, Gln, His, Leu, Met, Ser, Thr, and Val; hereafter referred to as AAmTORC1) activate mTORC1 in mouse embryonic fibroblast (MEF) and human embryonic kidney 293A (HEK293A) cells as judged by immunoblotting for the phosphorylation of its well-characterized substrate S6K1 at threonine 389 (pS6K1) (Fig. 1A).

Results

Conclusion