Arg-78 of Nprl2 catalyzes GATOR1-stimulated GTP hydrolysis by the Rag GTPases
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1-s2.0-S0021925820393923-main.pdf
Description
Published version
Size
1.86 MB
Format
Adobe PDF
Checksum (MD5)
4007b7437f95b5c4d1947a120d324ef7
Author(s)
Shen, Kuang
Valenstein, Max L
Gu, Xin
Sabatini, David M
Date Issued
2019
Journal
Journal of Biological Chemistry
Publisher
Elsevier BV
Version
Final published version
Abstract
mTOR complex 1 (mTORC1) is a major regulator of cell growth and proliferation that coordinates nutrient inputs with anabolic and catabolic processes. Amino acid signals are transmitted to mTORC1 through the Rag GTPases, which directly recruit mTORC1 onto the lysosomal surface, its site of activation. The Rag GTPase heterodimer has a unique architecture that consists of two GTPase subunits, RagA or RagB bound to RagC or RagD. Their nucleotide-loading states are strictly controlled by several lysosomal or cytosolic protein complexes that directly detect and transmit the amino acid signals. GATOR1 (GTPase-activating protein (GAP) activity toward Rags-1), a negative regulator of the cytosolic branch of the nutrient-sensing pathway, comprises three subunits, Depdc5 (DEP domain–containing protein 5), Nprl2 (NPR2-like GATOR1 complex subunit), and Nprl3 (NPR3-like GATOR1 complex subunit), and is a GAP for RagA. GATOR1 binds the Rag GTPases via two modes: an inhibitory mode that holds the Rag GTPase heterodimer and has previously been captured by structural determination, and a GAP mode that stimulates GTP hydrolysis by RagA but remains structurally elusive. Here, using site-directed mutagenesis, GTP hydrolysis assays, coimmunoprecipitation experiments, and structural analysis, we probed the GAP mode and found that a critical residue on Nprl2, Arg-78, is the arginine finger that carries out GATOR1’s GAP function. Substitutions of this arginine residue rendered mTORC1 signaling insensitive to amino acid starvation and are found frequently in cancers such as glioblastoma. Our results reveal the biochemical bases of mTORC1 inactivation through the GATOR1 complex.
MIT Department
Whitehead Institute for Biomedical Research
Massachusetts Institute of Technology. Department of Biology
Howard Hughes Medical Institute
Koch Institute for Integrative Cancer Research at MIT
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1074/JBC.AC119.007382
