Hybrid Structure of the RagA/C-Ragulator mTORC1 Activation Complex

Ming-Yuan Su; Kyle L Morris; Do Jin Kim; Yangxue Fu; Rosalie Lawrence; Goran Stjepanovic; Roberto Zoncu; James H Hurley

doi:10.1016/j.molcel.2017.10.016

Hybrid Structure of the RagA/C-Ragulator mTORC1 Activation Complex

Mol Cell. 2017 Dec 7;68(5):835-846.e3. doi: 10.1016/j.molcel.2017.10.016. Epub 2017 Nov 5.

Authors

Ming-Yuan Su¹, Kyle L Morris¹, Do Jin Kim¹, Yangxue Fu¹, Rosalie Lawrence¹, Goran Stjepanovic², Roberto Zoncu³, James H Hurley⁴

Affiliations

¹ Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA.
² Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
³ Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA. Electronic address: rzoncu@berkeley.edu.
⁴ Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Electronic address: jimhurley@berkeley.edu.

Abstract

The lysosomal membrane is the locus for sensing cellular nutrient levels, which are transduced to mTORC1 via the Rag GTPases and the Ragulator complex. The crystal structure of the five-subunit human Ragulator at 1.4 Å resolution was determined. Lamtor1 wraps around the other four subunits to stabilize the assembly. The Lamtor2:Lamtor3 dimer stacks upon Lamtor4:Lamtor5 to create a platform for Rag binding. Hydrogen-deuterium exchange was used to map the Rag binding site to the outer face of the Lamtor2:Lamtor3 dimer and to the N-terminal intrinsically disordered region of Lamtor1. EM was used to reconstruct the assembly of the full-length RagA^GTP:RagC^GDP dimer bound to Ragulator at 16 Å resolution, revealing that the G-domains of the Rags project away from the Ragulator core. The combined structural model shows how Ragulator functions as a platform for the presentation of active Rags for mTORC1 recruitment, and might suggest an unconventional mechanism for Rag GEF activity.

MeSH terms

Adaptor Proteins, Signal Transducing / chemistry*
Adaptor Proteins, Signal Transducing / genetics
Adaptor Proteins, Signal Transducing / metabolism
Binding Sites
Carrier Proteins / chemistry
Carrier Proteins / metabolism
Guanine Nucleotide Exchange Factors / chemistry
Guanine Nucleotide Exchange Factors / metabolism
Humans
Intracellular Signaling Peptides and Proteins
Mechanistic Target of Rapamycin Complex 1 / chemistry*
Mechanistic Target of Rapamycin Complex 1 / genetics
Mechanistic Target of Rapamycin Complex 1 / metabolism
Microscopy, Electron
Molecular Docking Simulation
Monomeric GTP-Binding Proteins / chemistry*
Monomeric GTP-Binding Proteins / genetics
Monomeric GTP-Binding Proteins / metabolism
Protein Binding
Protein Interaction Domains and Motifs
Protein Multimerization
Recombinant Proteins / chemistry
Recombinant Proteins / metabolism
Structure-Activity Relationship

Substances

Adaptor Proteins, Signal Transducing
Carrier Proteins
Guanine Nucleotide Exchange Factors
Intracellular Signaling Peptides and Proteins
LAMTOR1 protein, human
LAMTOR3 protein, human
LAMTOR4 protein, human
LAMTOR5 protein, human
RRAGC protein, human
Recombinant Proteins
ragulator complex protein LAMTOR2, human
Mechanistic Target of Rapamycin Complex 1
RRAGA protein, human
Monomeric GTP-Binding Proteins

Abstract

MeSH terms

Substances

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