5I2C

Arginine-bound CASTOR1 from Homo sapiens


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.801 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.172 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Mechanism of arginine sensing by CASTOR1 upstream of mTORC1.

Saxton, R.A.Chantranupong, L.Knockenhauer, K.E.Schwartz, T.U.Sabatini, D.M.

(2016) Nature 536: 229-233

  • DOI: 10.1038/nature19079

  • PubMed Abstract: 
  • The mechanistic Target of Rapamycin Complex 1 (mTORC1) is a major regulator of eukaryotic growth that coordinates anabolic and catabolic cellular processes with inputs such as growth factors and nutrients, including amino acids. In mammals arginine i ...

    The mechanistic Target of Rapamycin Complex 1 (mTORC1) is a major regulator of eukaryotic growth that coordinates anabolic and catabolic cellular processes with inputs such as growth factors and nutrients, including amino acids. In mammals arginine is particularly important, promoting diverse physiological effects such as immune cell activation, insulin secretion, and muscle growth, largely mediated through activation of mTORC1 (refs 4, 5, 6, 7). Arginine activates mTORC1 upstream of the Rag family of GTPases, through either the lysosomal amino acid transporter SLC38A9 or the GATOR2-interacting Cellular Arginine Sensor for mTORC1 (CASTOR1). However, the mechanism by which the mTORC1 pathway detects and transmits this arginine signal has been elusive. Here, we present the 1.8 Å crystal structure of arginine-bound CASTOR1. Homodimeric CASTOR1 binds arginine at the interface of two Aspartate kinase, Chorismate mutase, TyrA (ACT) domains, enabling allosteric control of the adjacent GATOR2-binding site to trigger dissociation from GATOR2 and downstream activation of mTORC1. Our data reveal that CASTOR1 shares substantial structural homology with the lysine-binding regulatory domain of prokaryotic aspartate kinases, suggesting that the mTORC1 pathway exploited an ancient, amino-acid-dependent allosteric mechanism to acquire arginine sensitivity. Together, these results establish a structural basis for arginine sensing by the mTORC1 pathway and provide insights into the evolution of a mammalian nutrient sensor.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GATS-like protein 3
A, B, C, D
329Homo sapiensGene Names: GATSL3
Find proteins for Q8WTX7 (Homo sapiens)
Go to UniProtKB:  Q8WTX7
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A, B, C, D
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
ARG
Query on ARG

Download SDF File 
Download CCD File 
A, B, C, D
ARGININE
C6 H15 N4 O2
ODKSFYDXXFIFQN-BYPYZUCNSA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

Unit Cell:
Length (Å)Angle (°)
a = 91.393α = 90.00
b = 82.601β = 116.23
c = 96.666γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling
PHENIXrefinement
PHENIXphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationCountryGrant Number
National Institutes of Health/National Cancer InstituteUnited StatesR01CA103866
National Institutes of Health/National Institute Of Allergy and Infectious DiseasesUnited StatesAI47389
Department of DefenseUnited StatesW81XWH-07- 0448

Revision History 

  • Version 1.0: 2016-08-10
    Type: Initial release
  • Version 1.1: 2016-08-17
    Type: Database references
  • Version 1.2: 2016-08-24
    Type: Database references
  • Version 1.3: 2017-09-27
    Type: Author supporting evidence, Database references, Derived calculations