Crystal structure of the BRS domain of BRAF

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.210 

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MEK drives BRAF activation through allosteric control of KSR proteins.

Lavoie, H.Sahmi, M.Maisonneuve, P.Marullo, S.A.Thevakumaran, N.Jin, T.Kurinov, I.Sicheri, F.Therrien, M.

(2018) Nature 554: 549-553

  • DOI: https://doi.org/10.1038/nature25478
  • Primary Citation of Related Structures:  
    5VR3, 5VYK

  • PubMed Abstract: 

    RAF family kinases have prominent roles in cancer. Their activation is dependent on dimerization of their kinase domains, which has emerged as a hindrance for drug development. In mammals, RAF family kinases include three catalytically competent enzymes (ARAF, BRAF and CRAF) and two pseudokinases (KSR1 and KSR2) that have been described as scaffolds owing to their apparent ability to bridge RAF isoforms and their substrate, mitogen-activated protein kinase kinase (MEK). Kinase suppressor of Ras (KSR) pseudokinases were also shown to dimerize with kinase-competent RAFs to stimulate catalysis allosterically. Although GTP-bound RAS can modulate the dimerization of RAF isoforms by engaging their RAS-binding domains, KSR1 and KSR2 lack an RAS-binding domain and therefore the regulatory principles underlying their dimerization with other RAF family members remain unknown. Here we show that the selective heterodimerization of BRAF with KSR1 is specified by direct contacts between the amino-terminal regulatory regions of each protein, comprising in part a novel domain called BRS in BRAF and the coiled-coil-sterile α motif (CC-SAM) domain in KSR1. We also discovered that MEK binding to the kinase domain of KSR1 asymmetrically drives BRAF-KSR1 heterodimerization, resulting in the concomitant stimulation of BRAF catalytic activity towards free MEK molecules. These findings demonstrate that KSR-MEK complexes allosterically activate BRAF through the action of N-terminal regulatory region and kinase domain contacts and challenge the accepted role of KSR as a scaffold for MEK recruitment to RAF.

  • Organizational Affiliation

    NE-CAT APS, Building 436E, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BRAF88Homo sapiensMutation(s): 0 
Gene Names: BRAF
UniProt & NIH Common Fund Data Resources
Find proteins for P15056 (Homo sapiens)
Explore P15056 
Go to UniProtKB:  P15056
GTEx:  ENSG00000157764 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP15056
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on SO4

Download Ideal Coordinates CCD File 
O4 S
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.210 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.563α = 90
b = 41.563β = 90
c = 98.855γ = 120
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-02-14
    Type: Initial release
  • Version 1.1: 2018-02-28
    Changes: Database references
  • Version 1.2: 2018-03-07
    Changes: Database references