5KKR

KSR2:MEK1 Complex Bound to the Small Molecule APS-2-79


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.509 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.250 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Small molecule stabilization of the KSR inactive state antagonizes oncogenic Ras signalling.

Dhawan, N.S.Scopton, A.P.Dar, A.C.

(2016) Nature 537: 112-116

  • DOI: 10.1038/nature19327

  • PubMed Abstract: 
  • Deregulation of the Ras-mitogen activated protein kinase (MAPK) pathway is an early event in many different cancers and a key driver of resistance to targeted therapies. Sustained signalling through this pathway is caused most often by mutations in K ...

    Deregulation of the Ras-mitogen activated protein kinase (MAPK) pathway is an early event in many different cancers and a key driver of resistance to targeted therapies. Sustained signalling through this pathway is caused most often by mutations in K-Ras, which biochemically favours the stabilization of active RAF signalling complexes. Kinase suppressor of Ras (KSR) is a MAPK scaffold that is subject to allosteric regulation through dimerization with RAF. Direct targeting of KSR could have important therapeutic implications for cancer; however, testing this hypothesis has been difficult owing to a lack of small-molecule antagonists of KSR function. Guided by KSR mutations that selectively suppress oncogenic, but not wild-type, Ras signalling, we developed a class of compounds that stabilize a previously unrecognized inactive state of KSR. These compounds, exemplified by APS-2-79, modulate KSR-dependent MAPK signalling by antagonizing RAF heterodimerization as well as the conformational changes required for phosphorylation and activation of KSR-bound MEK (mitogen-activated protein kinase kinase). Furthermore, APS-2-79 increased the potency of several MEK inhibitors specifically within Ras-mutant cell lines by antagonizing release of negative feedback signalling, demonstrating the potential of targeting KSR to improve the efficacy of current MAPK inhibitors. These results reveal conformational switching in KSR as a druggable regulator of oncogenic Ras, and further suggest co-targeting of enzymatic and scaffolding activities within Ras-MAPK signalling complexes as a therapeutic strategy for overcoming Ras-driven cancers.


    Organizational Affiliation

    Department of Oncological Sciences, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Kinase suppressor of Ras 2
B
319Homo sapiensMutation(s): 0 
Gene Names: KSR2
EC: 2.7.11.1
Find proteins for Q6VAB6 (Homo sapiens)
Go to Gene View: KSR2
Go to UniProtKB:  Q6VAB6
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Dual specificity mitogen-activated protein kinase kinase 1
C
395Oryctolagus cuniculusMutation(s): 0 
Gene Names: MAP2K1 (MEK1, PRKMK1)
EC: 2.7.12.2
Find proteins for P29678 (Oryctolagus cuniculus)
Go to Gene View: MAP2K1
Go to UniProtKB:  P29678
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
6U7
Query on 6U7

Download SDF File 
Download CCD File 
B
6,7-dimethoxy-~{N}-(2-methyl-4-phenoxy-phenyl)quinazolin-4-amine
C23 H21 N3 O3
PEKZLFZZBGBOPJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.509 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.250 
  • Space Group: P 61 2 2
Unit Cell:
Length (Å)Angle (°)
a = 139.680α = 90.00
b = 139.680β = 90.00
c = 221.730γ = 120.00
Software Package:
Software NamePurpose
XDSdata scaling
PHENIXrefinement
XDSdata reduction
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Cancer InstituteUnited StatesDP2 CA 186570-01

Revision History 

  • Version 1.0: 2016-08-31
    Type: Initial release
  • Version 1.1: 2016-09-14
    Type: Database references
  • Version 1.2: 2017-09-20
    Type: Author supporting evidence, Database references, Derived calculations