4NYI image
Deposition Date 2013-12-10
Release Date 2014-03-12
Last Version Date 2024-02-28
Entry Detail
PDB ID:
4NYI
Title:
Approach for Targeting Ras with Small Molecules that Activate SOS-Mediated Nucleotide Exchange
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.96 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
I 4 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:GTPase HRas
Gene (Uniprot):HRAS
Mutations:Y64A
Chain IDs:A (auth: Q)
Chain Length:167
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Molecule:GTPase HRas
Gene (Uniprot):HRAS
Chain IDs:B (auth: R)
Chain Length:167
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Molecule:Son of sevenless homolog 1
Gene (Uniprot):SOS1
Chain IDs:C (auth: S)
Chain Length:481
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange.
Proc.Natl.Acad.Sci.USA 111 3401 3406 (2014)
PMID: 24550516 DOI: 10.1073/pnas.1315798111

Abstact

Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active upstream receptor tyrosine kinases results in the deregulation of cellular signals governing growth and survival in ∼30% of all human cancers. However, the discovery of potent inhibitors of Ras has been difficult to achieve. Here, we report the identification of small molecules that bind to a unique pocket on the Ras:Son of Sevenless (SOS):Ras complex, increase the rate of SOS-catalyzed nucleotide exchange in vitro, and modulate Ras signaling pathways in cells. X-ray crystallography of Ras:SOS:Ras in complex with these molecules reveals that the compounds bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of multiple X-ray cocrystal structures. Mutational analyses confirmed the functional relevance of this binding site and showed it to be essential for compound activity. These molecules increase Ras-GTP levels and disrupt MAPK and PI3K signaling in cells at low micromolar concentrations. These small molecules represent tools to study the acute activation of Ras and highlight a pocket on SOS that may be exploited to modulate Ras signaling.

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Primary Citation of related structures