View source for 4us0


==The crystal structure of H-Ras and SOS in complex with ligands==
<StructureSection load='4us0' size='340' side='right'caption='[[4us0]], [[Resolution|resolution]] 2.17&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4us0]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4US0 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4US0 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NEQ:N-ETHYLMALEIMIDE'>NEQ</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4uru|4uru]], [[4urv|4urv]], [[4urw|4urw]], [[4urx|4urx]], [[4ury|4ury]], [[4urz|4urz]], [[4us1|4us1]], [[4us2|4us2]]</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4us0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4us0 OCA], [http://pdbe.org/4us0 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4us0 RCSB], [http://www.ebi.ac.uk/pdbsum/4us0 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4us0 ProSAT]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/RASH_HUMAN RASH_HUMAN]] Defects in HRAS are the cause of faciocutaneoskeletal syndrome (FCSS) [MIM:[http://omim.org/entry/218040 218040]]. A rare condition characterized by prenatally increased growth, postnatal growth deficiency, mental retardation, distinctive facial appearance, cardiovascular abnormalities (typically pulmonic stenosis, hypertrophic cardiomyopathy and/or atrial tachycardia), tumor predisposition, skin and musculoskeletal abnormalities.<ref>PMID:16170316</ref> <ref>PMID:16329078</ref> <ref>PMID:16443854</ref> <ref>PMID:17054105</ref> <ref>PMID:18247425</ref> <ref>PMID:18039947</ref> <ref>PMID:19995790</ref>   Defects in HRAS are the cause of congenital myopathy with excess of muscle spindles (CMEMS) [MIM:[http://omim.org/entry/218040 218040]]. CMEMS is a variant of Costello syndrome.<ref>PMID:17412879</ref>   Defects in HRAS may be a cause of susceptibility to Hurthle cell thyroid carcinoma (HCTC) [MIM:[http://omim.org/entry/607464 607464]]. Hurthle cell thyroid carcinoma accounts for approximately 3% of all thyroid cancers. Although they are classified as variants of follicular neoplasms, they are more often multifocal and somewhat more aggressive and are less likely to take up iodine than are other follicular neoplasms.  Note=Mutations which change positions 12, 13 or 61 activate the potential of HRAS to transform cultured cells and are implicated in a variety of human tumors.  Defects in HRAS are a cause of susceptibility to bladder cancer (BLC) [MIM:[http://omim.org/entry/109800 109800]]. A malignancy originating in tissues of the urinary bladder. It often presents with multiple tumors appearing at different times and at different sites in the bladder. Most bladder cancers are transitional cell carcinomas. They begin in cells that normally make up the inner lining of the bladder. Other types of bladder cancer include squamous cell carcinoma (cancer that begins in thin, flat cells) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). Bladder cancer is a complex disorder with both genetic and environmental influences.  Note=Defects in HRAS are the cause of oral squamous cell carcinoma (OSCC).<ref>PMID:1459726</ref>   Defects in HRAS are the cause of Schimmelpenning-Feuerstein-Mims syndrome (SFM) [MIM:[http://omim.org/entry/163200 163200]]. A disease characterized by sebaceous nevi, often on the face, associated with variable ipsilateral abnormalities of the central nervous system, ocular anomalies, and skeletal defects. Many oral manifestations have been reported, not only including hypoplastic and malformed teeth, and mucosal papillomatosis, but also ankyloglossia, hemihyperplastic tongue, intraoral nevus, giant cell granuloma, ameloblastoma, bone cysts, follicular cysts, oligodontia, and odontodysplasia. Sebaceous nevi follow the lines of Blaschko and these can continue as linear intraoral lesions, as in mucosal papillomatosis.<ref>PMID:22683711</ref>  [[http://www.uniprot.org/uniprot/SOS1_HUMAN SOS1_HUMAN]] Defects in SOS1 are the cause of gingival fibromatosis 1 (GGF1) [MIM:[http://omim.org/entry/135300 135300]]; also known as GINGF1. Gingival fibromatosis is a rare overgrowth condition characterized by a benign, slowly progressive, nonhemorrhagic, fibrous enlargement of maxillary and mandibular keratinized gingiva. GGF1 is usually transmitted as an autosomal dominant trait, although sporadic cases are common.<ref>PMID:11868160</ref>   Defects in SOS1 are the cause of Noonan syndrome type 4 (NS4) [MIM:[http://omim.org/entry/610733 610733]]. NS4 is an autosomal dominant disorder characterized by dysmorphic facial features, short stature, hypertelorism, cardiac anomalies, deafness, motor delay, and a bleeding diathesis. It is a genetically heterogeneous and relatively common syndrome, with an estimated incidence of 1 in 1000-2500 live births. Rarely, NS4 is associated with juvenile myelomonocytic leukemia (JMML). SOS1 mutations engender a high prevalence of pulmonary valve disease; atrial septal defects are less common.<ref>PMID:17143285</ref> <ref>PMID:17143282</ref> <ref>PMID:19020799</ref> <ref>PMID:19438935</ref> <ref>PMID:20683980</ref> <ref>PMID:20673819</ref> <ref>PMID:19953625</ref> <ref>PMID:21387466</ref>  
== Function ==
[[http://www.uniprot.org/uniprot/RASH_HUMAN RASH_HUMAN]] Ras proteins bind GDP/GTP and possess intrinsic GTPase activity.<ref>PMID:14500341</ref> <ref>PMID:9020151</ref> <ref>PMID:12740440</ref>  [[http://www.uniprot.org/uniprot/SOS1_HUMAN SOS1_HUMAN]] Promotes the exchange of Ras-bound GDP by GTP. 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Constitutively active mutant KRas displays a reduced rate of GTP hydrolysis via both intrinsic and GTPase-activating protein-catalyzed mechanisms, resulting in the perpetual activation of Ras pathways. We describe a fragment screening campaign using X-ray crystallography that led to the discovery of three fragment binding sites on the Ras:SOS complex. The identification of tool compounds binding at each of these sites allowed exploration of two new approaches to Ras pathway inhibition by stabilizing or covalently modifying the Ras:SOS complex to prevent the reloading of Ras with GTP. Initially, we identified ligands that bound reversibly to the Ras:SOS complex in two distinct sites, but these compounds were not sufficiently potent inhibitors to validate our stabilization hypothesis. We conclude by demonstrating that covalent modification of Cys118 on Ras leads to a novel mechanism of inhibition of the SOS-mediated interaction between Ras and Raf and is effective at inhibiting the exchange of labeled GDP in both mutant (G12C and G12V) and wild type Ras.

Small Molecule Binding Sites on the Ras:SOS Complex Can Be Exploited for Inhibition of Ras Activation.,Winter JJ, Anderson M, Blades K, Brassington C, Breeze AL, Chresta C, Embrey K, Fairley G, Faulder P, Finlay MR, Kettle JG, Nowak T, Overman R, Patel SJ, Perkins P, Spadola L, Tart J, Tucker JA, Wrigley G J Med Chem. 2015 Feb 26. PMID:25695162<ref>PMID:25695162</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4us0" style="background-color:#fffaf0;"></div>

==See Also==
*[[GTPase HRas|GTPase HRas]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Anderson, M]]
[[Category: Blades, K]]
[[Category: Brassington, C]]
[[Category: Breeze, A L]]
[[Category: Chresta, C]]
[[Category: Embrey, K]]
[[Category: Fairley, G]]
[[Category: Faulder, P]]
[[Category: Finlay, M R.V]]
[[Category: Kettle, J G]]
[[Category: Nowak, T]]
[[Category: Overman, R]]
[[Category: Patel, S J]]
[[Category: Perkins, P]]
[[Category: Spadola, L]]
[[Category: Tart, J]]
[[Category: Tucker, J]]
[[Category: Winter, J J.G]]
[[Category: Wrigley, G]]
[[Category: Signaling protein]]