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From Proteopedia
Structural evidence for feedback activation by RasGTP of the Ras-specific nucleotide exchange factor SOS
Structural highlights
DiseaseSOS1_HUMAN Defects in SOS1 are the cause of gingival fibromatosis 1 (GGF1) [MIM: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.[1] Defects in SOS1 are the cause of Noonan syndrome type 4 (NS4) [MIM: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.[2] [3] [4] [5] [6] [7] [8] [9] FunctionSOS1_HUMAN Promotes the exchange of Ras-bound GDP by GTP. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedGrowth factor receptors activate Ras by recruiting the nucleotide exchange factor son of sevenless (SOS) to the cell membrane, thereby triggering the production of GTP-loaded Ras. Crystallographic analyses of Ras bound to the catalytic module of SOS have led to the unexpected discovery of a highly conserved Ras binding site on SOS that is located distal to the active site and is specific for Ras.GTP. The crystal structures suggest that Ras.GTP stabilizes the active site of SOS allosterically, and we show that Ras.GTP forms ternary complexes with SOS(cat) in solution and increases significantly the rate of SOS(cat)-stimulated nucleotide release from Ras. These results demonstrate the existence of a positive feedback mechanism for the spatial and temporal regulation of Ras. Structural evidence for feedback activation by Ras.GTP of the Ras-specific nucleotide exchange factor SOS.,Margarit SM, Sondermann H, Hall BE, Nagar B, Hoelz A, Pirruccello M, Bar-Sagi D, Kuriyan J Cell. 2003 Mar 7;112(5):685-95. PMID:12628188[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Homo sapiens | Large Structures | Bar-Sagi D | Hall BE | Hoelz A | Kuriyan J | Margarit SM | Nagar B | Pirruccello M | Sondermann H
