Human Sos1: a guanine nucleotide exchange factor for Ras that binds to GRB2.
Science
; 260(5112): 1338-43, 1993 May 28.
Article
en En
| MEDLINE
| ID: mdl-8493579
ABSTRACT
A human complementary DNA was isolated that encodes a widely expressed protein, hSos1, that is closely related to Sos, the product of the Drosophila son of sevenless gene. The hSos1 protein contains a region of significant sequence similarity to CDC25, a guanine nucleotide exchange factor for Ras from yeast. A fragment of hSos1 encoding the CDC25-related domain complemented loss of CDC25 function in yeast. This hSos1 domain specifically stimulated guanine nucleotide exchange on mammalian Ras proteins in vitro. Mammalian cells overexpressing full-length hSos1 had increased guanine nucleotide exchange activity. Thus hSos1 is a guanine nucleotide exchange factor for Ras. The hSos1 interacted with growth factor receptor-bound protein 2 (GRB2) in vivo and in vitro. This interaction was mediated by the carboxyl-terminal domain of hSos1 and the Src homology 3 (SH3) domains of GRB2. These results suggest that the coupling of receptor tyrosine kinases to Ras signaling is mediated by a molecular complex consisting of GRB2 and hSos1.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Proteínas Fúngicas
/
Proteínas
/
Proteínas Proto-Oncogénicas p21(ras)
/
Proteínas de Ciclo Celular
/
Ras-GRF1
/
Proteínas Adaptadoras Transductoras de Señales
/
Proteínas de la Membrana
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Science
Año:
1993
Tipo del documento:
Article
País de afiliación:
Francia