The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

Sos1  -  son of sevenless homolog 1 (Drosophila)

Mus musculus

Synonyms: 4430401P03Rik, 9630010N06, AI449023, SOS-1, Son of sevenless homolog 1, ...
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

High impact information on Sos1

  • We propose a model in which Eps8 mediates the transfer of signals between Ras and Rac, by forming a complex with E3b1 and Sos-1 [1].
  • We have investigated the role of the mammalian Son of sevenless 1 (Sos1) protein in growth factor signaling in vivo by generating mice and cell lines that lacked the Sos1 protein [2].
  • To address the specificity or redundancy of these exchange factors, we have generated Sos1/Sos2 double- or RasGRP3-deficient B cell lines and determined their ability to mediate Ras activation upon B cell receptor (BCR) stimulation [3].
  • Impaired plasma membrane targeting of Grb2-murine son of sevenless (mSOS) complex and differential activation of the Fyn-T cell receptor (TCR)-zeta-Cbl pathway mediate T cell hyporesponsiveness in autoimmune nonobese diabetic mice [4].
  • These findings implicate mSOS as an important mediator of downregulation of Ras signaling in hyporesponsive NOD T cells [4].

Biological context of Sos1

  • Finally, we show that Vav1 is required for TCR-induced LAT phosphorylation, a key event for the activation of both phospholipase Cgamma1 and Sos1/2 [5].
  • Targeted disruption of both alleles of mouse sos1, which encodes a Ras-specific exchange factor, conferred mid-gestational embryonic lethality that was secondary to impaired placental development and was associated with very low placental ERK activity [6].
  • Although an msos1 plasmid did not induce phenotypic changes in NIH 3T3 cells, addition of a 15-codon myristoylation signal to its 5' end enabled the resulting plasmid, myr-sos1, to induce approximately one-half as many foci of transformed cells as a v-H-ras control [7].
  • This binding site is contained within the peptide N20, which corresponds to amino acids 1143-1162 of Sos1 [8].
  • Whilst the association of Sos1 and Grb2 following EGF stimulation is not cell type specific, we find that it is dependent on cell density and that the response to EGF differs to that induced by NGF [9].

Anatomical context of Sos1

  • The trophoblastic layers of sos1(-/-) embryos were poorly developed, correlating with high sos1 expression in wild-type trophoblasts [6].
  • We investigated the functional and physical interaction between mSOS and Fyn in T-cell hybridoma cells [10].
  • The activation of all three delta Raf:ER proteins in 3T3 cells led to the hyperphosphorylation of the resident p74raf-1 and mSOS1 proteins, suggesting the possibility of "cross-talk" between the different Raf kinases and feedback regulation of intracellular signaling pathways [11].

Associations of Sos1 with chemical compounds

  • Fms also formed complexes with Grb2 and Sos1, and neither contained phosphotyrosine [12].
  • Vav and Sos1 are Dbl family guanine nucleotide exchange factors, which activate Rho family GTPases in response to phosphatidylinositol 3-kinase products [13].
  • Grb2 is an adaptor protein that links receptor and cytoplasmic tyrosine kinases to the Ras signalling pathway by binding the Ras-specific guanine nucleotide exchange factor, Sos1, through its SH3 domains [8].
  • Inhibition studies with BIAcore using proline rich peptides derived from the C-terminus of Sos1 show that there is a single major binding site for Grb2 in Sos1 [8].

Enzymatic interactions of Sos1


Regulatory relationships of Sos1


Other interactions of Sos1

  • Second, Vav1 is required for recruitment of Sos1 and -2 to the transmembrane adapter protein LAT [5].
  • Immunoblot analysis of these precipitates revealed that insulin causes a marked hyperphosphorylation of Sos1 and a 50% decrease in Grb2 associated with Sos proteins under these conditions [15].
  • Lysates of such desensitized cells were quantitatively immunoprecipitated with an antiserum recognizing both Sos1 and Sos2 proteins or a specific anti-Sos2 antiserum [15].
  • In mSOS immunoprecipitates, Shc could be detected as well [16].
  • Here we report that mutations within the switch 2 domain of Ras (residues 62-69) inhibit activation of Ras by the mammalian GEFs, Sos1, and GRF/CDC25Mm [17].

Analytical, diagnostic and therapeutic context of Sos1


  1. EPS8 and E3B1 transduce signals from Ras to Rac. Scita, G., Nordstrom, J., Carbone, R., Tenca, P., Giardina, G., Gutkind, S., Bjarnegård, M., Betsholtz, C., Di Fiore, P.P. Nature (1999) [Pubmed]
  2. Mutation in Sos1 dominantly enhances a weak allele of the EGFR, demonstrating a requirement for Sos1 in EGFR signaling and development. Wang, D.Z., Hammond, V.E., Abud, H.E., Bertoncello, I., McAvoy, J.W., Bowtell, D.D. Genes Dev. (1997) [Pubmed]
  3. Requirement for Ras guanine nucleotide releasing protein 3 in coupling phospholipase C-gamma2 to Ras in B cell receptor signaling. Oh-hora, M., Johmura, S., Hashimoto, A., Hikida, M., Kurosaki, T. J. Exp. Med. (2003) [Pubmed]
  4. Impaired plasma membrane targeting of Grb2-murine son of sevenless (mSOS) complex and differential activation of the Fyn-T cell receptor (TCR)-zeta-Cbl pathway mediate T cell hyporesponsiveness in autoimmune nonobese diabetic mice. Salojin, K., Zhang, J., Cameron, M., Gill, B., Arreaza, G., Ochi, A., Delovitch, T.L. J. Exp. Med. (1997) [Pubmed]
  5. Vav1 transduces T cell receptor signals to the activation of the Ras/ERK pathway via LAT, Sos, and RasGRP1. Reynolds, L.F., de Bettignies, C., Norton, T., Beeser, A., Chernoff, J., Tybulewicz, V.L. J. Biol. Chem. (2004) [Pubmed]
  6. The Sos1 and Sos2 Ras-specific exchange factors: differences in placental expression and signaling properties. Qian, X., Esteban, L., Vass, W.C., Upadhyaya, C., Papageorge, A.G., Yienger, K., Ward, J.M., Lowy, D.R., Santos, E. EMBO J. (2000) [Pubmed]
  7. The Ras-specific exchange factors mouse Sos1 (mSos1) and mSos2 are regulated differently: mSos2 contains ubiquitination signals absent in mSos1. Nielsen, K.H., Papageorge, A.G., Vass, W.C., Willumsen, B.M., Lowy, D.R. Mol. Cell. Biol. (1997) [Pubmed]
  8. Quantitative analysis of Grb2-Sos1 interaction: the N-terminal SH3 domain of Grb2 mediates affinity. Sastry, L., Lin, W., Wong, W.T., Di Fiore, P.P., Scoppa, C.A., King, C.R. Oncogene (1995) [Pubmed]
  9. Sos1 rapidly associates with Grb2 and is hypophosphorylated when complexed with the EGF receptor after EGF stimulation. Hu, Y., Bowtell, D.D. Oncogene (1996) [Pubmed]
  10. Catalytic activity of the mouse guanine nucleotide exchanger mSOS is activated by Fyn tyrosine protein kinase and the T-cell antigen receptor in T cells. Li, B., Subleski, M., Fusaki, N., Yamamoto, T., Copeland, T., Princler, G.L., Kung, H., Kamata, T. Proc. Natl. Acad. Sci. U.S.A. (1996) [Pubmed]
  11. Conditionally oncogenic forms of the A-Raf and B-Raf protein kinases display different biological and biochemical properties in NIH 3T3 cells. Pritchard, C.A., Samuels, M.L., Bosch, E., McMahon, M. Mol. Cell. Biol. (1995) [Pubmed]
  12. Shc, Grb2, Sos1, and a 150-kilodalton tyrosine-phosphorylated protein form complexes with Fms in hematopoietic cells. Lioubin, M.N., Myles, G.M., Carlberg, K., Bowtell, D., Rohrschneider, L.R. Mol. Cell. Biol. (1994) [Pubmed]
  13. Control of intramolecular interactions between the pleckstrin homology and Dbl homology domains of Vav and Sos1 regulates Rac binding. Das, B., Shu, X., Day, G.J., Han, J., Krishna, U.M., Falck, J.R., Broek, D. J. Biol. Chem. (2000) [Pubmed]
  14. Shc associates with an unphosphorylated form of the p21ras guanine nucleotide exchange factor mSOS. de Vries-Smits, A.M., Pronk, G.J., Medema, J.P., Burgering, B.M., Bos, J.L. Oncogene (1995) [Pubmed]
  15. Disassembly of Son-of-sevenless proteins from Grb2 during p21ras desensitization by insulin. Cherniack, A.D., Klarlund, J.K., Conway, B.R., Czech, M.P. J. Biol. Chem. (1995) [Pubmed]
  16. Involvement of Shc in insulin- and epidermal growth factor-induced activation of p21ras. Pronk, G.J., de Vries-Smits, A.M., Buday, L., Downward, J., Maassen, J.A., Medema, R.H., Bos, J.L. Mol. Cell. Biol. (1994) [Pubmed]
  17. Involvement of the switch 2 domain of Ras in its interaction with guanine nucleotide exchange factors. Quilliam, L.A., Hisaka, M.M., Zhong, S., Lowry, A., Mosteller, R.D., Han, J., Drugan, J.K., Broek, D., Campbell, S.L., Der, C.J. J. Biol. Chem. (1996) [Pubmed]
  18. Light Chain 3 associates with a Sos1 guanine nucleotide exchange factor: its significance in the Sos1-mediated Rac1 signaling leading to membrane ruffling. Furuta, S., Miura, K., Copeland, T., Shang, W.H., Oshima, A., Kamata, T. Oncogene (2002) [Pubmed]
  19. Chromosomal localization of two genes encoding human ras exchange factors: SOS1 maps to the 2p22-->p16 region and SOS2 to the 14q21-->q22 region of the human genome. Chardin, P., Mattei, M.G. Cytogenet. Cell Genet. (1994) [Pubmed]
  20. B cell antigen receptor cross-linking induces phosphorylation of the p21ras oncoprotein activators SHC and mSOS1 as well as assembly of complexes containing SHC, GRB-2, mSOS1, and a 145-kDa tyrosine-phosphorylated protein. Saxton, T.M., van Oostveen, I., Bowtell, D., Aebersold, R., Gold, M.R. J. Immunol. (1994) [Pubmed]
WikiGenes - Universities