Egan, S.E., Giddings, B.W., Brooks, M.W., Buday, L., Sizeland, A.M., Weinberg, R.A. (1993). Association of Sos Ras exchange protein with Grb2 is implicated in tyrosine kinase signal transduction and transformation.  Nature 363(6424): 45--51.

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Review

The proteins Grb2-Sem-5, Shc and Sos have been implicated in the signalling pathway from tyrosine kinase receptors to Ras. Grb2-Sem-5 binds directly to murine Sos1, a Ras exchange factor, through two SH3 domains. Sos is also associated with ligand-activated tyrosine kinase receptors which bind Grb2-Sem-5, and with the Grb2-Sem-5 binding protein, Shc. Ectopic expression of Drosophila Sos stimulates morphological transformation of rodent fibroblasts. These data define a pathway by which tyrosine kinases act through Ras to control cell growth and differentiation.