Article: PDF OnlyThe role of Son of sevenless guanine nucleotide exchange factors in linking cell surface receptors with rasBowtell, David D. L. PhDCurrent Opinion in Endocrinology and Diabetes 3(5):p 388-396, October 1996. Buy Abstract The Son of sevenless (Sos) proteins link cytokine stimulation of cell surface receptors to ras activation by facilitating ras GDP-GTP exchange. This linkage appears to be controlled largely by the regulated formation of complexes of Sos, receptor, and adaptor proteins in the vicinity of membrane-bound ras. Interaction of Sos with Grb2, Shc, and other adaptor proteins is important for Sos to couple to ligand-activated receptors. Phosphorylation of Sos in response to ligand stimulation of cells may result in feedback dissolution of complexes of Sos and other signaling proteins, thereby terminating receptor-mediated ras activation. © Lippincott-Raven Publishers.