anti-SOS1, mAb (AF3F11)

Son of sevenless (SOS) is a guanine nucleotide exchange factor that activates Ras in response to growth factor stimulation. Sos1, and its closely related Sos2 paralog, are comprised of an N-terminal histone-binding domain, a RacGEF catalytic (DH) domain juxtaposed with a PH domain, a Ras exchanger motif (REM) domain, a RasGEF catalytic domain, and a C-terminal proline-rich region. Sos1 catalyzes the GDP-GTP exchange within the membrane-bound GTPase Ras and thereby switches on a key signaling circuit that involves the activation of MAPK cascade central to cellular proliferation, survival and differentiation. Growth factor stimulation rapidly induces the phosphorylation of Sos on multiple serine and threonine sites. Phosphorylation of residues within the Sos C-terminus by the MAP/ERK kinase disrupts the Grb2-Sos complex. Promotes the exchange of Ras-bound GDP by GTP.