Detection of Sos-1 by immunoblotting is possible by using a minimum antibody working dilution of 1:4,000 in whole extracts of A431 (human epidermoid carcinoma) and PC 12 (rat pheochromocytoma) cell lines. For indirect immunofluorescent staining a minimum working dilution of 1:500 may be used in cultured canine MDCK cells. The antibody is suitable for protein microarray.
Son of Sevenless (SOS) was first discovered in Drosophila, responsible for normal eye development. Two homologs in mouse and humans have been described, Sos-1 and Sos-2; mouse Sos-1 and Sos-2 are 70% identical. Mammalian Sos proteins are present in the inner cell membrane. Sos-1 is a dual guanine nucleotide exchange factor that activates Rac1 and Ras in response to growth factors. Sos-1 can associate also with the GRAP adaptor protein and it is also capable of forming complexes that exhibit Rac-specific guanine nucleotide exchange factor activity. Along with receptor tyrosine kinases, Sos-1 plays an important role in cellular migration and proliferation. In plants, Sos-1 is important to maintain salt concentration across the cell membranes.
Anti-Sos-1 specifically recognizes Sos-1 by immunoblotting (170 kDa). An additional band of lower molecular weight may be detected in some cell line extracts.
