Fibroblast growth factor receptor substrate 3 is a substrate for the fibroblast growth factor receptor. It is found in peripheral plasma membrane and functions in linking FGF receptor stimulation to activators of Ras.Xu et al. (1998) cloned and characterized SNT2. The deduced 492-amino acid protein is 49% identical to SNT1 . Both SNTs contain a myristylation sequence, a phosphotyrosine-binding (PTB) domain, and several tyrosine-containing motifs that govern GRB2 and SHP2 recruitment.Using yeast 2-hybrid interaction assays, Xu et al. (1998) showed that SNT1 and SNT2 directly bind to FGFR1. A juxtamembrane segment of FGFR1 and the PTB domain of the SNTs were both necessary and sufficient for interaction in yeast and in vitro, and FGFR-mediated SNT tyrosine phosphorylation in vivo required these segments.