FRS3 (fibroblast growth factor receptor substrate 3), also known as FRS2B (FRS2-beta), is a 492 amino acid lipid-anchor adapter protein that contains one IRS-type PTB domain. Colocalizing to neural tissues with Tuj1, FRS3 functions as a feedback inhibitor of EGFR family members by preventing heterodimer formation between EGFR and ErbB2, thereby acting as a potential tumor suppressor. FRS3 is phosphorylated upon stimulation by FGF-2 or NGF and, acting as an adapter protein, links c-Fgr and NGF receptors to downstream signaling pathways. Interfering with the phosphorylation and nuclear translocation of ERK-2, FRS3 down-regulates ERK-2 expression. FRS3 likely interacts directly with GRB2, SH-PTP2, Flg, and Trk A, and may be involved in MAP kinase activation.
FGFR substrate 3; FGFR-signaling adaptor SNT2; Fibroblast growth factor receptor substrate 3; FRS3; SNT-2; Suc1-associated neurotrophic factor target 2; suc1-associated neurotrophic factor target 2 (FGFR signalling adaptor); testicular tissue protein Li 71