Feedback inhibitor of fibroblast growth factor mediated Ras-MAPK signaling and ERK activation (PubMed:12604616). Regulates the nuclear ERK signaling pathway by spatially blocking nuclear translocation of activated ERK (By similarity). Mediates JNK activation and may be involved in apoptosis (PubMed:15277532). May inhibit FGF-induced FGFR1 tyrosine phosphorylation (PubMed:12604616). Might have a role in the early stages of fate specification of GnRH-secreting neurons (PubMed:23643382). Inhibits TGFB-induced epithelial-to-mesenchymal transition in lens epithelial cells (PubMed:25576668). Self-associates. Interacts with FGFR2 and phosphorylated MAP2K1 or MAP2K2. Associates with a MAP2K1/2-MAPK1/3 complex (By similarity). Interacts with FGFR1 and MAP3K7. Associated with the Golgi apparatus and is partially translocated to the plasma membrane upon stimulation. During early embryogenesis, predominantly expressed at 6.5 dpc and 9.5 dpc in the forebrain, mid-hindbrain boundary, branchial arches, somites, limb bud and tailbud. At 12.5 dpc additionally expressed in the diencephalon, optic stalk, pituitary, olfactory and oral epithelium, tooth primordia, somites, developing metanephric kidney and stomach. Expressed in the neopallial cortex, rhombic lip and dorsal regions of the myelencephalon and in the frontal nasal process. Expressed in the commissural plate and septal area of the forebrain and in the hippocampus, lens and optic cup. In the oral region, expressed in the tongue and in the mesenchyme of the first branchial arch. Also expressed in the developing inner ear. Expression patterns remain essentially unchanged at 15.5 dpc, with the addition of a strong expression in the submandibular gland.