FGFR-4 Protein, Human (Active, sf9)

FGFR-4 protein is a tyrosine-protein kinase that functions as a cell-surface receptor for fibroblast growth factors. It plays a crucial role in regulating cell proliferation, differentiation, migration, lipid metabolism, bile acid biosynthesis, glucose uptake, vitamin D metabolism, and phosphate homeostasis. One of its important functions is to facilitate the down-regulation of CYP7A1, the key enzyme in bile acid synthesis, in response to FGF19. Upon ligand binding, FGFR-4 phosphorylates PLCG1 and FRS2, leading to the activation of various signaling cascades. This activation results in the production of diacylglycerol and inositol 1,4,5-trisphosphate, which are important cellular signaling molecules. Additionally, phosphorylation of FRS2 triggers the recruitment of GRB2, GAB1, PIK3R1, and SOS1, leading to the activation of RAS, MAPK1/ERK2, MAPK3/ERK1, and the AKT1 signaling pathway. FGFR-4 also promotes the SRC-dependent phosphorylation of MMP14, a matrix protease, and facilitates its lysosomal degradation. The signaling of FGFR-4 is tightly regulated through receptor internalization and degradation, and MMP14 aids in this process. However, mutations that result in constitutive kinase activation or impair normal FGFR-4 inactivation can lead to aberrant signaling.