FGFR4/alpha-Klotho Reporter Assay System (human)

This is an all-inclusive cell-based luciferase reporter assay kit targeting the Human Fibroblast Growth Factor Receptor 4 and alpha-Klotho (FGFR4/alpha-Klotho). INDIGO's FGFR4/alpha-Klotho reporter assay utilizes proprietary mammalian cells that have been engineered to provide constitutive expression of the Human Fibroblast Growth Factor Receptor 4 and alpha-Klotho. In addition to FGFR4/alpha-Klotho Reporter Cells, this kit provides two optimized media for use during cell culture and in diluting the user's test samples, a reference agonist, Luciferase Detection Reagent, and a cell culture-ready assay plate. The principal application of this assay is in the screening of test samples to quantify any functional activity, either agonist or antagonist, that they may exert against human FGFR4/alpha-Klotho. This kit provides researchers with clear, reproducible results, exceptional cell viability post-thaw, and consistent results lot to lot. Kits must be stored at -80C. Do not store in liquid nitrogen. Note: reporter cells cannot be refrozen or maintained in extended culture. Features Ready to Use Upon Receipt Includes All Needed Components Contains Transfected Reporter Cells Eliminates Cell Licensing Fees Clear, Reproducible Results Consistent Results Lot to Lot Product Specifications Target Type Growth Factor Receptor Species Human Receptor Form Hybrid Assay Mode Kit Components FGFR4/alpha-Klotho Reporter Cells Cell Recovery Medium (CRM) Compound Screening Medium (CSM) FGF-23, (ref. activator, in PBS/0.1% BSA ) Detection Substrate Detection Buffer White, sterile, cell-culture ready assay plate Shelf Life 6 months Shipping Requirements Dry Ice Storage temperature -80C. Target Background The family of Fibroblast Growth Factors (FGFs) comprise approximately 23 members that are related by core sequence and structure conservation, with the majority of FGFs being secreted signaling proteins. Secreted FGFs are predominantly autocrine and paracrine factors, with only three members evolved to function as endocrine factors. FGFs bind and activate FGF Receptors (FGFRs) which, themselves, are members of the family of high-affinity tyrosine kinase receptors. Paracrine FGFs show high affinity towards the extracellular matrix (ECM) component heparin sulfate (HS) and are thus retained in the ECM and function locally. In contrast, the atypical endocrine subfamily of FGFs, that comprise FGF-19, FGF-21, and FGF-23, have reduced affinity for HS and can therefore escape from the ECM into the circulation to reach target distant organs. However, this subfamily typically requires association with members of the Klotho family of proteins as cofactors for efficient binding to their cognate receptor(s). FGF-23 is a principal regulator in the maintenance of serum phosphorus concentration by inhibiting renal tubular phosphate reabsorption. Unfortunately, various FGF-23-mediated disorders exist. The most common of these is X-linked hypophosphoatemia (XLH). Additional disorders of FGF-23 signaling include autosomal dominant and recessive hypophosphophatemic rickets, fibrous dysplasia, and tumor-induced osteomalacia. Consequently, FGF-23 and FGFR4/alpha-Klotho command considerable interest as therapeutic targets in drug development and drug safety screening. FGFR4 and alpha-Klotho are both single-pass transmembrane proteins. FGFR4 has an extracellular ligand-binding domain, transmembrane domain, and intracellular tyrosine kinase domain. It has been established that FGFR4 association with the co-receptor alpha-Klotho generates a scaffold that is essential for endocrine growth factor binding interactions, such as those with FGF-23. Following growth factor binding, the activated tyrosine kinase activities of the FGFR initiate intracellular signaling cascades that may include RAS-MAPK, PI3-AKT, PLCgamma and/or STAT pathways. For example, activation of the PLCgamma pathway leads to an increase of intracellular calcium. One prominent outcome of the FGF/FGFR > PLCgamma pathway is that calcineurin, a calcium-dependent phosphatase, dephosphorylates and activates the transcription factor NFAT. It is FGFR4/alpha-Klotho signal transduction via the Ca+2calcineurin / NFAT cascade that is exploited by the reporter cells provided in this kit. Protein function: Tyrosine-protein kinase that acts as cell-surface receptor for fibroblast growth factors and plays a role in the regulation of cell proliferation, differentiation and migration, and in regulation of lipid metabolism, bile acid biosynthesis, glucose uptake, vitamin D metabolism and phosphate homeostasis. Required for normal down- regulation of the expression of CYP7A1, the rate-limiting enzyme in bile acid synthesis, in response to FGF19. Phosphorylates PLCG1 and FRS2. Ligand binding leads to the activation of several signaling cascades. Activation of PLCG1 leads to the production of the cellular signaling molecules diacylglycerol and inositol 1,4,5-trisphosphate. Phosphorylation of FRS2 triggers recruitment of GRB2, GAB1, PIK3R1 and SOS1, and mediates activation of RAS, MAPK1/ERK2, MAPK3/ERK1 and the MAP kinase signaling pathway, as well as of the AKT1 signaling pathway. Promotes SRC-dependent phosphorylation of the matrix protease MMP14 and its lysosomal degradation. FGFR4 signaling is down-regulated by receptor internalization and degradation, MMP14 promotes internalization and degradation of FGFR4. Mutations that lead to constitutive kinase activation or impair normal FGFR4 inactivation lead to aberrant signaling. [The UniProt Consortium]