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FGFR/β-Klotho Reporter Assay Kit

1 x-96 well format assays
3 x-32 assays in-96 well format
1 x-384 well format assays
1 x-96 well format assays
3 x-32 assays in-96 well format
1 x-384 well format assays

Product Description and Product Data

This is an all-inclusive cell-based luciferase reporter assay kit targeting the Human Fibroblast Growth Factor Receptor 1c and β-Klotho (FGFR/β-Klotho). INDIGO’s FGFR/β-Klotho reporter assay utilizes proprietary mammalian cells that have been engineered to provide constitutive expression of the Human Fibroblast Growth Factor Receptor 1c and β-Klotho. In addition to FGFR/β-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 FGFR/β-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.


  • 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 TypeGrowth Factor Receptor
Receptor FormNative
Assay ModeAntagonist
Kit Components
  • FGFR/β-Klotho Reporter Cells
  • Cell Recovery Medium (CRM)
  • Compound Screening Medium (CSM)
  • FGF-21, (ref. activator; in PBS/0.1% BSA )
  • Detection Substrate
  • Detection Buffer
  • White, sterile, cell-culture ready assay plate
Shelf Life6 months
Orthologs AvailableNo
Shipping RequirementsDry Ice
Storage temperature-80C


FGFR1c/β-Klotho Activation dose response analyses. Activation dose-response assays were performed according to the protocol provided in this Technical Manual. 200 l / well of FGFR1c/β-Klotho Reporter Cell suspension was dispensed into the 96-well assay plate, which was then incubated for 4 hours. The concentrated stock of FGF-21 (provided) and FGF-19 (Sino Biological) were further diluted using CSM to produce treatment media at the desired assay concentrations. As expected, the growth factor FGF-23, which requires α-Klotho, shows no activity. The pre-culture media were discarded from the assay wells and 200 l per well of the prepared treatment media were dispensed (n = 3/conc.), including ‘untreated’ control wells. Following a 22 hr incubation period treatment media were discarded, Luciferase Detection Reagent was added, and luminescence intensity per well was quantified. Values of average relative light units (RLU) and corresponding values of standard deviation (SD), percent coefficient of variation (%CV), Fold-Activation and Z’5 were determined for each treatment concentration. Non-linear regression analyses of Fold Activation vs. Log10[ng/mL] and EC50 determinations were performed using GraphPad Prism software.

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.

FGF-21 a liver secreted endocrine FGF, has been identified as a factor that has multiple beneficial effects on obesity-related disorders. For example, it is a potent activator of glucose uptake in primary human adipocytes. In addition, FGF-21 has been shown to protect diet-induced obesity and diabetic illness in animals. Consequently, the associated metabolic benefits of the endocrine FGFs have promoted considerable interest in therapeutic development and drug safety screening.

INDIGO’s Human Fibroblast Growth Factor Receptor Receptor 1c and β-Klotho (FGFR/β-Klotho) assay utilizes proprietary human cells that have been engineered to provide constitutive expression of the Human Fibroblast Growth Factor Receptor 1c and β-Klotho. FGFR1c and β-Klotho are both single-pass transmembrane proteins. FGFR1c has an extracellular ligand-binding domain, transmembrane domain, and intracellular tyrosine kinase domain. It has been established that FGFR association with the co-receptor β-Klotho generates a scaffold that is essential for endocrine growth factor binding interactions, such as those with FGF-21 and FGF-19. Following growth factor binding, the activated tyrosine kinase activities of the FGFR initiate intracellular signaling cascades that may include RAS-MAPK, PI3-AKT, PLCγ and/or STAT pathways. It is FGFR1c/β-Klotho signal transduction via the RAS-MAPK-ERK1/2 cascade that is exploited by the reporter cells in this assay.

INDIGO’s FGFR/β-Klotho Reporter Cells contain the luciferase reporter gene functionally linked to an Elk-1 responsive promoter. Activated Elk-1 binds to the response elements to initiate the formation of a complete transcription complex that drives Luc gene expression. Quantifying relative changes in luciferase activity in the treated reporter cells relative to the untreated cells provides a sensitive, dose-dependent surrogate measure of drug-induced changes in FGFR1c/β-Klotho activity.

The principal application of this reporter assay is in the screening of test materials to quantify any functional interactions, either activating or inhibitory, that they may exert against FGFR1c/β-Klotho or the coupled RAS-MAPK pathway.

Also available as a service

Fibroblast Growth Factor Receptor 1c and β-Klotho (FGFR/β-Klotho)

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