Acidic and basic fibroblast growth factors (FGFs) are members of a family of multifunctional polypeptide growth factors that stimulate proliferation of cells of mesenchymal, epithelial and neuroectodermal origin. Like other growth factors, FGFs act by binding and activating specific cell surface receptors. These include the Flg receptor or FGFR-1, the Bek receptor or FGFR-2, FGFR-3, FGFR-4, FGFR-5 and FGFR-6. These receptors usually contain an extracellular ligand-binding region containing three immunoglobulin-like domains, a transmembrane domain and a cytoplasmic tyrosine kinase domain. The gene encoding human FGFR-3 maps to chromosome 4p16 and is alternatively spliced to produce three isoforms that are expressed in brain, kidney and testis. Defects in FGFR-3 are associated with several diseases, including Crouzon syndrome, achondroplasia, thanatophoric dysplasia, craniosynostosis adelaide type and hypochondroplasia. Mutations in FGFR-3 are also a cause of some bladder and cervical cancers.
Background References
1. Delpuech O et al. Identification of Pharmacodynamic Transcript Biomarkers in Response to FGFR Inhibition by AZD4547. Mol Cancer Ther 15:2802-2813 (2016).
2. Capelletti M et al. Identification of recurrent FGFR3-TACC3 fusion oncogenes from lung adenocarcinoma. Clin Cancer Res 20:6551-8 (2014).
Sequence Similarity
Belongs to the protein kinase superfamily. Tyr protein kinase family. Fibroblast growth factor receptor subfamily.
Tissue Specificity
Expressed in brain, kidney and testis. Very low or no expression in spleen, heart, and muscle. In 20- to 22-week old fetuses it is expressed at high level in kidney, lung, small intestine and brain, and to a lower degree in spleen, liver, and muscle. Isoform 2 is detected in epithelial cells. Isoform 1 is not detected in epithelial cells. Isoform 1 and isoform 2 are detected in fibroblastic cells.
Post-translational Modification
Autophosphorylated. Binding of FGF family members together with heparan sulfate proteoglycan or heparin promotes receptor dimerization and autophosphorylation on tyrosine residues. Autophosphorylation occurs in trans between the two FGFR molecules present in the dimer. Phosphorylation at Tyr-724 is essential for stimulation of cell proliferation and activation of PIK3R1, STAT1 and MAP kinase signaling. Phosphorylation at Tyr-760 is required for interaction with PIK3R1 and PLCG1.; Ubiquitinated. Is rapidly ubiquitinated after ligand binding and autophosphorylation, leading to receptor internalization and degradation. Subject to both proteasomal and lysosomal degradation.; N-glycosylated in the endoplasmic reticulum. The N-glycan chains undergo further maturation to an Endo H-resistant form in the Golgi apparatus.
Western blot analysis of FGFR3 on different lysates with Rabbit anti-FGFR3 antibody (ET1703-65) at 1/1,000 dilution.
Lane 1: HepG2 cell lysate (10 µg/Lane) Lane 2: rat skin tissue lysate (20 µg/Lane) Lane 3: mouse hippocampus tissue lysate (20 µg/Lane)
Exposure time: 5 seconds; ECL: K1801
Blocking: 5% NFDM/TBST, 1 hour at room temperature Primary antibody: ET1703-65, 1/1,000 in 5% NFDM/TBST, overnight at 4 ℃ Secondary antibody: Goat anti-Rabbit IgG-HRP (HA1001), 1/50,000 in 5% NFDM/TBST, 1 hour at room temperature
Predicted band size: 87.7 kDa Observed band size: 95 kDa
Western blot analysis of FGFR3 on different lysates with Rabbit anti-FGFR3 antibody (ET1703-65) at 1/1,000 dilution.
Lane 1: Hela cell lysate Lane 2: MCF-7 cell lysate
Lysates/proteins at 10 µg/Lane. Exposure time: 10 seconds; ECL: K1801
Blocking: 5% NFDM/TBST, 1 hour at room temperature Primary antibody: ET1703-65, 1/1,000 in 5% NFDM/TBST, overnight at 4 ℃ Secondary antibody: Goat anti-Rabbit IgG-HRP (HA1001), 1/50,000 in 5% NFDM/TBST, 1 hour at room temperature
Predicted band size: 87.7 kDa Observed band size: 95 kDa
☑ Knockdown (KD)
Western blot analysis of FGFR3 on different lysates with Rabbit anti-FGFR3 antibody (ET1703-65) at 1/1,000 dilution.
Lane 1: HEK293-si NT cell lysate Lane 2: HEK293-si FGFR3 cell lysate
Lysates/proteins at 10 µg/Lane.
Predicted band size: 88 kDa Observed band size: 130 kDa
Exposure time: 1 minute;
4-20% SDS-PAGE gel.
ET1703-65 was shown to specifically react with FGFR3 in HEK293-si NT cells. Weakened band was observed when HEK293-si FGFR3 sample was tested. HEK293-si NT and HEK293-si FGFR3 samples were subjected to SDS-PAGE. Proteins were transferred to a PVDF membrane and blocked with 5% NFDM in TBST for 1 hour at room temperature. The primary antibody (ET1703-65, 1/1,000) and Loading control antibody (Rabbit anti-HSP90, ET1605-56, 1/10,000) were used in 5% BSA at room temperature for 2 hours. Goat Anti-rabbit IgG-HRP Secondary Antibody (HA1001) at 1:50,000 dilution was used for 1 hour at room temperature.
Immunohistochemical analysis of paraffin-embedded human bladder cancer tissue with Rabbit anti-FGFR3 antibody (ET1703-65) at 1/10,000 dilution.
The section was pre-treated using heat mediated antigen retrieval with Tris-EDTA buffer (pH 9.0) for 20 minutes. The tissues were blocked in 1% BSA for 20 minutes at room temperature, washed with ddH2O and PBS, and then probed with the primary antibody (ET1703-65) at 1/10,000 dilution for 1 hour at room temperature. The detection was performed using an HRP conjugated compact polymer system. DAB was used as the chromogen. Tissues were counterstained with hematoxylin and mounted with DPX.
Immunohistochemical analysis of paraffin-embedded human kidney tissue with Rabbit anti-FGFR3 antibody (ET1703-65) at 1/10,000 dilution.
The section was pre-treated using heat mediated antigen retrieval with Tris-EDTA buffer (pH 9.0) for 20 minutes. The tissues were blocked in 1% BSA for 20 minutes at room temperature, washed with ddH2O and PBS, and then probed with the primary antibody (ET1703-65) at 1/10,000 dilution for 1 hour at room temperature. The detection was performed using an HRP conjugated compact polymer system. DAB was used as the chromogen. Tissues were counterstained with hematoxylin and mounted with DPX.
ICC staining of FGFR3 in MCF-7 cells (red). Formalin fixed cells were permeabilized with 0.1% Triton X-100 in TBS for 10 minutes at room temperature and blocked with 10% negative goat serum for 15 minutes at room temperature. Cells were probed with the primary antibody (ET1703-65, 1/50) for 1 hour at room temperature, washed with PBS. Alexa Fluor®594 Goat anti-Rabbit IgG was used as the secondary antibody at 1/1,000 dilution. The nuclear counter stain is DAPI (blue).
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