Recombinant Human FGF R2α (IIIc)

Recombinant Human FGF R2α (IIIc) is a valuable tool for research applications due to its well-characterized biological activity, high purity, and utility in studying fibroblast growth factor (FGF) signaling pathways. Here are several reasons why you should consider using this recombinant protein in your research:

1. Specific Inhibition of FGF Signaling

Recombinant Human FGF R2α (IIIc) acts as a soluble receptor that can bind and sequester FGF ligands, particularly FGF acidic (FGF-1). This property allows it to inhibit FGF-dependent cellular responses, such as proliferation, making it ideal for:

• Studying the role of FGF signaling in cell proliferation, migration, and differentiation.
• Investigating the effects of FGF pathway modulation in disease models (e.g., cancer, tissue regeneration).

2. High Purity and Consistency

The protein is typically produced with high purity (>90% by SDS-PAGE) and low endotoxin levels (<0.1 EU/µg), ensuring reliable and reproducible results in sensitive assays. This is critical for:

• Cell-based assays where contamination can affect outcomes.
• In vivo studies requiring minimal immune stimulation.

3. Well-Defined Biological Activity

The biological activity of Recombinant Human FGF R2α (IIIc) is validated by its ability to inhibit FGF acidic-dependent proliferation of NR6R-3T3 mouse fibroblasts, with a typical ED₅₀ in the range of 0.5–2 ng/ml. This makes it suitable for:

• Dose-response studies.
• Functional validation of FGF pathway involvement.

4. Fc Fusion Tag for Detection and Purification

Many recombinant forms of FGF R2α (IIIc) are produced as Fc fusion proteins, which:

• Facilitate easy detection using anti-Fc antibodies.
• Allow for simple purification using Protein A/G affinity chromatography.
• Can be used in complex formation studies (e.g., with IgG or other Fc-binding partners).

5. Stability and Ease of Use

The lyophilized form of the protein is stable for extended periods when stored properly (-20°C to -70°C), making it convenient for long-term storage and repeated use without significant loss of activity.

6. Applications in Disease and Regeneration Research

FGFR2IIIc is implicated in various physiological and pathological processes, including:

• Tissue regeneration and wound healing.
• Cancer progression (e.g., colorectal carcinoma).
• Angiogenesis and vascular development.

7. Compatibility with Diverse Assay Formats

The protein can be used in a variety of experimental setups, including:

• Cell proliferation and survival assays.
• Ligand binding and competition studies.
• In vivo animal models for tissue repair or disease.

In summary, Recombinant Human FGF R2α (IIIc) is a versatile and reliable reagent for probing FGF signaling, modulating cellular responses, and advancing research in areas such as regenerative medicine, oncology, and developmental biology. Its high purity, defined activity, and ease of use make it an excellent choice for both basic and applied research applications.

Suitability as an ELISA Standard

Recombinant Human FGF R2α (IIIc) is not appropriate for use as a standard or calibrant in ELISA assays designed to quantify fibroblast growth factors (FGFs). Here's why:

Key Considerations

Protein Identity and Function

FGF R2α (IIIc) is a fibroblast growth factor receptor, not a growth factor ligand itself. ELISA standards must match the target analyte being measured. If your assay is designed to quantify FGF ligands (such as FGF basic/FGF-2, FGF acidic/FGF-1, or FGF-21), you require standards composed of the actual FGF protein, not its receptor.

Cross-Reactivity Issues

The FGF R2α (IIIc)/Fc chimera has been documented as showing no cross-reactivity in FGF acidic-specific ELISA assays. This demonstrates that receptor proteins do not behave as suitable substitutes for ligand standards in growth factor quantification assays.

Appropriate Standard Selection

For ELISA calibration, you should use:

• Purified recombinant FGF proteins matching your target analyte (e.g., recombinant human FGF basic for FGF-2 quantification)
• Lyophilized standards provided by assay kit manufacturers, which are typically calibrated against highly purified, E. coli-expressed recombinant growth factors
• Standards with documented purity (>90% by SDS-PAGE) and biological activity specifications

The FGF R2α (IIIc) protein you have may be valuable for other applications such as receptor binding studies or functional assays, but it should not be repurposed as an ELISA standard for growth factor quantification.

Recombinant Human FGF R2α (IIIc) has been validated primarily for use as a functional inhibitor of FGF (fibroblast growth factor) signaling, specifically by inhibiting FGF acidic-dependent proliferation in cell-based assays.

Key validated applications in published research and technical documentation include:

• Inhibition of FGF-Dependent Cell Proliferation: The most direct and consistently validated application is its use to inhibit FGF acidic (FGF1)-dependent proliferation of NR6R-3T3 mouse fibroblasts. This is a standard bioassay for confirming the biological activity of recombinant FGF receptors, particularly Fc fusion proteins, and demonstrates its utility in studying FGF signaling pathways and receptor-ligand interactions.

• Receptor-Ligand Binding and Competition Assays: As a soluble receptor, FGF R2α (IIIc) can be used in binding studies to assess the specificity and affinity of FGF ligands, or to compete with endogenous receptors for ligand binding in vitro. This application is implied by its use as an inhibitor in proliferation assays and is a common use for recombinant receptor ectodomains.

• Potential Use in Functional Blocking Experiments: By acting as a decoy receptor, recombinant FGF R2α (IIIc) can be used to block FGF signaling in various cell-based or biochemical assays, allowing researchers to dissect the role of FGF2 and related ligands in processes such as cell proliferation, migration, and differentiation.

• Tool for Studying Isoform-Specific FGF Signaling: The IIIc isoform of FGFR2 has distinct ligand-binding properties compared to other isoforms (e.g., IIIb), making it valuable for studies aiming to distinguish between the biological effects of different FGF ligands and receptor isoforms.

Summary Table: Validated Applications

Additional Notes:

• Published research on recombinant FGF R2α (IIIc) specifically is limited, and most applications are inferred from its validated use in standard bioassays and the general utility of recombinant FGF receptor ectodomains.
• There is no direct evidence in the provided search results of its use in in vivo models or clinical studies; most applications are in vitro or ex vivo.
• Applications for recombinant FGF2 (the ligand) are broader (e.g., tissue regeneration, wound healing), but these should not be conflated with the receptor protein.

If you require protocols or further technical details for a specific application, please specify the experimental context.

To reconstitute and prepare Recombinant Human FGF R2α (IIIc) protein for cell culture experiments, follow these best-practice steps based on available protocols for this and similar recombinant proteins:

1. Centrifuge the vial before opening to ensure all lyophilized protein is at the bottom.

2. Reconstitution buffer:

   • Use sterile phosphate-buffered saline (PBS), pH 7.2–7.3, as this is the buffer in which the protein was originally lyophilized.
   • For enhanced stability and to prevent adsorption, add a carrier protein such as 0.1%–0.5% bovine serum albumin (BSA) or human serum albumin to the PBS.

3. Reconstitution concentration:

   • A typical starting concentration is 100 µg/mL.
   • If a different concentration is required for your application, adjust accordingly, but avoid concentrations below 100 µg/mL to maintain stability.

4. Dissolving the protein:

   • Gently add the calculated volume of buffer to the vial.
   • Do not vortex; gently swirl or invert the vial to dissolve the protein.
   • If the protein appears as a film, allow it to fully dissolve by gentle mixing.

5. Aliquoting:

   • Once fully dissolved, aliquot the solution into single-use volumes to avoid repeated freeze-thaw cycles, which can degrade the protein.

6. Storage after reconstitution:

   • Store aliquots at 2–8°C for up to one month or at –20°C to –70°C for longer-term storage.
   • Avoid repeated freeze-thaw cycles.

7. Working solution for cell culture:

   • For cell culture, dilute the stock solution to the desired working concentration using cell culture medium or PBS with carrier protein (e.g., 0.1% BSA).
   • Filter sterilize if necessary, using a 0.2 µm filter.

Summary Table: Reconstitution and Storage

Additional notes:

• Always consult the lot-specific datasheet or certificate of analysis for any special instructions.
• For functional assays, confirm activity using a relevant bioassay if possible.

These steps will help ensure the stability and bioactivity of Recombinant Human FGF R2α (IIIc) for your cell culture experiments.