Recombinant Human FGF R1β (IIIb)

Recombinant Human FGF R1β (IIIb) is a purified form of the fibroblast growth factor receptor 1 beta isoform, specifically the IIIb splice variant, and is used in research to study FGF signaling, cell proliferation, differentiation, and tissue regeneration mechanisms. Its application is particularly valuable for dissecting receptor-ligand interactions, modeling disease pathways, and developing therapeutic strategies targeting FGF pathways.

Key scientific reasons to use Recombinant Human FGF R1β (IIIb) in research applications:

• FGF Signaling Studies: FGFR1β (IIIb) is a receptor tyrosine kinase that mediates cellular responses to fibroblast growth factors (FGFs), which are critical for cell growth, survival, migration, and differentiation. Using the recombinant receptor allows precise investigation of FGF-FGFR1β (IIIb) interactions, downstream signaling cascades, and receptor specificity.

• Disease Modeling: FGFR1β is expressed in basal epithelial and smooth muscle cells and is implicated in various pathologies, including cancer progression and chemoresistance, especially in subsets of acute myeloid leukemia (AML). Recombinant FGFR1β (IIIb) enables in vitro modeling of these disease processes and screening of potential inhibitors or therapeutic agents.

• Cellular and Molecular Assays: Recombinant FGFR1β (IIIb) can be used in binding assays, receptor activation studies, and cell-based functional assays to elucidate the biological effects of FGF ligands and to characterize receptor pharmacology.

• Protein Interaction and Structural Studies: The recombinant protein provides a consistent and defined reagent for structural biology, protein-protein interaction mapping, and biophysical analyses, facilitating the development of targeted therapeutics and diagnostics.

• Regenerative Medicine and Tissue Engineering: FGF signaling, mediated by FGFR1β, plays a pivotal role in tissue repair and regeneration, including bone and vascular tissue formation. Recombinant FGFR1β (IIIb) can be used to optimize growth factor delivery systems and study mechanisms of tissue regeneration.

Best practices for using recombinant FGFR1β (IIIb) include:

• Confirming protein purity and activity via SDS-PAGE and functional assays.
• Using appropriate controls to distinguish receptor-specific effects.
• Storing the lyophilized protein at recommended temperatures to maintain stability and bioactivity.

In summary, Recombinant Human FGF R1β (IIIb) is a critical tool for advancing research in cell signaling, disease modeling, and regenerative medicine by enabling precise manipulation and analysis of FGF receptor-mediated pathways.

Recombinant Human FGF R1β (IIIb) should not be used as a standard for quantification or calibration in ELISA assays designed to measure FGF basic (FGF2). Instead, a purified or recombinant FGF basic (FGF2) protein that matches the analyte of interest should be used for the standard curve.

Supporting details:

• ELISA standards must match the analyte: For accurate quantification, the standard curve in an ELISA must be generated using a purified or recombinant form of the same protein that the assay is designed to detect. Using a different protein, even if related (such as a receptor instead of the ligand), will not provide valid quantification.

• FGF R1β (IIIb) is a receptor, not the ligand: FGF R1β (IIIb) is a splice variant of the fibroblast growth factor receptor 1, not FGF basic (FGF2) itself. ELISA kits for FGF basic/FGF2 are calibrated and validated using recombinant FGF basic, not its receptor.

• Interference, not calibration: In fact, documentation for FGF basic ELISA kits specifically notes that recombinant human FGF R1β (IIIb) can interfere with the assay at concentrations above 7.41 ng/mL, potentially leading to inaccurate results if present. This means the receptor can disrupt the assay, not serve as a standard.

• Best practice: The standard curve should be prepared using a purified or recombinant FGF basic (FGF2) protein, ideally the same isoform and from the same species as your samples. This ensures the assay's antibodies recognize the standard and sample identically, allowing for accurate quantification.

Summary Table:

Recommendation:
Use a recombinant or purified FGF basic (FGF2) protein as your standard for ELISA quantification of FGF2. Do not use FGF R1β (IIIb), as it is not the analyte and may interfere with assay performance.

Based on the provided search results, there is no direct evidence that Recombinant Human FGF R1β (IIIb) has been validated for specific applications in published research. The available information focuses on related proteins and receptors, but not specifically on the validated applications of Recombinant Human FGF R1β (IIIb).

Here is a summary of what the results do indicate:

• FGFR1-IIIb (not R1β): One study (result ) describes the expression of FGFR1-IIIb in L6 rat skeletal muscle myoblasts and its use in cross-linking and receptor binding studies. This suggests that FGFR1-IIIb has been used in basic research settings to study receptor-ligand interactions, but does not specify validated therapeutic or clinical applications.

• FGF R1β (IIIc): Result describes Recombinant Human FGF R1β (IIIc), which is a different isoform. It mentions that FGF R1β supports progression and chemoresistance in subsets of acute myeloid leukemias (AML), indicating a potential role in cancer research, but this is not the same as R1β (IIIb).

• Other FGF Receptors: Results and provide details on other FGF receptors (FGF R2α (IIIb) and FGF R1β (IIIc)), but not on FGF R1β (IIIb).

In summary, the provided results do not contain information on validated applications for Recombinant Human FGF R1β (IIIb) in published research. The studies mentioned focus on related isoforms and receptors, primarily in the context of basic research and cancer, but not specifically on R1β (IIIb).

Reconstitution Protocol

Initial Preparation

Before opening the vial, centrifuge the lyophilized protein for 20-30 seconds to ensure all material settles to the bottom and recovers any protein lodged in the cap or on the vial sides. This step is critical for maximizing protein recovery.

Reconstitute the lyophilized Recombinant Human FGF R1β (IIIb) protein in sterile water or an appropriate buffer solution. The specific reconstitution buffer may vary depending on your application, so consult the product documentation for optimal conditions. Avoid vortexing or vigorous pipetting during reconstitution, as this can denature the protein. Instead, gently pipette the solution down the sides of the vial to dissolve the lyophilized powder.

Recommended Concentration

Reconstitute to a concentration between 0.1 to 1.0 mg/mL. For example, if you have 100 µg of protein, add between 100 µL and 1 mL of sterile water to achieve the desired concentration range.

Storage and Stability

Long-term Storage

Store the lyophilized protein desiccated at -20°C to -70°C for 6 to 12 months. Use a manual defrost freezer to maintain consistent temperatures and prevent temperature fluctuations.

Post-Reconstitution Storage

After aseptic reconstitution, you have two storage options:

• Short-term: Store at 2°C to 8°C for up to one month under sterile conditions
• Long-term: Store at -20°C to -70°C for up to 3 months under sterile conditions

Critical Handling Considerations

Minimize freeze-thaw cycles, as repeated freezing and thawing can compromise protein integrity and biological activity. If you anticipate multiple uses, aliquot the reconstituted solution into smaller portions before freezing to avoid repeated thawing of the entire stock.

Verification and Quality Control

After reconstitution, confirm the presence of the protein product by running a small aliquot (as little as 10 ng) on SDS-PAGE. You should observe a protein band at the expected molecular weight. For Recombinant Human FGF R1β (IIIb), note that while the predicted molecular mass is approximately 56 kDa, the actual molecular weight observed on SDS-PAGE typically appears at 90-100 kDa due to the Fc fusion protein tag.