Recombinant Mouse Follistatin

Recombinant Mouse Follistatin is widely used in research applications due to its ability to modulate key signaling pathways, particularly those involving the transforming growth factor beta (TGF-β) family, and its demonstrated effects on muscle growth, cell differentiation, and disease models.

Key scientific reasons to use recombinant mouse follistatin:

• Regulation of TGF-β Family Signaling: Follistatin acts as an antagonist by binding to activin, bone morphogenetic proteins (BMPs), myostatin, GDF-11, and TGF-β1, thereby blocking their interaction with signaling receptors. This allows researchers to study the effects of inhibiting these pathways in various biological contexts, such as development, tissue regeneration, and disease.

• Muscle Growth and Disease Models: Recombinant follistatin has been shown to increase muscle mass in mouse models, including those for spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), and Duchenne muscular dystrophy. Its administration leads to improved motor function, increased muscle mass, and extended lifespan in disease models, making it a valuable tool for studying muscle physiology and potential therapeutic interventions.

• Cell Culture and Bioassays: In vitro, recombinant mouse follistatin is used to inhibit the activity of activin A and other TGF-β family members, affecting cell proliferation and differentiation. It is commonly applied in cell culture systems to dissect signaling mechanisms or as a standard in ELISA assays.

• Developmental Biology: Follistatin knockout mice display defects in skeletal and muscle development, highlighting its essential role in embryogenesis and tissue formation. Recombinant protein enables controlled studies of these processes.

• Inflammation and Tumor Biology: Follistatin is implicated in modulating inflammatory responses and has been studied as a tumor suppressor, with effects on cell migration, apoptosis, and cytokine secretion. Recombinant protein allows for mechanistic studies in these areas.

Typical research applications include:

• Cell culture experiments to modulate TGF-β signaling.
• In vivo studies of muscle growth, regeneration, and disease.
• Bioassays investigating cell proliferation, differentiation, and apoptosis.
• ELISA standards for quantifying follistatin or related pathway components.

Best practices:

• Select the appropriate isoform and carrier (e.g., with or without BSA) based on your application (cell culture, in vivo, ELISA).
• Avoid repeated freeze/thaw cycles to maintain protein activity.

In summary, recombinant mouse follistatin is a versatile tool for investigating signaling pathways, muscle biology, and disease mechanisms, and is essential for studies requiring precise modulation of TGF-β family activity.

You can use recombinant mouse Follistatin as a standard for quantification or calibration in ELISA assays, provided that the recombinant protein is of high purity, its concentration is accurately known, and it is compatible with the antibodies and detection system used in your specific ELISA format.

Key considerations and supporting details:

• Purity and Characterization: The recombinant protein should be highly purified (typically >95%) and well-characterized, with a defined concentration and sequence corresponding to the native protein or the specific isoform targeted by your assay.
• Carrier Protein: Some protocols recommend using recombinant proteins with a carrier protein (such as BSA) for ELISA standards to enhance stability and reproducibility, unless the presence of a carrier interferes with your assay.
• Isoform and Epitope Compatibility: Ensure the recombinant Follistatin isoform (e.g., FS288, FS315) matches the isoform recognized by your ELISA antibodies, as different isoforms or tags (such as His-tags) may affect antibody binding and quantification accuracy.
• Validation: Ideally, the recombinant standard should be validated in your ELISA system to confirm that it produces a standard curve parallel to that of native Follistatin, ensuring accurate quantification. Some ELISA kits are designed to detect both recombinant and native Follistatin, while others may specify detection of only native protein.
• Preparation: Prepare the standard curve using serial dilutions of the recombinant protein in the same buffer as your samples to minimize matrix effects.

Limitations and Best Practices:

• Not all recombinant proteins are validated for use as ELISA standards; check the product datasheet or technical documentation for explicit validation in ELISA applications.
• If your ELISA kit is designed only for native Follistatin, using a recombinant standard may result in inaccurate quantification due to differences in glycosylation, folding, or epitope presentation.
• Always run a pilot experiment to compare the standard curve generated with recombinant Follistatin to that of a native standard (if available) to assess parallelism and accuracy.

Summary Table: Recombinant Mouse Follistatin as ELISA Standard

In summary, recombinant mouse Follistatin can be used as an ELISA standard if it is validated for this purpose and matches the assay requirements. Always consult the technical documentation for your specific recombinant protein and ELISA kit, and validate performance in your assay system.

Recombinant Mouse Follistatin has been validated for several applications in published research, primarily in the context of cell culture, in vivo studies, and bioassays involving muscle growth, TGF-β signaling, and disease models.

Key validated applications include:

• Cell Culture: Used to study its effects on cell proliferation, differentiation, and signaling pathways, particularly in the context of TGF-β family signaling (including activin, BMPs, and myostatin).
• Bioassays: Employed to inhibit the activity of activin A in cell-based assays, such as the proliferation of MPC-11 cells, and to assess its interaction with other TGF-β family ligands.
• In Vivo Studies: Systemic administration in mice has been validated for:
  • Muscle growth and regeneration: Increasing muscle mass and improving muscle function in models of muscle wasting diseases, such as spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), and Duchenne muscular dystrophy.
  • Neuroprotection: Improving motor function and extending lifespan in SMA mouse models.
  • Inflammation and metabolic disease: Investigating its role as a mediator of inflammation in obesity and other metabolic conditions.
  • Cancer research: Studying its tumor suppressor functions and effects on tumor cell proliferation, migration, and apoptosis.
  • Developmental biology: Examining its regulatory role in organ development, such as lung and kidney development, via modulation of BMP and Wnt signaling pathways.

Additional validated uses:

• Functional Studies (FuncS): Used to assess its biological activity in various functional assays, including inhibition of follicle-stimulating hormone release and stimulation of progesterone production in granulosa cells.
• SDS-PAGE: Validated for protein characterization and purity assessment by electrophoresis.

Summary Table of Validated Applications

These applications are supported by multiple peer-reviewed studies and product validation data, demonstrating the versatility of recombinant mouse follistatin in both basic and translational research.

To reconstitute and prepare Recombinant Mouse Follistatin protein for cell culture experiments, dissolve the lyophilized protein in sterile water or phosphate-buffered saline (PBS) at a concentration of 0.1 mg/mL to 0.5 mg/mL, depending on the specific formulation and experimental requirements.

Step-by-step protocol:

• Centrifuge the vial briefly before opening to ensure all powder is at the bottom.
• Add sterile water or PBS to achieve the desired concentration (commonly 0.1 mg/mL for most cell culture applications; some protocols recommend up to 0.5 mg/mL in PBS).
• Gently pipet the solution up and down, washing the sides of the vial to ensure complete dissolution. Do not vortex, as vigorous mixing may denature the protein.
• Allow several minutes for complete reconstitution at room temperature.
• If required for stability, add a carrier protein such as 0.1–1% BSA or HSA, especially for long-term storage or when working at low concentrations.
• Aliquot the solution to avoid repeated freeze-thaw cycles. Store aliquots at −20°C or −80°C for long-term use; short-term storage (up to one week) can be at 2–8°C.
• Before use in cell culture, dilute the stock solution to the working concentration in your cell culture medium, ensuring compatibility with your assay and cell type.

Additional notes:

• Always consult the specific product datasheet for recommended buffer and concentration, as some preparations may require PBS instead of water.
• Avoid repeated freeze-thaw cycles to maintain protein activity.
• For sensitive applications, confirm the absence of endotoxin and verify biological activity as needed.

Summary Table:

This protocol ensures optimal solubility and stability of recombinant mouse follistatin for cell culture experiments.