Recombinant Human Heregulin-β1 (HRG1-β EGF Domain)

Recombinant Human Heregulin-β1 (HRG1-β EGF Domain) is widely used in research due to its critical role as a growth factor that modulates cell proliferation, differentiation, migration, and survival, particularly through activation of the ERBB family of receptor tyrosine kinases.

Key reasons to use HRG1-β EGF Domain in research applications:

• Growth Factor Activity: HRG1-β1 is a potent stimulator of cell proliferation, especially in epithelial, glial, neuronal, and skeletal muscle cells. It is commonly used to stimulate proliferation in human MCF-7 breast cancer cells as a bioassay standard, with an ED50 typically ≤ 0.5 ng/ml, indicating high specific activity.
• Receptor Signaling Studies: HRG1-β1 is the canonical ligand for ERBB3 and ERBB4 receptors, leading to heterodimerization with ERBB2 (HER2) and activation of downstream signaling pathways such as MAPK and PI3K. This makes it essential for dissecting ERBB receptor biology and related signaling cascades.
• Cancer Research: HRG1-β1 is implicated in tumorigenesis, metastasis, and invasiveness of breast and other epithelial cancers. It is used to model and study cancer cell proliferation, migration, invasion, and drug response in vitro.
• Developmental Biology: HRG1-β1 plays a vital role in the development of the nervous system and heart, including Schwann cell differentiation, neuromuscular junction formation, and cardiac trabeculation. It is used to study neuronal and cardiac development and differentiation.
• Wound Healing and Regeneration: HRG1-β1 stimulates epidermal cell migration and differentiation, integrin expression, and is involved in tissue repair and wound healing models.
• Neurobiology: It regulates neurotransmitter receptor expression, promotes Schwann cell and oligodendrocyte development, and has been shown to modulate neuroinflammatory responses and neurogenesis.
• Versatility: The EGF domain is the minimal active region required for receptor binding and biological activity, making the recombinant EGF domain a precise tool for mechanistic studies.

Typical applications include:

• Cell proliferation and migration assays
• Signal transduction studies
• Cancer cell biology and metastasis models
• Neuronal and cardiac differentiation protocols
• Wound healing and tissue regeneration assays

Summary:
Use recombinant HRG1-β EGF Domain when you need a defined, potent ligand to activate ERBB3/ERBB4 signaling, model cancer or developmental processes, or study cell proliferation, migration, and differentiation in a controlled, reproducible manner.

Yes, Recombinant Human Heregulin-β1 (HRG1-β EGF Domain) can be used as a standard for quantification or calibration in ELISA assays, provided it is formulated and validated for this purpose. Recombinant proteins containing the EGF domain of Heregulin-β1 are commonly used as ELISA standards, especially when supplied with a carrier protein such as BSA to enhance stability and reproducibility.

Key considerations for use as an ELISA standard:

• Formulation: The protein should be supplied in a formulation suitable for ELISA, often with BSA as a carrier to prevent adsorption and loss during dilution and handling. Carrier-free formulations are available but may require additional precautions to prevent protein loss.
• Validation: Ensure the recombinant protein is validated for use as an ELISA standard. Some suppliers specifically recommend their BSA-containing formulations for ELISA calibration, while carrier-free versions are intended for applications where BSA may interfere.
• Purity and Activity: The protein should be highly pure (typically >98% by SDS-PAGE) and retain its biological activity, as confirmed by bioassays or functional testing.
• Concentration and Reconstitution: Follow recommended protocols for reconstitution (e.g., in PBS with 0.1% BSA) and storage to maintain stability and reproducibility.

Limitations and best practices:

• Bioassay vs. ELISA Standard: Proteins labeled for use as ELISA standards are not always validated for bioassays, and vice versa. Confirm the intended application with the product documentation.
• Calibration Curve: Prepare a standard curve using serial dilutions of the recombinant protein to quantify unknown samples accurately.
• Matrix Effects: If quantifying in complex biological samples, consider potential matrix effects and validate recovery and linearity.

Summary Table: ELISA Standard Use

In conclusion: Recombinant Human Heregulin-β1 (HRG1-β EGF Domain) is suitable as an ELISA standard if it is formulated and validated for this use. Always consult the product datasheet and follow recommended protocols for optimal results.

Recombinant Human Heregulin-β1 (HRG1-β EGF Domain) has been validated for several applications in published research, primarily centered on its role as a growth factor and its effects on cell signaling, proliferation, and differentiation. Key applications supported by the literature include:

1. Cell Proliferation Assays

   • HRG1-β EGF Domain has been used to stimulate proliferation of human breast cancer cell lines such as MCF-7, with activity measured by dose-dependent proliferation assays (ED50 ≤ 0.5 ng/ml, specific activity ≥ 2.0 × 10⁶ units/mg) [2, 3, 5, 15].

2. Wound Healing and Epidermal Migration

   • It has been shown to stimulate epidermal migration and differentiation of epidermal cells, supporting its use in wound healing studies [1, 15].

3. Neuronal and Glial Cell Studies

   • HRG1-β EGF Domain is used to promote proliferation and differentiation of neuronal and glial cells, including Schwann cells, and has been applied in studies of nerve regeneration and remyelination [4, 6, 13].

4. Cancer Research and Metastasis

   • The protein is validated for studies on breast cancer metastasis, promoting proliferation, migration, and invasion of breast cancer cells, and has been used in assays to investigate tumor cell invasiveness and signaling pathways (e.g., MAPK, PI3K) [2, 8, 9, 14].

5. Cardiac and Muscle Cell Differentiation

   • HRG1-β EGF Domain has been used to study cardiomyocyte development and differentiation, including the survival and maturation of cardiomyocytes derived from embryonic stem cells .

6. Bioassay and Residual Testing

   • It has been used in cell-based bioassays to assess the effectiveness of heregulin addition and removal in cell therapy cultures, particularly in Schwann cell cultures for regenerative medicine applications .

7. In Vivo Studies

   • The protein has been applied in animal models to study effects on neurogenesis, learning and memory, and neuroinflammatory responses .

8. Receptor Signaling Studies

   • HRG1-β EGF Domain is used to activate ErbB/HER receptor signaling pathways (ERBB2, ERBB3, ERBB4), making it a tool for studying downstream signaling cascades such as MAPK and PI3K [2, 4].

These applications demonstrate the versatility of Recombinant Human Heregulin-β1 (HRG1-β EGF Domain) in both basic research and translational studies, particularly in cancer biology, neuroscience, and regenerative medicine.

Reconstitution Guidelines

Recombinant Human Heregulin-β1 (HRG1-β1) is supplied as a lyophilized powder and requires proper reconstitution before use in cell culture applications. The protein is a 7.5 kDa polypeptide consisting of the EGF domain of heregulin-β1, spanning 65 amino acid residues.

Solvent Selection

Multiple reconstitution solvents are suitable depending on your specific experimental requirements:

• Sterile distilled water - commonly used for general applications
• Sterile PBS (phosphate-buffered saline) - recommended for many cell culture protocols
• 10 mM acetic acid - alternative aqueous buffer option
• Sterile deionized water - acceptable for most applications

The choice of solvent should be determined by compatibility with your specific assay or cell culture system.

Reconstitution Concentration

The standard reconstitution concentration is 100 μg/mL. However, some protocols recommend a range of 0.1–1.0 mg/mL depending on your downstream application requirements.

Carrier Protein Considerations

When reconstituting, consider whether your experiments require carrier protein supplementation:

• With carrier protein: Reconstitute in PBS containing at least 0.1% human or bovine serum albumin (BSA)
• Carrier-free formulations: Reconstitute in sterile PBS without additional carrier proteins

The addition of BSA helps stabilize the protein during storage and use, particularly when preparing dilute working solutions.

Pre-Reconstitution Preparation

Before opening the vial, perform a quick spin to collect any protein residue from the vial walls and cap. This ensures you recover all the lyophilized material during reconstitution.

Storage After Reconstitution

Once reconstituted, follow these storage protocols to maintain protein stability:

• Short-term storage (up to 1 week): Store at 2–8°C
• Long-term storage: Store at −20°C to −70°C in a manual defrost freezer
• Critical: Avoid repeated freeze-thaw cycles, as this can compromise protein activity

For extended storage beyond one week, freezing at −20°C or −70°C is strongly recommended.

Typical Application Concentration

In cell culture experiments, heregulin-β1 is typically used at a 10 nM concentration in culture media supplemented with serum and other growth factors. This concentration provides mitogenic stimulation for various cell types while maintaining physiological relevance.

Quality Considerations

Verify that your reconstituted protein meets purity standards (typically >97%) and contains minimal endotoxin contamination (less than 0.1 ng per μg of protein). These parameters are critical for reliable cell culture results and reproducible experimental outcomes.