- Other Names
- Inhibin BA (INHBA), Inhibin B-1, Follicule stimulating hormone-releasing protein (FRP), FSH releasing protein, FSH releasing factor, Erythroid differentiation factor (EDF)
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- Product Citations
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Activin A was initially identified in ovarian fluid as a stimulator of FSH secretion from anterior pituitary cells. Activin A is a member of the TGF-β1 family which includes TGFs, activins, Nodal, growth and differentiation factors (GDF), and bone morphogenetic proteins (BMPs). Activin A is a dimer of the beta A subunits of human inhibin; the beta A subunit binds the beta B subunit of inhibin to form Activin AB. The beta B subunit also exists as a heterodimer to form Activin B. Activin A binds two type I and two type II serine/threonine kinase receptors at the same time. The type II receptor kinase is constitutively active and phosphorylates the type I receptor after the formation of the ligand-receptor complex. Five type II receptors have been identified: ActRIIA, ActRIIB, BMPRII, TGFβRII, and MISRII. ActRIIB binds to Activin A, BMP-2, BMP-7, GDF-8, and GDF-11. The type I receptors are named activin receptor-like kinases 1 to 7 (ALK1-7), and Activins bind to ALK4 and ALK7. Follistatin (FS) is a natural Activin A antagonist; FS neutralizes its biologic activities by preventing Activin A interaction with its receptors. Activin A has pleiotropic functions. It is a morphogen during embryonal development, regulating chondrogenic and osteogenic differentiation of mesenchymal progenitor cells (MPC). Activin A has been associated with neuroprotection, apoptosis, and fibrosis. Also, high levels of Activin A have been found in synovial fluid from patients with rheumatoid arthritis, inflammatory bowel disease, and gout. In addition, it has been speculated that Activin A, in collaboration with TGF-β1 and IL-25, promotes Th9 generation and the development of allergic pathology. Mature human Activin A shares 100% amino acid sequence identity with bovine, feline, mouse, porcine, and rat Activin A.Product Details
- Human Activin A, amino acids (Gly311-Ser426) (Accession# M13436), was expressed in E. coli.
- Molecular Mass
- The 116 amino acid recombinant protein has a predicted molecular mass of 12.9 kD. The predicted N-terminal amino acid is Gly. Recombinant human Activin A is a disulfide bond linked homodimer.
- >98%, as determined by Coomassie stained SDS-PAGE and HPLC analysis.
- Lyophilized, carrier-free.
- Endotoxin Level
- Less than 0.1 ng per µg of protein.
- Storage & Handling
- Unopened vial can be stored at -20°C or -70°C. For maximum results, quick spin vial prior to opening. Reconstitute in water to a concentration of 0.1-1.0 mg/ml. Do not vortex. It is recommended to further dilute in a buffer, such as 5% Trehalose, and store working aliquots at -20°C to -80°C. Avoid repeated freeze/thaw cycles.
- ED50 is ≤ 2.0 ng/ml, corresponding to a specific activity of ≥ 5 x 105 units/mg as determined by its ability to inhibit the proliferation of mouse MPC-11 cells.
- Application Notes
This product reacts with human, chicken, dog, frog, mouse, and rat.
Activin A is expressed by a wide range of cells such as BM-derived stromal fibroblasts, aortic smooth muscle cells, pulmonary epithelium, and CD4+ T cells.
- Activin A plays a key role in embryogenesis, neointimal formation after arterial injury, early stages of chondrogenesis, osteogenesis, and hematopoiesis. Activin A drives Th9 differentiation in vitro. It is induced by Angiotensin II and alpha Thrombin and regulated by Follistatin. Activin A is induced by inflammatory cytokines and inhibited by glucocorticoids.
- The receptors for Activin A are expressed by many stromal cells, among them fibroblasts, hepatocytes, myometral cells, vascular endothelial cells, and neuronal progenitor cells.
- Type I receptors ALK4 and ALK7, Type II receptors ActRIIA and ActRIIB.
- Cell Type
- Embryonic Stem Cells, Hematopoietic stem and progenitors, Neural Stem Cells
- Biology Area
- Cell Biology, Neuroscience, Stem Cells, Synaptic Biology
- Molecular Family
- Cytokines/Chemokines, Growth Factors
- Antigen References
1. Schwall RH, et al. 1988. Mol. Endocrinol. 2:1237.
2. Hashimoto M, et al. 1992. J. Biol. Chem. 267:4999.
3. Shav-Tal Y and Zipori D. 2002. Stem Cells 20:493.
4. Dohi T et al. 2005. Gastroenterology 128:411.
5. Tsuchida K, et al. 2008. Endocr. J. 55:11.
6. Djouad F, et al. 2010. Steam Cell Res. Ther. 1:11.
7. Sako D, et al. 2010. J. Biol. Chem. 285:21037.
8. Jones CP, et al. 2012. J. Allergy Clin. Immunol. 129:1000.
- Gene ID
- 3624 View all products for this Gene ID
- View information about Activin A on UniProt.org
- Does specific activity of a recombinant protein vary between lots?
Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
- Have your recombinants been tested for stability?
Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
- How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
- Use formula Specific activity (Units/mg) = 10e6/ ED50 (ng/mL)
- How does the activity of your recombinant proteins compare to competitors?
We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
- What is the specific activity or ED50 of my recombinant protein?
The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.