Activin A Protein, Mouse (HEK 293, His)

Activin A, a multifunctional cytokine, is a member of TGF-β superfamily. Activin A first binds to the type II activin receptors (ActIIRA or ActRIIB) on the member surface, and then recruits and phosphorylates type I activin receptors (ActRI). Activin A primarily signal through SMAD2/3 proteins to regulate a variety of functions, including inflammation, fibrosis, and tumorigenesis^[1]. Activin A Protein, Mouse (HEK293, His) is produced in HEK293 cellswith a C-Terminal His-tag. It  consists of 424 amino acids (M1-S424).

Activin is a member of transforming growth factor-β (TGF-β) superfamily consisting of two inhibin β subunits linked by disulfide bonds. Activin A is expressed widely in various tissues and cells with strong bioactivities and is the mostly studied activin^[1].
The sequence of amino acids in Activin A proteins from different species is very stable, which leads to the conclusion that in the process of evolution, Activin A has been only slightly altered, and that both in humans and in animals, its function is similar.
Activin exists in three basic molecular forms composed of two inhibin β subunits: activin A (βAβA), activin B (βBβB), and activin AB (βAβB). Activin A binds with high affinity to activin type II receptors, which recruit type I receptors and are necessary for the activation of Smad2/3 signaling. The phosphorylated ActRI activates Smad2 and Smad3, which form a complex with Smad4 to translocate to the nucleus. Activin and TGF-β share the same signaling pathway at the level of Smad2/3/4. Activin A exerts a variety of biological functions including regulation of hematopoietic cell proliferation, neuron differentiation, pituitary hormone secretion, and tissue repair. It is also involved in the process of many diseases, for example, inflammation, fibrosis and tumorigenesis^[1][2].
Activin A has pro- and anti-tumorigenic functions depending on the tumor type. In breast, liver and colon cancers, activin signals were revealed to inhibit tumor cell growth. In addition, tumor tissues were revealed to express decreased levels of activin A or increased levels of activin antagonists or demonstrated the downregulation of activin receptors or Smad proteins. Moreover, its roles include embryonic differentiation, trophoblast invasion of the uterine wall in early pregnancy, and fetal/neonate brain protection in hypoxic conditions. Activin A also regulates bone formation and regeneration, enhances joint inflammation in rheumatoid arthritis, and triggers pathogenic mechanisms in the respiratory system^[1][2].

Recombinant Activin A (-1 ng/mL; for 12 and 24 h) inhibits the proliferation of myeloma cell line NS-1 cells and induces NS-1 cell apoptosis. Activin A upregulates the expression of CHOP, GADD34, caspase-3, and caspase-12. Moreover, both Smad3 and p-Smad3 levels are increased with treatment of activin A in NS-1 cells^[1].

Recombinant Activin A (2 ng/1 µL; intratumoral injection; for 6 days) inhibits the growth of solid tumors in tumor-bearing mice with NS-1 cells^[1].

1.Measured in a cell proliferation assay using HT-29 human colon cancer cell. The ED₅₀ for this effect is 6.407 ng/mL, corresponding to a specific activity is 1.561×10⁵ units/mg.
2.Measured by its ability to inhibit proliferation of MPC-11 cells. The ED₅₀ for this effect is typically 0.8-4 μg/mL.
3.Measured by its ability in a ELISA.
3.1. Immobilized human ACVR2B at 10 μg/mL (100 μl/well) can bind biotinylated mouse INHBA-His, The EC₅₀ of biotinylated mouse INHBA-His is 0.161 μg/mL.
3.2 Immobilized mouse INHBA-his at 10 μg/mL (100 μl/well) can bind human Follistatin Protein, The EC₅₀ of human Follistatin Protein is 0.39 μg/mL.

Mouse

HEK293

C-His

Q3UY39 (S21-S424)

16323  [NCBI]

Approximately 18&43 kDa

Greater than 90% as determined by reducing SDS-PAGE

Lyophilized powder

Lyophilized from a 0.2 μm filtered solution of PBS or 20 mM PB, 150 mM NaCl, pH 7.4

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.

• [1]. Ge J, et al. Involvement of CHOP in activin A induced myeloma NS 1 cell apoptosis. Oncol Rep. 2019;42(6):2644-2654.  [Content Brief]

  [2]. Enrrico Bloise, et al. Activin A in Mammalian Physiology. Physiol Rev. 2019 Jan 1;99(1):739-780.  [Content Brief]