Activin A

Recombinant human protein Activin A: An Alpha in the TGF Beta Family

One of the defining characteristics of life is the ability to reproduce. In humans, a major player in setting up and maintaining reproductive machinery is activin A. It is a heterodimeric protein that is a member of the TGF Beta family (Figure 1). Activin A acts in paracrine and autocrine mechanisms, binding to its cognate receptor and exerting downstream effects through the Smad pathway (Figure 2). Besides reproduction, activin A has been implicated in the regulation of islets and the immune response. For regenerative medicine, it is used to help maintain stem cell pluripotency and self-renewal in vitro (1, 2).

Proteintech’s HumanKine® Activin A

Proteintech’s HumanKine® Activin A is made from HEK293 human cells, conferring authentic glycosylation and folding in addition to superior stability and activity.

Product name	Catalog number	ED50	Purity
Activin A	HZ-1138	3.4 ng/mL	>95%

Animal-free recombinant proteinsHumankine® products are created in HEK293 cells using animal-free components. Our human expression system ensures that proteins have native conformation and post-translational modifications to optimize biological activity.
Animal-free Lyophilized and Carrier Free (CF)	Expressed in human cells Endotoxin free

Discovery of Activin A

Activin A’s discovery was published by two groups in back-to-back Nature papers (3, 4). Both identified it using purified extracts of pig follicular fluid. The extracts containing activin A were found to stimulate the release of follicle-stimulating hormone from rat anterior pituitary cells and were biochemically characterized. Subsequent studies discovered that it plays integral roles in reproduction. It is critical for female fertility with roles in development and luteolysis (5). For males, deficiency can impact testes size and function (6). Mutations of activin A are also associated with reproductive cancers (7).

There is much excitement surrounding activin A in the literature. It has recently been identified as a promising biomarker for kidney injury (8) and has been implicated in lung (9) and breast (10) cancers. Reproduction may have been the start of activin A’s scientific story, but there is still more to be told.

Figure 1

SDS-PAGE gel with Coomassie blue staining of purified activin A from CHO cell and HumanKine® systems, demonstrating the formation of mature activin A dimers.

Figure 2

Activity of HumanKine® Activin A determined by the dose-dependent inhibition of proliferation of the MPC11 cell line

The activity of HumanKine® Activin A was determined by the dose-dependent inhibition of proliferation of the MPC11 cell line (mouse plasmacytoma cell line) using Promega CellTiter96® Aqueous Non-Radioactive Cell Proliferation Assay.

Figure 3