Activins Family

1. Activins Family Overview Activins, members of the TGF-beta superfamily, are disulfide-linked dimeric proteins originally purified from gonadal fluids as proteins that stimulated pituitary follicle stimulating hormone (FSH) release. Identified in 1986, activin enhances FSH biosynthesis and secretion, and participates in the regulation of the menstrual cycle. Many other functions have been found to be exerted by activin, including roles in cell proliferation, differentiation, apoptosis, metabolism, homeostasis, immune response, wound repair, and endocrine function. Activins Structure Activin is a dimer composed of two identical or very similar beta subunits. However, in contrast to activin, the second component of the inhibin dimer is a more distantly-related alpha subunit. The activin protein complexes are both dimeric in structure, and, in each complex, the two monomers are linked to one another by a single disulfide bond. The following is a list of the most common activin complexes and their subunit composition: Table 1. Activin complexes and their subunit composition Dimer subunits Class Activity Complex 1 2 Activin A βA βA Activin stimulates FSH secretion Activin AB βA βB Activin B βB βB

2. In mammals, four beta subunits have been described, called activin βA, activin βB, activin βC and activin βE. A fifth subunit, activin βD, has been described in Xenopus laevis. Two activin βA subunits give rise to activin A, one βA, and one βB subunit gives rise to activin AB, and so on. Various, but not all theoretically possible, heterodimers have been described. The subunits are linked by a single covalent disulfide bond. The βC subunit is able to form activin heterodimers with βA or βB subunits. Members of activins family Table 2. Activins family related products Activins Activin Activin Receptor Type IA Activin RIIB ACVR1 Activins Receptor ACVR1B ACVR1C ACVR2A ACVR2B ACVRL1 Follistatin FSTL1 FSTL3 Activins Modulators FSTL4 FSTL5 Cellular functions Activin is produced in the gonads, pituitary gland, placenta, and other organs: In the ovarian follicle, activin increases FSH binding and FSH-induced aromatization. It participates in androgen synthesis enhancing LH action in the ovary and testis. In the male, activin enhances spermatogenesis.  https://www.creative-diagnostics.com/activins-family.htm