Description
Activins are homodimers or heterodimers of the various beta subunit isoforms, belonging to the TGF-beta family. Mature Activin B has two chains of 123 amino acids residues (betaB-betaB). Activin exhibits a wide range of biological activities, including mesoderm induction, neural cell differentiation, bone remodelling, haematopoiesis, and reproductive physiology. Activins plays a key role in the production and regulation of hormones such as FSH, LH, GnRH and ACTH. Inhibins/Activins are protein that are formed by the dimerization of two subunits, i. e. an α (alpha) with either beta A (betaA) - Inhibin A or beta B (betaB) - Inhibin B. The subunits betaA and betaB can also form homodimers or heterodimers called Activin: Activin A (betaA -betaA), Activin B (betaB -betaB) and Activin AB (betaA -betaB). The Activin gene family comprises the additional, but poorly characterized members" Activin betaC (betaC), beta D (betaD) and beta E (betaE). As with other members of the super-family, Activins interact with two types of cell surface trans-membrane receptors (Types I and II) which have intrinsic serine/threonine kinase activities in their cytoplasmic domains, Activin type 1 receptors, ACVR1, ACVR1B, ACVR1C and Activin type 2 receptors, ACVR2A, ACVR2B