activin a

Activin A is a dimeric protein belonging to the transforming growth factor-beta (TGF-β) superfamily. It is composed of two βA subunits and functions as a hormone, growth factor, and cytokine. Activin A regulates numerous physiological processes including cellular proliferation and differentiation, embryonic development, reproductive function (notably by enhancing follicle-stimulating hormone biosynthesis), wound healing, bone formation and regeneration, immune modulation, and neuronal survival. In cancer biology, activin A promotes tumor cell growth and migration, contributes to immune evasion and cachexia (muscle wasting), and is associated with poor prognosis in several cancers. Elevated levels are implicated in diseases such as colorectal cancer, breast cancer (especially postmenopausal women), rheumatoid arthritis (joint inflammation), fibrodysplasia ossificans progressiva (FOP; abnormal bone formation), metabolic disorders like atherosclerosis (where it can be protective when expressed in the liver), pulmonary arterial hypertension via its signaling pathway effects on vascular remodeling/inflammation, as well as roles in stem cell differentiation toward mesoendodermal lineages[1][3][5][6][8]. Activin A exerts its effects by binding to type II activin receptors which recruit type I receptors leading to SMAD2/3 phosphorylation—a canonical TGF-β signaling cascade[4][5]. Its biological activity can be neutralized by inhibins or follistatin.

Other names

inhibin beta A chainINHBATGF-beta family member