INHBA (Inhibin, β A) is a morphogen belonging to the TGFβ superfamily. It encodes a protein reffered to as activin A. It is expressed in both α- and β-cells of pancreatic islets. It is composed of two nearly anti-parallel activin A monomers separated by a 2-fold symmetry axis. Each monomer consists of the canonical TGF-β fold.
INHBA (Inhibin, β A) is associated with various cellular activities such as cell differentiation, proliferation, activation and apoptosis. It has binding affinity for both the type I and type II serine/threonine kinase receptors. INHBA directly binds to the extracellular domain of the type II receptor, ActRIIB, which further adhere to the outer edges of the activin finger regions. It controls genetic expression of islet β cells. In non-small cell lung cancer (NSCLC), it acts as an autocrine factor in the maintenance of mesenchymal properties of cancer-initiating cells (CICs) to promote metastasis.
