Activin A/Inhibin Beta A [H9]

Activin A is a widely expressed homodimer of two beta A chains. Activin A exerts its biological activities by binding to the type 2 serine/threonine kinase Activin RIIA which then noncovalently associates with the type 1 serine/threonine kinase Activin RIB/ALK-4. Signaling through this receptor complex leads to Smad activation and regulation of activin-responsive gene transcription. The bioactivity of Activin A is regulated by a variety of mechanisms. BAMBI, Betaglycan, and Cripto are cell-associated molecules that function as decoy receptors or limit the ability of Activin A to induce receptor complex assembly. The intracellular formation of Activin A can be prevented by the incorporation of the beta A subunit into Activin AC or Inhibin A.