[Function, molecular structure and gene expression regulation of erythroid differentiation factor (EDF/activin A)].

: Erythroid differentiation factor (EDF), initially found as a differentiation inducer of murine erythroleukemia cells, also acts on normal erythroid progenitors in vitro and in vivo. Furthermore, it is produced endogenously and supporting in vivo erythropoiesis. EDF is structurally identical to activin A, a gonadal protein with follicle stimulating hormone releasing activity, and belongs to TGF beta superfamily. Its activity could be regulated by follistatin, a binding protein with neutralizing activity against EDF/activin A. Molecular cloning of EDF/activin A receptor cDNA has revealed its domain structure characteristic to serine/threonine kinase.