Rabbit Monoclonal Antibody to Activin Receptor Type IIB

Activins are dimeric growth and differentiation factors which belong to the transforming growth factor~beta (TGF~beta) superfamily of structurally related signaling proteins. Activins signal through a heteromeric complex of receptor serine kinases which include at least two type I (I and IB) and two type II (II and IIB) receptors. These receptors are all transmembrane proteins, composed of a ligand~binding extracellular domain with cysteine~rich region, a transmembrane domain, and a cytoplasmic domain with predicted serine/threonine specificity. Type I receptors are essential for signaling; and type II receptors are required for binding ligands and for expression of type I receptors. Type I and II receptors form a stable complex after ligand binding, resulting in phosphorylation of type I receptors by type II receptors. Type II receptors are considered to be constitutively active kinases. This gene encodes activin A type IIB receptor, which displays a 3~ to 4~fold higher affinity for the ligand than activin A type II receptor. [provided by RefSeq, Jul 2008]