Bone Morphogenetic Protein Receptor II (BMPR-II) is a Type II Serine/Threonine Kinase that mediates cellular responses to BMPs. BMPR-II is characterized by lacking of a GS domain, and presence of a C-terminal extension typical of type II receptors. BMPRII binds BMP2, BMP4 and BMP7 weakly in the absence of type I receptor, and the binding can be facilitated by the presence of the type I receptor, including BMPR-IA/Brk1, BMPR-IB, and ActR-I. BMPR-II plays a key role in cell growth. Defects in BMPR-II have been linked to primary pulmonary hypertension. Human and mouse BMPR-II are highly conserved and share 97 % amino acid sequence identity.