Reproduced with permission from [34].
Figure 1: Mutations in BMPR2 and ALK-1 in the development of idiopathic pulmonary arterial hypertension.
Top Diagram:In the normal vascular smooth muscle cell binding of the BMP ligand to the complex of BMPR-I and BMPR-II and subsequent phosphorylation of Smad 1, 2 and 8 modulates transcription resulting in growth arrest. Mutations BMPR-II lead to defective Smad signaling resulting in increased cell proliferation.
Bottom Diagram: In pulmonary endothelial cells mutations in both ALK-1 and endoglin finally promote loss of cell growth regulation. A mechanism which is also involved in hemorrhagic telangiectasia.