Yin and Yang in BMP signaling: Impact on the pathology of diseases and potential for tissue regeneration

Bone morphogenetic proteins (BMPs) are multi-functional growth factors belonging to the transforming growth factor β (TGFβ) superfamily. BMPs are expressed in a large variety of tissues and organs, where they exhibit pleiotropic functions during development as well as in the adult organism. Thus maintenance of the BMP signaling pathways requires strict control and regulation by antagonists, co-receptors and inhibitors. BMPs exert their signals by binding to hetero-oligomeric signaling complexes composed of type I and type II receptors with serine/threonine kinase activity. They play a decisive role in the development of several diseases but are also involved in self-renewal of stem cells and tissue regeneration. These insights may lead to the design of future therapeutic treatments. This review focuses on the differential BMP signaling pathways initiated at distinct oligomerized signaling complexes as well as on the pathological aspects of BMP signaling in diseases and their potential for tissue regeneration.