The bone morphogenetic protein receptor, type IA is also known as BMPR1A or ALK3 is a protein which in humans is encoded by the BMPR1A gene. BMPR1A has also been designated as CD292 (cluster of differentiation 290). The bone morphogenetic protein (BMP) receptors are a family of transmembrane serine/threonine kinases that include the type I receptors BMPR1A (this protein) and BMPR1B and the type II receptor BMPR2. These receptors are also closely related to the activin receptors, ACVR1 and ACVR2. Alk3-mediated BMP signaling in AV endocardial/mesenchymal cells plays a central role during cushion morphogenesis.