Bone morphogenetic protein receptor type IA, Bone morphogenetic protein receptor type IB, Bone morphogenetic protein receptor type II (BMPR-IA (or BMPR1A), BMPR-IB (or BMPR1B), BMPR-II (or BMPR2))

Bone morphogenetic protein receptor type IA (BMPR-IA/BMPR1A), type IB (BMPR-IB/BMPR1B), and type II (BMPR-II/BMPR2) are transmembrane serine/threonine kinase receptors that function as essential mediators of BMP signaling, a branch of the TGF-beta superfamily signaling network. Upon BMP ligand binding, these receptors form heteromeric complexes (two type I and two type II receptors), in which the constitutively active type II receptor phosphorylates and activates the type I receptor. This in turn leads to intracellular SMAD-dependent signal transduction, regulating diverse processes such as bone and cartilage development, cell fate decisions, and tissue homeostasis. Dysfunction or mutation in these receptors is associated with multiple human diseases, including certain cancers, pulmonary arterial hypertension, and inherited syndromes like juvenile polyposis.

Other names

BMPR1A (BMPR-IA, ALK3, CD292)BMPR1B (BMPR-IB, ALK6)BMPR2 (BMPR-II)ALK: Activin receptor-like kinase, with BMPR-IA = ALK3 and BMPR-IB = ALK6Bone morphogenetic protein type I/II receptorCD292 (for BMPR1A)

Ligand (BMP) binding leads to heterotetrameric complex formation (type I + type II receptors) Type II receptor phosphorylates and activates the type I receptor (serine/threonine kinase activity) Activated type I receptor phosphorylates receptor-regulated SMADs (R-SMADs; SMAD1/5/8), which then modulate gene transcription Inhibition (by kinase inhibitors or decoy receptors) blocks downstream signaling and cellular responses