Both type 1 and 2 bone morphogenetic protein receptors have a single transmembrane segment. Additionally, both types have a cysteine-rich extracellular domain and a cytoplasmic serine threonine kinase domain.[3] Type 1 contains a glycine-serine-rich domain to be phosphorylated by type 2 kinase domain, initiating the signaling transduction pathway of the SMAD signaling cascade.[3] The wrist epitope motif on BMP-2 has a high-affinity binding site for BMPR-IA. The knuckle epitope motif on BMP-2 has a low-affinity binding site for BMPR-II.[4]
^Pasche B (December 2008). "The TGF Family. Cold Spring Harbor Monograph Series, Volume 50. Edited by Rik Derynck, Kohei Miyazono. Cold Spring Harbor (New York): Cold Spring Harbor Laboratory Press. xiv-1114 p.; ill.; index. 9780879697525. 2008". The Quarterly Review of Biology. 83 (4): 405–405. doi:10.1086/596254.
^ abMace PD, Cutfield JF, Cutfield SM (December 2006). "High resolution structures of the bone morphogenetic protein type II receptor in two crystal forms: implications for ligand binding". Biochemical and Biophysical Research Communications. 351 (4): 831–8. doi:10.1016/j.bbrc.2006.10.109. PMID17094948.
^Miyazono K, Shimanuki T (January 2008). "Chapter 55: Bone morphogenetic protein receptors and actions.". In Bilezikian JP, Raisz LG, Martin TJ (eds.). Principles of bone biology (Third ed.). San Diego: Academic Press. pp. 1177–1196. doi:10.1016/B978-0-12-373884-4.00069-0. ISBN978-0-12-373884-4.