BMPR2

Bone morphogenetic protein receptor type II or BMPR2 is a serine/threonine receptor kinase. It binds Bone morphogenetic proteins, members of the TGF beta superfamily of ligands. BMPs are involved in host of cellular functions including osteogenesis, cell growth and cell differentiation. Signaling in the BMP pathway begins with the binding of a BMP to the type II receptor. This causes the recruitment of a BMP type I receptor, which it phosphorylates. The Type I receptor phosphorylates an R-SMAD a transcriptional regulator.

Function

Unlike the TGFβ type II receptor, which has a high affinity for TGF-β1, BMPR2 does not have a high affinity for BMP-2, BMP-7 and BMP-4, unless it is co-expressed with a type I BMP receptor^[1]. In TGF beta signaling all of the receptors exist in homodimers before ligand binding. In the case of BMP receptors only a small fraction of the receptors exist in homomeric forms before ligand binding. Once a ligand has bound to a receptor, the amount of homomeric receptor oligomers increase, suggesting that the equilibrium shifts towards the homodimeric form^[1]. The low affinity for ligands suggests that BMPR2 may differ in the from other type II TGF beta receptors in that the ligand may bind the type I receptor first^[2].

An inactivating mutation in the BMPR2 gene has been linked to primary pulmonary hypertension. ^[3]

References

1. ^ ^{a b} Gilboa, L; Nohe A, Geissendorfer T, Sebald W, Henis YI, Knaus P. (March 2000). "Bone morphogenetic protein receptor complexes on the surface of live cells: a new oligomerization mode for serine/threonine kinase receptors". Mol Biol Cell. 11 (3). http://www.molbiolcell.org/cgi/content/full/11/3/1023. Retrieved on 2006-07-03. 
2. ^ Kirsch, T; Nickel J, Sebald W. (July 2000). "BMP-2 antagonists emerge from alterations in the low-affinity binding epitope for receptor BMPR-II". Embo J. 19 (13): 3314. doi:10.1093/emboj/19.13.3314. PMID 10880444. http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=10880444. Retrieved on 2006-07-03. 
3. ^ http://www.genomenewsnetwork.org/articles/08_00/pulmonary_BMPR2.shtml

BMPR2 functions (among others) to inhibit the proliferation of vascular smooth muscle so when this gene is altered vascular smooth muscle proliferates and leads to pulmonary hypertension which among other things can lead to cor pulmonale. (robbins and cotran for usmle step 1).