PTGIR (prostacyclin receptor, IP) is a G protein-coupled receptor that binds prostacyclin (prostaglandin I2 or PGI2). The activity of this receptor is mediated by G(s) proteins which activate adenylate cyclase. PTGIR plays a cardioprotective role and dysfunction contributes to risk for cardiovascular events such as atherothrombosis. It is involved in the vasodilator system and mutations or dysfunction in PTGIR are also thought to contribute to migraine attacks. In immunohistochemistry, PTGIR has membranous positivity in the central nervous system, thymus, on endothelial and smooth muscle cells of the vascular network and at variable levels in most other tissues. References: Curr Mol Med. 2011 Oct;11(7):517-28, PMID: 21707517; Iran J Psychiatry. 2017 Jul; 12(3): 219–222, PMID: 29062375