Structure and function of the prostanoid receptors.

Prostanoids, which consist of the prostaglandins (PGs) and the thromboxanes (TXs), exert a variety of actions in the body, which are mediated via specific cell surface receptors. They consist of five types of receptors named the TP, IP, EP, FP and DP receptors. The EP receptor have four subtypes, the EP1, EP2, EP3 and EP4 receptors. However, none of the receptors had been isolated and cloned until the TXA2 receptor was purified from human blood platelets and its cDNA cloned. By homology screening in mouse cDNA libraries, the structures of all of the mouse prostanoid receptors have been identified.These studies have clearly shown that all of the prostanoid receptors belong to the G-protein-coupled, rhodopsin-type receptor superfamily, and that they constitute a new subfamily of receptors. On the other hand, their ligand binding characteristics and signal transduction were studied using the expresson system of the cloned receptors. These studies have clarified the structure and function of the prostanoid receptors.