CLONING AND EXPRESSION OF A CDNA FOR THE HUMAN PROSTAGLANDIN-E RECEPTOR-EP(1) SUBTYPE

A functional cDNA clone coding for the human prostaglandin E receptor EP1 subtype has been isolated from a human erythroleukemia cell cDNA l ibrary probed by low-stringency hybridization using a polymerase chain reaction fragment of the human thromboxane receptor. The human EP1 re ceptor is comprised of 402 amino acids with a predicted molecular mass of 41,858 and has the topography common to all G-protein-coupled rece ptors with seven predicted transmembrane spanning domains. Prostagland in (PG) E2 challenge of Xenopus oocytes injected with EP1 cDNA resulte d in an increase in intracellular Ca2+. In addition, the rank order of potency for prostaglandins in competition for [H-3]PGE2 specific bind ing to membranes prepared from EP1 cDNA transfected COS cells was PGE2 > PGE1 > PGF2alpha > PGD2. Furthermore, the EP1 receptor-selective an tagonists AH 6809 and SC19220 were more potent than the EP2 receptor-s elective agonist butaprost in these competition binding assays. In sum mary, therefore, we have cloned the human EP1 receptor subtype which i s functionally coupled to an increase in intracellular Ca2+.