Cloning and expression of a cDNA for the human prostacyclin receptor

Abstract

A functional cDNA for the human prostacyclin receptor was isolated from a cDNA library of CMK cells, a human megakaryocytic leukaemia cell line. The cDNA encodes a protein consisting of 386 amino acid residues with seven putative transmembrane domains and a deduced molecular weight of 40,956. [³H]Iloprost specifically bound to the membrane of CHO cells stably expressing the cDNA with a Kd of 3.3 nM. This binding was displaced by unlabelled prostanoids in the order of iloprost = cicaprost ⪢ carbacyclin ⪢ prostaglandin E₁ (PGE₁) > STA₂. PGE₂, PGD₂ and PGF_2α did not inhibit it. Iloprost in a concentration‐dependent manner increased the cAMP level and generated inositol trisphosphate in these cells, indicating that this human receptor can couple to multiple signal transduction pathways.