Cloning and expression of three isoforms of the human EP₃ prostanoid receptor

Abstract

Functional cDNA clones coding for three isoforms of the human prostaglandin E receptor EP, subtype have been isolated from kidney and uterus cDNA libraries. The three isoforms, designated hEP,_,, hEP,_,, and hEP,_,,,, have open reading frames corresponding to 390,388 and 365 amino acids, respectively. They differ only in the length and amino acid composition of their carboxy-terminal regions, beginning at position 360. The human EP, receptor has seven predicted transmembrane spanning domains and therefore belongs to the G-protein-coupled receptor family. The rank order of potency for prostaglandins and related analogs in competition for [3H]PGE, specific binding to membranes prepared from transfected COS cells was comparable for all three isoforms, and as predicted for the EP, receptor, with PGEz = PGE, >> PGF, = iloprost > PGD, >> U46619. In addition, the EP,-selective agonist MB28767 was a potent competing ligand with an IC, value of 0.3 nM, whereas the EP,-selective antagonist AH6909 gave IC,, values of 2-7 PM and the EP,-selective agonist butaprost was inactive. In summary, we have cloned three isoforms of the human EP, receptor having comparable ligand binding properties.

Cloning and expression of a cDNA for the human prostacyclin receptor

“…5 shows a comparison of the amino acid sequences among the cloned human prostanoid receptors. The human IP receptor shares 37% overall amino acid identity with human EP, [20] receptor and 34,3 1,29, and 28% identity with human TP [21], EP, [22], EP, [23], and FP [24] receptors, respectively. The amino acid identity is mainly restricted to the transmembrane domains, especially the VII, which is the most conserved, with the V being the least conserved.…”

A specific prostaglandin E2 receptor and its role in modulating salivary secretion in the female tick, Amblyomma americanum (L.)

“…These four PGE receptor subtypes have been cloned from various tissues (Sugimoto et al, 1992;Honda et al, 1993;Watabe et al, 1993;Adam et al, 1994;Breyer et al, 1994;Nam.ha et al, 1994;Regan et al, 1994;Sando et al, 1994;Yang et al, 1994;Nishigaki et al, 1995). The molecular structures show that they contain seven hydrophobic segments corresponding to the putative transmembrane domains, suggesting that they belong to the family of G protein-coupled rhodopsin-type receptors Narumiya, 1996).…”

Assembling NMR structures for the intracellular loops of the human thromboxane A2 receptor: Implication of the G protein-coupling pocket

“…Each prostanoid exerts their function by binding to its specific prostanoid receptor. All known prostanoid receptors belong to the rhodopsin-type G protein-coupled receptor (GPCR) superfamily [3][4][5][6][7][8][9][10][11]. G protein-coupled receptors (GPCRs) form a large superfamily of membrane proteins with seven transmembrane domains [12].…”