Cloning and expression of the EP3-subtype of human receptors for prostaglandin E2.

Prostaglandin E2 (PGE2) is a potent mediator in many human tissues that is recognized by three distinct subtypes of receptors (Rs), designated EP1, EP2 and EP3. A cDNA from a human kidney library encodes a 367 amino acid protein, of 85% homology with the mouse EP3R, that is expressed predominantly in kidney tissue. Human EP3Rs of transfectants bound [3H]-PGE2 with a mean Kd of 2.6 nM and native specificity. In contrast to the reliance of EP2RS on increases in the intracellular concentration of cyclic AMP ([cAMP]i) for cellular signaling, EP3Rs transduce both decreases in [cAMP]i and modest increases in [Ca++]i.