Cloning of a novel human prostaglandin receptor with characteristics of the pharmacologically defined EP2 subtype.
A cDNA that when expressed has the binding and functional characteristics of the pharmacologically defined EP2 prostaglandin (PG) receptor [Cardiovasc. Drug Rev. 11:165-179 (1993)] has been cloned from a human placenta library. This clone, known as Hup-4, encodes a protein of 358 amino acids that has only approximately 30% overall identity with other PG receptors, including mouse and human clones that have been designated as EP2 receptors [J. Biol. Chem. 268:7759-7762 (1993); Biochem. Biophys. Res. Commun. 197:263-270 (1993)]. In COS-7 cells transfected with Hup-4, PGE2 stimulated the formation of cAMP with an EC50 of approximately 50 nM. The EP2-selective agonists AH13205 and butaprost were also active, with EC50 values in the range of 2-6 microM. The order of potency of PGs for competition with binding of [3H]PGE2 to membranes prepared from COS-7 cells transfected with Hup-4 was PGE2 > or = PGE1 > 16,16-dimethyl-PGE2 > or = 11-deoxy-PGE1 > butaprost > AH13205 > 19(R)-OH-PGE2. Natural PGs and analogues that are selective for the FP (PGF2a), DP (PGD2), EP1 (sulprostone), EP3 (MB 28767), and EP4 (1-OH-PGE1) receptors were inactive or competed poorly with the binding of [3H]PGE2 (< 50% displacement of specific binding at 10 microM). Northern blot analysis showed the presence of a Hup-4 message of approximately 3.1 kilobases in mRNA from human lung and placenta. Reverse transcription-polymerase chain reaction studies also indicated that Hup-4 is probably expressed in human uterus and in HL-60 (human promyelocytic leukemia) cells. Our findings suggest that Hup-4 encodes the pharmacologically defined EP2 receptor, whereas the mouse and human cDNAs previously classified as EP2 may represent another EP receptor subtype or the recently defined EP4 subtype [Prostaglandins 47:151-168 (1994)].
Regan
J W
JW
Department of Pharmacology and Toxicology, University of Arizona, Tucson 85721.
Bailey
T J
TJ
Pepperl
D J
DJ
Pierce
K L
KL
Bogardus
A M
AM
Donello
J E
JE
Fairbairn
C E
CE
Kedzie
K M
KM
Woodward
D F
DF
Gil
D W
DW
D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary; D004789:Enzyme Activation; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018078:Receptors, Prostaglandin E / Q000235:genetics* / Q000378:metabolism; D015290:Second Messenger Systems
D018076:DNA, Complementary; D012333:RNA, Messenger; D018078:Receptors, Prostaglandin E; D000242:Cyclic AMP; D000262:Adenylyl Cyclases