January 1999, Volume 126, Issue 1, Pages 365 - 371

Original Article

Identification of a region of the C-terminal domain involved in short-term desensitization of the prostaglandin EP4 receptor Murat Bastepe & Barrie Ashby1 Department of Pharmacology, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, Pennsylvania 19140, U.S.A.     1Author for correspondence: E-mail: bashby00@nimbus.temple.edu

Keywords

Prostaglandin EP4 receptor;   cyclic AMP;   agonist-induced desensitization;   deletion mutagenesis;   site-directed mutagenesis

Abstract

1   The prostaglandin EP4 receptor, which couples to stimulation of adenylyl cyclase, undergoes rapid agonist-induced desensitization when expressed in CHO-K1 cells. 2   Truncation of the 488-amino acid receptor at residue 350 removes the carboxy-terminal domain and abolishes desensitization. 3   To further delineate residues involved in desensitization, the receptor was truncated at position 408, 383 or 369. Receptors truncated at position 408 or 383 underwent PGE2-induced desensitization, whereas the receptor truncated at position 369 displayed sustained activity, indicating that the essential residues for desensitization lie between 370 and 383. 4   The six serines in the 14-amino acid segment between residues 370 and 383 were mutated to alanine, retaining the entire C-terminal domain. Desensitization was absent in cells expressing this mutant. 5   The results indicate involvement of serines located between 370 and 382 in rapid desensitization of the EP4 receptor.

Received 21 July 1998; Revised 7 October 1998; Accepted 13 October 1998

^© Macmillan Publishers Ltd 1999