HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 279, Issue 37, 38386-38394, September 10, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/37/38386    most recent M405335200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wietfeld, D. Articles by Berger, H. Search for Related Content PubMed PubMed Citation Articles by Wietfeld, D. Articles by Berger, H. Social Bookmarking                      What's this?

Regulation of the Coupling to Different G Proteins of Rat Corticotropin-releasing Factor Receptor Type 1 in Human Embryonic Kidney 293 Cells^*

Doreen Wietfeld, Nadja Heinrich, Jens Furkert, Klaus Fechner, Michael Beyermann, Michael Bienert, and Hartmut Berger

From the Institute of Molecular Pharmacology, Robert-Rössle-Strasse 10, Berlin 13125, Germany

The regulation of G protein activation by the rat corticotropin-releasing factor receptor type 1 (rCRFR1) in human embryonic kidney (HEK)293 (HEK-rCRFR1) cell membranes was studied. Corresponding to a high and low affinity ligand binding site, sauvagine and other peptidic CRFR1 ligands evoked high and low potency responses of G protein activation, differing by 64-fold in their EC₅₀ values as measured by stimulation of [³⁵S]GTPS binding. Contrary to the low potency response, the high potency response was of lower GTPS affinity, pertussis toxin (PTX)-insensitive, and homologously desensitized. Distinct desensitization was also observed in the adenylate cyclase activity, when its high potency stimulation was abolished and the activity became low potently inhibited by sauvagine. From these results and immunoprecipitation of [³⁵S]GTPS-bound G_s and G_i subunits it is concluded that the high and low potency [³⁵S]GTPS binding stimulation reflected coupling to G_s and G_i proteins, respectively, only G_s coupling being homologously desensitized. Immunoprecipitation of [³⁵S]GTPS-bound G_q/11 revealed additional coupling to G_q/11, which also was homologously desensitized. Although G_q/11 coupling was PTX-insensitive, half of the sauvagine-stimulated accumulation of inositol phosphates in the cells was PTX-sensitive, suggesting involvement of G_i in addition to G_q/11in the stimulation of inositol metabolism. It is concluded that CRFR1 signals through at least two different ways, one leading to G_s- and G_q/11-mediated signaling steps and desensitization and another leading to G_i -mediated signals without being desensitized. Furthermore, the concentrations of the stimulating ligand and GTP and desensitization may be part of a regulatory mechanism determining the actual ratio of the coupling of CRFR1 to different G proteins.

Received for publication, May 13, 2004 , and in revised form, July 1, 2004.

^* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

To whom correspondence should be addressed. Tel.: 49-30-94793-273; Fax: 49-30-94793-159; E-mail: berger{at}fmp-berlin.de.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				M. Alken, A. Schmidt, C. Rutz, J. Furkert, G. Kleinau, W. Rosenthal, and R. Schulein The Sequence after the Signal Peptide of the G Protein-Coupled Endothelin B Receptor Is Required for Efficient Translocon Gating at the Endoplasmic Reticulum Membrane Mol. Pharmacol., April 1, 2009; 75(4): 801 - 811. [Abstract] [Full Text] [PDF]

				M. F. Mesleh, W. A. Shirley, C. E. Heise, N. Ling, R. A. Maki, and R. P. Laura NMR Structural Characterization of a Minimal Peptide Antagonist Bound to the Extracellular Domain of the Corticotropin-releasing Factor1 Receptor J. Biol. Chem., March 2, 2007; 282(9): 6338 - 6346. [Abstract] [Full Text] [PDF]

				C. Rutz, A. Renner, M. Alken, K. Schulz, M. Beyermann, B. Wiesner, W. Rosenthal, and R. Schulein The Corticotropin-releasing Factor Receptor Type 2a Contains an N-terminal Pseudo Signal Peptide J. Biol. Chem., August 25, 2006; 281(34): 24910 - 24921. [Abstract] [Full Text] [PDF]

				E. W. Hillhouse and D. K. Grammatopoulos The Molecular Mechanisms Underlying the Regulation of the Biological Activity of Corticotropin-Releasing Hormone Receptors: Implications for Physiology and Pathophysiology Endocr. Rev., May 1, 2006; 27(3): 260 - 286. [Abstract] [Full Text] [PDF]