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

J. Biol. Chem., Vol. 281, Issue 40, 29949-29961, October 6, 2006

This Article Full Text Full Text (PDF) All Versions of this Article: 281/40/29949    most recent M602262200v1 Alert me when this article is cited 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 Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Paquet, M. Articles by Hall, R. A. Search for Related Content PubMed PubMed Citation Articles by Paquet, M. Articles by Hall, R. A. Social Bookmarking                      What's this?

The PDZ Scaffold NHERF-2 Interacts with mGluR5 and Regulates Receptor Activity^*

Maryse Paquet, Matthew J. Asay, Sami R. Fam, Hiroyuki Inuzuka, Amanda M. Castleberry, Heide Oller, Yoland Smith^¶, C. Chris Yun^||, Stephen F. Traynelis, and Randy A. Hall¹

From the Department of Pharmacology, the Department of Neurology, the ^¶Yerkes National Primate Research Center, and the ^||Division of Digestive Disease, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322

The two members of the group I metabotropic glutamate receptor family, mGluR1 and mGluR5, both couple to G_q to mediate rises in intracellular calcium. The alternatively spliced C termini (CT) of mGluRs1&5are known to be critical for regulating receptor activity and to terminate in motifs suggestive of potential interactions with PDZ domains. We therefore screened the CTs of both mGluR1a and mGluR5 against a PDZ domain proteomic array. Out of 96 PDZ domains examined, the domain that bound most strongly to mGluR5-CT was the second PDZ domain of the Na⁺/H⁺ exchanger regulatory factor 2 (NHERF-2). This interaction was confirmed by reverse overlay, and a single point mutation to the mGluR5-CT was found to completely disrupt the interaction. Full-length mGluR5 robustly associated with full-length NHERF-2 in cells, as assessed by co-immunoprecipitation and confocal microscopy experiments. In contrast, mGluR1a was found to bind NHERF-2 in vitro with a weaker affinity than mGluR5, and furthermore mGluR1a did not detectably associate with NHERF-2 in a cellular context. Immunohistochemical experiments revealed that NHERF-2 and mGluR5 exhibit overlapping patterns of expression in mouse brain, being found most abundantly in astrocytic processes and postsynaptic neuronal elements. In functional experiments, the interaction of NHERF-2 with mGluR5 in cells was found to prolong mGluR5-mediated calcium mobilization and to also potentiate mGluR5-mediated cell death, whereas coexpression of mGluR1a with NHERF-2 had no evident effects on mGluR1a functional activity. These observations reveal that NHERF-2 can selectively modulate mGluR5 signaling, which may contribute to cell-specific regulation of mGluR5 activity.

Received for publication, March 10, 2006 , and in revised form, August 3, 2006.

^* This work was supported in part by National Institutes of Health grants (to R. A. H., Y. S., S. F.T., and C. C. Y.), a W. M. Keck Foundation award (to R. A. H.), and an National Institutes of Health base grant to the Yerkes Primate Center. 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.

¹ To whom correspondence should be addressed: Dept. of Pharmacology, Emory University School of Medicine, 5113 Rollins Research Center, 1510 Clifton Rd., Atlanta, GA 30322. Tel.: 404-727-3699; Fax: 404-727-0365; E-mail: rhall{at}pharm.emory.edu.

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