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

J. Biol. Chem., Vol. 282, Issue 29, 21285-21300, July 20, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/29/21285    most recent M701555200v1 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 Free, R. B. Articles by Sibley, D. R. Search for Related Content PubMed PubMed Citation Articles by Free, R. B. Articles by Sibley, D. R. Social Bookmarking                      What's this?

D₁ and D₂ Dopamine Receptor Expression Is Regulated by Direct Interaction with the Chaperone Protein Calnexin^*

From the Molecular Neuropharmacology Section, NINDS, National Institutes of Health, Bethesda, Maryland 20892-9405

As for all proteins, G protein-coupled receptors (GPCRs) undergo synthesis and maturation within the endoplasmic reticulum (ER). The mechanisms involved in the biogenesis and trafficking of GPCRs from the ER to the cell surface are poorly understood, but they may involve interactions with other proteins. We have now identified the ER chaperone protein calnexin as an interacting protein for both D₁ and D₂ dopamine receptors. These protein-protein interactions were confirmed using Western blot analysis and co-immunoprecipitation experiments. To determine the influence of calnexin on receptor expression, we conducted assays in HEK293T cells using a variety of calnexin-modifying conditions. Inhibition of glycosylation either through receptor mutations or treatments with glycosylation inhibitors partially blocks the interactions with calnexin with a resulting decrease in cell surface receptor expression. Confocal fluorescence microscopy reveals the accumulation of D₁-green fluorescent protein and D₂-yellow fluorescent protein receptors within internal stores following treatment with calnexin inhibitors. Overexpression of calnexin also results in a marked decrease in both D₁ and D₂ receptor expression. This is likely because of an increase in ER retention because confocal microscopy revealed intracellular clustering of dopamine receptors that were co-localized with an ER marker protein. Additionally, we show that calnexin interacts with the receptors via two distinct mechanisms, glycan-dependent and glycan-independent, which may underlie the multiple effects (ER retention and surface trafficking) of calnexin on receptor expression. Our data suggest that optimal receptor-calnexin interactions critically regulate D₁ and D₂ receptor trafficking and expression at the cell surface, a mechanism likely to be of importance for many GPCRs.

Received for publication, February 21, 2007

^* This work was supported in part by the Intramural Research Program of NINDS, National Institutes of Health. 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 Recipient of an NINDS Competitive Fellowship from the National Institutes of Health.

² Recipient of an NIGMS Pharmacology Research Associate Program Fellowship.

³ To whom correspondence should be addressed: Molecular Neuropharmacology Section, NINDS, National Institutes of Health, 5625 Fishers Ln., Rm. 4S-04, MSC 9405, Bethesda, MD 20892-9405. Tel.: 301-496-9316; Fax: 301-480-3726; E-mail: sibley{at}helix.nih.gov.

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

This article has been cited by other articles:

				R. Glozman, T. Okiyoneda, C. M. Mulvihill, J. M. Rini, H. Barriere, and G. L. Lukacs N-glycans are direct determinants of CFTR folding and stability in secretory and endocytic membrane traffic J. Cell Biol., March 23, 2009; 184(6): 847 - 862. [Abstract] [Full Text] [PDF]

				L. Achour, M. G. H. Scott, H. Shirvani, A. Thuret, G. Bismuth, C. Labbe-Jullie, and S. Marullo CD4-CCR5 interaction in intracellular compartments contributes to receptor expression at the cell surface Blood, February 26, 2009; 113(9): 1938 - 1947. [Abstract] [Full Text] [PDF]

				S. Kaewsuk, R. K. Tannenberg, S.-W. Kuo, S. T. Bjorkman, P. Govitrapong, A. Stadlin, and P. R. Dodd Regional Expression of Dopamine D1 and D2 Receptor Proteins in the Cerebral Cortex of Asphyxic Newborn Infants J Child Neurol, February 1, 2009; 24(2): 183 - 193. [Abstract] [PDF]

				L. A. Hazelwood, R. B. Free, D. M. Cabrera, M. Skinbjerg, and D. R. Sibley Reciprocal Modulation of Function between the D1 and D2 Dopamine Receptors and the Na+,K+-ATPase J. Biol. Chem., December 26, 2008; 283(52): 36441 - 36453. [Abstract] [Full Text] [PDF]

				P. M. H. Markkanen and U. E. Petaja-Repo N-Glycan-mediated Quality Control in the Endoplasmic Reticulum Is Required for the Expression of Correctly Folded {delta}-Opioid Receptors at the Cell Surface J. Biol. Chem., October 24, 2008; 283(43): 29086 - 29098. [Abstract] [Full Text] [PDF]

				G. D. Stanwood Protein-Protein Interactions and Dopamine D2 Receptor Signaling: A Calcium Connection Mol. Pharmacol., August 1, 2008; 74(2): 317 - 319. [Abstract] [Full Text] [PDF]