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

J. Biol. Chem., Vol. 281, Issue 6, 3067-3074, February 10, 2006

This Article Full Text Full Text (PDF) All Versions of this Article: 281/6/3067    most recent M506721200v1 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 Google Scholar Google Scholar Articles by Chen, Y. L. Articles by Loh, H. H. Search for Related Content PubMed PubMed Citation Articles by Chen, Y. L. Articles by Loh, H. H. Social Bookmarking                      What's this?

Sustained Activation of Phosphatidylinositol 3-Kinase/Akt/Nuclear Factor B Signaling Mediates G Protein-coupled -Opioid Receptor Gene Expression^*

From the Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455

Expression of the -opioid receptor gene (dor) is tightly controlled during neuronal differentiation and developmental stages. Such distinct temporal and spatial expression of dor during development suggests a role for the -opioid receptor in early developmental events. However, little is known about intracellular signaling pathways that control dor expression. A well established cell line model for the study of gene expression during neuronal differentiation is the rat adrenal pheochromocytoma PC12 cell line. Here we found that the constitutively activated TrkA/phosphatidylinositol 3-kinase/Akt (protein kinase B)/NF-B survival cascade mediates dor expression during nerve growth factor (NGF)-induced differentiation of PC12h cells. Biochemical experiments showed that constitutive phosphorylation of Akt and IB correlates with NGF-induced dor expression. Overexpression of the transcriptional activator NF-B/p65 increased dor promoter activity. Overexpression of the NF-B signaling super inhibitor mutant IB (S32A/S36A) abolished the effect of p65 and blocked NGF-induced activation of NF-B signaling, resulting in a significant reduction in dor promoter activity. Treatment with SN50, an NF-B-specific nuclear translocation peptide inhibitor, inhibited the translocation of NF-B, resulting in a reduction of dor mRNA. The gel shift assay supported the fact that there exists an NF-B-binding site on the dor promoter. RNA interference experiments using NF-B/p65 small interfering RNA confirmed that NF-B signaling is required for dor expression. Our findings not only provide a new mechanistic explanation for NGF-induced dor expression but also shed some light on the molecular mechanism of the temporal and spatial expression of dor and the roles of the -opioid receptor during neuronal differentiation.

Received for publication, June 21, 2005 , and in revised form, November 2, 2005.

^* This work was supported by National Institutes of Health Grants DA-000564, DA-001583, DA-011806, DA07339, and KO5-DA-70554 (to H. H. L.) and K05-DA000513 (P.-Y. L.) and by the A. & F. Stark Fund of the Minnesota Medical Foundation. 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, University of Minnesota School of Medicine, 6–120 Jackson Hall, 321 Church St. S.E., Minneapolis, MN 55455. Tel.: 612-626-6539; Fax: 612-625-8408; E-mail: chenx112{at}tc.umn.edu.

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