QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: mol.104.005215v1 67/5/1690    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services 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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Brady, A. E. Articles by Limbird, L. E. Search for Related Content PubMed PubMed Citation Articles by Brady, A. E. Articles by Limbird, L. E.

ORIGINAL ARTICLE

2-Adrenergic Agonist Enrichment of Spinophilin at the Cell Surface Involves Subunits of G_i Proteins and Is Preferentially Induced by the _2A-Subtype

Departments of Pharmacology (A.E.B., Q.W., L.E.L.) and Molecular Physiology and Biophysics (M.R.), Vanderbilt University Medical Center, Nashville, Tennessee; Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, New York (P.G.); and Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut (P.B.A.)

Abstract

Agonist activation regulates reciprocal interactions of spinophilin and arrestin with the _2A- and _2B -adrenergic receptor (AR) subtypes via their 3i loop. Because arrestin association with G protein-coupled receptor is preceded by redistribution of arrestin to the cell surface, the present studies explored whether agonist activation of the _2A- and _2B -AR subtypes also led to spinophilin enrichment at the cell surface. Live cell imaging studies using a green fluorescent protein-tagged spinophilin examined spinophilin localization and its regulation by ₂ -AR agonist. Agonist activation of _2A-AR preferentially, compared with the _2B-AR, led to spinophilin enrichment at the cell surface in human embryonic kidney 293 cells and in mouse embryo fibroblasts derived from spinophilin null mice. Activation of the LEESSSS_2A-AR, which has enriched association with spinophilin compared with the wild-type (WT) _2A-AR, does not show an enhanced redistribution of spinophilin to the surface compared with WT _2A-AR, demonstrating that the ability or affinity of the receptor in binding spinophilin may be independent of the ability of the receptor to effect spinophilin redistribution to the surface. Agonist-evoked enrichment of spinophilin at the cell surface seems to involve downstream signaling events, manifested both by the pertussis toxin sensitivity of the process and by the marked attenuation of spinophilin redistribution in cells expressing the -adrenergic receptor kinase-C tail, which sequesters subunits of G proteins. Together, the data suggest that agonist-evoked spinophilin enrichment at the cell surface is caused by receptor-evoked signaling pathways and is independent of the affinity of the receptor for the spinophilin molecule.

Received for publication July 26, 2004.

Accepted for publication February 10, 2005.

Address correspondence to: Dr. Qin Wang, Department of Pharmacology, Vanderbilt University Medical Center, 464 Robinson Research Bldg., Nashville, TN 37232-6600. E-mail: qin.wang{at}vanderbilt.edu

This article has been cited by other articles:

				R. Lu, Y. Li, Y. Zhang, Y. Chen, A. D. Shields, D. G. Winder, T. Angelotti, K. Jiao, L. E. Limbird, Y. Zhou, et al. Epitope-tagged Receptor Knock-in Mice Reveal That Differential Desensitization of {alpha}2-Adrenergic Responses Is because of Ligand-selective Internalization J. Biol. Chem., May 8, 2009; 284(19): 13233 - 13243. [Abstract] [Full Text] [PDF]

				M. A. Mines, J. S. Goodwin, L. E. Limbird, F.-F. Cui, and G.-H. Fan Deubiquitination of CXCR4 by USP14 Is Critical for Both CXCL12-induced CXCR4 Degradation and Chemotaxis but Not ERK Activation J. Biol. Chem., February 27, 2009; 284(9): 5742 - 5752. [Abstract] [Full Text] [PDF]

				O. Bloom, J. J. Unternaehrer, A. Jiang, J.-S. Shin, L. Delamarre, P. Allen, and I. Mellman Spinophilin participates in information transfer at immunological synapses J. Cell Biol., June 6, 2008; 181(2): 203 - 211. [Abstract] [Full Text] [PDF]

				J. Xu, Y. Chen, R. Lu, C. Cottingham, K. Jiao, and Q. Wang Protein Kinase A Phosphorylation of Spinophilin Modulates Its Interaction with the {alpha}2A-Adrenergic Receptor (AR) and Alters Temporal Properties of {alpha}2AAR Internalization J. Biol. Chem., May 23, 2008; 283(21): 14516 - 14523. [Abstract] [Full Text] [PDF]