MolPharm

Home Help [Feedback] [For Subscribers] [Archive] [Search] --
QUICK SEARCH:   [advanced]


     

Molecular Pharmacology Fast Forward
First published on June 27, 2007; DOI: 10.1124/mol.107.038075

This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
mol.107.038075v1
72/4/812    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Author home page(s):
Catherine H. Berlot
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Yost, E. A.
Right arrow Articles by Berlot, C. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yost, E. A.
Right arrow Articles by Berlot, C. H.


Received for publication May 11, 2007.
Revised June 24, 2007.
Accepted for publication June 26, 2007.

Live Cell Analysis of G Protein {beta}5 Complex Formation, Function, and Targeting

Evan A. Yost 1, Stacy M. Mervine 1, Jonathan L. Sabo 1, Thomas R. Hynes 1, Catherine H. Berlot 1*

1 Weis Center for Research, Geisinger Clinic

* Address correspondence to: E-mail: chberlot{at}geisinger.edu

Abstract

The G protein {beta}5 subunit differs from other {beta} subunits in having divergent sequence and subcellular localization patterns. Although {beta}5{gamma}2 modulates effectors, {beta}5 associates with R7 family regulators of G protein signaling (RGS) proteins when purified from tissues. To investigate {beta}5 complex formation in vivo, we used multicolor bimolecular fluorescence complementation in HEK-293 cells to compare the abilities of 7 {gamma} subunits and RGS7 to compete for interaction with {beta}5. Among the {gamma} subunits, {beta}5 interacted preferentially with {gamma}2, followed by {gamma}7, and efficacy of phospholipase C-{beta}2 activation correlated with amount of {beta}5{gamma} complex formation. {beta}5 also slightly preferred {gamma}2 over RGS7. In the presence of co-expressed R7BP, {beta}5 interacted similarly with {gamma}2 and RGS7. Moreover, {gamma}2 interacted preferentially with {beta}1 rather than {beta}5. These results suggest that multiple co-expressed proteins influence {beta}5 complex formation. Fluorescent {beta}5{gamma}2 labeled discrete intracellular structures including the endoplasmic reticulum and Golgi apparatus, while {beta}5RGS7 stained the cytoplasm diffusely. Co-expression of {alpha}o targeted both {beta}5 complexes to the plasma membrane and {alpha}q also targeted {beta}5{gamma}2 to the plasma membrane. The constitutively activated {alpha}o mutant, {alpha}oR179C, produced greater targeting of {beta}5RGS7 and less of {beta}5{gamma}2 than did {alpha}o. These results suggest that {alpha}o may cycle between interactions with {beta}5{gamma}2 or other {beta}{gamma} complexes when inactive, and {beta}5RGS7 when active. Moreover, the ability of {beta}5{gamma}2 to be targeted to the plasma membrane by {alpha} subunits suggests that functional {beta}5{gamma}2 complexes can form in intact cells and mediate signaling by G protein-coupled receptors.


Key words: G protein regulation, RGS proteins, Fluorescence techniques


This article has been cited by other articles:


Home page
 Mol. Pharmacol.Home page
C. E. Zeller and H. G. Dohlman
Illuminating Gbeta5 Signaling
Mol. Pharmacol., October 1, 2007; 72(4): 810 - 811.
[Abstract] [Full Text] [PDF]


Home Help [Feedback] [For Subscribers] [Archive] [Search] --
All ASPET Journals Molecular Pharmacology Pharmacological Reviews
Molecular Interventions Drug Metabolism and Disposition

Copyright © 2007 by the American Society for Pharmacology and Experimental Therapeutics