The beta1-adrenergic receptor (beta1AR) is a G protein-coupled receptor that mediates many of the physiological effects of adrenaline and noradrenaline. Little is known, however, about the molecular mechanisms of beta1AR targeting and regulation in cells. This project aims to study the interaction between the beta1tAR and MAGI-2, a previously-unknown intracellular beta1AR binding partner that associates with the beta1AR carboxyl-terminus via a high-affinity PDZ domain-mediated interaction. The functional significance of the beta1AR/MAGI-2 association is completely unknown. MAGI-2 may be either a scaffolding protein important for subcellular localization of the beta1AR, a regulatory protein that modulates receptor G protein coupling, or a signaling intermediate that couples the beta1AR to diverse intracellular signaling pathways. These possibilities will be explored with a combination of in vitro and cellular experiments. The in vitro experiments will determine the specificity of the beta1AR/MAGI-2 interaction and the potential ability of MAGI-2 to facilitate the formation of complexes between the beta1AR and other proteins. The cellular experiments will focus on the ability of MAGI-2 to regulate the subcellular distribution of the beta1AR and/or to alter beta1AR signaling to effectors such as adenylyl cyclase and MAP kinase. Furthermore, immunostaining of MAGI-2 and beta1AR in primary neuronal cultures and in brain sections will be examined in order to determine how well the two proteins co-localize in native tissues. These studies will provide mechanistic insight into localization and regulation of the beta1AR, a receptor that is a common target for therapeutics used in the treatment of heart disease and other disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM060982-02
Application #
6363341
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Cole, Alison E
Project Start
2000-03-01
Project End
2005-02-28
Budget Start
2001-03-01
Budget End
2002-02-28
Support Year
2
Fiscal Year
2001
Total Cost
$214,200
Indirect Cost
Name
Emory University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Yun, C Chris; Sun, Hong; Wang, Dongsheng et al. (2005) LPA2 receptor mediates mitogenic signals in human colon cancer cells. Am J Physiol Cell Physiol 289:C2-11
Hall, Randy A (2004) Studying protein-protein interactions via blot overlay or Far Western blot. Methods Mol Biol 261:167-74
Wang, Lixin; Kolachala, Vasantha; Walia, Baljit et al. (2004) Agonist-induced polarized trafficking and surface expression of the adenosine 2b receptor in intestinal epithelial cells: role of SNARE proteins. Am J Physiol Gastrointest Liver Physiol 287:G1100-7
He, Junqi; Bellini, Michele; Xu, Jianguo et al. (2004) Interaction with cystic fibrosis transmembrane conductance regulator-associated ligand (CAL) inhibits beta1-adrenergic receptor surface expression. J Biol Chem 279:50190-6
Hall, Randy A (2004) Beta-adrenergic receptors and their interacting proteins. Semin Cell Dev Biol 15:281-8
Xu, Jianguo; He, Junqi; Castleberry, Amanda M et al. (2003) Heterodimerization of alpha 2A- and beta 1-adrenergic receptors. J Biol Chem 278:10770-7
Hall, Randy A; Lefkowitz, Robert J (2002) Regulation of G protein-coupled receptor signaling by scaffold proteins. Circ Res 91:672-80
He, Junqi; Xu, Jianguo; Castleberry, Amanda M et al. (2002) Glycosylation of beta(1)-adrenergic receptors regulates receptor surface expression and dimerization. Biochem Biophys Res Commun 297:565-72
Xu, J; Paquet, M; Lau, A G et al. (2001) beta 1-adrenergic receptor association with the synaptic scaffolding protein membrane-associated guanylate kinase inverted-2 (MAGI-2). Differential regulation of receptor internalization by MAGI-2 and PSD-95. J Biol Chem 276:41310-7
Hu, L A; Tang, Y; Miller, W E et al. (2000) beta 1-adrenergic receptor association with PSD-95. Inhibition of receptor internalization and facilitation of beta 1-adrenergic receptor interaction with N-methyl-D-aspartate receptors. J Biol Chem 275:38659-66