The spatiotemporal regulation of intracellular trafficking and signaling of G protein-coupled receptors (GPCRs) is a critical aspect of integrated responses of the cell to hormones. Indeed, defective transport and dysfunction of GPCRs are associated with the pathogenesis of many human diseases. Our overall objective is to define the molecular mechanisms underlying the maturation and signal propagation of GPCRs and their roles in modulating cellular responses to hormones and drugs. Under this broad objective, the focus of the current proposal is to elucidate the mechanisms of nascent GPCR export from the endoplasmic reticulum (ER) to the cell surface and GPCR-mediated activation of the mitogen-activated protein kinase pathway in neuroblastoma-glioma NG108 and human embryonic kidney HEK293 cell lines by using alpha2B-adrenergic receptor (alpha2B-AR) as a model GPCR. We have demonstrated that alpha2B-AR export from the ER is modulated by a highly conserved triple arginine (3R) motif. The 3R motif mediates receptor interaction with selective Sec24 isoforms, components of COPII-coated transport vesicles. Our studies have also revealed a novel function for GGAs [monomeric Golgi-localizing, 3-adaptin ear domain homology, ADP ribosylation factor (ARF)-binding proteins]. GGAs associate with alpha2B-AR and are required for alpha2B-AR transport from the trans-Golgi network (TGN) to the plasma membrane. Furthermore, we have identified a novel signaling pathway in which the di-tryptophan motif-mediated, agonist-dependent interaction of alpha2B-AR with the small GTPase ARF1 dictates the activation of the conventional Raf1-MEK-ERK1/2 cascade by the receptor.
The Specific Aims are: 1) to elucidate the mechanism of COPII vesicle-mediated alpha2B-AR export from the ER, 2) to determine the function of GGAs in alpha2B-AR transport from the TGN to the cell surface, and 3) to define the function and mechanism of alpha2B-AR- and ARF1-mediated activation of the Raf1-MEK-ERK1/2 pathway. Overall, these studies will reveal novel molecular mechanisms underlying export trafficking and signal regulation of GPCRs. The information generated from these studies may open new directions for designing drugs to treat diseases involving abnormal trafficking and functioning of GPCRs.

Public Health Relevance

This proposal will study the intracellular trafficking and functional regulation of G protein-coupled receptors. These receptors regulate a variety of cell functions under physiological and pathological conditions and are the targets for drugs to treat many diseases. The successful completion of these studies will open a new direction for designing drugs to treat human diseases involving abnormal trafficking and functioning of G protein-coupled receptors.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM076167-07
Application #
8277899
Study Section
Molecular Neuropharmacology and Signaling Study Section (MNPS)
Program Officer
Ainsztein, Alexandra M
Project Start
2006-05-01
Project End
2014-04-30
Budget Start
2012-05-01
Budget End
2013-04-30
Support Year
7
Fiscal Year
2012
Total Cost
$302,363
Indirect Cost
$100,563
Name
Georgia Regents University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
966668691
City
Augusta
State
GA
Country
United States
Zip Code
30912
Davis, Jason E; Xie, Xiayang; Guo, Jianhui et al. (2016) ARF1 promotes prostate tumorigenesis via targeting oncogenic MAPK signaling. Oncotarget 7:39834-39845
Zhang, Maoxiang; Davis, Jason E; Li, Chunman et al. (2016) GGA3 Interacts with a G Protein-Coupled Receptor and Modulates Its Cell Surface Export. Mol Cell Biol 36:1152-63
Zhou, Fuguo; Dong, Chunmin; Davis, Jason E et al. (2015) The mechanism and function of mitogen-activated protein kinase activation by ARF1. Cell Signal 27:2035-44
Lan, Tien-Hung; Wu, Guangyu; Lambert, Nevin A (2015) Lateral diffusion contributes to FRET from lanthanide-tagged membrane proteins. Biochem Biophys Res Commun 464:244-8
Wu, Guangyu; Davis, Jason E; Zhang, Maoxiang (2015) Regulation of α2B-Adrenerigc Receptor Export Trafficking by Specific Motifs. Prog Mol Biol Transl Sci 132:227-44
Zhu, Shu; Zhang, Maoxiang; Davis, Jason E et al. (2015) A single mutation in helix 8 enhances the angiotensin II type 1a receptor transport and signaling. Cell Signal 27:2371-9
Jang, Ji Hyun; Chun, Jung Nyeo; Godo, Shigeo et al. (2015) ROS and endothelial nitric oxide synthase (eNOS)-dependent trafficking of angiotensin II type 2 receptor begets neuronal NOS in cardiac myocytes. Basic Res Cardiol 110:21
Yang, Junjun; Yao, Wei; Qian, Guisheng et al. (2015) Rab5-mediated VE-cadherin internalization regulates the barrier function of the lung microvascular endothelium. Cell Mol Life Sci 72:4849-66
Lan, Tien-Hung; Liu, Qiuju; Li, Chunman et al. (2015) BRET evidence that β2 adrenergic receptors do not oligomerize in cells. Sci Rep 5:10166
Bertuccio, Claudia A; Lee, Shih-Liang; Wu, Guangyu et al. (2014) Anterograde trafficking of KCa3.1 in polarized epithelia is Rab1- and Rab8-dependent and recycling endosome-independent. PLoS One 9:e92013

Showing the most recent 10 out of 44 publications