title: Regulation of α2B-Adrenergic Receptor Cell Surface Transport by GGA1 and GGA2.
abstract: The molecular mechanisms that control the targeting of newly synthesized G protein-coupled receptors (GPCRs) to the functional destinations remain poorly elucidated. Here, we have determined the role of Golgi-localized, γ-adaptin ear domain homology, ADP ribosylation factor-binding proteins 1 and 2 (GGA1 and GGA2) in the cell surface transport of α2B-adrenergic receptor (α2B-AR), a prototypic GPCR, and studied the underlying mechanisms. We demonstrated that knockdown of GGA1 and GGA2 by shRNA and siRNA significantly reduced the cell surface expression of inducibly expressed α2B-AR and arrested the receptor in the perinuclear region. Knockdown of each GGA markedly inhibited the dendritic expression of α2B-AR in primary cortical neurons. Consistently, depleting GGA1 and GGA2 attenuated receptor-mediated signal transduction measured as ERK1/2 activation and cAMP inhibition. Although full length α2B-AR associated with GGA2 but not GGA1, its third intracellular loop was found to directly interact with both GGA1 and GGA2. More interestingly, further mapping of interaction domains showed that the GGA1 hinge region and the GGA2 GAE domain bound to multiple subdomains of the loop. These studies have identified an important function and revealed novel mechanisms of the GGA family proteins in the forward trafficking of a cell surface GPCR.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., Augusta, GA 30912, USA.
authors.forename: Maoxiang
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., Augusta, GA 30912, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., Augusta, GA 30912, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., Augusta, GA 30912, USA.
authors.forename: Alvin V
authors.initials: AV
authors.lastname: Terry
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., Augusta, GA 30912, USA.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Wu
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D021381:Protein Transport / Q000502:physiology; D018341:Receptors, Adrenergic, alpha-2 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; C407306:GGA adaptor proteins; C405944:GGA2 protein, human; D018341:Receptors, Adrenergic, alpha-2; D000242:Cyclic AMP; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3