title: The adenosine 2b receptor is recruited to the plasma membrane and associates with E3KARP and Ezrin upon agonist stimulation.
abstract: We have previously shown that adenosine is formed in the intestinal lumen during active inflammation from neutrophil-derived 5'-AMP. Acting through the adenosine A2b receptor (A2bR), the luminally derived adenosine induces vectorial chloride secretion and a polarized secretion of interleukin-6 to the intestinal lumen. Although some G protein-coupled receptors interact with anchoring or signaling molecules, not much is known in this critical area for the A2bR. We used the model intestinal epithelial cell line, T84, and Caco2-BBE cells stably transfected with GFP-A2b receptor to study the intestinal A2bR. The A2bR is present in both the apical and basolateral membranes of intestinal epithelia. Apical or basolateral stimulation of the A2bR induces recruitment of the receptor to the plasma membrane and caveolar fractions. The A2bR co-immunoprecipitates with E3KARP and ezrin upon agonist stimulation. Ezrin interacts with E3KARP and PKA and the interaction between ezrin and E3KARP is enhanced by agonist stimulation. Our data suggest that the A2bR is recruited to the plasma membrane upon apical or basolateral agonist stimulation and interacts with E3KARP and ezrin. We speculate that such an interaction may not only anchor the A2bR to the plasma membrane but may also function to stabilize the receptor in a signaling complex in the plasma membrane.
authors.affiliation: Division of Digestive Diseases, Department of Medicine, Emory University, Atlanta, Georgia 30322, USA. ssitar2@emory.edu
authors.forename: Shanthi V
authors.initials: SV
authors.lastname: Sitaraman
authors.forename: Lixin
authors.initials: L
authors.lastname: Wang
authors.forename: Michelle
authors.initials: M
authors.lastname: Wong
authors.forename: Matthias
authors.initials: M
authors.lastname: Bruewer
authors.forename: Michael
authors.initials: M
authors.lastname: Hobert
authors.forename: C-H
authors.initials: CH
authors.lastname: Yun
authors.forename: Didier
authors.initials: D
authors.lastname: Merlin
authors.forename: James L
authors.initials: JL
authors.lastname: Madara
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D008954:Models, Biological; D010750:Phosphoproteins / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D058906:Purinergic P1 Receptor Agonists; D043704:Receptor, Adenosine A2B; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D017923:Sodium-Hydrogen Exchangers; D000099149:Ezrin
chemical_list: D000241:Adenosine; D017868:Cyclic AMP-Dependent Protein Kinases; D003598:Cytoskeletal Proteins; D003902:Detergents; D049452:Green Fluorescent Proteins; D015850:Interleukin-6; D008164:Luminescent Proteins; D010750:Phosphoproteins; D058906:Purinergic P1 Receptor Agonists; D043704:Receptor, Adenosine A2B; D018047:Receptors, Purinergic P1; D011993:Recombinant Fusion Proteins; D017923:Sodium-Hydrogen Exchangers; D000099149:Ezrin; C093376:sodium-hydrogen exchanger regulatory factor