title: The adenosine A2A receptor interacts with the actin-binding protein alpha-actinin.
abstract: Recently, evidence has emerged that heptaspanning membrane or G protein-coupled receptors may be linked to intracellular proteins identified as regulators of receptor anchoring and signaling. Using a yeast two-hybrid screen, we identified alpha-actinin, a major F-actin-cross-linking protein, as a binding partner for the C-terminal domain of the adenosine A2A receptor (A2AR). Colocalization, co-immunoprecipitation, and pull-down experiments showed a close and specific interaction between A2AR and alpha-actinin in transfected HEK-293 cells and also in rat striatal tissue. A2AR activation by agonist induced the internalization of the receptor by a process that involved rapid beta-arrestin translocation from the cytoplasm to the cell surface. In the subsequent receptor traffic from the cell surface, the role of actin organization was shown to be crucial in transiently transfected HEK-293 cells, as actin depolymerization by cytochalasin D prevented its agonist-induced internalization. A2ADeltaCTR, a mutant version of A2AR that lacks the C-terminal domain and does not interact with alpha-actinin, was not able to internalize when activated by agonist. Interestingly, A2ADeltaCTR did not show aggregation or clustering after agonist stimulation, a process readily occurring with the wild-type receptor. These findings suggest an alpha-actinin-dependent association between the actin cytoskeleton and A2AR trafficking.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Barcelona, 08028 Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Burgueño
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Blake
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Benson
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Tinsley
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Esapa
authors.forename: Enric I
authors.initials: EI
authors.lastname: Canela
authors.forename: Petronila
authors.initials: P
authors.lastname: Penela
authors.forename: Josefa
authors.initials: J
authors.lastname: Mallol
authors.forename: Federico
authors.initials: F
authors.lastname: Mayor
authors.forename: Carmen
authors.initials: C
authors.lastname: Lluis
authors.forename: Rafael
authors.initials: R
authors.lastname: Franco
authors.forename: Francisco
authors.initials: F
authors.lastname: Ciruela
mesh_terms: D000185:Actinin / Q000737:chemistry* / Q000502:physiology; D000199:Actins / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D004705:Endocytosis; D006801:Humans; D051381:Rats; D017207:Rats, Sprague-Dawley; D043705:Receptor, Adenosine A2A / Q000737:chemistry* / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D014162:Transfection; D020798:Two-Hybrid System Techniques
chemical_list: D000199:Actins; D043705:Receptor, Adenosine A2A; D016194:Receptors, N-Methyl-D-Aspartate; D000185:Actinin; D015638:Cytochalasin D