title: Functional map of arrestin binding to phosphorylated opsin, with and without agonist.
abstract: Arrestins desensitize G protein-coupled receptors (GPCRs) and act as mediators of signalling. Here we investigated the interactions of arrestin-1 with two functionally distinct forms of the dim-light photoreceptor rhodopsin. Using unbiased scanning mutagenesis we probed the individual contribution of each arrestin residue to the interaction with the phosphorylated apo-receptor (Ops-P) and the agonist-bound form (Meta II-P). Disruption of the polar core or displacement of the C-tail strengthened binding to both receptor forms. In contrast, mutations of phosphate-binding residues (phosphosensors) suggest the phosphorylated receptor C-terminus binds arrestin differently for Meta II-P and Ops-P. Likewise, mutations within the inter-domain interface, variations in the receptor-binding loops and the C-edge of arrestin reveal different binding modes. In summary, our results indicate that arrestin-1 binding to Meta II-P and Ops-P is similarly dependent on arrestin activation, although the complexes formed with these two receptor forms are structurally distinct.
authors.affiliation: Paul Scherrer Institute, Laboratory for Biomolecular Research, CH-5323, Villigen, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Peterhans
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany.
authors.forename: Ciara C M
authors.initials: CC
authors.lastname: Lally
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Ostermaier
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin, Germany.
authors.forename: Martha E
authors.initials: ME
authors.lastname: Sommer
authors.affiliation: Paul Scherrer Institute, Laboratory for Biomolecular Research, CH-5323, Villigen, Switzerland.
authors.forename: Jörg
authors.initials: J
authors.lastname: Standfuss
mesh_terms: D000818:Animals; D019393:Arrestin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D008958:Models, Molecular; D009154:Mutation; D055355:Opsins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D000072417:Protein Domains
chemical_list: D019393:Arrestin; D055355:Opsins