title: Substrate-induced changes in the dynamics of rhodopsin kinase (G protein-coupled receptor kinase 1).
abstract: G protein-coupled receptor (GPCR) kinases (GRKs) instigate the desensitization of activated GPCRs via phosphorylation that promotes interaction with arrestins, thereby preventing the interaction of GPCRs with heterotrimeric G proteins. A current proposed model of GRK1 activation involves the binding of activated rhodopsin (Rho*) to the N-terminal region of GRK1. Perhaps concomitantly, this N-terminal region also stabilizes a closed, active conformation of the kinase domain. To further probe this model, we mapped changes in the backbone flexibility of GRK1 as it binds to its two substrates, adenosine triphosphate (Mg(2+)·ATP) and Rho*. We found that the conformational flexibility of GRK1 was reduced in the presence of either Mg(2+)·ATP or Rho*, with Mg(2+)·ATP having the greatest effect. In a truncated form of GRK1 lacking the N-terminal region (ΔN-GRK1), peptides that directly interact with ATP were not as dramatically stabilized by adding Mg(2+)·ATP, and dynamics were greater in the interface between the large lobe of the kinase domain and the regulator of the G protein signaling homology domain. In the presence of Mg(2+)·ATP, the influence of Rho* versus Rho on GRK1 dynamics was negligible.
authors.affiliation: Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
authors.forename: Tivadar
authors.initials: T
authors.lastname: Orban
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Huang
authors.forename: Kristoff T
authors.initials: KT
authors.lastname: Homan
authors.forename: Beata
authors.initials: B
authors.lastname: Jastrzebska
authors.forename: John J G
authors.initials: JJ
authors.lastname: Tesmer
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D051606:G-Protein-Coupled Receptor Kinase 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D012243:Rhodopsin / Q000737:chemistry; D012374:Rod Cell Outer Segment / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D000255:Adenosine Triphosphate; D012243:Rhodopsin; D051606:G-Protein-Coupled Receptor Kinase 1