Substrate-Induced Changes in the Dynamics of Rhodopsin Kinase (G Protein-Coupled Receptor Kinase 1)

作者：Orban Tivadar; Huang Chih chin; Homan Kristoff T; Jastrzebska Beata; Tesmer John J G^*; Palczewski Krzysztof

来源：Biochemistry, 2012, 51(16): 3404-3411.

DOI：10.1021/bi300295y

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 (Mg2+.ATP) and Rho*. We found that the conformational flexibility of GRK1 was reduced in the presence of either Mg2+.ATP or Rho*, with Mg2+.ATP having the greatest effect. In a truncated form of GRK1 lacking the N-terminal region (Delta N-GRK1), peptides that directly interact with ATP were not as dramatically stabilized by adding Mg2+.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 Mg2+.ATP, the influence of Rho* versus Rho on GRK1 dynamics was negligible.

• 出版日期2012-4-24