RT Journal Article
SR Electronic
T1 Structural Determinants Influencing the Potency and Selectivity of Indazole-Paroxetine Hybrid G Protein-Coupled Receptor Kinase 2 Inhibitors
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP mol.117.110130
DO 10.1124/mol.117.110130
A1 Renee Bouley
A1 Helen V Waldschmidt
A1 M. Claire Cato
A1 Alessandro Cannavo
A1 Jianliang Song
A1 Joseph Y Cheung
A1 Xin-Qiu Yao
A1 Walter J Koch
A1 Scott D Larsen
A1 John J Tesmer
YR 2017
UL http://molpharm.aspetjournals.org/content/early/2017/10/25/mol.117.110130.abstract
AB G protein-coupled receptor kinases (GRKs) phosphorylate activated receptors to promote arrestin binding, decoupling from heterotrimeric G proteins, and internalization. GRK2 and GRK5 are overexpressed in the failing heart and thus have become therapeutic targets. Previously, we discovered two classes of GRK2-selective inhibitors, one stemming from GSK180736A, a ROCK1 inhibitor, and the other from paroxetine, a selective serotonin-reuptake inhibitor. These two classes of compounds bind to the GRK2 active site in a similar configuration, but contain different hinge-binding "warheads": indazole and benzodioxole, respectively. We surmised from our prior studies that an indazole would be the stronger hinge binder, and would impart increased potency when substituted for benzodioxole in paroxetine derivatives. To test this hypothesis, we synthesized a series of hybrid compounds that allowed us to compare the effects of inhibitors that differ only in the identity of the warhead. The indazole-paroxetine analogs were indeed more potent than their respective benzodioxole derivatives but lost selectivity. To investigate how these two warheads dictate selectivity, we determined crystal structures of three of the indazole hybrid compounds (CCG224061, CCG258284, and CCG258748) in complex with GRK2 - Gβγ. Comparison of these structures with those of analogous benzodioxole-containing complexes confirmed that the indazole-paroxetine hybrids form stronger interactions with the hinge of the kinase, but also stabilize a distinct conformation of the kinase domain of GRK2 compared to previous complexes with paroxetine analogs. This conformation is analogous to that which can be assumed by GRK5, at least partially explaining the loss in selectivity.