2 research outputs found
Identification and StructureâFunction Analysis of Subfamily Selective G Protein-Coupled Receptor Kinase Inhibitors
Selective
inhibitors of individual subfamilies of G protein-coupled
receptor kinases (GRKs) would serve as useful chemical probes as well
as leads for therapeutic applications ranging from heart failure to
Parkinsonâs disease. To identify such inhibitors, differential
scanning fluorimetry was used to screen a collection of known protein
kinase inhibitors that could increase the melting points of the two
most ubiquitously expressed GRKs: GRK2 and GRK5. Enzymatic assays
on 14 of the most stabilizing hits revealed that three exhibit nanomolar
potency of inhibition for individual GRKs, some of which exhibiting
orders of magnitude selectivity. Most of the identified compounds
can be clustered into two chemical classes: indazole/dihydropyrimidine-containing
compounds that are selective for GRK2 and pyrrolopyrimidine-containing
compounds that potently inhibit GRK1 and GRK5 but with more modest
selectivity. The two most potent inhibitors representing each class,
GSK180736A and GSK2163632A, were cocrystallized with GRK2 and GRK1,
and their atomic structures were determined to 2.6 and 1.85 Ă
spacings, respectively. GSK180736A, developed as a Rho-associated,
coiled-coil-containing protein kinase inhibitor, binds to GRK2 in
a manner analogous to that of paroxetine, whereas GSK2163632A, developed
as an insulin-like growth factor 1 receptor inhibitor, occupies a
novel region of the GRK active site cleft that could likely be exploited
to achieve more selectivity. However, neither compound inhibits GRKs
more potently than their initial targets. This data provides the foundation
for future efforts to rationally design even more potent and selective
GRK inhibitors
Structure-Based Design, Synthesis, and Biological Evaluation of Highly Selective and Potent G Protein-Coupled Receptor Kinase 2 Inhibitors
G protein-coupled
receptors (GPCRs) are central to many physiological
processes. Regulation of this superfamily of receptors is controlled
by GPCR kinases (GRKs), some of which have been implicated in heart
failure. GSK180736A, developed as a Rho-associated coiled-coil kinase
1 (ROCK1) inhibitor, was identified as an inhibitor of GRK2 and co-crystallized
in the active site. Guided by its binding pose overlaid with the binding
pose of a known potent GRK2 inhibitor, Takeda103A, a library of hybrid
inhibitors was developed. This campaign produced several compounds
possessing high potency and selectivity for GRK2 over other GRK subfamilies,
PKA, and ROCK1. The most selective compound, <b>12n</b> (CCG-224406),
had an IC<sub>50</sub> for GRK2 of 130 nM, >700-fold selectivity
over
other GRK subfamilies, and no detectable inhibition of ROCK1. Four
of the new inhibitors were crystallized with GRK2 to give molecular
insights into the binding and kinase selectivity of this class of
inhibitors