Labeling of CC Chemokine Receptor 2 with a Versatile Intracellular Allosteric Probe

Interest in affinity-based probes (AfBPs) as novel tools
to interrogate
G protein-coupled receptors (GPCRs) has gained traction in recent
years. AfBPs represent an interesting and more versatile alternative
to antibodies. In the present study, we report the development and
validation of AfBPs that target the intracellular allosteric pocket
of CCR2, a GPCR of interest for the development of therapies targeting
autoimmune and inflammatory diseases and also cancer. Owing to the
two-step labeling process of these CCR2 AfBPs through the incorporation
of a click handle, we were successful in applying our most efficient
probe in a variety of in vitro experiments and making
use of multiple different detection techniques, such as SDS-PAGE and
LC/MS-based proteomics. Collectively, this novel probe shows high
selectivity, versatility, and applicability. Hence, this is a valuable
alternative for CCR2-targeting antibodies and other traditional tool
compounds and could aid in target validation and engagement in drug
discovery.