Insertion of Nanoluc into the Extracellular Loops as a Complementary Method To Establish BRET-Based Binding Assays for GPCRs.

Luminescence-based techniques play an increasingly important role in all areas of biochemical research, including investigations on G protein-coupled receptors (GPCRs). One quite recent and popular addition has been made by introducing bioluminescence resonance energy transfer (BRET)-based binding assays for GPCRs, which are based on the fusion of nanoluciferase (Nluc) to the N-terminus of the receptor and the occurring energy transfer via BRET to a bound fluorescent ligand. However, being based on BRET, the technique is strongly dependent on the distance/orientation between the luciferase and the fluorescent ligand.

Shining light on the histamine H receptor: Synthesis of carbamoylguanidine-type agonists as a pharmacological tool to study internalization.

So far, only little is known about the internalization process of the histamine H receptor (HR). One promising approach to study such dynamic processes is the use of agonistic fluorescent ligands. Therefore, a series of carbamoylguanidine-type HR agonists containing various fluorophores, heterocycles, and linkers (28-40) was synthesized.

Quantitative Determination and Imaging of Gα Signaling in Live Cells via Split-Luciferase Complementation.

G Protein-coupled receptors (GPCRs) transduce signals elicited by bioactive chemical agents (ligands), such as hormones, neurotransmitters, or cytokines, across the cellular membrane. Upon ligand binding, the receptor undergoes structural rearrangements, which cause the activation of G proteins. This triggers the activation of signaling cascades involving amplification, which takes place after every stage of the cascade.

Fluorescent H Receptor Squaramide-Type Antagonists: Synthesis, Characterization, and Applications.

Fluorescence labeled ligands have been gaining importance as molecular tools, enabling receptor-ligand-binding studies by various fluorescence-based techniques. Aiming at red-emitting fluorescent ligands for the hHR, a series of squaramides labeled with pyridinium or cyanine fluorophores (-) was synthesized and characterized. The highest hHR affinities in radioligand competition binding assays were obtained in the case of pyridinium labeled antagonists - (p : 7.

UR-DEBa242: A Py-5-Labeled Fluorescent Multipurpose Probe for Investigations on the Histamine H and H Receptors.

Comprehensively characterized fluorescent probes for the histamine H receptor (HR) and especially for the HR orthologs [e.g., human (h) and mouse (m)] are highly needed as versatile complementary tools to radioligands.