Related Experiment Video
Updated: Feb 9, 2026

Quantifying Agonist Activity at G Protein-coupled Receptors
Published on: December 26, 2011
G Protein-Coupled Receptor Kinase 3 (GRK3) in Olfaction
Sayoko Ihara1,2, Kazushige Touhara3,4
1Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Abstract:
Like in other sensory systems, adaptation is an essential process in the olfactory system, required for its proper functioning. However, the precise molecular mechanism underlying the adaptation process has not been fully understood, especially at the receptor level. Here, we describe methods to evaluate the role of GRK3, one of the members of the GRK family responsible for the desensitization of non-olfactory G-protein-coupled receptor (GPCR), in desensitization of olfactory receptor (OR) using a heterologous expression system. As a parameter to characterize the degree of desensitization, we measure (1) the maximal response to an agonist by either cAMP or Ca2+ imaging assay and (2) the kinetic time course for recovery to basal levels by Ca2+ imaging assay. Differences in the degree of desensitization in the presence or absence of GRK3 can be examined by comparing these parameters, leading to evaluation of GRK3.
Related Concept Videos
G-protein Coupled Receptors
G Protein-coupled Receptors
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases
Receptor Tyrosine Kinases
Transducer Mechanism: G Protein–Coupled Receptors
GPCRs are also called heptahelical,...

