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Updated: Jun 7, 2026

Quantifying Agonist Activity at G Protein-coupled Receptors
Published on: December 26, 2011
Assessment of constitutive activity in E-type prostanoid receptors
Hiromichi Fujino1, Toshihiko Murayama, John W Regan
1Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
Abstract:
The potential for G-protein-coupled receptors (GPCRs) to show constitutive activity is emerging as one of the fundamental properties of GPCRs signal transduction. Indeed, of the four subtypes of E-type prostanoid (EP) receptors, the EP3 and EP4 subtypes show constitutive activity in addition to their innate ligand-dependent activation of signaling pathways. The constitutive activity of the EP3 and EP4 receptor subtypes was discovered during the initial characterizations of these receptors and may be important for setting the basal level of cellular tone in the given signaling pathway. This chapter introduces some of the methods that can be used to study the constitutive activity of the EP receptors.
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