Ligand-bound and induced GPCR signaling can be studied by detecting second messenger molecules. GPCRs coupled to Gαs or Gαi activate the cAMP pathway, which stimulates or inhibits the accumulation of cellular cAMP. GPCR coupled to Gαq activates the PLC pathway, which induces the release of calcium. Second messenger assays enables measurement and characterization of both the agonist and the antagonist.
Calcium Assay
GPCRs can induce the PLC pathway releasing calcium as second messenger following ligand binding. A majority of GPCR cell lines from GenScript can utilize calcium assay for measurement and characterization. These include Gαq-coupled GPCR cell lines, and Gαs or Gαi-coupled GPCR cell lines with co-expression of Gα15.
Figure 1: GLP-1 (7-37)-induced concentration-dependent stimulation of intracellular calcium mobilization in GLP-1R and Gα15 co-expression CHO-K1 cells (Cat. No. M00451 GenScript).
Figure 2: Substance P-induced concentration-dependent stimulation of intracellular calcium mobilization in NK1 expression CHO-K1 cells (Cat. No. M00199, GenScript).
cAMP assay
Gαs or Gαi-coupled GPCR cell lines induce cAMP pathway using cAMP as second messenger following ligand binding. cAMP assay is a simple and straightforward method for measurement and characterization of binding between GPCR and its ligands.
Figure 3: Dose dependent stimulation of intracellular cAMP mobilization upon treatment with dopamine in D1 expression CHO-K1 cells (Cat. No. M00247, GenScript).
